photosynthesis

Question 1

photosynthesis is:

Answer 1

the process of making energy from sunlight. sunlight, CO2, and water are used to make sugars with high chemical energy and oxygen.

Question 2

photosynthesis takes place in:

Answer 2

the chloroplasts.

Question 3

chloroplast numbers:

Answer 3

• usually 40-200 in a photosynthetic cell
• up to 500 000 chloroplasts in one square millimeter in a regular leaf

Question 4

thylakoids are/contain:

Answer 4

little disks inside chloroplasts. they contain molecules that absorb solar energy in the thylakoid membrane.

Question 5

when stacked, thylakoids from:

Answer 5

grana.

Question 6

stroma:

Answer 6

stroma is the fluid-filled interior that surrounds grana.

Question 7

inside stroma:

Answer 7

there are enzymes that catalyze the conversion of CO2 and water into carbohydrates.

Question 8

photons are:

Answer 8

packets of energy that absorb light.

Question 9

wavelengths of visible light are associated with:

Answer 9

photons carrying different amounts of energy.

Question 10

shorter wavelength photons:

Answer 10

carry large amounts of energy.

Question 11

longer wavelength photons:

Answer 11

carry small amounts of energy.

Question 12

all light travels:

Answer 12

AT THE SAME SPEED

Question 13

a pigment is:

Answer 13

a compound that absorbs certain wavelengths of visible light.

Question 14

light-dependant reactions are initiated when:

Answer 14

the pigments in the thylakoid membrane absorb light energy.

Question 15

the main type of photosynthetic pigment is:

Answer 15

chlorophyll. it’s green!

Question 16

the types of chlorophyll are:

Answer 16

chlorophyll a and chlorophyll b

Question 17

chlorophyll is green because:

Answer 17

it absorbs blue and red light and reflects green light.

Question 18

carotenoids are:

Answer 18

a class of pigments that absorb blue and green light and reflect red, orange, and yellow light.

Question 19

beta-carotene is:

Answer 19

the pigment that makes carrots orange. can also be converted into vitamin A.

Question 20

a photosystem is:

Answer 20

a core group of chlorophyll molecules and proteins in the center of the cluster.

Question 21

when a pigment molecule absorbs a photon:

Answer 21

it passes the energy to a unique pair of chlorophyll a molecules associated with the reaction center.

Question 22

the reaction center is:

Answer 22

a group of proteins.

Question 23

the antenna complex is:

Answer 23

a collection of proteins and pigments that capture and funnel light. it includes all the surrounding pigment molecules that gather the light energy.

Question 24

antenna complexes transfer:

Answer 24

light energy to the reaction center.

Question 25

what happens when the antenna complex transfer the light energy to the reaction center?

Answer 25

an electron in the reaction center becomes excited. said electron then has enough energy to be picked up by an electron accepting molecule, which is reduced. this molecule is then at a higher energy level.

Question 26

the photosystems found in chloroplasts and algae are called:

Answer 26

photosystem i and photosystem ii

Question 27

P700 is:

Answer 27

the reaction center pigment molecule in photosystem i

Question 28

P680 is:

Answer 28

the reaction center pigment molecule in photosystem ii

Question 29

the photosynthesis electron chain consists of:

Answer 29

protein molecules with prosthetic groups attached.

Question 30

prosthetic groups:

Answer 30

non-peptide molecules bound to a protein that facilitates its function. ie, coenzymes.

Question 31

the energy harnessed by both photosystems is used to:

Answer 31

produce ATP and NADPH

Question 32

photophosphorylation is when:

Answer 32

the electron transport chain in the thylakoid membrane facilitates the movement of H+ ions to create a proton gradient that powers the production of ATP via ATP synthase.

Question 33

explain the photolysis of water.

Answer 33

water is broken down by light energy to form oxygen moves in the lumen of the thylakoid. hydrogen’s electrons are donated to the oxidized chlorophyll molecules in photosystem ii.

Question 34

explain the cyclic electron pathway.

Answer 34

this pathway only uses P700 (photosystem 1). it absorbs energy, exciting an electron, which is then passed to ferredoxin (FD). once passed to ferredoxin, it eventually makes its way to b6-fcomplex, where it’s then passed back to P700 to make another cycle. every time the electron is passed to another carrier molecule, it loses energy so that when it goes back to P700, it is at a low energy state and ready to be re-excited. this process only makes ATP; NADPH, which is required to synthesize sugars, is not made.

Question 35

explain the non-cyclic electron pathway.

Answer 35

both photosystems are utilized in this pathway, creating ATP and NADPH. electrons are replaced via the splitting of water.

Question 36

an alternate name for the light-independent stage is:

Answer 36

the Calvin Cycle.

Question 37

the three steps in the Calvin Cycle are:

Answer 37

carbon fixation, reduction of PGA, regeneration of RuBP

Question 38

light-independent stage takes place after x in x?

Answer 38

takes place after the energy from light-dependent reactions is transferred to the independent stage. takes place in the stoma of the chloroplast.

Question 39

give a summary of carbon fixation.

Answer 39

a molecule of CO2 enters the stoma through the stomata of the leaf. it combines with RuBP, a five carbon molecule, to make an extremely unstable 6C molecule. this then splits into two 3C molecules called 3PG. this reaction is catalyzed by the rubisco enzyme. this process has to happen three times to proceed to the next stage (needs six molecules of 3PG)

Question 40

give a summary of fixation.

Answer 40

the 3PG is phosphorylated by ATP, turning it into 1,3-BPG. this molecule is then reduced by NADPH into G3P. some G3P molecules leave the cell to make glucose while others continue onto step 3.

Question 41

give a summary of regeneration of RuBP.

Answer 41

ATP gives energy so that G3P turns into RuBP. the Calvin Cycle must happen six times to make one molecule of glucose.

Question 42

numbers in the Calvin Cycle.

Answer 42

of the twelve G3P molecules made in the six cycles of the Calvin Cycle, ten regenerate RuBP and two make glucose.