Chapter 5

Question 1

Photosynthesis is carried out by

Answer 1

Plants, algae, some protists and cyanobacteria

Question 2

What do all photosynthesizing organisms contain

Answer 2

Chlorophyll

Question 3

Photo autototrophs

Answer 3

Primary producers, make their own food from the sin

Question 4

Waxy cuticle

Answer 4

Most important adaption for plants- prevents water loss

Question 5

Stomata

Answer 5

Opens during the day, allowing carbon dioxide to water and be used for photo synthesis

Closed at night to conserve water

Question 6

Transpiration

Answer 6

Loss of water vapour through the stomata

Question 7

Rubisco

Answer 7

Most abundant enzyme on earth

Supposed to catalyze reaction of CO2

Sometimes turns O2 into RuBP- slows the calvin cycle, consumes ATP and releases carbon (called photo res

Binds with CO2 75% of the time

Photorespiration happens when stomata are partially closed because less CO2 can enter

Question 8

C3 plants

Answer 8

Cool environment

Question 9

C4 plants

Answer 9

Hot

Calvin cycle and c4 cycle run at the same place, different time

“Kranz anatomy”

Mesophyll cells contain PEPcase (has no affinity to oxygen) which catalyzes the addition of CO2, forming oxaloacetic acid which has 4 carbons

Requires less nitrogen so can thrive in nutrient poor soil

Requires more ATP but there is more sun

Question 10

CAM Plants

Answer 10

Desert

Crassulacean acid metabolism

Run Calvin cycle and C4 cycle at the same time but different places

Stomata is only open at night when it is cooler and CO@ gets stored in organic acid (malate) using PEPcase

Calvin cycle keeps going in daylight but stomata remains closed

Question 11

Similarities between photosynthesis and cellular respiration

Answer 11

Both use electron transport chains and ATP synthase complexes to generate ATP via chemiosmosis

Both have inner folded membranes that create separated fluid filled spaces that allow proton gradients to be established

Both have their own unique DNA

Question 12

What do NADH and NADPH do

Answer 12

Carry high energy electrons to electron transport chains

Question 13

Photo respiration

Answer 13

That catalyst of O2 instead of CO2 by rubisco into RuBP which slows the carbon cycle, consumes ATP and results in a release of carbon

Question 14

Photoexitation (photoxidation)

Answer 14

Photos (light) excite chlorophyll electrons, in leaves photosystems absorb this light and covert it to ATP and NADH

Question 15

Photosystems consist of

Answer 15

Antenna complex: several hundred pigment molecules

Reaction center: Chlorophyll a

Question 16

Non cyclic electron flow

Answer 16

1) Photon strikes ps2. Excited e- is captured by pheophytin and transferred to (PQ) and then to ETC
2) 2 proteins spin water into 2H+ and 1/2 O2
3) e- pass through the ETC which also pumps protons from storm to thylakoid lumen
4) Electrons excited in photosystem 1 reduce ferredoxin which passes e- to NADPH reductase which in turn reduces NADP+ to NADPH
5) Chemiosmosis

Question 17

Antenna complex

Answer 17

A cluster of light absorbing pigments embedded in the thylakoid membrane able to capture and transfer energy to special chlorophyll a molecules in the reaction centre. Chlorophyll b and cartinoids

Question 18

Reaction center

Answer 18

A complex of proteins and pigments that contain the primary electron acceptor

Question 19

Absorption spectrum

Answer 19

A plot of the amount of light energy of various wavelengths that a substance absorbs

Question 20

Action spectrum

Answer 20

A plot of the effectiveness of light energy of different wavelengths in a chemical process

Question 21

Primary electron acceptor

Answer 21

A molecule capable of accepting electrons and becoming reduced during photosynthesis

Question 22

Chlorophyll a

Answer 22

light absorbing head and CH3 R group. During photosynthesis becomes oxidized and donates an electron to a primary electron acceptor

Question 23

Chlorophyll b

Answer 23

Light absorbing head and CHO R group.

Question 24

VO2 max definition

Answer 24

Measurement of a bodies capacity to generate the energy required for physical activity

Question 25

Chromatography

Answer 25

Used to separate mixtures

Question 26

What can happen when an electron absorbs a photon

Answer 26

1) Return to ground state by emitting a photon
2) Return to ground state, energy is transferred in a different electron in a neighbouring pigment molecule
3) High energy electron can be accepted by the primary acceptor

Question 27

Buildup of protein gradient across the thylakoid membrane

Answer 27

1) Protons are taken into lumen due to redo of pq as it moves from ps2 to the cytochrome complex and back
2) For each H2O molecule that splits in the lumen, there are two additional protons
3) There is a proton removed from each molecule of NADPH formed

Question 28

How do protons move through across the thylakoid membrane from the lumen to the stroma

Answer 28

Proton motive force