AP Exam Review

Question 1

Atomic number

Answer 1

Protons + electrons

Question 2

Atomic mass

Answer 2

Protons + neutrons (make up the nucleus)

Question 3

Ionic bonds

Answer 3

1 or more electron is transferred from 1 atom to another

Question 4

Covalent bonds

Answer 4

Atoms share 1 pair of valence electrons

Question 5

Changes in # of different particles

Answer 5

Change in electron # -> same element, different charge / bonding behavior
Change in proton # -> different element
Change in neutron # -> isotope

Question 6

Electron movement from 1 shell to another

Answer 6

Electron moves closer to nucleus -> energy is released
Electron moves away from nucleus -> energy is stored

Question 7

Compound

Answer 7

Substance with 2 or more different elements in a fixed ratio (ie, table salt = Na:Cl 1:1)

Question 8

Element

Answer 8

Substance that can’t be broken down into other substances through chemical reactions

Question 9

Monosaccharide functions

Answer 9

• Available source of energy
• Transport sugar in animals because -OH groups are polar and dissolve easily in blood

Question 10

Disaccharide functions

Answer 10

• Bonded through dehydration synthesis
• Transport sugar in plants because many -OH groups with electronegative oxygens make them dissolve in water

Question 11

Polysaccharide examples + functions (animals)

Answer 11

Glycogen - stores glucose/sugar for later use

Question 12

Polysaccharide examples + functions (plants / non-animals)

Answer 12

Amylose (plants) - stores polysaccharides in plants
Cellulose (plants) - structural, made of beta-glucose so can’t be broken down
Chitin (arthropods/fungi) - structural, same as cellulose but different organisms

Question 13

Triglycerides

Answer 13

Long-term storage of energy due to CH bonds
Made of glycerol (3-carbon alcohol) at 1 end and 3 fatty acid, long carbon chains attached to it (can be saturated or unsaturated)

Question 14

Terpenes

Answer 14

• Pigments like chlorophyll
• Nonpolar/hydrophobic tail anchors in the membrane
• Long chain of carbons w/ methyl groups

Question 15

Prostaglandins

Answer 15

• Messengers
• Stimulate smooth muscle and vasodilation
• Uterine contraction
• Soluble in cell membrane
• Ring w/ 2 long carbon chains

Question 16

Steroids

Answer 16

Made of rings (hexagons/pentagons) - includes reproductive hormones and cholesterol, which makes cell membranes flexible

Question 17

Bonds between amino acids

Answer 17

2 amino acids can bind through dehydration synthesis
- Covalent bond forms between carbon of carboxyl group & nitrogen of amino group
- They bond front of first + rear of second

Question 18

Protein folding

Answer 18

1) Sequence of amino acids depends on DNA sequence
2) Folding due to H-bond interactions (alpha helix / beta pleated sheet)
3) Tertiary - occurs when protein encounters water (hydrophobic on the inside, hydrophilic on the inside)
4) Different proteins may bind together

Question 19

Blood pH regulation

Question 20

Specific properties of water

Answer 20

1) High specific heat
2) Universal solvent
3) Polar molecule
4) Cohesion and adhesion (capillary action / surface tension)

Question 21

Isotope

Answer 21

Different version of an element
Same: element, # of electrons, # of protons, atomic number, atomic properties
Different: atomic mass, # of neutrons

Question 22

Isomer

Answer 22

Compounds with the same number of the same atoms, but arranged differently (ie, C6H12O6 can form glucose or sucrose)

Question 23

Na+/K+ pump steps

Answer 23

1) There is lots of Na+ (sodium) outside the cell and lots of K+ (potassium) inside the cell (resting state)
2) 3 Na+ ions from the cytoplasm bind to the sodium-potassium pump
3) The pump is phosphorylated, leading to a conformational change in which it loses affinity for the Na+ currently bound
4) The 3 Na+ ions (that were just bound) are released outside (against concentration gradient)
5) The new shape has a high affinity for K+
6) 2 K+ bind from the outside of the cell, causing the phosphate group to detach
7) The protein undergoes another conformational change in which it has a low affinity for K+
8) The K+ currently in the pump are then released, going into the inside of the cell (against concentration gradient)
9) Affinity for Na+ is high again -> cycle repeats

Question 24

6 types of membrane proteins

Answer 24

1) Cell identity markers - glycoproteins, glycolipids, establish self v. other
2) Cell-cell adhesion proteins - help 2+ cells adhere to each other and pack tightly (ie, epithelial tissue)
3) Enzymes - catalyze reactions happening in the membrane
4) Gates - selectively allows molecules to enter
5) Receptors - receives to a hormone/ neurotransmitter
6) Proteins that attach to cytoskeleton - gives cell structure ie, actin and microtubules

Question 25

4 kinds of signaling

Answer 25

1) Paracrine - cells communicate locally through the intercellular / interstitial fluid; involves mast cells which spread the message 2) Contact-dependent - cell membranes must be touching to communicate 3) Neuronal - occurs between neurons & target cells, similar to paracrine but no mast cell 4) Endocrine - long-distance, hormones travel in the bloodstream

Question 26

Cytolysis

Answer 26

Plant cell bursts

Question 27

Plasmolysis

Answer 27

Plant cell shrinks

Question 28

Exergonic reactions

Answer 28

- Energy leaves - Negative Gibbs free energy (-ΔG) - Energetically favorable - Spontaneous - the reaction can proceed on its own, but would take so long that enzymes are needed - Products have less free energy than reactants

Question 29

Energy coupling

Answer 29

Energy produced by exergonic reactions drive endergonic ones (ie, ATP drives photosynthesis)

Question 30

Activation energy

Answer 30

Amount of energy required to strain reactant molecules so that bonds break and reaction can occur (needed to start both exergonic and endergonic reactions)

Question 31

Cofactor/coenzyme

Answer 31

Cofactor: Any nonprotein molecule that an enzyme needs in order to function permanently (ie, zinc) Coenzyme: A cofactor that is an organic molecule (ie, vitamins)

Question 32

Endergonic reactions

Answer 32

- Energy is stored as molecules become more complex / ordered - Enthalpy increases - Positive Gibbs free energy (+ΔG) - Products have more free energy than reactants