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BIOLOGY I And overview of Biology: The Nature of Science
and Biology
BIOLOGY: THE SCIENCE OF OUR LIVES
Biology literally means "the study of life". Biology is such a broad field, covering the minute workings of chemical machines inside our cells, to broad scale concepts of ecosystems and global climate change.
Biologists study intimate details of the human brain, the composition of our genes, and even the functioning of our reproductive system.
Biologists recently all but completed the deciphering of the human genome, the sequence of deoxyribonucleic acid (DNA) bases that may determine much of our innate capabilities and predispositions to certain forms of behavior and illnesses. DNA sequences have played major roles in criminal cases (O.J. Simpson, as well as the reversal of death penalties for many wrongfully convicted individuals), as well as the impeachment of President Clinton (the stain at least did not lie).
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We are bombarded with headlines about possible
health risks from favorite foods (Chinese,
Mexican, hamburgers, etc.) as well as the
potential benefits of eating other foods such as
cooked tomatoes.
Informercials tout the benefits of metabolism-
adjusting drugs for weight loss. Many people are
turning to herbal remedies to ease arthritis pain,
improve memory, as well as improve our moods.
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Can a biology book give you the answers to these questions? No, but it will enable you learn how to sift through the biases of investigators, the press, and others in a quest to critically evaluate the question.
To be honest, five years after you are through with this class it is doubtful you would remember all the details of metabolism.
However, you will know where to look and maybe a little about the process of science that will allow you to make an informed decision.
Will you be a scientist? Yes, in a way. You may not be formally trained as a science major, but you can think critically, solve problems, and have some idea about what science can and cannoit do.
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DIAGNOSTIC ASSESSMENT
YOU WILL HAVE ONLY 12 MINUTES TO DELIVER IT…
IT DOESN’T COUNT FOR YOUR THIS PARTIAL GRADE, BUT IF YOU DO NOT
HAVE ENOUGHT SERIOUSNESS YOU WILL LOST 5 FINAL PARTIAL POINTS…
Contesta lo que a continuación se te indica.
What theories and biological principles do you know?
Why Biology is considered a scientific area?
How many different study areas of Biology do you know? What do you know about them?
Write at least 5 examples of Biology applications in your all-day life.
How many kinds of microscopes do you know or heard about and what is used for each kind of this? What kind of another lab’s equipment do you know or heard about and what it is used for?
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THEORIES CONTRIBUTING TO MODERN
BIOLOGY
Modern biology is based on several great ideas, or
theories:
1. The Cell Theory
2. The Theory of Evolution by Natural
Selection
3. Gene Theory
4. Homeostasis
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CELL THEORY
Robert Hooke (1635-1703), one of the first scientists to use a microscope to examine pond water, cork and other things, referred to the cavities he saw in cork as “cells", Latin for chambers.
Mattias Schleiden (in 1838) concluded all plant tissues consisted of cells. In 1839, Theodore Schwann came to a similar conclusion for animal tissues.
Rudolf Virchow, in 1858, combined the two ideas and added that all cells come from pre-existing cells, formulating the Cell Theory.
Thus there is a chain-of-existence extending from your cells back to the earliest cells, over 3.5 billion years ago. The cell theory states that all organisms are composed of one or more cells, and that those cells have arisen from pre-existing cells.
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GENE THEORY
In 1953, American scientist James Watson and British scientist Francis Crick developed the model for deoxyribonucleic acid (DNA), a chemical that had (then) recently been deduced to be the physical carrier of inheritance.
Crick hypothesized the mechanism for DNA replication and further linked DNA to proteins, an idea since referred to as the central dogma.
Information from DNA "language" is converted into RNA(ribonucleic acid) "language" and then to the "language" of proteins. The central dogma explains the influence of heredity (DNA) on the organism (proteins).
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HOMEOSTASIS THEORY
Homeostasis is the maintainence of a dynamic range of conditions within which the organism can function.
Temperature, pH, and energy are major components of this concept.
Theromodynamics is a field of study that covers the laws governing energy transfers, and thus the basis for life on earth. Two major laws are known: the conservation of matter and energy, and entropy. The universe is composed of two things: matter (atoms, etc.) and energy.
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DARWINIAN EVOLUTION
Charles Darwin, former divinity student and former medical student, secured (through the intercession of his geology professor) an unpaid position as ship's naturalist on the British exploratory vessel H.M.S. Beagle.
The voyage would provide Darwin a unique opportunity to study adaptation and gather a great deal of proof he would later incorporate into his theory of evolution.
On his return to England in 1836, Darwin began (with the assistance of numerous specialists) to catalog his collections and ponder the seeming "fit" of organisms to their mode of existence. He eventually settled on four main points of a radical new hypothesis:
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MAIN POINTS OF DARWINIAN EVOLUTION
Adaptation: all organisms adapt to their environments.
Variation: all organisms are variable in their traits.
Over-reproduction: all organisms tend to reproduce beyond their environment's capacity to support them (this is based on the work of Thomas Malthus, who studied how populations of organisms tended to grow geometrically until they encountered a limit on their population size).
Since not all organisms are equally well adapted to their environment, some will survive and reproduce better than others -- this is known as natural selection. Sometimes this is also referred to as "survival of the fittest".
In reality this merely deals with the reproductive success of the organisms, not solely their relative strength or speed.
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Alfred Russel Wallace Charles Darwin
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In 1858, Darwin received a letter from Wallace, in which Darwin's as-yet-unpublished theory of evolution and adaptation was precisely detailed. Darwin arranged for Wallace's letter to be read at a scientific meeting, along with a synopsis of his own ideas.
To be correct, we need to mention that both Darwin and Wallace developed the theory, although Darwin's major work was not published until 1859 (the book On the origin of Species by Means of Natural Selection, considered by many as one of the most influential books written [follow the hyperlink to view an online version]).
While there have been some changes to the theory since 1859, most notably the incorporation of genetics and DNA into what is termed the "Modern Synthesis" during the 1940's, most scientists today acknowledge evolution as the guiding theory for modern biology.
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DIVERSITY OF LIFE
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DIVERSITY OF LIFE…
SOME EMPLOYED CHACTERISTICS FOR LIVING BEINGS CLASSIFICATION
DOMINIO REINO TIPO DE
CÉLULAS
NÚMERO DE
CÉLULAS
PRINCIPAL
MODO DE
NUTRICIÓN
Bacteria Not well defined
yet
Procaryotic Unicellular Absortion,
Phtotosynthesis
Archaea Not well defined
yet
Procaryotic
Unicellular
Absortion
Eukarya Protista Eucaryotic Unicellular
/ Multicellular
Absortion,
Ingestion
or
Phtotosynthesis
Fungi Eucaryotic Multicellular Absortion
Plantae Eucaryotic Multicellular Phtotosynthesis
Animalia Eucaryotic Multicellular Ingestion
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WHAT IS LIFE
A quality that distinguishes a vital functioning being from a
dead body.
A quality that seems to be intangible and not easy to define.
Sustantial internal force or activity that allows you to be or
act.
Activity stage of organic beings.
Soul and Body together.
