Physical Properties

• Due to the polar nature of water

• Hydrogen bond- weak attraction between hydrogen on adjacent molecules such as water

H H O

H H

OHydrogen bond

Water and it’s importance to Life

• Life evolved in water

• Water’s unique properties have made life as we know it possible

Physical Properties• Heat of vaporization- amount of

energy that is released or gained when changing state from liquid to gas or back

Physical Properties• High Specific Heat- the amount of

heat absorbed or released when water changes temperature by one degree C. ( 1 cal. )

Ice Floats

• As a liquid water’s hydrogen bonds continuously break and reform

• As a solid four molecules form hydrogen bonds creating crystals with open channels and thus fewer molecules per area.

Physical Properties• Water reaches maximum density

at 4 degrees C.

• Water is a universal solvent due to it’s polar nature

Evaluate the importance of the following and explain the

property of water responsible.• Cytoplasm is 98 % water

• Ice Floats

• Lake effect temperature moderation

• Evaporative Cooling

• Spring-Fall Overturn

Most Abundant Chemicals in Life

• Carbon

• Oxygen

• Hydrogen

• Nitrogen

• Ca, P, K, S, Na, Cl, Mg > 4 %

96 %

Carbon is special

• Tetrahedral structure- four valence electrons shared

• Covalent bonds - stability

Carbon is Special

• Variations are possible in carbon molecules that provide diversity

• Isomers are possible structural- differ in structure

same chemical formula geometric-differ in spatial

relationship enantiomers-mirror images of

each other

Condensation Synthesis

A B+ A B + H2O

A and B could be monosaccharides or amino acids

Hydrolysis

+ H2O +

Addition of water breaks the bond

Polymers

Polymers are repeating units of monomers. They are very important to Biology.

They are made or synthesized by the removal of water called CONDENSATION SYNTHESIS

They are broken down by the addition of water orHYDROLYSIS

Classes of Biomolecules

• Carbohydrates- used for energy and structures( building living organisms)

• Lipids- used for energy storage, communication and structures

• Proteins- used for a variety of life functions

• Nucleic Acids-the instructions for building life

Carbohydrates

• Three common forms– Monosaccharides– Disaccharides– Polysaccharides

Carbohydrates

• Monosaccharides- single sugars or simple sugars,ex. Glucose ( C6H12O6)

• Disaccharides- double sugar, ex. Sucrose

• Polysaccharides- polymers of glucose such as: 1. Starch 2. Cellulose 3. Glycogen 4. Chitin

Review

• What will happen here?

AOH + HB = ?

And here:CH2OH CH2OH

OH

H

OH

OH

OH

OH

OH

OH

OH

O OH

H2O

Dehydration Synthesisor a Condensation Reaction

A + B = AB + H2O

CH2OH CH2OH

OH

OH

OH

OH

OH

OH

O OO

H2O

Review

• What will happen here?

AB + H2O = ?

And here:CH2OH CH2OH

OH

OH

OH

OH

OH

OH

O OH2O

O

Hydrolysis or Reaction

AB + H2O = AOH + HB

CH2OH CH2OH

OH

OH

OH

OH

OH

OH

O OOH

OH

Molecules have been HYDROLIZED!

GlucoseCH2OH

OH

H

OH

O

C

OH

OH

H

H H

H

Glucose has a chemical formulaof C6H12O6

CC

C

C

O

C

CC

C

CH2OH CH2OH

FRUCTOSE

HO H

OHOH

HH

Disaccharides

• Sucrose and Lactose

• 2 monosaccharides bonded together

CH2OH CH2OH

OH

OH

OH

OH

OH

O OO OH

Alpha or Beta?

Polysaccharides

• 3 or more Monosaccharides bonded togetherCH2OH CH2OH

OH

OH

OH

OH

OH

O OO

OH

OH

OH

CH2OH

O

O

Polysaccharide

• Starch-storage in plants

• Cellulose-structural part of plant cell wall

• Glycogen- storage in animals, liver

• Chitin – structural component for arthropods, exoskeleton. Also found in fungi.

