AP Biology Semester 1

5 unifying characteristics of all cells

1. Cell membrane

2. DNA

3. Cytoplasm

4. Ribosomes

5. Same gene --> protein pathway

Surface Area : Volume ratio

Determines the efficiency at which cells can transport necessary materials and eliminate wastes

SA:V ratio (small cells)

High SA:V ratio --> higher efficiency in transport

(lots SA : less V)

SA:V ratio (large cells)

Low SA:V ratio --> lower efficiency in transport

(less SA : lots V)

Adaptations to increase SA:V ratio - located along all levels of biological organization

(lots of SA)

1. Branching (root systems, neurons, lungs)

2. Projections (ileum - small intestines, root hair)

3. Flattening (golgi app., chloroplasts, flatworms)

4. Folding (rough ER, mitochondria, small intestine)

Prokaryotic Cells: Evolution

1st to evolve (3.5 bya)

Prokaryotic Cells: Classification

Bacteria

Archeabacteria

Prokaryotic Cells: Size and complexity

Small, simple internal network

Cell wall

Shape

Prokaryotic Cells: DNA

Single circular chromosome (tightly packed into nucleoid, free in cytoplasm) (plasmids - ring of DNA, accessory gene)

Prokaryotic Cells: Image

What does the Theory of Endosymbiosis explain?

The evolution of eukaryotic cells on a prokaryotic planet.

What is the relationship between two prokaryotic cells in the Theory of Endosymbiosis?

They live together and benefit one another.

What organelles in eukaryotes are thought to have originated from prokaryotic cells?

Mitochondria

Chloroplasts

What are some characteristics of mitochondria and chloroplasts?

They have their own DNA

Own ribosomes

Double membrane

Can reproduce on their own - semi-autonomous.

Eukaryotic Cells: Evolution

2nd to evolve (2.5 bya)

Eukaryotic Cells: Classification

Protista

Fungi

Plants

Animals

Eukaryotic Cells: Size and complexity

Large - can form multicellular organisms

Shape/function of each cell is unique

Eukaryotic Cells: DNA

Multiple, linear chromosomes

Nucleus - surrounded by nuclear envelope

Eukaryotic Cells: Image

Endomembrane Network - true membrane-bound organelles

Compartmentalization - different locations for different reactions promotes organelle specificity and efficiency

Materials localized

Increased rate of reactions

Complexity for the cell itself & the cell's role in multicellular organisms

Metabolism

Obtain and use materials - ENERGY - chemical reaction

Homeostasis

Maintain a stable internal environment

heredity (DNA —> protein)

Store, use, copy, & transfer genetic info

METABOLISM: Chloroplasts

Perform photosynthesis - 6CO2 + 6H2O --> C6H12O6 + 6O2

Generate glucose

Compartments increase SA

METABOLISM: Mitochondria

Perform cellular respiration - C6H12O6 + 6CO2 --> 6CO2 + 6H2O + ATP

Generate ATP

Folding increase SA

METABOLISM: Chloroplasts and mitochondria are evidence of endosymbiosis

1. Own DNA

2. Own ribosomes

3. Double membrane

4. Reproduce on own

METABOLISM: Chloroplasts and mitochondria are examples of

Compartmentalization - localized function (decrease V = increase rate of reaction)

Increased surface area - flattening & folding

HOMEOSTASIS: Cell membrane

Plasma membrane - flexible membrane through which cells transport materials + communicate with other cells

HOMEOSTASIS: Cell wall

Rigid barrier - support & structure (plants, fungi, bacteria, & same protists)

HOMEOSTASIS: Vacuole (membrane)

HOMEOSTASIS: Central vacuole (membrane)

Storage - water, pigment, starch, sugar

H2O maintains turgor pressure

HOMEOSTASIS: Lysosome (membrane)

Waste breakdown - contains digestive enzymes - recycles old organelles and pathogens

HOMEOSTASIS: Cilia (surface projections)

Many short - move from place to place & move across a surface

HOMEOSTASIS: Flagella (surface projections)

Few long - moves from place to place

HOMEOSTASIS: Smooth

Lipid synthesis, detoxification, no ribosomes attached

HEREDITY

DNA to protein production pathway. Proteins, polypeptides regulate all cellular processes

HEREDITY: Nucleus

Stores DNA in eukaryotic cells. Site of transcription (DNA --> mRNA)

HEREDITY: Ribosome

Uses mRNA code to build a polypeptide chain of amino acids. Can be free-floating or attached to rough endoplasmic reticulum.

HEREDITY: Rough ER

Polypeptide folding into 3-D shape.

HEREDITY: Golgi apparatus

Packages and labels proteins for export to other cells

HEREDITY: Vesicle

Exports proteins via exocytosis

Binary fission

Bacteria reproduction

Mitosis

Asexual reproduction, growth, matinence, repair

Meiosis

Sexual reproduction from gametes like sperm & egg

Centrioles

Only in eukaryotic animal cells. Organize chromosomes during cell division

Covalent bonds – sharing a pair of valence electrons

Holds molecules together

Strongest

Holds the most potential energy, difficult to break

Solid line between atoms or two atoms together

Nonpolar covalent

No partially charged end

Nonpolar - Hydrophobic (water fearing)

EX: oils

Polar covalent

One atom in the bond is more electronegative - attracts electrons more than others

Polar - Hydrophilic (water loving)

Leads to hydrogen bonding

Ionic bonds - attraction between ions

Ions - atoms that have a charge based on the loss or gain of electrons

Not as strong as covalent bonds

Hydrogen bonds – attraction between polar molecules and their partially charged ends

Reversible - form, break, and re-form

Weaker

These are the bonds that break when H2O boils

Results from polarity & lead to all properties of H2O

Polar molecule

Unsharing of a pair of valence electrons "sticky"