Period of time that occurs since the birth of an animal or a
vegetable to its death
DEFINITION OF LIFE It seems that is
difficult to give a
“definition” for
this term
We can not use a
simple definition,
because life is more
than simply the sum
of its parts…. So we
must take advantadge
of this complexity to
understand it….
CHARACTERISTICS OF
LIVING THINGS
LIVING THINGS:
Have a complex, organized structure that consists
largely of organic molecules.
Respond to stimuli from their environment.
Follow the process of: Homeostasis.
Acquire and use materials and energy from their
environment and convert it in different forms.
Grow.
Reproduce using a molecular blueprint called DNA.
Have the capacity to evolve.
Los seres vivos no pueden definirse como la suma de sus partes. La cualidad de la
vida surge como resultado de las increíblemente complejas interacciones
ordenadas de estas partes. Dado que está basado en esas propiedades
emergentes, la vida es una cualidad fundamentalmente intangible, imposible
definir de manera simple. Sin embargo, las características de los seres vivos, son:
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1. Los seres vivos tienen una estructura compleja, organizada, que consta en buena parte de moléculas orgánicas (niveles de organización, células)
2. Los seres vivos responden a los estímulos de su ambiente (Órganos sensoriales y sistemas musculares)
3. Los seres vivos mantienen activamente su compleja estructura y su ambiente interno; este proceso se denomina homeostasis
4. Los seres vivos obtienen y usan materiales y energía de su ambiente y los convierten en diferentes formas (nutrimentos-metabolismo-energía-fotosíntesis-quimiosíntesis)
5. Los seres vivos crecen (implica la conversión de materiales obtenidos del ambiente para formar las moléculas específicas del cuerpo del organismo)
6. Los seres vivos se reproducen, utilizando un patrón molecular llamado ADN (El ADN de un organismo es su copia genética o su manual de instrucción molécular, una guía para la construcción, y en parte, para el funcionamiento de su cuerpo)
7. Los seres vivos, en general y como un todo, poseen la capacidad de evolucionar (los organismos modernos descendieron, con modificaciones, de formas de vida preexistentes, y que en última instancia, todas las formas de vida del planeta tienen un antepasado común)
CHARACTERISTICS OF LIVING THINGS
1. Organization. Living things exhibit a high level of organization, with multicellular organisms being subdivided into cells, and cells into organelles, and organelles into molecules, etc.
2. Homeostasis. is the maintenance of a constant (yet also dynamic) internal environment in terms of temperature, pH, water concentrations, etc. Much of our own metabolic energy goes toward keeping within our
own homeostatic limits.
If you run a high fever for long enough, the increased temperature will damage certain organs and impair your proper functioning.
Swallowing of common household chemicals, many of which are outside the pH (acid/base) levels we can tolerate, will likewise negatively impact the human body's homeostatic regime.
Muscular activity generates heat as a waste product. This heat is removed from our bodies by sweating. Some of this heat is used by warm-blooded animals, mammals and birds, to maintain their internal temperatures.
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3. Adaptation. Living things are suited to their mode of existence. Charles Darwin began the recognition of the marvellous adaptations all life has that allow those organisms to exist in their environment.
4. Reproduction and heredity. Since all cells come from existing cells, they must have some way of reproducing, whether that involves asexual (no recombination of genetic material) or sexual (recombination of genetic material).
Most living things use the chemical DNA (deoxyribonucleic acid) as the physical carrier of inheritance and the genetic information.
Some organisms, such as retroviruses of which HIV is a member), use RNA (ribonucleic acid) as the carrier.
The variation that Darwin and Wallace recognized as the wellspring of evolution and adaptation, is greatly increased by sexual reproduction.
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5. Growth and development. Even single-celled organisms grow. When first formed by cell division, they are small, and must grow and develop into mature cells. Multicellular organisms pass through a more complicated process of differentiation and organogenesis (because they have so many more cells to develop).
6. Energy acquisition and release. One view of life is that it is a struggle to acquire energy (from sunlight, inorganic chemicals, or another organism), and release it in the process of forming ATP (adenosine triphosphate).
7. Detection and response to stimuli (both internal and external).
8. Interactions. Living things interact with their environment as well as each other. Organisms obtain raw materials and energy from the environment or another organism. The various types of symbioses (organismal interactions with each other) are examples of this.
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1. A (an) ____ is any part of an organism's environment that causes a reaction.
A)species B)adaptation C)stimulus D)organization
2 The process of natural changes that take place during an organism's life is called ____.
A)growth B)development C)response D)adaptation3
3. Drip-tip leaves allow plants to live in what kind of environment?
A)tropical B)windy C)cold D)desert4
4. Which of these is not an example of the body maintaining homeostasis?
A)red blood cells delivering oxygen B)emergence of an evolutionary adaptation C)lungs absorbing oxygen D)insulin production in the pancreas5
5. Which of the following constitutes the basic structural organization of life?
A)weather conditions in a habitat B)cell organelles that combine to form nuclei C)species living in an environment D)cells that make up tissues and structures
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INTERDISCIPLINARY
RELATIONSHIPS ON BIOLOGY
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Biology
Math
Physics Chemistry
History
Biostatistics
Biophysics
Bionycles Biochemistry
Biopolymers
Anthropology
Paleontology
Biomass
Biodynamics
BIOLOGY
Anatomy
Zoology
Botanics
Taxonomy
Biogenetics
Ecology
Ethology
Cryobiology
Citology Microbiology
Physiology Morphology
Medicine
Exobiology
Geology
Agriculture
Biophysics
Biotechnology
Biogeography
Biomedicine
Earth Sciences
Embriology
Pathology
Next slide: Important scientists in biology.
Remember you should know what they did.
There are some names highlighted.