Polysaccharides – Starch

• Plants use it as energy storage

• Difficult for humans to break down– Ex. Avoid a high starch diet

polysaccharides

Glucosemonomers

Polysaccharides – Cellulose(B 1, 4 linkage)

• Long fibers• Up to 15,000 Glucose units per strand• Most abundant biological substance on

earth– Ex. Cotton, Trees, Paper

• Why is cellulose so strong?• Why can’t humans breakdown cellulose

and cows can?

Polysaccharides – Glycogen

• Animals use it as energy storage

• Lots and lots of it in the liver

• Forms huge branched storage units which allow for easy break down for energy

Other polysaccharides

• Chitin– Found in the exoskeleton of insects, and

arthropods• Ex. Crabs, lobsters, grasshoppers

• Pectin– Found in plant cell walls– Provides rigidity

• Heteropolymers– Glycoproteins and peptidoglycans

ProteinPolymers of amino acids

With 20 natural amino acids thereare a variety of proteins

Amino AcidsThe building blocks of protein

N -C - CH

H

O

OH

H

R

R- there are twenty different R groups possible

Alanine

NH2-CH-COOH

CH3

Glycine

NH2-CH2-COOH

Peptide bond- is a bond between amino acidsa molecule of water is removed

Protein Structure

1. Primary- order of the amino acids2. Secondary- hydrogen bonds cause pleats and helix3. Tertiary- folds and loops create shape by R Group bonds4. Quaternary-interaction of several proteins

A protein with secondary structure

A protein with Tertiary Structure

Lipids

• Large molecules that do NOT have an affinity for water; not soluble in.

• May have hydrophobic-water fearing and hydrophilic-water loving parts.

Triglycerides

hydrophilic

hydrophobic

Types of Lipids

• Made of hydrocarbons - • Triglycerides- fats, waxes, and

oils(saturated all single bonds C-C, unsaturated have double C=C bonds

• Phospholipids- attached phosphate replaces one of the hydrocarbon tails

• Steroids- Ring Forms of Hydrocarbons cholesterol and some hormones

Triglycerides

• Saturated fats- single bonds make this a solid at room temperature and more difficult to digest.

Unsatured Fats

• Triglycerides that contain double bonds ( dehydrogenated) are liquids at room temp and more digestable

Nucleic Acids

• Made of monomers called nucleotides

• DNA- deoxyribonucleicacid

• RNA- ribonucleic acid

• These molecules carry all the hereditary information of living things

DNA Basic Composition

• DNA is made up of nucleotides

• Nucleotides are made of

…………...Deoxyribose sugar

……………Phosphate

……………Base

bases are guanine,cytosine, thymine and adenine

CATABOLISM

ANABOLISM

SYNTHESISRESPIRATION

ATP SYNTHESIS

FROM ADP + Pi

Free Energy

• Ability to do work in the cell or ecosystem.

Energy Transfer

• ATP formation

• + G

• ENDERGONIC

• Stores energy in phosphate bond

• ATP breakdown

• - G• EXERGONIC

• Releases energy between phosphates

Enzyme Characteristics

• Lower the activation energy

• Speed up the rate of a reaction

• Act as catalysts• Are proteins

(occasionally RNA)

Enzyme Characteristics

• Conformation or shape is most important feature ( Lock and Key Hypothesis)

• Substrate Specific

• Do NOT become part of reaction

Enzym

e activity.

pH7

Enzym

e activity.

pH7

Enzym

e activity.

Temperature o C10

Enzym

e activity.

Temperature o C10 30

Allosteric site

Active site

substrate

products

Enzyme

Cofactors• Non protein helpers for enzyme activity

• May bind to active site tightly or loosely

• Many are inorganic such as zinc or iron

• If organic they are called Coenzymes

Allosteric site

• Regulatory site other than the active site.

