chapter 9-10: bioenergetics and cellular respiration

Question 1

inputs of glycolysis

Answer 1

glucose, 2 NAD+, 2 ATP, 4 ADP + 4 Pi

Question 2

outputs of glycolysis

Answer 2

2 pyruvate, 2 NADH, 4 ATP (2 net ATP)

Question 3

formation of ATP during glycolysis is called…

Answer 3

substrate level phosphorylation

Question 4

substrate level phosphorylation

Answer 4

an enzyme directly transfers a phosphate group from another substrate to ADP

Question 5

how is glycolysis regulated?

Answer 5

excess ATP

Question 6

where does glycolysis occur

Answer 6

cytosol; all life can perform glycolysis; does not require oxygen

Question 7

pyruvate oxidation + processing

Answer 7

• eukaryotes with mitochondria take the products of glycolysis from the cytosol and bring it into the mitochondria
• pyruvate is shuttled from cytosol to mitochondrial matrix
• pyruvate is oxidized + processed into acetyl coA
• NAD+ is reduced
• first molecule of CO2 is formed

Question 8

what must be established to power ATP synthase?

Answer 8

H+ gradient

Question 9

oxidative phosphorylation (what is it)

Answer 9

production of ATP molecules by ATP synthase using the proton gradient established by redox reactions of the central electron transport chain; we get much more ATP this way

Question 10

what do the products of glycolysis power

Answer 10

citric acid cycle

Question 11

to power the ATP synthase enzyme what does there need to be

Answer 11

high concentration of H+ ions in the intermembrane space; these ions come from citric acid cycle; high concentration comes from ETC via redox reaction and active transport

Question 12

where do carbons in the citric acid cycle go

Answer 12

they become carbon dioxide gas

Question 13

what is happening in the citric acid cycle

Answer 13

a 6 carbon molecule is catabolized into a 3 carbon molecule; ATP made by substrate level phosphorylation

Question 14

main purpose of citric acid cycle

Answer 14

NAD+ and FAD2+ are reduced to NADH and FADH2

Question 15

what carries hydrogen atoms from citric acid cycle to ETC

Answer 15

NADH and FADH2

Question 16

electron transport chain

Answer 16

purpose: create a pool of H+ ions in intermembrane space of mitochondria
how: uses energy from an electron to carry out active transport of H+ against the concentration gradient

Question 17

ATP synthase

Answer 17

pool of H+ ions between mitochondrial membranes flow through the ATP synthase enzyme and spin it like a turbine - mechanical energy is transferred to ATP

Question 18

aerobic respiration of glucose is___ (ender or exergonic)

Answer 18

exergonic

Question 19

anaerobic respiration

Answer 19

mitochondrial metabolism is blocked due to no oxygen - smaller amounts of ATP made in cytosol during glycolysis + fermentation

Question 20

what type of fermentation occurs in humans

Answer 20

lactic acid

Question 21

what type of fermentation occurs in yeast

Answer 21

alcoholic

Question 22

glycolysis and cellular respiration (O2 present)

Answer 22

glycolysis, pyruvate, pyruvate oxidation, citric acid cycle, ETC / ATP synthesis, CO2 and H2O

Question 23

glycolysis and fermentation

Answer 23

glycolysis, pyruvate, fermentation, lactate or alcohol

Question 24

3 metabolic pathways involved in harvesting energy of glucose to make ATP

Answer 24

1. glycolysis - generates little ATP
2. respiration (aerobic) - generates many ATP - 32 ATP per glucose
3. fermentation (anaerobic) - 2 ATP per glucose

Question 25

chloroplasts

Answer 25

- descendant from cyanobacterium (a photosynthesizing prokaryote) - endosymbiosis - triple membrane - thylakoids are a series of internal membrane systems and the site of photosynthesis

Question 26

photosynthesis

Answer 26

- endergonic, anabolic - sunlight provides energy - CO2 reduced to form glucose - H2O oxidized to form O2 - certain wavelengths of light drive photosynthesis

Question 27

2 parts of photosynthesis

Answer 27

1. light dependent reactions - collect light energy, oxidize H2O, store energy as ATP and NADPH 2. light independent reactions - use ATP and NADPH to reduce CO2 and produce carbohydrates

Question 28

what wavelengths of light are most effective at triggering photosynthesis

Answer 28

violet-blue and red

Question 29

what are the light reactions

Answer 29

photosystem 1 and 2 (2 comes first)

Question 30

photosystem 2

Answer 30

- photon energy of light is captured (electrons excited) and passed to a chlorophyll a; changes resonance of molecule - loses an excited electron; electron hole is created - water is split, causing: -release of O2, accumulation of H+ in thylakoid lumen which runs ATP synthase

Question 31

3 possible outcomes when an electron is excited

Answer 31

fluorescence / heat, resonance energy transfer, reduction / oxidation

Question 32

resonance energy transfer + redox in photosystem 2

Answer 32

1. pigments absorb photon 2. energy transferred to reaction center giving an electron in pheophytin 3. electron relaxes back to ground state through redox reactions in an ETC

Question 33

ATP synthase in thylakoid membrane

Answer 33

- ETC actively transports H+ to thylakoid lumen - creates a high concentration of H+ that flows through ATP synthase to make ATP

Question 34

photosystem 1

Answer 34

- reduces NADP+ - cyclic electron flow

Question 35

cyclic electron flow

Answer 35

- excited electrons are transferred back to ETC to generate ATP instead of reducing NADP; produces extra ATP to meet the energy needs of the Calvin cycle

Question 36

light independent reactions

Answer 36

- CO2 fixation and the Calvin cycle - takes place in the stroma - CO2 reduced to carbohydrates - enzymes in stoma use energy in ATP and NADPH to reduce CO2

Question 37

rubisco

Answer 37

- earths most prevalent enzyme - makes sugar from CO2 gas - 8 active sites

Question 38

the calvin cycle

Answer 38

CO2 goes in and a carbohydrate comes out, ATP used rather than generated 1. fixing carbon by RuBisCo 2. reducing 3-phosphoglutarate (3PGA) 3. regenerating ribulose 1, 5-bisphosphate (RuBP)

Question 39

the different fates of G3P

Answer 39

- regenerates RuBP - directly fuel glycolysis at the energy payout phase - converted and exported to the cytoplasm to make glucose - polymerized into starch molecules and stored in chloroplasts

Question 40

problem with rubisco

Answer 40

cannot distinguish between CO2 and O2 - if binds to O2, leads to carbon loss called photorespiration

Question 41

C4 plants

Answer 41

- fix carbon to a 4 carbon molecule - 3 carbon compound + CO2 - PEP carboxylase

Question 42

C3 plants

Answer 42

- RuBP + CO2 -> 2 3-carbon organic acids - rubisco

Question 43

strategies for photosynthesis

Answer 43

C4 plants: carbon fixing and calvin cycle occur in different cell types; spatial separation CAM plants: carbon fixing and calvin cycle occur at different times of day; temporal separation (CO2 stored at night and used during the day)

Question 44

photosynthesis has led to...

Answer 44

- formation of ozone layer - colonization of land - successful ATP formation by oxidative phosphorylation