• Robert Hooke
• Alexander von Humboldt
• John Needham
• Edward Jenner
• Jean Baptiste de Lamarck
• Gottfried Reinhold Treviranus
• Karl Friedrich Burdach
• Robert Brown
• Rudolf Virchow
• Lynn Margulis
• Matthias Jakob Schleiden
• Paul Ehrlich
• Ernest Haeckel
• Ernest Mayer
• Robert Whittaker
• William Smith
• Charles Lyell
• Christian Gram
• Robert Briggs
• Alexander Oparin
• Francis Crick
• James Watson
• Rosalind Franklin
• Gregor Mendel
• Carl von Linné (Carlos Linneo)
• Ernst Haeckel
• Georges Louis Leclerc, Conde de Buffon
• Georges Cuvier
• Carl Woese
• S.J. Singer & G.L. Nicolson
• Melvin Calvin & Andy Benson
• Hans Adolf Krebs
• Camillo Golgi
• Harold Urey & Stanley Miller
• John Tyndall
• Carl Woese
• Linus Pauling
• James Hutton
• George Beadle
• Alexander Fleming
• Louis Pasteur
• Francesco Redi
• Charles Darwin
Important Scientists in Biology
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Biología: examples
Morphophysiologic caracteristics of
living beings aplicación de conocimientos
biológicos a nivel personal
Evolutive relationships
among different groups of organisms
Earth´s origin of life
Exobiology
Rivers and basins Studyng and conservation
Seas study and conservation
Aquariums, Forests and jungles
Natural History Museums
Zoologics
Apiculture Aviculture
Piscicultura
Veterinary research
Cattle raising research
Agricultural research
Biomedical research
Biotecnology
Genetic engineering
Genetics and living beings
interbreeding
Develop and Growing of Living
Beings
INTERDISCIPLINARY RELATIONSHIPS OF
BIOLOGICAL SCIENCES
In accord of Taxonomic criterium, they group together as:
Zoología (Zoology). Animal studies
Botánica (Botany). Plants studies
Micología (Micology). Mushrooms studies
Protozoología (Protozoology). Protozoans studies
Bacteriología (Bacteriology). Bacteria studies
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Sub-branches Implies
Mastozoology Mammals
Ornitology Birds
Herpetology Anphibians and reptiles
Ictiology Fishes
Entomology Insects
Carcinology Crustaceans
Malacology Moluscs
Helmintology Planes and cylindric worms
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Principales ramas
biológicas y su campo de estudio
Micología (hongos)
Anatomía (organos, aparatos, sistemas)
Embriología (formación y desarrollo de
los embriones)
Zoología (animales)
Bacteriología (bacterias)
Ecología (interrelaciones seres vivos-
ambiente)
Patología (enfermedade
s)
Ingeniería genética
(organismos y productos
transgénicos) Evolución (origen y
cambios en las especies)
Histología (tejidos)
Paleontología (fósiles)
Ficología (algas)
Genética (variaciones y
herencia)
Protozoología (protozoarios)
Taxonomía (clasificación de los seres
vivos)
Fisiología (funciones)
Botánica (plantas)
Etología (caracter y
comportamiento)
CONTINUITY REFERS TO LIVING BEING´S CAPACITY OF REPRODUCTION.
THE MAIN BIOLOGY´S BRANCHES ARE DESCRIBED BELOW:
Branch Field of study
Genetics Biological inheritance and variations
Evolution Origin and change of organisms
Phisiology Living beings functions
Anatomy Organs and systems description
Histology Tissues
Citology Cells
Embriology Embrio´s development
Paleontology Fossils and organisms origin
Ecology Interrelationship between abiotic and biotic factors
Taxonomy Living beings classification
Etology Temperament and behaviour
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Principales ciencias que interactuan
con la Biología
Ciencias de la salud
(previene y trata
problemas de salud humana
Ética (principios y valores de conducta)
Matemáticas
(estadística, probabilidad
es, porcentajes,
etc.)
Sociología (leyes y
fenómenos sociales)
Historia (aporta
datos que contribuyen al estudio de la Biología)
Física (relación
entre materia y energía)
Química (cambios y reacciones
de la materia
viva)
Geografía (origen,
estructura y evoluón de la Tierra)
Lógica (proporciona bases para
el razonamiento científico)
Antropología (al ser humano)
Etnología (las razas humanas)
Ciencias de la Tierra (origen y
evolución de la Tierra)
SCIENCE AND
THE SCIENTIFIC
METHOD
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SCIENCE AND THE SCIENTIFIC METHOD
Science is an objective, logical, and repeatable attempt to understand the principles and forces operating in the natural universe. Science is from the Latin word, scientia, to know.
Good science is not dogmatic, but should be viewed as an ongoing process of testing and evaluation. One of the hoped-for benefits of students taking a biology course is that they will become more familiar with the process of science.
Humans seem innately interested in the world we live in. Young children drive their parents batty with constant "why" questions. S
Science is a means to get some of those whys answered. When we shop for groceries, we are conducting a kind of scientific experiment. If you like Brand X of soup, and Brand Y is on sale, perhaps you try Brand Y. If you like it you may buy it again, even when it is not on sale. If you did not like Brand Y, then no sale will get you to try it again.
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LA BIOLOGÍA SE DEDICA AL ESTUDIO DE LOS SERES
VIVOS Y TODO LO QUE CON ELLOS SE RELACIONA.
CONSTRUCCIÓN DEL CONOCIMIENTO (a partir de la reactivación de los conocimientos previos)
Elementos que lo integran Características
Sujeto cognoscitivo Es la persona que capta ideas o juicios referentes a algún
aspecto de la realidad mediante su capacidad cognoscitiva
Objeto del conocimiento Es la cosa o ente conocido. Existe cierta correlación entre el
sujeto del conocimiento y el objeto que puede llegar a
modificar los pensamientos del sujeto
Operación cognoscitiva Proceso psicofisiológico que pone en contacto mediante
pensamientos al sujeto con el objeto.
Pensamientos Expresiones mentales de los objetos conocidos. Cada objeto
que se conoce, deja huellas en la memoria del sujeto
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CARACTERÍSTICAS DE LA CIENCIA
Característica Porque
Objetiva Trata de alcanzar la verdad y describir los hechos, incluso
produciendo nuevos hechos para reforzar las explicaciones
Racional Porque investiga para adquirir conocimientos y aplica la
lógica para establecer las relaciones que existen entre
diferentes hechos.
Verificable Como los conocimientos científicos son objetivos, pueden ser
verificados en cualquier momento y en cualquier parte del
mundo porque la ciencia es universal.
In order to conduct science, one must know the rules of the game (imagine playing Monopoly and having to discover the rules as you play!
Which is precisely what one does with some computer or videogames (before buying the cheatbook).
The scientific method is to be used as a guide that can be modified. In some sciences, such as taxonomy and certain types of geology, laboratory experiments are not necessarily performed.
Instead, after formulating a hypothesis, additional observations and/or collections are made from different localities.
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STEPS IN THE SCIENTIFIC METHOD
COMMONLY INCLUDE:
Observation: defining the problem you wish to
explain.
Hypothesis: one or more falsifiable explanations
for the observation.
Experimentation: Controlled attempts to test
one or more hypotheses.
Conclusion: was the hypothesis supported or
not? After this step the hypothesis is either
modified or rejected, which causes a repeat of the
steps above.
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WATCH THE SCIENTIFIC METHOD MOVIE…
After a hypothesis has been repeatedly tested, a hierarchy of scientific thought develops.
Hypothesis is the most common, with the lowest level of certainty.
A theory is a hypothesis that has been repeatedly tested with little modification, e.g. The Theory of Evolution.
A Law is one of the fundamental underlying principles of how the Universe is organized, e.g. The Laws of Thermodynamics, Newton's Law of Gravity.
Science uses the word theory differently than it is used in the general population. Theory to most people, in general nonscientific use, is an untested idea. Scientists call this a hypothesis.
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Scientific experiments are also concerned with
isolating the variables.
A good science experiment does not
simultaneously test several variables, but rather
a single variable that can be measured against a
control.