Enzyme

substrate

Enzyme-Substrate Complex

Competitive Inhibitor

Noncompetitive Inhibitor

inhibitor

Active conformation

Inactive form

activatorActive site

Allosteric Regulation

Allostericsite

inhibitor

Feedback inhibition

• Product may cause negative feedback (act to inhibit, disrupt conformation)

• Reactants may cause positive feedback ( act to preserve enzyme conformation)

Enzyme a Enzyme b Enzyme c

Endproduct

Initialsubstance

- feedback

Prokaryotic Cells

• Lack a nucleus

• Lack membrane bound organells

• Include bacteria and other Monerans

Eukaryotic Cells

• Have a nucleus

• Have membrane bound organells

• Plants, Animals, Fungi, and Protists have these cell types

Organells Membrane Bound ( endomembrane)NucleusEndoplasmic reticulum (rough)Endoplasmic reticulum ( smooth )Golgi apparatusLysosomeVacuolesVesiclesPeroxisome ( single membrane) MitochoindriaChloroplasts

Non membrane bound organellsNucleolusMicrotubulesMicrofilamentsCentriolesCiliaFlagella

Nucleus

• Chromatin- DNA organized with protein (histone)

• Controls Protein Synthesis• Double Membrane with pores may be continious with ER

• Nucleolus- made of and synthesizes RNA

Endoplasmic Reticulum

• Rough ER- contains ribosome for protein synthesis

• Smooth ER- lacks ribosomes, synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons

Muscle ER- calcium ion transfer

ER and protein synthesis and Transport Vesicles

• Export Proteins – become enclsed in vesicle of the ER Pinch closed

Especially secretory proteins ( glycoproteins )

E R..

Golgi Apparatus

• Manufacture, storage shipping , and packaging secretion products

• Cis

• Trans

• Vesicles

cis

trans

Phospholipids are amphipathic - have both hydrophobicand hydrophilic portions

hydrophilic

hydrophobic

Membrane Fluidity

• Unsaturated hydrocarbons in the phospholipids make it flow laterally

• Cholesterol maintains some rigidity at low temperatures and prevents too much fluidity at high

Membrane proteins

• Integral-penetrate into or through the lipid bilayer

• used for transport

• Peripheral protein- attach to the surface of the lipid layer

• used for- receptors, recognition(carbohydrates attached)

Permeablility

• What passes through easily

• Oxygen

• Carbon dioxide

• water

• What does not pass through easily

• ions

• proteins

• carbohydrates

Transport

• Passive• Requires no

expenditure of ATP• Moves from high to

low• Can be facilitative-

aided by protein conformation change

• Gatted channels

• Active• Requires ATP energy • Generally moves

from low to high• Gatted channels• Na-K pump• Proton Pumps• Phagocytosis or

Pinocytosis

Solutions

• Homogeneous-same throughout

• solvent- what you are dissolving into

• solute- what you dissolve

solution

*

SOLVENT

SOLUTE

*

* *

*

Hypertonic

.5M glucose .5M glucoseDistilled water1.5 M glucose

Water Balance

• Plasmolysis( plasmolyzed) plant cell shrinks or looses water

• Flacid -plant cell gains water and looses at same rate

• Turgid- Plant cell gains

Plasmolysis

• Membrane shrinks due to water loss

• Restricted to cells with walls

• Occurs in a Hypertonic environment

Facilitated Diffusion• Proteins make movement of polar

molecules, ions, or larger compounds possible by providing a passage.

• Often protein changes conformation

• NO ATP required

• Movement from high to low concentration

Active Transport

• Sodium Potasium Pump

• Proton pumps

Membrane Potential

• Voltage across a membrane

• -50 to-200 millivolts

• Electrochemical gradients- combination of ion potential and electric charge difference

Gated Channels

• Chemical or electrical impulses cause them to change shape-OPEN

Na-K Pump

• Membrane Potential-voltage difference across a membrane

• Chemical Gradient-difference in concentration of solute across a membrane

• Electro-chemical Gradient- combination of the above ex.

