UNIT 1: WELLNESS & HOMEOSTASIS

Biology notes 1Mr.Yeung

WHAT IS UNIT 1 ABOUT?Wellness & Homeostasis

• 0. Wellness (Reading labels/homeostasis/serving size)

• 1. Cell Biology (Ch.3)

• Cell organelles

• Cell types

• 2. Membrane structure and Function (Ch.4)

• 3. Metabolism and Energy (Ch.6)

• ATP

WHAT DO YOU KNOW ABOUT THE HUMAN BODY?• Take each of the organs, tissues, cells, parts of the body

and arrange them in their appropriate locations.

CONCEPT MAP OF THE UNIT

Understand Apply

Relate

Read

Cells

Energy

Cell origins

InstrumentsProkaryoticEukaryotic

Cell theory

Types of microscopesOrganelles

Membrane

Enzymes

Diffusion

Do this!

1. Grab a slide and place a drop of methylene blue on it.2. Take a toothpick and rub it against the insides of your

cheeks (don’t do it too hard!)3. Stir the end of the toothpick into the methylene blue4. Cover the drop with a cover slip5. Place under the microscope and observe

WHAT DID YOU JUST SEE?

Now… imagine that you are living the 16th century.

What can you tell people what you just saw?

http://www.bbc.co.uk/staticarchive/742e4ca780f38fc30d7f645838936c65b92c744f.jpg

More importantly, how do you prove and justify your points?

In  the  past:Spontaneous  genera0on

•Since Aristotle’s time (4 B.C), there was an belief that cells magically appeared.

•Eg) Leave meat out and you’ll get maggots

•This was proved not true by (1765 - 1767), Lazzaro Spallanzani

What is a cell?

The smallest functional and structural living unit of life

What does that mean?If we were to break down an organism to the

smallest living part, you will see cells.

Red blood cellsNerve cells

Plant Cells

WHERE DO CELLS COME FROM?

Cell theory1.All living organisms are composed of one or more cells

2.Cells are the basic functional and structural unit of an organism.

3.All cells must come from pre-existing cells!

1. Use energy 3. Control functions2. Sense the environment

5. Eliminate wastes4. Build and repair

6. Reproduce

Life’s requirements for survival Keep the 6 requirements in mind to fully

understand and appreciate cell biology

CELL TYPES

Eukaryotic Cell Prokaryotic Cell

Can be both unicellular or multicellular Unicellular

Lacks a membrane-bound nucleusContains a nucleus (with red blood cells as an exception)

Bacteria are prokaryoticAnimal cells, plant cells, fungi and protists are eukaryotes

Eukaryotic Cell

Prokaryotic Cell

PROKARYOTIC CELLS• Pro - “before” Karyote - “nut

or kernal”, prokaryotic cells are thought to have existed before eukaryotic cells

• They lack a true membrane-bounded nucleus.

• Contains a cell wall containing peptidoglycan, an unique molecule for bacteria, made from sugar molecules joined together.

A plasma membrane still exists

PROKARYOTIC CELLS

• The peptidoglycan is a key component in designing antibiotics.

• A capsule further surrounds the cell wall containing a slime layer.

Prokaryotic cells’ locomotion

• Contains a long tail called flagella to help bacteria move.

• Some contains a fimbriae that are tiny “arms” that stick out to attach to surfaces.

PROKARYOTE’S GENETIC MATERIAL

• Contains a single chromosome in the nucleiod (not surrounded by membranes).

• Contains plasmids which are small rings of DNA.

• Smaller ribosomes for protein synthesis.

PROKARYOTE CELL SUMMARYStructure & Locomotion

• cell wall with peptidoglycan and capsule

• flagella for locomotion

• fimbriae for attachement

Genetic storage

• 1 chromosome (circular DNA)

• located in nucleoid in cytoplasm

• contains plasmids but not restricted to prokaryotes

EUKARYOTIC CELL

ORGANELLES

• Review of organelles:

• Nucleus (Nuclear membrane, nucleolus,)

• Cytoplasm

• Mitochondria

• Vacuoles

• Ribosomes

• Endoplasmic reticulum (Rough & Smooth)

• Golgi apparatus

• Lysosome

• Cilia

• Cell membrane

CELL MEMBRANE (CH.4)Key Points:

•Determines what can come in and leave the cell.

•Contains a phospholipid bilayer

•Two layers with a “head” near the surface and “tail” inside the bilayer.

•The “head” portion is hydrophilic (water loving) while “tail” is hydrophobic (water fearing)

•Proteins are scattered around the membrane

More info on the cell membrane in the next chapter

NUCLEUS

Key points:

· Function: control center of cell

· Contains DNA

· Surrounded by double membrane (nuclear envelope)

· Continuous with the rough ER

· Nuclear pores: control what enters/leaves nucleus

· Chromatin: complex of DNA + proteins; makes up

chromosomes

· Nucleolus: region where ribosomal subunits are formed

RIBOSOMESKey  Points:  Func0on:  protein  synthesis  Composed  of  rRNA  +  protein  Large  subunit  +  small  subunit  

Types:  Free  ribosomes:  float  in  cytosol,  

produce  proteins  used  within  cell  

Bound  ribosomes:  aFached  to  ER,  make  proteins  for  export  from  cell

The next 3 organelles are classified as the Endomembrane system- collectively functions as a regulatory system for proteins and

metabolism

ENDOPLASMIC RETICULUM (ER)What  it  is:    Network  of  membranes  and  sacs  

Types:  Rough  ER:  ribosomes  on  surface  

Func0on:  package  proteins  for  secre0on,  send  transport  vesicles  to  Golgi,  make  replacement  membrane  

Smooth  ER:  no  ribosomes  on  surface  Func0on:  synthesize  lipids,  detox  drugs  &  poisons,  store  Ca2+

GOLGI APPARATUSFunc<on:  synthesis  &  packaging  of  materials  (small  molecules)  for  transport  (in  vesicles);  produce  lysosomes  

Series  of  flaFened  membrane  sacs  (cisternae)

LYSOSOMEFunc<on:  intracellular  diges0on;  recycle  cell’s  materials;  programmed  cell  death  (apoptosis)  

Contains  hydroly<c  enzymes

VACUOLESFunc<on:  storage  of  materials  (food,  water,  minerals,  pigments,  poisons)  

Membrane-­‐bound  vesicles  Eg.  food  vacuoles,  contrac0le  vacuoles  

Plants:  large  central  vacuole  -­‐-­‐  stores  water,  ions

MITOCHONDRIAFunc0on:  site  of  cellular  respira.on  Double  membrane:  outer  and  inner  membrane  

Cristae:  folds  of  inner  membrane;  contains  enzymes  for  ATP  produc0on;  increased  surface  area  to    ATP  made  

Matrix:  fluid-­‐filled  inner  compartment

CILIA AND FLAGELLA

Flagella:  long  and  few;  propel  through  water  Cilia:  short  and  numerous;  locomo0on  or  move  fluids  

Endosymbiont theory

The Theory on how the first

Eukaryotic cell started

·Mitochondria & chloroplasts

share similar origin

·Prokaryotic cells engulfed by

ancestors of eukaryotic cells

·Evidence:

·Double-membrane structure

(mitochondria)

·Have own ribosomes & DNA

·Reproduce independently

within cell