Scientific controlled experiments are situations
where all factors are the same between two test
subjects, except for the single experimental
variable. 40
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SCIENTIFIC PRINCIPLES
TODA INVESTIGACIÓN CIENTÍFICA SE APOYA EN PRINCIPIOS CIENTÍFICOS
1. La causalidad natural es el principio de que todos los sucesos tienen causas naturales. Por ejemplo,
en otros tiempos se pensó que la epilepsia era consecuencia de una disposición divina. Hoy se sabe
que es una enfermedad del cerebro en la que grupos de células nerviosas se activan de manera
incontrolable. No hace mucho había quien argumentaba que los fósiles no son prueba de la evolución,
sino que Dios los colocó en la Tierra para poner a prueba nuestra fe. Si no podemos confiar en las
pruebas que nos proporciona la Naturaleza, la ciencia se convierte en un empeño futil…
2. Las leyes naturales que rigen los sucesos son válidas en todo lugar y en todo momento. Las leyes de
la gravedad, el comportamiento de la luz y las interacciones de los átomos, son las mismas ahora que
hace mil millones de años y se cumplen tanto en Moscu como en Nueva York, o incluso Marte.
La uniformidad en el espacio y el tiempo resulta especialmente indispensable en Biología, porque
muchos hechos ocurrieron antes de que hubiera seres humanos para observarlos. Hay quienes creen
que cada uno de los diferentes tipos de organismos fue creado individualmente en algún momento
del pasado por intervención directa de Dios, filosofía que se conoce como Creacionismo. No se puede
demostrar que tal idea es falsa, no obstante, el creacionismo se opone tanto a la causalidad natural
como a la uniformidad en el tiempo.
3. La investigación científica se basa en el supuesto de que las personas perciben los sucesos naturales
de forma similar. Todos los seres humanos perciben los sucesos naturales básicamente de la misma
manera y que esas percepciones nos proporcionan información confiable acerca del mundo que nos
rodea. No se puede decir lo mismo de los sistemas de valores, ya que son subjetivos, no objetivos, y
por tanto, la ciencia no puede resolver ciertos tipos de problemas filosóficos o morales, como la
moralidad del aborto.
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YOU ARE CAMPING AND YOU GO TO TURN ON
YOUR FLASHLIGHT AND IT DOESN’T WORK. SO
WHAT IS WRONG WITH IT?
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You will use scientific "hypothetical-deductive reasoning" to decide.
Hypothesis: Maybe the batteries are dead?
Prediction: If we change the batteries with fresh ones the flashlight should work.
Experiment to test that hypothesis: we replace the batteries.
Results: Well if it was the batteries then the flashlight should work.
If it wasn’t the batteries then we need to formulate a new hypothesis and test it.
A good hypothesis allows us to make predictions, the "if …then" statement. "If the batteries are dead, then replacing them will make the flashlight work".
COLLABORATIVE ACTIVITY 1. WORKING
DEEP INSIDE SCIENCE
Stand up and make up a team of 3
You will only have 15 minutes to get the job ready!
Between all the members of the team will have to generate a brainstorm and to choose one example (like the last one!) (4 minutes)
Rol 1: One person in the team has to generate a different template, like the last slide example, showing the different steps of the scientific method (the template or draft it’s just a papersheet in which you will draw and write your example)
Rol 2: another has to take the time (time keeper) and to visit other teams for to get ideas and for to not repeat the same example! (5 minutes)
Rol 3: the next guy will help in the elaboration of the final draft and will explain it to all the whole group (2 minutes to deliver it)
The final result will be delivered to the teacher at the the end of the class in a like- lab’s report papersheet
The last team to deliver their job will be the only one in to expose to the rest of the class, otherwise will be a kind of fairy elected team picking up a piece of paper of a plastic bag… (4 minutes to expose it)
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LEVELS OF
ORGANIZATION
From sub particles to
Ecological levels…
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HOMEWORK
Everyone have to read the next article called
Biological complexity and integrative levels or
organization
We will discuss the topic two classes ahead… It
will be like a brief exam, so If you do not answer
the questions or discuss about the article, you
will be losing points in your grading…
Link:
https://docs.google.com/document/edit?id=15Evdt
OkzqebeH0x1mqYngf5gD0wKw9JsE2iKeICuYU
M&hl=en&authkey=CPaI8ocN 45
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LEVELS OF ORGANIZATION
CHEMICAL LEVEL: ATOMS TO BIOMOLECULES
Atoms Most of the Universe consists of matter and energy.
Energy is the capacity to do work.
Matter has mass and occupies space.
All matter is composed of basic elements that cannot be broken
down to substances with different chemical or physical properties.
Elements are substances consisting of one type of atom,
for example Carbon atoms make up diamond, and also graphite. Pure (24K) gold is composed of only one type of atom, gold atoms. Atoms are the smallest particle into which an element can be divided.
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PROTONS
The proton is located in the center (or nucleus) of an atom,
each atom has at least one proton.
Protons have a charge of +1, and a mass of approximately 1
atomic mass unit (amu).
Elements differ from each other in the number of protons they
have, e.g. Hydrogen has 1 proton; Helium has 2.
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The neutron also is located in the atomic nucleus (except in Hydrogen).
The neutron has no charge, and a mass of slightly over 1 amu.
Some scientists propose the neutron is made up of a proton and electron-like particle.
The electron is a very small particle located outside the nucleus.
Because they move at speeds near the speed of light the precise location of electrons is hard to pin down.
Electrons occupy orbitals, or areas where they have a high statistical probability of occurring.
The charge on an electron is -1. Its mass is negligible (approximately 1800 electrons are needed to equal the mass of one proton).
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TABLE 1. SUBATOMIC PARTICLES OF USE
IN BIOLOGY.
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The atomic number is the number of protons an atom has. It is characteristic and unique for each element.
The atomic mass (also referred to as the atomic weight) is the number of protons and neutrons in an atom. Atoms of an element that have differing numbers of neutrons (but a constant atomic number) are termed isotopes.
Biochemical pathways can be deciphered by using isotopic tracers. The age of fossils and artifacts can be determined by using
radioactive isotopes, either directly on the fossil (if it is young enough) or on the rocks that surround the fossil (for older fossils like dinosaurs).
Isotopes are also the source of radiation used in medical diagnostic and treatment procedures.
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MOLECULES EXAMPLES…
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CHEMICAL REACTION
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CELLULAR LEVELS OF ORGANIZATION
Cells: microscopic units of living matter
Each individual begins as a single cell that is
capable of mitosis and differentiation
As a consequence of mitosis and differentiation, four cell
groups develop
At the cellular level we find the above biomolecules
associated with one another to form complex and highly
organized and highly specialized structures within the
cell called "organelles". These sub-cellular organelles
are each designed to perform specific functions within
the cell.
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"The cell" itself is the basic structural and functional unit of life.
The cell is the smallest and simplest part of living matter that can carry on all the activities necessary for life. Each cell consists of a discrete body of jelly-like cytoplasm surrounded by a cell membrane. The organelles are suspended within the cytoplasm.
Tissues:
In most multicellular organisms cells, associate to form tissues, such as muscle tissue or nervous tissue.
Organs:
Tissues are arranged into functional structures called organs, such as the heart or stomach.
Organ Systems:
Each major group of biological functions is performed by a coordinated group of tissues and organs called an organ system. The "circulatory and digestive system" are examples of organ systems.
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ECOLOGICAL LEVELS OF ORGANIZATION
The Organism Functioning together with great precision, the organ systems make up
the complex multicellular organism. Organisms interact to form still more complex levels of biological organization.