• Na+,K+, Cl-(8.13)

Exocytosis and Endocytosis

• Phagocytosis- engulf pseudopodia

• Pinocytosis- gulps

• Receptor mediated pinocytosis

Signal Transduction

• Binding of extracellular molecule to receptor protein see model on pg. 156 Campbell

Cell types determine cycle

• Prokaryotes- binary fission circular chromosome attaches to inner membrane. Replication is followed by reattachment at two sites.

• Eukaryotes-have a larger genome and nuclear genetic material must be carried on several chromosomes by specialized structures.

No spindle fibers

Can be Confusing?ChomosomesChromatidsSister chromatidsHomologous chromosomesCentromereCentrosomeCentriolesKinetochoreNonkinetochore

Chromosomes

DNA is continuous and wound around protein which is coiledand super coiled into a dark staining body.

Chromosomes can be seen as having two arms and often one is longer.

When duplicated the chromosome has identical sister chromatids held together at the centromere.

chromatid

centromereSister chromatid

Chromosome Number is fixed in each species

Diploid Number Monoploid (haploid)

2n n

46 in humans 23 in humans

Somatic Cells-bodycells

Gametes-egg, sperm, pollen.

Cell Cycle

Events in the growth, development andreproduction of the cell.

Go cells have stopped dividing or have lostthe potential to divide.

G1- gap or growth after cell division. Cell grows in size. this stage contains the RESTRICTION point

S- synthesis of new DNA from existing template(replication)

G2- gap 2 or growth prior to cell division

M- mitosis or chromosome division

C- cytokinesis or cell division

Interphase= G1, S, and G2

Control of Cell Cycle

Restriction point- go/no go control during G1

G0 - a non-dividing stage for a cell

Growth Factors-compounds which regulate growth and division. Ex.PDGF platelet derived growth factor

Density-dependent inhibition- crowding inhibits celldivision.Adhesiveness- cells ECM causes them to stick together

Metastasis-cells(cancerous) migrate

Cell Clock Regulators

• Proteins ( enzymes) regulate cell cycle

• Produced by internal cell clock genes

• Protooncogenes- cause cells to divide

• Tumor suppressor genes- prevent cell division

Cancer and the Cell Cycle

• Normal Cells

• Adhesive

• Contact inhibition

• Cancer cells

• Lost adhesiveness

• Lost contact inhibition

Principles of Heredity• Alternative versions of genes (alleles)

account for variations in a trait.• For each character, an organism inherits

two alleles, one from each parent.• If alleles differ, then the dominant will be

fully expressed over the recessive.• The two alleles segregate (separate)

during gamete formation.• Alleles on different chromosomes

segregate independently of one another

Crossing over

During prophase of meiosis homologous pairs may exchange

genetic material.

New Genetic Combinations

• Recombination during fertilization brings together two sets of genetic instructions

• Meiosis-crossing over brings about new combinations

• Random genetic mutation can result in random genetic change

Electron CarriersNAD+ nicotinamide adenine

dinucleotide

NAD+ When oxidized

NADH +2 H+ When reducedFAD or FADH2

Types of Respiration

• Anaerobic-without oxygen 1. Alcoholic fermentaion 2.Acetic Acid fermentaion 3. Lactic Acid fermentaion

• Aerobic-with oxygen

• ALL OF THESE BEGIN WITH THE ANAEROBIC PROCESS OF GLYCOLYSIS

GLYCOLYSIS

Glucose is made ready to metabolize by addition of phosphates and then it is broken down into 2- 3 carbon compounds (PYRUVATE)

