Cell Respiration and Photosynthesis

Question 1

what is cell respiration?

Answer 1

the controlled release of energy from organic compounds to produce ATP

Question 2

why is ATP a good source of energy?

Answer 2

ATP from cell respiration is immediately available

Question 3

what does cell respiration involve generally?

Answer 3

the oxidation and reduction of compounds

Question 4

what is oxidation in terms of electrons and hydrogen ions?

Answer 4

• involves the loss of electors
• the loss of hydrogen ions

Question 5

what is reduction in terms of electrons and hydrogen ions?

Answer 5

• gain of electrons
• gain of hydrogen ions

Question 6

what happens to glucose in cell respiration?

Answer 6

glucose in the cytoplasm is broken down by glycolysis into pyruvate, yielding a small amount of ATP

Question 7

outline the 3 steps of glycolysis

Answer 7

• phosphorylation: adding phosphates (2 ATP to 2 ADP)
• lysis: splitting glucose into 2 trios phosphate molecules
• oxidation: 2 hydrogens removed from trios phosphate

Question 8

what does phosphorylation do to molecules?

Answer 8

makes them less stable

Question 9

what happens to pyruvate during anaerobic respiration?

Answer 9

pyruvate is converted into lactate, ethanol and CO2 in the cytoplasm, which no further ATP yield (aka 2 ATP from glycolysis produced)

Question 10

what happens to pyruvate during aerobic respiration?

Answer 10

it’s decarboxylated and oxidized

Question 11

what happens in the link reaction generally?

Answer 11

pyruvate is converted into acetyl CoA

Question 12

what happens to the acetyl groups in the Krebs cycle?

Answer 12

oxidation of acetyl groups is coupled to the reduction of hydrogen carriers, liberating CO2

Question 13

what happens to the energy released by oxidation reaction?

Answer 13

the energy released is carried to the cristae of the inner mitochondrial membrane by reduced NAD and FAD

Question 14

what is the transfer of electors in the electron transport chain coupled to?

Answer 14

Proton pumping

Question 15

what happens to protons in chemeosmosis?

Answer 15

protons diffuse through ATP synthase to generate ATP

Question 16

why is oxygen needed in the electron transport chain?

Answer 16

oxygen needed to bind with the free protons (hydrogen) to form water to maintain the hydrogen gradient

Question 17

what is photosynthesis?

Answer 17

the production of carbon compounds in plant cells using light energy

Question 18

what is visible light from the sun composed of?

Answer 18

a range of wavelengths (colors), with red having longest wavelength and violet the shortest (red is lower energy, violet is highest energy)

Question 19

what is chlorophyll and what does it do?

Answer 19

it’s the main photosynthetic pigment (includes a and b) and absorbs red and blue light most effectively, and reflects green light the most

Question 20

what does the photolysis (splitting with light) of water produce?

Answer 20

• electrons for light dependent reactions
• protons for the reduction of NADP
• oxygen as a waste product

Question 21

why is energy needed in photosynthesis?

Answer 21

to produce carbohydrates and other carbon compounds from CO2

Question 22

describe the relationship between the structure and function of mitochondrion

Answer 22

• cristae provide more SA
• small inter-membrane space creates gradient
• matrix for reactions

Question 23

outline the changes to earth’s atmosphere, oceans, and rock deposition due to photosynthesis

Answer 23

• prokaryotes started photosynthesis 3.5 bill years ago
• great oxidation event rose O2 levels to 2% 2.2 bill years ago
• earth’s first glaciation period @ the same time
• boring billion followed: O2 levels about 2%
• due to land plants, O2 levels grew to todays (21%)
• rise in O2 levels led to iron rick rocks

Question 24

what is an absorption spectrum for chlorophyll

Answer 24

measures how much light is absorbed versus the wavelength

Question 25

describe chromatography

Answer 25

• filter paper with tissue on end is dipped into solvent
• solvent ascends carrying pigments from tissue
• diff pigments moves at different rates: creating different layers of pigment
• r-value calculated by rise of pigment/rise of tallest pigment

Question 26

outline the 3 limiting factors in photosynthesis

Answer 26

• light: light dependent reactions shut down at night
• temp: enzymes work better at higher temps because more kinetic energy, but too high of temp drops photosynthesis
• CO2 concentration: can shut down Calvin cycle in carbon fixation step

Question 27

define oxidative phosphorylation

Answer 27

when hydrogen and CO2 are removed from pyruvate in link reaction + last step of respiration

Question 28

summarize the products and location of glycolysis, link reaction, Krebs cycle, and oxidative phosphorylation (including the electron transport chain and chemeosmosis) in cell respiration

Answer 28

• glycolysis (cytoplasm): glucose in - 2 pyruvate out, 2 net ATP out, 2 NADH out
• link reaction (mitochondrial matrix): 2 pyruvate in - 2 acetyl CoA out, 2 CO2 out, 2 NADH out
• Krebs cycle (mitochondrial matrix): 2 acetyl CoA in - 4 CO2 out, 2 ATP out, 6 NADH out, 2 FADH2 out
• Oxidative phosphorylation (inner membrane of mitochondria): 10 NADH in, 2 FADH2 in - 25-28 more ATP out