Populations All the members of one species that live in the same area make up
a population.
Community The population of organisms that inhabit a particular area and
interact with one another form a community. Thus a community can be comprised of hundreds of different types of life forms. The study of how organisms of a community relate to one another and with their non-living environment is called "ecology".
Ecosystem A community, together with its non-living environment is referred to
as an "ecosystem". An ecosystem can be as small as a pond (or even a puddle) or as vast as the great plains of North American or the Arctic tundra.
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Ecosystem The largest ecosystem
is the plant Earth
with all its
inhabitants - "The
Biosphere".
CHEMICAL BONDS
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CHEMICAL BONDS; THE "GLUE" THAT
HOLDS MOLECULES TOGETHER.
Hydrogen "H" usually exists as the molecule (H2). A hydrogen molecule is more stable than two hydrogen atoms, therefore, energy must be expended in order to "break" the hydrogen molecule into its component atoms.
Atoms are "most stable" when their outermost orbitals are filled. Two hydrogen atoms, each of which has one electron, can "share" the electrons so that each effectively has two electrons ion the 1s orbital. Thereby completing it and establishing the most stable arrangement.
As the atoms approach each other, each nucleus begins to attract the electron held by the other nucleus. Eventually, the electron clouds overlap and fuse into one "molecular orbital". Like an atomic orbital, a molecular orbital is most stable when filled by a pair of electrons. This shared orbital acts ad a "chemical bond" between the two atoms and resembles a strong "spring", in its properties. It can be compressed, stretched and bent to a certain extent without breaking, it can also spin like and axil or vibrate.
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An atom can form as many bonds as there are unpaired
electrons in its outermost orbital. The bond between two
atoms of hydrogen is called a "covalent bond".
One biologically important element that hydrogen can also
bond to is carbon.
Carbon has a total of six electrons. Two in its 1s orbital and four
electrons in the outermost (second) orbital. This second energy
level (orbital) can accommodate a maximum of eight electrons.
Therefore, carbon is looking for four additional electrons to fill its
2p orbitals, and give it maximum stability.
The unfilled orbitals of four hydrogen can form four covalent
bonds by a sharing of pairs of electrons between carbon and
hydrogen.
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Covalent bonds Double covalent bonds
The kinds of bonds in methane (CH4) are "single
bonds", meaning only one pair of electrons is shared
between two atoms. But two atoms can share two or
three pairs of electrons forming "double or triple"
bonds. Carbon atoms often form double bonds. For
example Ethylene.
IONIC BONDS
Where covalent bonds involve shared electrons, "ionic bonds" are formed when one atom gives up an electron from an outer shell (orbital) and the other atom adds the free electron to its outer most orbital, thereby holding the atoms together in an energetically stable unit.
When an atom loses an electron it would have one more positively charged proton (+) then electrons, therefore, the atom would be carrying an overall net charge of (1+). When an atom gains and electron it contains one more electron than protons and therefore would be carrying a net charge of (1-).
Atoms which have gained or lost electrons are called ions. Ions are charged, atoms or molecules. Anions carry a negative charge eg. (Cl-) while cations carry a positive charge (Na+).
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IONIC BONDS
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IONIC BONDS
Ionic bonds are formed when atoms become ions by gaining or losing electrons.
Chlorine is in a group of elements having seven electrons in their outer shells. Members of this group tend to gain one electron, acquiring a charge of -1.
Sodium is in another group with elements having one electron in their outer shells. Members of this group tend to lose that outer electron, acquiring a charge of +1.
Oppositely charged ions are attracted to each other, thus Cl- (the symbolic representation of the chloride ion) and Na+ (the symbol for the sodium ion, using the Greek word natrium) form an ionic bond, becoming the molecule sodium chloride,.
Ionic bonds generally form between elements in Group I (having one
electron in their outer shell) and Group VIIa (having seven electrons in their outer shell). Such bonds are relatively weak, and tend to disassociate in water, producing solutions that have both Na and Cl ions.
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HYDROGEN BONDS
Hydrogen bonds, result from the weak electrical attraction
between the positive end of one molecule and the negative
end of another.
Individually these bonds are very weak, although taken in
a large enough quantity, the result is strong enough to hold
molecules together or in a three-dimensional shape.
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Molecules are compounds in which the elements are in definite, fixed ratios.
Those atoms are held together usually by one of the three types of chemical bonds discussed above. For example: water, glucose, ATP.
Mixtures are compounds with variable formulas/ratios of their components. For example: soil.
Molecular formulas are an expression in the simplest whole-number terms of the composition of a substance. For example, the sugar glucose has 6 Carbons, 12 hydrogens,
and 6 oxygens per repeating structural unit. The formula is written C6H12O6.
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CHEMISTRY II: WATER AND ORGANIC
MOLECULES
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STRUCTURE OF WATER
Water is polar covalently bonded within the
molecule.
This unequal sharing of the electrons results in a
slightly positive and a slightly negative side of the
molecule.
Other molecules, such as Ethane, are nonpolar,
having neither a positive nor a negative side
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Water has been referred to as the universal
solvent.
Living things are composed of atoms and
molecules within aqueous solutions (solutions
that have materials dissolved in water).
Solutions are uniform mixtures of the molecules
of two or more substances.
The solvent is usually the substance present in
the greatest amount (and is usually also a liquid).
The substances of lesser amounts are the solutes. 73
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SOLUBILITY
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The solubility of many molecules is determined by their molecular structure. You are familiar with the phrase
"mixing like oil and water." The biochemical basis for this phrase is that the organic macromolecules known as lipids (of which fats are an important, although often troublesome, group) have areas that lack polar covalent bonds.
The polar covalently bonded water molecules act to exclude nonpolar molecules, causing the fats to clump together.
The structure of many molecules can greatly influence their solubility. Sugars, such as glucose, have many hydroxyl (OH) groups, which tend to increase the solubility of the molecule.
HYDROGEN POTENTIAL (PH)
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Water tends to disassociate into H+ and OH- ions.
In this disassociation, the oxygen retains the electrons and only one of the hydrogens, becoming a negatively charged ion known as hydroxide.
Pure water has the same number (or concentration) of H+ as OH- ions.
Acidic solutions have more H+ ions than OH- ions.
Basic solutions have the opposite. An acid causes an increase in the numbers of H+ ions and a base causes an increase in the numbers of OH- ions.
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The pH scale is a logarithmic scale representing the concentration of H+ ions in a solution.
Remember that as the H+ concentration increases the OH- concentration decreases and vice versa .
If we have a solution with one in every ten molecules being H+, we refer to the concentration of H+ ions as 1/10. Remember from algebra that we can write a fraction as a negative exponent, thus 1/10 becomes 10-1. Conversely 1/100 becomes 10-2 , 1/1000 becomes 10-3, etc.
Logarithms are exponents to which a number (usually 10) has been raised. For example log 10 (pronounced "the log of 10") = 1 (since 10 may be written as 101). The log 1/10 (or 10-1) = -1. pH, a measure of the concentration of H+ ions, is the negative log of the H+ ion concentration. If the pH of water is 7, then the concentration of H+ ions is 10-7, or 1/10,000,000. In the case of strong acids, such as hydrochloric acid (HCl), an acid secreted by the lining of your stomach, [H+] (the concentration of H+ ions, written in a chemical shorthand) is 10-1; therefore the pH is 1.