This yields a net gain of 2 ATP

ACETYL COA FRORMATION

• Pyruvate is converted into a 2 Carbon compound and added to an enzyme

• CO2 is released

Kreb’s Cycle

• Breaks C-H-O bonds• Energy is transferred via carriers

to other steps• CO2 released• Some small amount of ATP is

produced

Electron Transport

• Hydrogen Pathway- pumps H ions

• Electron Transfer

• Chemiosmosis- H ions flow through ATP syntase proteins to make ATP from ADP + P

Substrate level phosphorylation

• ATP is formed as a direct transfer of

electrons from the substrate to as ADP + P ATP

Oxidative phosphorylation

• Electrons made available in metabolism are transferred to oxygen and ATP is produced in the process. Chemiosmosis

Fermentation generates ATP by substrate level phosphorylation.It is anaerobicThree Types:

Alcoholic-

Lactic Acid- 2NAD+2Lactate

2 Ethanol +2CO2+NAD

Photosynthesis

CO2+H2O light CnH2n0n+O2

Light- measured as an absorption spectrum, the wavelengths that are most important are different for different types of autotrophs

light

PS1

PS2

Calvin CycleCalvinCycle

ATP

NADPH

Photolysisand Photophosphorylation

O2 CnHnOn

CO2H2O

Thylakoid

Stroma

Light rxn. Dark rxn.

Visible Spectrum

Absorbed Absorbed680-700

Reflected

Chl a

Photosystem I P700

700nm LIGHT

Primary acceptor

pq

pc

Cytochromecomplex

Photosystem IIP680

NADP+ + 2H

NADPH

680nm

-e

Photosystem I

• Also known as P700-receives electrons from those released in PSII to replace photoexcited electrons uses light at far end of the red wavelength

• PSI 700• PSII 680 the II in PSII H2O

Photosystem II• P680• due to an association with different

proteins • this system utilizes different

wavelengths• causes water to split capturing it’s

electron• it then transfers the electron to

PSII chlorophyll molecules

Noncyclic Electron FlowWater is split (photolysis) and electrons pass continuously from water to NADP+.Primary electron acceptors pass photoexcited electron to the electron transport chain(Pq), (Pc), cytochromes..

Generates O2, NADPH, and ATP

Uses both PSI and PSII

Cyclic Electron Flow

Excited Electrons pass through the electron transport chain from P700 (PS I ) and return to the starting point.Uses only PSI

Only ATP is generated

Calvin Cycle

6ATP

3ATP

3ADP

6ADP

6NADPH

6NADP

3CO2

G3P--GlucoseRegeneration RuBP

Carbon Fixation

rubiscoRuBP

Photorespiration

CO2 can act as a limiting factor.In cases where there is not sufficient Carbon dioxide plants will combine oxygen with RuBP to form compoundsthat are broken down into CO2

Adaptations for Photosynthesis

• C4 Plants• CO2 is added to PEP

phosphophenolpyruvate

• stored in BUNDLE SHEATH CELLS near veins of leaf

• example- Corn

• CAM plants

• in hot dry areas plants must close stomates

• CO2 taken in at night is stored as an acid

Discovery of DNA1. Frederick Griffith

– Was studying Streptococcus Pneumonia– Smooth vs. Rough Strains– Smooth had a mucous coat and were

pathogenic (caused pneumonia)– Rough were non-pathogenic– Conducted an experiment with mice– Found out that the Rough bacteria

became transgenic

Discovery of DNA2. Avery, McCarty and MacLeod

– What was the genetic material in Griffith’s experiment?

– Purified the heat–killed S-bacteria• Into DNA, RNA, and Protein

– Mixed each with the R cells to see which one transformed

Discovery of DNA3. Hershey-Chase Experiment

– Studied viruses that infect bacterial cells– Bacteriophages– Protein or DNA responsible for take-charge

actions of the virus?– Tagged the Protein with radioactive S

• Why?

– Tagged the DNA with radioactive P• Why?

The Structure of DNA:a double helix?

