Ecology - Abiotic Factors: CO2 Availability/Temperature

Question 1

What is the definition of ecology?

Answer 1

study of organisms’ relationship to environment

Question 2

What are the examination of ecological factors?

Answer 2

abiotic and biotic

Question 3

What does abiotic and biotic provide clues to?

Answer 3

how plants adapted to different environmental conditions on land

Question 4

What are the key abiotic factors that determine plant distribution?

Answer 4

temperature
water (precipitation)

Question 5

what is the definition of adaptation?

Answer 5

characteristic that promotes plant’s survival and reproduction in the environment that it has

Question 6

what does adaptation includes?

Answer 6

• external morphological modifications
• histological changes in tissues/cells
  -physiological specializations (photosynthetic pathways)

Question 7

True or False

any plant that is able to survive and reproduce in that environment has adapted to that environment?

Answer 7

True

Question 8

What is photosynthesis?

Answer 8

involves light captures, electron transport, carbohydrate biosynthesis

Question 9

What are the environmental factors that affect photosynthetic rates directly?

Answer 9

• light
  -temperature
  -CO2 concentrations

Question 10

What are the environmental factors that affect photosynthetic rates indirectly?

Answer 10

-water (humidity/ soil moisture)
- nutrients

Question 11

what does environmental stress led to for plants?

Answer 11

unique adaptations to permit survival in less than ideal conditions

Question 12

what are the 5 key environmental factors affect photosynthesis?

Answer 12

1. effect of CO2 concentration/fluxes
2. effect of temperature changes
3. effect of light availability/ quality
4. effect of water availability
5. effect of soil conditions (nutrient levels)

Question 13

what is photosynthesis controlled by?

Answer 13

“supply” and “demand” of photosynthetic palisade/spongy mesophyll cells for CO2 or by CO2 inside leaf cells

Question 14

Where is photosynthesis happening in leaf?

Answer 14

inside leaf cells

Question 15

where is supply of CO2 thru gas exchange controlled by?

Answer 15

stomata that are controlled by guard cells

Question 16

what do guard cells respond to?

Answer 16

water levels that are impacted by temperature

Question 17

what does photosynthesis require?

Answer 17

coordination of all cell activity within leaf

Question 18

what is the ancestoral pathway?

Answer 18

C3 photosynthetic pathways

Question 19

what plants are considered C3 plants?

Answer 19

most plants

Question 20

What does the C3 plants do?

Answer 20

maintain CO2 in leaves above the CO2

Question 21

What is the CO2 compensation point?

Answer 21

intracellular CO2 concentrations in leaf cells that support photosynthetic balance of cellular respiration rates

Question 22

what is the photosynthetic CO2 consumption?

Answer 22

respiratory CO2 production

Question 23

what does leaves in C3 plants regulate?

Answer 23

internal [CO2] between limits imposed by Calvin Cycle

Question 24

What does the Calvin Cycle do?

Answer 24

• capacity to re-generate RuBP
• carboxylation capacity of Rubisco

Question 25

What are the certain conditions that with Rubisco -oxygenase function favoured in C3 plants?

Answer 25

1. high temperatures 2. low CO2 concentrations 3. high O2 concentrations

Question 26

What happens when hot and dry to plants?

Answer 26

- stomata close to reduce water loss - reduces gas exchange CO2 levels drop, O2 accumulates

Question 27

how is balance between two Cycles determined?

Answer 27

1. kinetic properties of plant's Rubisco 2. relative concentration of substrates (CO2 and O2) 3. temperature (affects stomatal opening/closing)

Question 28

What does increasing in external temperature do to plants?

Answer 28

1) modifies kinetic constants of Rubisco - favours oxygenation over carboxylation 2)lowers CO2 concentration in a solution more than for O2 - favours oxygenation over carboxylation

Question 29

what does increasing temperature favours?

Answer 29

photorespiration over the Calvin Cycle C3 pathway

Question 30

True or False many photosynthetic organisms do photorespire?

Answer 30

False

Question 31

what happens when plants do not show photorespiration?

Answer 31

normal Rubisco

Question 32

how are alternative pathways evolve?

Answer 32

through modifications of photosynthetic pathways

Question 33

what are the alternative pathways with CO2 concentrating mechanisms?

Answer 33

1. C4 photosynthetic Carbon Fixation Pathway 2. CAM (Crassulacean Acid Metabolism) Pathway

Question 34

what oxygenase activity of Rubisco limit?

Answer 34

photosynthesis especially under warmer temperatures and water stress

Question 35

What does C4 photosynthesis evolve?

Answer 35

compensate for low atmospheric [CO2} using spatial separation

Question 36

What is C4 pathway?

Answer 36

spatial separation

Question 37

where does evolved C4 pathway live?

Answer 37

terrestrial habitats where temperature was high

Question 38

what happens to plants with older C3 pathway?

Answer 38

could not compete with plants with the new C4 pathway

Question 39

what happens to C4 plants with CO2 concentrating mechanisms?

Answer 39

at carboxylation sites in chloroplasts is saturating for Rubisco activity

Question 40

What are C4 plants require?

Answer 40

less Rubisco than C3 plants for similar rates of photosynthesis

Question 41

What does C4 plants use more efficiently than C3 plants?

Answer 41

water and nitrogen

Question 42

What does C4 plants use less efficiently than C3 plants?

Answer 42

light - have higher energy requirement

Question 43

what are the shade plants classified?

Answer 43

C3 plants because of lower energy requirements under low light conditions

Question 44

what is CAM pathway and for what?

Answer 44

Crassulacean Acid Metabolic Pathway for temporal separation

Question 45

What does CAM pathway occur in?

Answer 45

cacti, orchids, bromeliads, other succulents

Question 46

What happens during CAM pathway to plants?

Answer 46

opposite to C3 and C4 plants stomata open at night (during cooler conditions) and closed at day

Question 47

where are plants that are lowest transpiration ratio in?

Answer 47

desert-adapted plants with CAM photosynthesis

Question 48

What is the transpiration ratio?

Answer 48

water lost (g) : CO2 uptake (g)

Question 49

what is the transpiration Ratio for C3 plants?

Answer 49

500 : 1

Question 50

What is the transpiration ratio for C4 plants?

Answer 50

250 : 1

Question 51

What is the transpiration ratio for CAM plants?

Answer 51

50 : 1

Question 52

what is the range ratio of water loss?

Answer 52

greater than 250 to 500 molecules of H2O : 1 molecule CO2

Question 53

why is water loss a problem?

Answer 53

dehydration, wilting

Question 54

what is the benefit of water loss?

Answer 54

leaf cooling

Question 55

what is the problem of high temperatures on leaves?