AP Biology Unit 3 Exam

need to know for the unit 3 exam

free energy

energy available in system to do work

breaking bonds ______ energy

require

forming bonds _____ energy

release

catabolic/exergonic

a polymer is broken down into monomers which increases entropy

anabolic/endergonic

monomers form a polymer which decreases entropy

entropy

disorder and randomness

enzyme

speeds up reactions and reduces the energy required to carry out reaction without being consumed by the reaction

factors that affect enzymes

pH, heat, cold, competitive inhibitors, and non-competitive inhibitors

cofactors (inorganic ions) and coenzymes (vitamins)

bind near or at active site to provide appropriate shape or substrate to bind

competitive inhibitor

binds to active site to block substrates with binding

non-competitive inhibitor

binds to allosteric site which alters the shape of the active site, preventing binding of substrate

activator

binds to allosteric site to make the active site the appropriate shape to bind with substrate

cooperativity

substrate itself is the activator for enzyme with quaternary structure

purpose of cellular respiration

create a usable form of energy for the cell

reactants in cellular respiration

glucose and oxygen

products of cellular respiration

water and carbon dioxide

what happens in glycolysis?

1 glucose molecule is broken down into 2 pyruvate molecules

other than pyruvate, what are the products in glycolysis?

2 ATP and 2 NADH

what is oxidized in glycolysis?

glucose

what is reduced in glycolysis?

NAD+

what is evidence glycolysis was earliest pathway to evolve?

does not require oxygen; Earth’s environment barely had oxygen long ago

what happens in the immediate step in cellular respiration?

the 2 pyruvate (3-carbon) lose a carbon each to produce 2 acetyl-CoA (2-carbon)

when pyruvate is turned into acetyl-CoA, what are the other products created?

2 CO2 and 2 NADH

what happens in the Kreb’s cycle (citric acid cycle)?

acetyl-CoA and oxaloacetate form citric acid which then help generate electron carriers, NADH and FADH2 that bring electrons to the ETC

what is released through the Kreb’s cycle?

6 NADH, 2 FADH2, 2 GTP (ATP), and 4 CO2

proton-motive force

H+ concentration gradient; moves from high to low concentration

how is the proton-motive force created in oxidative phosphorylation?

NADH and FADH2 release their electrons into the ETC which helps pump H+ ions from low to high contentration using active transport which builds up H+ ions in the inner membrance space

how is ATP synthesized in oxidative phosphorylation?

H+ moves down concentration gradient through ATP synthase which provides energy for the formation of ATP from ADP and Pi

what is the purpose of photosynthesis?

to produce sugar for cellular respiration

reactants of photosynthesis

carbon dioxide and water

products of photosynthesis

sugar and oxygen

where do light-dependent reactions occur?

thykaloid membrane

what happens in the photosystems?

electrons of the chlorophyll are energized and enter the ETC

which photosystem does sunlight enter first?

photosystem II; once electrons are energized, it allows for the breakdown of water into oxygen and H+

purpose of the first ETC in photosynthesis

pumps H+ from the stroma into the thykaloid space in order to create a proton-motive force which is used in ATP synthesis

why do electrons enter another photosystem in photosynthesis?

electrons enter a second photosystem (photosystem I) to get re-energized by the sunlight and then enter the second ETC

purpose of the second ETC in photosynthesis

provide energy to form NADPH from NADP+ and H+

how do pigments in photosystem II re-generate electrons?

when water is broken down into oxygen and H+, electrons get replaced

why do light-dependent reactions switch to cyclic electron flow periodically?

because ATP is depleted quickly in the next phase (Calvin cycle), a cyclie electron flow quickens the ATP generating process

purpose of the Calvin cycle

use ATP and NADPH to convert CO2 to sugar

where does the Calvin cycle take place?

stroma of a chloroplast

first step of the calvin cycle: carbon fixation

enzyme, rubisco brings together 3 CO2 and 3 RuBP (5-carbon) to form unstable 3 6-carbon compounds which immediately breaks down into 6 3-carbon sugars

second step in the Calvin cycle: reduction

6 ATP phosphorolate (add phosphorus) 6 3-carbon sugars; 6 NADPH then reduce the 6 sugars to create 6 G3P; one G3P is released leaving 5 in the cycle

third and final step in Calvin cycle: regeneration

3 ATP are used to rearrage 5 G3P into 3 RuBP to restart the Calvin cycle again

primary productivity

measures how much solar energy is converted to organic compounds in a period of time

gross primary productivity (GPP)

total amount of oxygen or biomass produced

net primary productivity (NPP)

amount of oxygen or biomass left over after producers perform cellular respiration