• Chargaff’s Nucleic Acid Ratios1. Measured the base compositions of

several species

2. Percentage of each base present• Human DNA

1. A = 30% and T = 29%

2. G = 20% and C = 19%

• Rosalind Franklin and Maurice Wilkins use X-Ray diffraction to view structure

• Watson and Crick propose a double helix using their X-Ray pictures

The Structure of DNA:a double helix?

DNA Double Helix

DNA: Three Parts

• DNA is made up of nucleotides

• Nucleotides are made of– Deoxyribose sugar– Phosphate– Base

• Guanine, Cytosine, Thymine and Adenine

DNA: The Deoxyribose Sugar

DNA: The Phosphate

DNA: The Nitrogenous Bases

• Purines• Adenine and Guanine • Double Ring Structure

• Pyrimidines• Thymine and Cytosine• Single Ring Structure

Single Stranded DNA

Nucleotides can only be added to the 3’ endof the nucleotide and therefore addition ofnew nucleotides is always 5’-----> 3’

DNA is anti-parallel!!

DNA STRUCTURE

How does it know to pair up?

• ADENINE ALWAYS PAIRS WITH THYMINE

• Two hydrogen bonds

• GUANINE ALWAYS PAIRS WITH CYTOSINE

• Three hydrogen bonds

Why do they pair up?

• Double helix had a uniform diameter

• Purine + Purine– = too wide

• Pyrimidine + Pyrimidine– = too narrow

• Purine + Pyrimidine– = fits the x-ray data

One last look

Why does it twist?

DNA Replication

Meselson-Stahl demonstrate theSemiconservative Replication of DNA using radioactive nitrogen

Why must DNA Replicate?

•Species Survival– DNA must replicate BEFORE cell

division•Synthesis during Interphase

•All genes must be present in the daughter cells

Origins of Replication

• Sites along DNA that contain specific nucleotides are recognized by specific proteins that initiate process

• In eukaryotes there are hundreds of thousands of such points

• Form replication bubbles

How does DNA Replicate?

• Hydrogen bonds break, forming bubbles• Enzymes unwind and unzip• Free nucleotides in the nucleus start

process of complementary base pairing• Nucleotides are fused together by DNA

Polymerase only 5’ to 3’• Results in two identical double helixes

Replication Steps• DNA helicase enzymes open double

strand• DNA uncoils and unzips exposing the

DNA template • Primase adds a RNA primer as binding

proteins hold strands together• DNA polymerase attaches to template at

replication fork• Nucleoside triphosphates add bases

pairing A-T and G-C as new strand is added to a 3’ end, primer removed

replication3

How does DNA Replicate?

How does DNA Replicate?

Leading Strand is Continuous

• A single RNA primers initiates the addition of nucleotides to the 3’ end of the leading strand

Lagging Strand

• Must wait for replication fork to open and then add primer

• Form Okazaki fragments

• RNA is removed only after addition of about 100 to 200 nucleotides

• Fragments are joined by a ligase enzyme ( DNA glue)

DNA Replication

The result

• DNA Replication results in TWO double helixes. DNA unwinds and unzips, and new daughter strands form, each complementary to an old parental strand.

RNA - Structure• “Ribonucleic Acid” – different from

DNA• Always Single Stranded• Ribose Sugar Base Unit• Phosphate group (same in DNA)• Nitrogenous Bases

– Cytosine always pairs with Guanine– BUT! Adenine always pairs with

URACIL• (different in DNA!!!!!)