ORGANIC MOLECULES
(BIOMOLECULES)
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ORGANIC MOLECULES
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Organic molecules are those that: 1) formed by the actions of living things; and/or 2) have a carbon backbone.
Methane (CH4) is an example of this. If we remove the H from one of the
methane units below, and begin linking them up, while removing other H units, we begin to form an organic molecule.
(NOTE: Not all methane is organically derived, methane is a major component of the atmosphere of Jupiter, which we think is devoid of life).
When two methanes are combined, the resultant molecule is Ethane, which has a chemical formula C2H6. Molecules made up of H and C are known as hydrocarbons.
FUNCTIONAL GROUPS
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Scientists eventually realized that specific chemical properties were a result of the presence of particular functional groups. F
unctional groups are clusters of atoms with characteristic structure and functions. Polar molecules (with +/- charges) are attracted to water molecules and are hydrophilic. Nonpolar molecules are repelled by water and do not dissolve in water; are hydrophobic.
Hydrocarbon is hydrophobic except when it has an attached ionized functional group such as carboxyl (acid) (COOH), then molecule is hydrophilic.
Each organic molecule group has small molecules
(monomers) that are linked to form a larger
organic molecule (macromolecule).
Monomers can be joined together to form
polymers that are the large macromolecules
made of three to millions of monomer subunits.
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Macromolecules are constructed by covalently bonding monomers by condensation reactions where water is removed from functional groups on the monomers.
Cellular enzymes carry out condensation (and the reversal of the reaction, hydrolysis of polymers). Condensation involves a dehydration synthesis because a water is removed (dehydration) and a bond is made (synthesis).
When two monomers join, a hydroxyl (OH) group is removed from one monomer and a hydrogen (H) is removed from the other. This produces the water given off during a condensation
reaction. Hydrolysis (hydration) reactions break down polymers in reverse of condensation; a hydroxyl (OH) group from water attaches to one monomer and hydrogen (H) attaches to the other. 81
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MAIN BIOMOLECULES
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THE MOST IMPORTANT MACROMOLECULES
IN BIOLOGY…
There are four classes of macromolecules
(polysaccharides, triglycerides, polypeptides,
nucleic acids). These classes perform a variety of
functions in cells.
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BIOMOLECULES SUMMARY… LAS PRINCIPALES MOLÉCULAS BIOLÓGICAS
Clase de molécula Principales subtipos
(subunidades en paréntesis)
Ejemplo Función
Carbohidrato:
normalmente contiene
carbono, oxígeno e
hidrógeno y tiene la
formula aproximada
(CH2O)n
Monosacárido: azúcar simple
Disacárido: dos monosacáridos
enlazados
Polisacárido: muchos
monosacáridos (normalmente
glucosa) enlazados
Glucosa
Sacarosa
Almidón
Glucógeno
Celulosa
Importante fuente de energía para las
células; subunidad con la que se hacen casi
todos los polisacáridos
Principal azúcar transportado dentro del
cuerpo de las plantas terrestres
Almacén de energía en plantas
Almacén de energía en animales
Material estructural de plantas
Lípido:
Contiene una proporción
elevada de carbono e
hidrógeno; suele ser no
polar e insoluble en agua
Tliglicerido: tres ácidos grasos
unidos a glicerol
Cera: número variable de ácidos
grasos unidos a un alcohol de
cadena larga
Fosfolípido: grupo fosfato polar
y dos ácidos grasos unidos a
glicerol
Esteroide: 4 anillos fusionados
de átomos de carbono, con
grupos funcionales unidos
Aceite, grasa
Ceras en la cutícula
de las plantas
Fosfatidilcolina
Colesterol
Almacén de energía en animales y algunas
plantas
Cubierta impermeable de las hojas y tallos
de plantas terrestres
Componente común de las membranas de
las células
Componente común de las membranas de
las células eucarióticas; precursor de otros
esteroides como testosterona, sales biliares
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BIOMOLECULES…
LAS PRINCIPALES MOLÉCULAS BIOLÓGICAS
Clase de molécula Principales subtipos
(subunidades en paréntesis)
Ejemplo Función
Proteína:
Cadenas de aminoácidos;
contiene carbono,
hidrógeno, oxígeno,
nitrógeno y azufre
(aminoácidos) Queratina
Seda
Hemoglobina
Proteína helicoidal, principal componente
del pelo
Proteína producida por polillas y arañas
Proteína globular formada por 4
subunidades peptídicas; transporta oxígeno
en la sangre de los vertebrados
Acido nucleico:
Formado por subunidades
llamadas nucleótidos;
puede ser uno solo o una
cadena larga de
nucleótidos.
Ácidos nucleicos de cadena larga
Nucleótidos individuales
Acido
desoxirribonucleico
(ADN)
Acido Ribonucleico
(ARN)
Trifosfato de
adenosina (ATP)
Monofosfato de
adenosina cíclico
(AMP cíclico)
Material genético de todas las células vivas
Material genético de algunos virus; en las
células vivas es indispensable para transferir
la información genética del ADN a las
proteínas
Principal molécula portadora de energía a
corto plazo en las células
Mensajero intracelular
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CARBOHYDRATES
Sugars…
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CARBOHYDRATES
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Carbohydrates have the general formula [CH2O]n where n is a number between 3 and 6.
Carbohydrates function in short-term energy storage (such as sugar); as intermediate-term energy storage (starch for plants and glycogen for animals); and as structural components in cells (cellulose in the cell walls of plants and many protists), and chitin in the exoskeleton of insects and other arthropods.
Sugars are structurally the simplest carbohydrates.
They are the structural unit which makes up the other types of carbohydrates. Monosaccharides are single (mono=one) sugars. Important monosaccharides include ribose (C5H10O5), glucose (C6H12O6), and fructose (same formula but different structure than glucose).
ALFA AND BETA GLUCOSE
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DISACCHARIDES
are formed when two monosaccharides are chemically
bonded together.
Sucrose, a common plant disaccharide is composed of the
monosaccharides glucose and fructose.
Lactose, milk sugar, is a disaccharide composed of glucose
and the monosaccharide galactose.
The maltose that flavors a malted milkshake (and other
items) is also a disaccharide made of two glose molecules
bonded together
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DISACCHARIDES: "DEHYDRATION SYNTHESIS".
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When two monosaccharides are
joined together they form a
"disaccharide".
This linking of two sugars involves
the removal of a molecule of H2O
(water) and is therefore called a
"dehydration linkage". The
reaction is called "dehydration
synthesis".
e.g. Glucose + Glucose = Maltose
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Polysaccharides
These are long chains
of monosaccharides
linked together by
dehydration linkages.
POLYSACCHARIDES
are large molecules composed of individual monosaccharide units. A common plant polysaccharide is starch which is made up of many glucoses (in a polypeptide these are referred to as glucans).
Two forms of polysaccharide, amylose and amylopectin makeup what we commonly call starch.
