Photosynthesis

Question 1

what organisms undergo photosynthesis?

Answer 1

plants, algae, some bacteria

Question 2

carbon fixation

Answer 2

process where plants convert inorganic CO2 into organic matter for biological processes eg. cellular respiration

Question 3

photosynthesis chemical equation

Answer 3

6CO2 + 6H2O -> (light) C6H12O6 + 6O2

Question 4

Importance of photosynthesis

Answer 4

1. main source of oxygen in the atmosphere
2. removes CO2 from the atmosphere
3. light energy is converted into chemical energy which is used throughout the food chain

Question 5

cellular respiration

Answer 5

process by which organisms break down glucose to make ATP

Question 6

relationship between cellular respiration and photosynthesis

Answer 6

symbiotic processes (existing simultaneously in a way which benefits all)

Question 7

inputs and outputs of cellular respiration

Answer 7

inputs: glucose, oxygen
outputs: ATP, carbon dioxide water

Question 8

what is a chloroplast and what does it do?

Answer 8

• cell organelle in photosynthetic organisms
• contains chlorophyll which captures light energy converting it to chemical energy

Question 9

parts of a chloroplast

Answer 9

inner membrane, outer membrane, thylakoids, granum, stroma lamellae

Question 10

thylakoid

Answer 10

flattened discs that contain chlorophyll

Question 11

granum

Answer 11

stack of thylakoids

Question 12

function of the hydrophobic tail in chlorophyll

Answer 12

Anchors chlorophyll in thylakoid membrane

Question 13

function of the porphyrin ring in chlorophyll

Answer 13

circular structure that contains Mg and absorbs light energy

Question 14

process of capturing energy

Answer 14

pigment absorbs light energy, electrons become excited, jump energy levels, excited electrons start photosynthesis reactions

Question 15

light dependent stage location and goals

Answer 15

• occurs in thylakoid membrane
• converts light energy into chemical energy (ATP, NADPH), oxygen is produced as a byproduct

Question 16

light dependent stage step 1

Answer 16

light energy is absorbed by Photosystem II, energy used to break water up into oxygen gas, hydrogen ions and electrons, electrons begin to move through transport chain

Question 17

What is Photosystem II made up of?

Answer 17

lipids, proteins, contains chlorophyll

Question 18

light dependent stage step 2

Answer 18

excited electrons move through transport chain, cytochrome B6 (enzyme) transports hydrogen ions into lumen of the thylakoid

Question 19

light dependent stage step 3

Answer 19

movement of H+ is driven by electrons moving through electron transport chain, creates a high concentration of ions inside the thylakoid

Question 20

light dependent stage step 4

Answer 20

excited electrons reach photosystem I losing some energy through the chain, more light is absorbed, electrons reacts with NADp and H+ ion to form NADPH, NADPH carries electrons to next stage

Question 21

light dependent stage step 5

Answer 21

high H+ concentration in thylakoid allows H+ to diffuse from in the lumen to the stroma, drives ATP synthase protein to produce ATP

Question 22

light independent stage location and goals

Answer 22

occurs in the stroma
- takes CO2 turns it into glucose, requires ATP and NADPH energy from light dependent stage

Question 23

light independent stage step 1

Answer 23

carbon fixation: CO2 combines with RuBP to make 2 molecules of 3 - PGA, catalysed by rubisco

Question 24

light independent stage step 2

Answer 24

reduction: 3PGA is converted to G3P (3 carbon sugar), requires energy (ATP, NADPH)

Question 25

light independent stage step 3

Answer 25

regeneration: some G3P drawn away to make glucose, rest recycled to make 5 carbon RuBP (requires ATP)

Question 26

enzyme

Answer 26

protein that speeds up rate of reaction

Question 27

collision theory

Answer 27

higher temp = higher rate of reaction until temp gets too high

Question 28

reaction rate of lower temp

Answer 28

less kinetic energy in particles, fewer collisions = less product = slower reaction rate

Question 29

reaction rate of higher temp

Answer 29

more kinetic energy in particles, more successful collisions = more product made = faster reaction rate

Question 30

denaturation

Answer 30

conformational change in enzyme due to high temperatures, cannot perform function = loss of biological activity

Question 31

enzyme use in photosynthesis

Answer 31

light independent reactions depend on enzymes = dependent on temp

Question 32

rate limiting factors

Answer 32

- temp (40C limit) - light intensity - CO2 concentration

Question 33

why might oxygen concentration in the air decrease with a plant in a dark room?

Answer 33

No photosynthesis happening, cellular respiration occurs (oxygen is a reactant), oxygen used up = concentration decreases

Question 34

limiting factors of light dependent stage

Answer 34

light intensity and wavelength

Question 35

stroma lamellae

Answer 35

flat membranous tubules that connect the thylakoids of the various grana