Four kinds of RNA

• Ribosomal RNA

• Messenger RNA

• Transfer RNA

• snRNA ribozyme in spliceosome

rRNA

• Ribosomal RNA or rRNA • represents about 70% of cellular RNA

• joins with Ribosomal proteins to make the cellular organelle: RIBOSOMES

• FUNCTION – As a manufactured ribosome, supplies a location for tRNA to join with mRNA to synthesize a protein

mRNA2. Messenger RNA or mRNA

• represents about 10% of cellular RNA • contains the sequence of bases coding for

a particular amino acid sequence in a polypeptide chain

• removal of non-coding, internal sequences (introns)

• modification of the 5' base (cap)• addition of adenines to 3' end (poly A tail)

FUNCTION – reads the DNA code (base sequence) and becomes a copy that is read at the ribosome to make a protein

hn RNA

• Pre-mRNA contains introns-non-coding regions as well as exons-coding regions

Processing mRNA

• Deletion of introns

• Join exons

• Add cap ( GTP) and poly A tail

RNA splicing

• Spliceosome-several

snurps• snRNPs small nuclear

Ribonucleoproteins-splicing enzyme( cuts and glues)

Transcription• DNA unzips at the locus of the gene

being coded• mRNA makes a copy of the gene

• Then…• mRNA is enzymatically modified

– A cap and a tail are added

• it then leaves the nucleus and finds a ribosome (composed of rRNA and protein)

tRNA• Transfer RNA or tRNA

• represents about 20% of cellular RNA • each tRNA molecule is specific for one

amino acid • there is an enzyme for each amino acid

which recognizes the amino acid and its specific tRNA and joins the two together

• the specific joining of tRNA to amino acid is the only place where the “genetic code" applies

FUNCTION – Pairs with Amino Acids and delivers them to ribosomes at the right time to synthesize a protein

Protein Synthesis

• Why should cells do this?– Cells would not be able to grow and change without

proteins.– Proteins are found everywhere:

• As enzymes, cell membranes, muscles, heart, blood…

• What happens when proteins are not made correctly or not made at all?– Ex. Cystic Fibrosis

• What part of DNA holds the code for the protein?

PROTEIN SYNTHESISEveryone is involved

• Transcription

DNA, mRNA

• Translation

mRNA, rRNA and tRNA

Pre-Translation

• mRNA binds to the ribosome

• Meanwhile, tRNAs are attaching to their amino acids using tRNA Transferase

• Free tRNAs, with their amino acids attached, circulate in the cytoplasm and match up with the triplet codes in the mRNA

TranslationInitiation• The first tRNA enters the ribosome at the A

site• The second tRNA enters the ribosome (at the

P site) and the amino acids are bonded together = PEPTIDE BOND

Elongation• Both tRNAs shift in one direction and make

room for the next tRNA to enter the ribosome• this pattern continues until the protein is

complete

Termination• Stop codon is read – UAA, UAG, UGA

http://gslc.genetics.utah.edu/basic/firefly/index.html

Quick DefinitionsA-site – aminoacyl-tRNA binding siteP-site – peptidyl-tRNA binding siteTriplet code – DNACodon – RNAAnti-codon - tRNAIntrons – removed from initial mRNAExons – bonded together to make the

finished mRNA product for translationPolyribosomes – more than one ribosome

reading the mRNA at one time

Codons and anti-codonsTriplet code on DNA TACmRNA copies it: CODON AUGtRNA carries the ANTICODON UACThe Genetic code reads the codon

AUG, the amino acid: Methionine

• 45 different anti-codons exist• AUG is always the initiation codon• GTP supplies energy needed to synthesize

protein• initiator tRNA always carries Methionine first!• Initiation factors - proteins that bring all parts

together (mRNA, small subunit, large subunit, and tRNAs)

Genetic Code

• Interprets what the DNA triplet code reads

• Is written in both DNA base language A, G, C, T or RNA base language A, G, C, U

• Determines the order for Amino Acids

• Is universal within all species

• Reads the same as the anti-codon (on tRNA) except T is now U

Genetic Code

Gene RegulationControl of gene expression occurs at four levels in

human cells:Transcription and posttranscription control

(nucleus)Translation and posttranslation control (cytoplasm)• Various cells express different genes• Genes can be turned on or off• Genes respond to activity outside of the cell• Control of transcription is most important

regulatory mechanism (binding factors and enhancers) Presence of TF determines specialization