The formation of the ester bond by condensation (the removal of water from a molecule) allows the linking of monosaccharides into disaccharides and polysaccharides. Glycogen (see Figure 12) is an animal storage product that accumulates in the vertebrate liver.
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CELLULOSE (HOMOPOLYSACARID)
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is a polysaccharide found in plant cell walls. Cellulose forms the
fibrous part of the plant cell wall.
In terms of human diets, cellulose is indigestible, and thus forms an important, easily obtained part of dietary fiber.
As compared to starch and glycogen, which are each made up of mixtures of a and b glucoses, cellulose (and the animal structural polysaccharide chitin) are made up of only b glucoses.
HETEROPOLYSACARIDS
Chitin: is an important structural material in the outer coverings
of insects, crabs, and lobsters. In chitin the basic subunit is not
glucose (but N-acetyl-D-glucoseamine) in 1-4 linkages. These
polymers are made very hard when impregnated with calcium
carbonate.
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LIPIDS
Fatty acids
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LIPIDS
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are involved mainly with long-term energy storage.
They are generally insoluble in polar substances such as water.
Secondary functions of lipids include structural components (as in the case of phospholipids that are the major building block in cell membranes) and "messengers" (hormones) that play roles in communications within and between cells.
Lipids are composed of three fatty acids (usually) covalently bonded to a 3-carbon glycerol. The fatty acids are composed of CH2 units, and are hydrophobic/not water soluble.
Fatty acids can be saturated (meaning they have as many hydrogens bonded to their carbons as possible) or unsaturated (with one or more double bonds connecting their carbons, hence fewer hydrogens).
A fat is solid at room temperature, while an oil is a liquid under the same conditions. The fatty acids in oils are mostly
unsaturated,
while those in fats are mostly saturated.
Lipids include the compounds commonly known as fats, oils, and waxes. We will look at three important classes of lipids.
THE TRIGLYCERIDES
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Both fats and oils are "triglycerides". These molecules are made up of 3 long chain "fatty acids" attached to a 3 carbon molecule called "glycerol".
The carboxyl and the fatty acids are attached to the -OH groups of the Glycerol via a "dehydration synthesis" reaction to yield an "ester" bond.
Function: storage of energy - "fat" in animals, and "oils" in plants.
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Animals convert excess sugars (beyond their glycogen storage capacities) into fats.
Most plants store excess sugars as starch, although some seeds and fruits have energy stored as oils (e.g. corn oil, peanut oil, palm oil, canola oil, and sunflower oil).
Fats yield 9.3 Kcal/gm, while carbohydrates yield 3.79 Kcal/gm. Fats thus store six times as much energy as glycogen.
Fats and oils function in long-term
energy storage.
SATURATED AND UNSATURATED FATTY
ACIDS
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Saturated Fatty Acid: These are fatty acids
which contain the maximum possible number of
hydrogen atoms. That is each carbon in the chain
has two hydrogen atoms attached to it. It is
"saturated" with hydrogen atoms.
Unsaturated Fatty Acid: These are fatty acids which
contain carbon-to-carbon "double" bonds. Therefore since a
carbon atom can have only 4 covalent bonds, there is one
less bond available for hydrogen, therefore there is one less
hydrogen. (The carbons are not "saturated" with hydrogen
atoms.)
CL
AS
S A
CT
IVIT
Y
Directions.
1. Work in teams
of three
2. Read the next 6
slides
3. To generate a
mindmap over
all the 6 slides
in a papersheet
4. Generate a
table showing
differences
between cis
and trans
1. Answer the next questions:
1. What are satured and unsatured
fatty acids?
2. Are both of them good or bad for
your healthy?
3. What is an eicosanoid?
4. What is hydrogenation? What is
used for?
5. What are Cis and trans
configuration?
6. Which is best for your health of both
of them?
7. What is the meaning of LDL and
HDL and what is used for each one
of them?
8. Why is trans bad for your brain and
heart?
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FATTY ACID CONFIGURATIONS
TRANS FATS: WHAT'S UP WITH THAT?
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Double bonds bind carbon atoms tightly and prevent rotation of the carbon atoms along the bond axis. This gives rise to configurational isomers which are arrangements of atoms that can only be changed by breaking the bonds.
Cis configuration (oleic Acid)
Trans configuration (Elaidic
acid)
What are Trans Fats?
Configurational isomers
Cis means "on the same side" and Trans means "across"
or "on the other side"
WHAT IS HYDROGENATION AND PARTIAL
HYDROGENATION?
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Unsaturated fats exposed to air oxidize to create compounds that have rancid, stale, or unpleasant odors or flavors.
Hydrogenation is a commercial chemical process to add more hydrogen to natural unsaturated fats to decrease the number of double bonds and retard or eliminate the potential for rancidity.
Unsaturated oils, such as soybean oil, which contain unsaturated fatty acids like oleic and linoleic acid, are heated with metal catalysts in the presence of pressurized hydrogen gas.
Hydrogen is incorporated into the fatty acid molecules and they become saturated with hydrogen. Oleic acid (C18:1) and linoleic acid (C18:2) are both converted to stearic acid (C18:0) when fully saturated.
The liquid vegetable oil becomes a solid saturated fat (shortening with a large percentage of tristearin).
By comparison, animal fats seldom have more than 70% saturated fatty acid radicals. In the table above, for example, lard has 54% unsaturated fatty acid radicals.
METABOLISM OF FATS -- WHY ARE TRANS
FATS BAD?
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Metabolism of natural 20-carbon polyunsaturated fatty acids like arachidonic acid results in the biosynthesis of mediators with potent physiological effects such as prostaglandins, prostacyclins, thromboxanes, leucotrienes, and lipoxins.
These substances are known collectively as eicosanoids because they contain 20 carbon atoms (Greek eikosi = 20).
However, polyunsaturated trans fatty acids cannot be used to produce useful mediators because the molecules have unnatural shapes that are not recognized by enzymes such as cyclooxygenase and lipoxygenase.
Metabolism of natural C20 Cis fatty
acids produces powerful
eicosanoids.
Although low levels of trans-vaccenic acid
occur naturally in some animal food
products, partially hydrogenated oils contain
a large proportion of diverse trans fatty
acids.
When large amounts of Trans fatty acids are
incorporated into the cells, the cell
membranes and other cellular structures
become malformed and do not function
properly.
TRANS IS BAD FOR YOUR HEART…
Trans fats are bad for your heart.
Dietary trans fats raise the level of low-density lipoproteins (LDL or "bad cholesterol") increasing the risk of coronary heart disease. Trans fats also reduce high-density lipoproteins (HDL or "good cholesterol"), and raise levels of triglycerides in the blood.
Both of these conditions are associated with insulin resistance which is linked to diabetes, hypertension, and cardiovascular disease.
Harvard University researchers have reported that people who ate partially hydrogenated oils, which are high in Trans fats, had nearly twice the risk of heart attacks compared with those who did not consume hydrogenated oils. B
ecause of the overwhelming scientific evidence linking Trans fats to cardiovascular diseases, the Food and Drug Administration will require all food labels to disclose the amount of Trans fat per serving, starting in 2006.
