Photosynthesis

Question 1

photosynthesis

Answer 1

process by which plants, algae, and some bacteria use the sun’s energy to produce its own food (energy)

Question 2

autotrophs

Answer 2

self-feeder - use inorganic molecules to produce organic compounds

Question 3

heterotrophs

Answer 3

consume organic compounds

Question 4

What is the photosynthesis equation

Answer 4

6 H2O + 6 CO2 —–> C6H12O6 + 6O2

6 molecules of water plus 6 molecules of carbon dioxide equals glucose plus 6 molecules of oxygen

Question 5

Where does photosynthesis occur

Answer 5

in the chloroplasts

Question 6

pigments

Answer 6

capture light energy at various wavelengths

Question 7

what are the type of pigments?

Answer 7

Chlorophyll A and Accessory pigments (chlorophyll b and carotenoids)

Question 8

Chlorophyll a

Answer 8

most abundant with a green pigment - it reflects green light and absorbs red and blue light

Question 9

Accessory pigments

Answer 9

allows plant to absorb more energy than with chlorophyll a alone

Question 10

Chlorophyll B

Answer 10

reflects green light and absorbs red and blue

Question 11

carotenoids

Answer 11

appear red, orange, and yellow (absorb longer wavelengths)

Question 12

stomata (stoma)

Answer 12

small openings in the epidermis of the stem or leaf that allow for an exchange of CO2 and O2

Question 13

mesophyll

Answer 13

internal cells of the leaf where the chloroplasts are located

Question 14

Stroma

Answer 14

(NOT STOMA) gelatinous fluid that contains DNA, ribosomes, enzymes, and Grana and are composed of stacks of thylakoids which are studded with photosynthetic pigments (enclosed: makes the thylakoid space)

Question 15

Photosystem

Answer 15

Very organized system that consists of chlorophyll a and accessory pigments

Question 16

How many chlorophyll a and accessory pigments?

Answer 16

300 Chlorophyll A and 50 accessory pigments - all absorb energy but only 1 (chlorophyll a) molecule uses the energy

Question 17

Reaction center

Answer 17

chlorophyll a molecule in photosynthetic reaction

Question 18

antenna pigments

Answer 18

all other pigments in system (chlorophyll a and accessory) that relay/pass along their absorbed energy to the reaction center

Question 19

What are the two stages of photosynthesis?

Answer 19

light reactions (photo) and carbon reactions (synthesis)

Question 20

light reactions

Answer 20

convert the sun’s energy to chemical energy - light dependent reaction that occurs in the thylakoid membrane and produces ATP and NADPH

Question 21

Carbon reactions

Answer 21

light independent reaction that occurs in the stroma and converts ATP and NADPH to glucose

Question 22

NADPH

Answer 22

electron carrier that reduces CO2 in the carbon reactions

Question 23

Carbon reactions: Calvin cycle

Answer 23

uses NADPH and ATP to assemble CO2 into sugars (Cyclic and all plants use this cycle

Question 24

C3 (Calvin Cycle

Answer 24

3 carbon molecule (PGA) is the first stable compound; C3 plants use ONLY this pathway to fix carbon

Question 25

weakness of C3

Answer 25

inefficient on cloudy days

Question 26

photorespiration

Answer 26

when rubisco uses O2 instead of CO2 and loses CO2 that is already fixed, wasting ATP and NADPH

Question 27

where does photorespiration usually occur?

Answer 27

in hot, dry climates

Question 28

dilemma of photorespiration

Answer 28

stomata open or closed; open: risk losing water, dry up, wilt; closed: run out of O2 and build up of CO2

Question 29

C4

Answer 29

light reactions occur in mesophyll cells and CO2 combines with a 4-C compound

Question 30

what happens when CO2 combines with a 4-C compound?

Answer 30

molecule then moves to bundle-sheath cells for Calvin cycle; no exposure to atmospheric O2 (rubisco more likely to bump into CO2); this is COSTLY as molecules must transport CO2 to bundle-sheath (2 ATP)

Question 31

CAM (crassulacean acid metabolism)

Answer 31

open stomata to fix carbon at night only (closed during the day); combines with a 4-C compound and is stored in large vacuoles

Question 32

What happens when the carbon combines with a 4-C compound and is stored in large vacuoles?

Answer 32

stored molecule moves from vacuoles to chloroplast and releases CO2 and the Calvin cycle begins, then less CO2 is available