• Some binding factors are sensitive to hormones

DNA Technology

• Biotechnology or genetic engineering – the use of natural biological systems to produce a product desired by human beings

• Examples include:• Gene Cloning• DNA Amplification• Transgenic Organisms• Gene Therapy• Chromosome Mapping and Sequencing

Gene Cloning

Gene Cloning• Recombinant DNA – DNA from two different

sources (human and E. coli)• Plasmid – circular DNA used to transport the

gene into the organism• Enzymes needed – Restriction and Ligase• Host cell – usually bacteria, wall must

become competent in order for the bacteria to uptake the plasmid

• Restriction enzyme cleaves DNA and allows for DNA fragment to insert at the sticky ends

• Vector – method of transporting a gene (virus, plasmid)

pVIB lux genes

2 genes to produce LUCIFERASE

Aldehyde (energy source) synthesis

several genes

Regulatory genes to turn of and on

DNA Amplification

Polymerase Chain Reaction – PCR

• Used to make multiple copies of the same gene

• Copies can be examined to see if they match any other sources

• Prevents constant extraction from the organism and better results

Other Technologies• Recombinant DNA - gene

splicing

• Transgenic organism- an organism that contains another organism’s DNA

Transgenic Organisms

• Transgenic – possessing gene(s) from another organism

• Gene Pharming – Using transgenic farm animals to produce pharmaceuticals

ex. CF, cancer, blood clots

• Genetically altering crops to be resistant to insects and produce larger

http://biology.about.com/science/biology/gi/dynamic/offsite.htm?site=http://abcnews.go.com/sections/science/DailyNews/gmcorn%5Fbutterflies000821.html

• Suicide Genes• Insulin

Gene Therapy

• Delivering the defective gene to the cells that need it to produce a protein

• Familial hypercholesteremia

• SCID – severe combined immunodeficiency syndrome (missing maturation enzyme for T and B cells)

Chromosome Mapping

• 100,000 human genes

• RFLPs – Restriction Fragment Length Polymorphisms – used to probe a region of DNA – visible under a microscope

• Restriction enzymes – sequence AA

• Specific base digestion– CF LAB

Human Genome Project

• HGP – due for completion in 2002

• Already sequenced the Fruit Fly and E. Coli

Gene Therapy

• Delivering the defective gene to the cells that need it to produce a protein

• Cystic Fibrosis

• Vector – method of transporting a gene (virus, plasmid)

– Mechanical - usually a laboratory tool used (inoculating loop)

– Biological - part or whole of an organism (bacteria)

Chromosome Mapping

• 30,000 human genes

• RFLPs – Restriction Fragment Length Polymorphisms – used to tag a region of DNA – visible under a microscope

• Restriction enzymes – sequence AA

• Specific base digestion

Sanger Method of DNA Sequencing1. Heat DNA Strands until they separate2. Add nucleotides and DNA Polymerase3. Add Dedeoxynucleotides (A, T, G, and

C) at different time periods to stop replication

4. Place fragments in to Gel Electrophoresis

5. Allow to migrate and read the Base Sequence

Electrophoresis

Human Genome Project

• HGP – due for completion in 2002

• Already sequenced the Fruit Fly and E. Coli

• The ultimate goal of HGP is to associate human traits and inherited diseases with particular genes.

• It promises to revolutionize both therapeutic and preventive medicine techniques for many human diseases.

Human Genome Project

• Genome - the complete collection of an organism's genetic material.

• The human genome is composed of an estimated 30,000

• A single human chromosome may contain more than 250 million DNA base pairs, and it is estimated that the entire human genome consists of about 3 billion base pairs.

DNA Fingerprinting

• Treat suspects’ blood with the same restriction enzyme

• Place sample in Gel Electrophoresis• Allow samples to migrate• Compare the suspects with the blood

found at the crime scene• Used in Criminal Trials: OJ Simpson

– OJ – DNA was an exact match yet he was found not guilty?