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TRANS IS BAD FOR YOUR BRAIN…
Trans fats are bad for your brain.
Trans fats also have a detrimental effect on the brain and nervous system. Neural tissue consists mainly of lipids and fats.
Myelin, the protective sheath that covers communicating neurons, is composed of 30% protein and 70% fat. Oleic acid and DHA are two of the principal fatty acids in myelin.
Studies show that trans fatty acids in the diet get incorporated into brain cell membranes, including the myelin sheath that insulates neurons. These synthetic fats replace the natural DHA in the membrane, which affects the electrical activity of the neuron.
Trans fatty acid molecules alter the ability of neurons to communicate and may cause neural degeneration and diminished mental performance.
Neurodegenerative disorders such as multiple sclerosis (MS), Parkinson's Disease, and Alzheimer's Disease appear to exhibit membrane loss of fatty acids.
Unfortunately, our ingestion of trans fatty acids starts in infancy. A Canadian study showed that an average of 7.2% of the total fatty acids of human breast milk consisted of trans fatty acids which originated from the consumption of partially hydrogenated vegetable oils by the mothers.
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WHAT ARE OMEGA-3 AND OMEGA-6 FATTY
ACIDS?
HOMEWORK: INDIVIDUAL! SEARCH ABOUT
BOTH OMEGA ACIDS, IN AT LEAST TWO
DIFFERENT WEBSITES (OBVIOUSLY
WiTHOUT LOOKING FOR IN rincondelvago,
wikipedia, monografias, etc. You may look for in
the next website http://www.clo3.com/home.php
Search for function
Key benefits of omega 3
Why are they so necessary for human diet
Tridimensional shape
DELIVERY FORM: VIA EMAIL TO
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PHOSPHOLIPIDS
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These molecules are structurally similar to the triglycerides, but they differ in one important respect. Triglycerides have 3 fatty acid chains, but the phospholipids have only 2 fatty acid chains and one phosphate (-) group.
The negatively charged phosphate group (and its various end groups) cause this end of the molecule to form a "polar" covalent bond with glycerol. That is this end of the phospholipid molecule is "polar" while the fatty acid chain is "non-polar".
Therefore one end of the molecule is charged (-), i.e. polar and the other end of the molecule is not charged (neutral), i.e. non-polar.
Since water is also a polar molecule the polar end of
the phospholipid is "attracted" to the + ends of the
water molecules. It is said to be "hydrophillic" (or
water loving). While the neutral end of the
phospholipid molecule is non-polar, i.e. is repelled by
the "polar" water molecules, it is said to be
"hydrophobic" (water fearing).
THIS DUEL NATURE OF THE PHOSPHOLIPID
MOLECULE MAKES IT VERY USEFUL AS A
COMPONENT OF CELL MEMBRANES.
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AMINOACIDS, PEPTIDES AND
PROTEINS
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PROTEINS
Main protein functions
Function Example
Structure Colagen in skin, keratine in hair, nails and horns
Motion Actine and miosine in muscles
Defense Antibodies in blood stream
Almacenamiento Zeatine in cornpops
Signals Growth hormone in blood stream
Catalysis Enzimes: they catalize almost every chemical
reaction within cells, DNA polimerase (produces
DNA); pepsine (digers proteins); amilase (digers
carbohydrates); ATP synthetase (produces ATP) 111
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These are very large 3 dimensional macromolecules. They are very
important as structural molecules in the cell, as energy sources,
and most importantly as "enzymes", (protein catalysts which
speed up chemical reactions in the cell without the need for high
temperature or drastic pH changes).
Proteins are often called "polypeptides" because they are made of
long chains of building blocks called "amino acids"
STRUCTURE OF SOME AMINO ACIDS
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- R groups can be any of 20 different forms giving 20 naturally
occurring amino acids (in living things)
STRUCTURE OF PROTEINS
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Primary Structure (or primary level of organization)
Definition. "The sequence of amino acids in the polypeptide chain.“
Amino acids are bound together with a "peptide" bond.
SECONDARY LEVEL OF ORGANIZATION
OF POLYPEPTIDES
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There are two types of secondary structure in proteins, the α helix and the β pleated sheet.
The attraction of the R groups within the same chain can cause the chain to twist into a "right handed" coil.
This " α helix" is held together by hydrogen bonds between the hydrogen and oxygen atoms of the amino acid backbone (amino groups and carboxyl groups).
Such "Intrachain Hydrogen Bonding" often predominate in "globular proteins".
Keratin is a structural protein found in hair and nails, skin, and
tortoise shells. The aHelix nature of wool is what makes it shrink.
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Another form of secondary structure the β pleated sheet, is caused by hydrogen bonding between the hydrogen atoms (amino group) and the oxygen atoms (carboxyl group) of amino acids on two chains (or more) lying side-by-side.
The β pleated sheet structure is often found in many structural proteins, such as "Fibroin", the protein in spider webs.
THE TERTIARY STRUCTURE OF
PROTEINS
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When "proline", an oddly shaped amino acid occurs in the polypeptide chain a "kink" in the ahelix develops. Kinks can also be caused by repulsive forces between adjacent charged R groups. These kinks create a 3 dimensional chain arrangement, ie. the "Tertiary" Structure
This 3 dimensional shape is also held together by weak hydrogen bonds but also by much stronger "disulfide" bonds between two amino acids of cystine ("covalent") disulfide "bridges" (linkages)
cystine -- s -- s -- cystine
QUATERNARY STRUCTURE OF PROTEINS
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This last level of organization is simply taking 2 or more 3 dimensional (tertiary proteins) and sticking them together to form a larger protein.
Many enzymes and transport proteins are made of two or more parts.
STRUCTURE OF PROTEINS
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DENATURE
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Proteins when heated can unfold or "Denature".
This loss of three dimensional shape will usually be accompanied
by a loss of the proteins function.
If the denatured protein is allowed to cool it will usually refold
back into it’s original conformation.
NUCLEIC ACIDS
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These macromolecules include the Ribonucleic Acids (RNA's) and the Deoxyribonucleic Acids (DNA's).
They are also long chain macromolecules. The repeating subunits (building blocks) of these molecules are called "nucleotides".
Nucleotides have three parts,
a sugar (usually the six carbon sugar ribose or deoxyribose), a phosphate group (P04) and a base (which contains nitrogen).
BASIC STRUCTURE
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Nucleic acids form long chains by linking the phosphate groups to the sugars. The nitrogen bases stick out to the side. When DNA is formed there are two chains of nucleotides, each of which tends to coil around the other forming the so called "double helix".
The two strands of DNA are said to form the "DNA molecule".
Note: that one strand runs in one "direction" and the other strand runs in the opposite "direction".
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Deoxyribonucleic acid (DNA) is composed of deoxyribose sugar and four nitrogen bases, Complementary base paired, as follows;
Adenine = = = Thymine
Guanine = = = Cytosine
RNA differs from DNA in that there is only one strand, and RNA uses ribose as its sugar, and RNA substitutes Uracil for Thymine.
Adenine - Uracil
Guanine - Cytosine
The DNA double helix. Some differences between each
nucleic acid
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