AP BIO Semester 1

How do hydrogen bonds form?

negative oxygen end of one water molecule is attracted to the positive hydrogen end of another water molecule; responsible for most properties of water

cohesion

Attraction between molecules of the same substance

adhesion

An attraction between molecules of different substances

capillary action

the combined force of attraction among water molecules and with the molecules of surrounding materials

high specific heat

A property of water. Water can absorb lots of heat before changing temperature

water is less dense as a solid

ice expands as it freezes so it floats

hydroxyl group

OH-

carbonyl group

C=O

carboxyl group

COOH

amino group

NH2

phosphate group

PO4

dehydration synthesis

A chemical reaction in which two molecules are bonded together with the removal of a water molecule.- makes polymers

Hydrolysis

A chemical process that splits a molecule by adding water. breaks down polymers

monomer of carbs

monosaccharides

monomer of lipids

glycerol and fatty acids

monomer of protein

amino acid

monomer of nucleic acids

nucleotides

examples of carbohydrate polymers

starch, cellulose, glycogen

examples of lipid polymers

Triglycerides, Phospholipids, Steroids,

examples of nucleic acid polymers

DNA and RNA

example of protein polymer

polypeptide

what determines the primary structure of a protein

sequence of amino acids

secondary structure of protein

coils and folds due to the hydrogen bonding within the polypeptide backbone

tertiary structure of protein

3D folding due to interactions between the side chains of the amino acids

quaternary structure of protein

results when a protein consists of multiple polypeptide chains

components of a nucleotide

nitrogenous base, phosphate, pentose sugar

how are DNA and RNA different

DNA: deoxyribose, double strand, and thymine

RNA: ribose, single strand, and uracil

Differences between prokaryotic and eukaryotic cells

Prokaryotes- no nucleus (DNA found in nucleoid region), no membrane bound organelles, smaller, one circular chromosomes, bacteria. Eukaryotes- nucleus, organelles, larger, many linear chromosomes, plants and animals

path of protein to final product

mRNA produced in nucleus-- ribosome-- Rough ER-- Golgi-- Vesicle

ribosome

Makes proteins

rough ER

A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm; covered with ribosomes that make membrane proteins and secretory proteins.

Smooth ER

makes lipids and detoxifies the cell

Golgi

A system of membranes that modifies and packages proteins for export by the cell

Lysosome

cell organelle filled with enzymes needed to break down certain materials in the cell

vacuole

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

mitochondria

breaks down glucose into ATP

chloroplast

converts sunlight into glucose

what happens to the surface area to volume ratio as a cell grows?

decreases

Do you want a large or small SA:V ratio?

high

What adaptations do cells have to increase their ratio

Developing folds (mitochondria membrane), projections (microvilli on intestinal cells), elongated shapes

What molecule embeds itself within the membrane and affects fluidity?

cholesterol

what type of molecules are able to pass through the membrane?

small, nonpolar, and hydrophobic

passive transport

the movement of substances across a cell membrane without the use of energy by the cell; moves substances down the concentration gradient

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

facilitated diffusion

passive transport that requires a channel or carrier protein

hypertonic solution

A solution in which the concentration of solutes is greater than that of the cell that resides in the solution; cell will lose water and shrink

isotonic solution

A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution; cell stays same size

hypotonic solution

A solution in which the concentration of solutes is less than that of the cell that resides in the solution; cell gains water and will burst if animal cell

active site

the region on the enzyme where the substrate binds

substrate

reactant of an enzyme-catalyzed reaction

allosteric site

A specific receptor site on some part of an enzyme molecule remote from the active site.

how do enzymes speed up chemical reactions?

by lowering the activation energy

competitive inhibition

Inhibitor competes with substrate for active site.

noncompetitive inhibition

inhibitor binds elsewhere on the enzyme; changes shape of active site so that the substrate cannot bind

where do light independent (Calvin Cycle) reactions occur?

stroma of the chloroplast

where do light dependent reactions occur?

thylakoid membrane of the chloroplast

what is produced in the light reactions?

ATP and NADPH

How are electrons lost from photosystem II replaced?

splitting water; oxygen is released in the process

what is the hydrogen gradient created in the light reactions used to do?

used by ATP synthase to create ATP

what are the products of the light reaction used for in the Calvin cycle?

provide energy for glucose production

Where does glycolysis occur?

cytoplasm

how many ATPs are produced during glycolysis

2 ATP

Where does the Krebs cycle occur?

mitochondrial matrix

where does the electron transport chain occur?

inner membrane of mitochondria (cristae)

how many ATPs are produced during the electron transport chain?

32-34

what is the role of oxygen in the electron transport chain?

final electron acceptor- joins with H to form water

direct contact cell signaling

May exchange signals through gap junctions or plasmodesmata

Cell-cell recognition. Membrane proteins of neighboring cells contact

paracrine signaling

secreted molecules diffuse locally and trigger a response in neighboring cells

synaptic signaling

a nerve cell releases neurotransmitter molecules into a synapse, stimulating the target cell

long-distance signaling

endocrine signaling- hormones released into circulatory system

reception (cell signaling)

ligand binds to receptor

transduction (cell signaling)

conversion of an extracellular signal to an intracellular signal in a signal transduction pathway that is amplified and relayed by second messengers

response (cell signaling)

the transduced signal triggers a specific response in the target cell

extracellular receptors

are NOT LIPID soluable and are unable to penetrate a plasma membrane, instead bind to receptor proteins at the OUTER surface of the plasma membrane (extracellular receptors) EX: GPCRs, ligand gated ion channels

intracellular receptors

receptors located inside the cell rather than on its cell membrane; hydrophobic Ex. steroids, hormones, nitric oxide

why do second messengers do?

relay the message and amplify the signal (cyclic AMP)

what responses can a cell have to a signal?

Trigger a protein that can alter membrane permeability, trigger an enzyme that will change a metabolic process, or trigger a protein that turns genes on or off

G1

Cell growth

S

DNA replication

G2

Cell prepares to divide

prophase

chromatin condenses, nucleoli disappear, duplicated chromosomes appear as sister chromatids, spindle begins to form, centrosomes move away from each other

prometaphase

nuclear envelope fragments, spindle enters nuclear area and some attach to kinetochores

metaphase

centrosomes are at opposite poles, chromosomes line up in middle, microtubules are attached to each kinetochore

anaphase

sister chromatids separate and move to opposite ends of the cell due to shortening of microtubules, cell elongates

telophase

two daughter nuclei form, nucleoli reappear, chromosomes become less condensed

cytokinesis

division of cytoplasm- animals cells- cleavage furrow, plant cells- cell plate

end result of mitosis

2 identical daughter cells (diploid)

what happens if a cell does not pass the G1 checkpoint?

it will enter G0

What happens if a cell does not pass the G2 checkpoing?

will try to repair and if not trigger apoptosis

What happens to levels of CDKs and cyclins during the cell cycle?

CDKs remain constant and cyclins fluctuate

What happens when a cyclin binds to a CDK

It becomes an active CDK complex which phosphorylates target proteins which help regulate key events in the cell cycle

contrast mitosis and meiosis

1. Mitosis produces 2 cells identical to the original cell. Meiosis produces 4 cells that are genetically different than the original cell.

2. Mitosis -diploid, meiosis- haploid

3. Mitosis produces somatic cells. Meiosis produces gametes or sex cells.

4. Mitosis- 1 division, Meiosis- 2 division

If an egg cell has 20 chromosomes, how many would the somatic cell have?

40

diploid =24. what is the haploid number

12

Prophase 1 of meiosis

synapsis (tetrad formation) and crossing over occurs