Cohesion

H-bonds form between 2 or more H2O molecules

Surface tension - caused by H-bonds

Adhesion

H2O forms H-bonds with another substance/surface

Capillary action

Movement of water up a narrow tube

Universal solvent

Dissolves other polar charged substance

Density of ice

Water is less dense when it is frozen

High specific heat

Resists change in temperature (homeostasis)
Moderate Earth's temperature
Moderate organisms temperature

High heat of vaporization

The amount of heat 1g of water must absorb to change from liquid to gas

Evaporative cooling

As water evaporates, the surface cools

Chemical equilibrium

The point at which reactions offset one another

H2O molecules image

Living systems are approximately __% water and __% biomolecules

71

29

Monomer

One single subunit
EX: monosaccharides, fatty acids, amino acids, nucleotides

Polymer

Many subunits
EX: carbohydrates (polysaccharides), lipids, polypeptides/protein, nucleic acid (DNA/RNA)

Dehydration synthesis

Monomer --> polymer
- Removal of H2O to form a new covalent bond
- Coordinated by enzymes - proteins specifically shaped to catalyze reactions

Hydrolysis

Polymer --> monomer
- H2O "added" to break the covalent bond between subunits in polymer
-Coordinated by specific enzymes

Macromolecules

Made of C, H, O, N

4 groups of macromolecules

1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic acids

CARBOHYDRATES (polar): Atoms

CH2O
- Ratio 1:2:1
EX: Glucose (C6H12O6), Fructose (C5H10O5)

CARBOHYDRATES (polar): Monomer

Monosaccharide

CARBOHYDRATES (polar): Polymer

Disaccharide
Polysaccharide

CARBOHYDRATES (polar): Functions

1. Energy supply - sugar used in cellular respiration to make ATP
2. Energy storage - short-term & accessible
3. Structure - cell wall in plants & fungi

CARBOHYDRATES (polar): Common structure image

CARBOHYDRATES (polar): Monosaccharide?

A simple sugar, such as glucose, which has the formula C6H12O6 and is used to make ATP.

CARBOHYDRATES (polar): Disaccharide?

A carbohydrate formed from two monosaccharides, such as sucrose (table sugar) and maltose (two glucose monomers).

CARBOHYDRATES (polar): Polysaccharides?

Carbohydrates that consist of long chains of monosaccharides, such as starch and glycogen.

CARBOHYDRATES (polar): Starch?

A polysaccharide found in plants, consisting of a linear chain of glucose with a single point for hydrolysis.

CARBOHYDRATES (polar): Glycogen?

A polysaccharide found in animals, consisting of a branched chain of glucose with many points for hydrolysis, which increases the release of glucose.

CARBOHYDRATES (polar): Cellulose?

A polysaccharide found in the cell wall of plants
Linear chain of glucose

LIPIDS (nonpolar): Atoms

C H O
High amount of C-H

LIPIDS (nonpolar): Monomer

Fatty acids

LIPIDS (nonpolar): Polymer

Not true polymer - growth is finite

LIPIDS (nonpolar): Saturated fatty acid (animal)

- Each carbon is full of hydrogen
- Linear shape = allows fatty acids to pack tightly together
- Solid at room temp - high melting point

LIPIDS (nonpolar): Unsaturated fatty acid (plants)

- Have one or more C=C (double-bonded C)
- Double bond adds a bend to fatty acid - decreases tight packing (space between molecules)
- Liquid at room temp - low melting point

LIPIDS (nonpolar): Functions

1. Energy storage
2. Protection = warmth, waterproofing
3. Structure - cell membrane
4. Communication

LIPIDS (nonpolar): Triglyceride

Glycerol + 3 fatty acids (energy storage in C-H

LIPIDS (nonpolar): Phospholipid

- Cell membrane
- Fatty acid tails
- Combine saturated and unsaturated

LIPIDS (nonpolar): Steroid

- Fatty acid folded into 4 rings
- Cholesterol
- Hormones (estrogen, testosterone, progesterone

PROTEINS: Atoms

C, H, O, N

PROTEINS: Monomer

Amino acid

PROTEINS: Polymer

Polypeptide

PROTEINS: Functions

1. Enzymes - a catalyst in a chemical reaction
2. Structure
3. Carrier/transport
4. Cell communication - signals/receptors
5. Defense
6. Movement

PROTEINS: Primary structure

- Found in ribosomes
- Linear polypeptide - chain of amino acids coded in DNA

PROTEINS: Bonds in primary structure

- Covalent bonds - dehydration synthesis
- Peptide bonds between amino acid backbone (strongest)

PROTEINS: Secondary structure

Repeatedly coiled and folded polypeptide chains
- Found in RER
- Within a small section of polypeptide
- Local folding
- Beta pleated sheet or Alpha helix

PROTEINS: Bonds in secondary structure

H-bonds between N-C-C backbones

PROTEINS: Tertiary structure

Overall structure of a polypeptide resulting from the interaction between side chains and amino acids
- Whole polypeptide folding
- Distant amino acids interact
- 3-D form

PROTEINS: Bond in tertiary structure

Bonds dependent on R group
- Covalent bond on disulfide bridge (S-S) (strong)
- Ionic bond - attraction between acidic (-) and basic (+) amino acids (weak)
- Hydrogen bonds ( OH---H)

PROTEINS: Quaternary structure

Overall structure that results from the aggregation of these polypeptide units
- Multiple polypeptides bind together

PROTEINS: Bonds in quaternary structure

Bonds vary

PROTEINS: Amino acid groups

Connected to the N-C-C backbone
1. Amino group
2. Carboxyl group
3. R group