Transfer of energy in an ecosystem

Question 1

Define heterotrophs

Answer 1

Organisms that ingest material from other organisms

Question 2

Define primary consumers

Answer 2

Herbivores - eat plant material

Question 3

Define secondary consumers

Answer 3

Carnivores - feed on consumers

Question 4

Define tertiary consumers

Answer 4

Feed on carnivores

Question 5

Define trophic levels

Answer 5

Position a species occupies in a food chain

Question 6

Define detrivores

Answer 6

Primary consumers that feed on dead organic material called detritus

Question 7

Define decomposers

Answer 7

Species of bacteria and fungi that feed on dead remains and faeces

Question 8

Define limiting factors

Answer 8

When a process is affected by more than one factor its rate is limited by the factor furthest from its optimum value
in UK main one is CO2 conc

Question 9

Define GPP

Answer 9

Rate at which energy is incorporated into organic molecules

Total energy transferred from light energy to glucose

Question 10

Define NPP

Answer 10

Rate at which energy is transferred into organic molecules to make biomass
Total energy left to make new biomass

Question 11

Whats the equation linking NPP and GPP

Answer 11

NPP=GPP-R

Question 12

What is the formula for the percentage efficiency of photosynthesis

Answer 12

GPP divided by amount of light energy striking plant x100

Question 13

What happens to respiration rate?

Answer 13

Doesn’t vary in plants as its fixed rate

Question 14

Describe efficency

Answer 14

5% reflected
40% absorbed by chlorophyll
50% not absorbed but evaporated
5% transmitted through

Question 15

Describe producers to primary consumers

Answer 15

2-10% goes to make biomass - not efficient
Not all available food gets eaten due to feeding limitations
Undigested food remains in faeces - cellulose -no enzymes to break it down
Food is used in respiration

Question 16

Describe primary to secondary consumers

Answer 16

Over 10% of energy in herbivores ends up in new biomass

Most of a herbivore is eaten by carnivore

Question 17

Why aren’t there more than four or five trophic levels?

Answer 17

Energy entering a trophic level is transferred to surroundings in respiration, transferred to next trophic level or to decomposers
So there’s no more than four or five levels as energy is insufficient to support

Question 18

What is the thylakoid membrane (CHLOROPLAST STRUCTURE)

Answer 18

Interconnected flattened fluid-filled sacs

Proteins, chlorophyll, electron carriers here

Question 19

What is the thylakoid space (CHLOROPLAST STRUCTURE)

Answer 19

Fluid in thylakoid membrane sacs with enzymes for photokysis

Question 20

What is the stroma (CHLOROPLAST STRUCTURE)

Answer 20

Fluid surrounding thylakoid membrane - enzymes for light independent reaction

Question 21

What is the granum (CHLOROPLAST STRUCTURE)

Answer 21

Stack of thylakoids joined to one another

Question 22

What is the inner membrane of the chloroplast?

Answer 22

Transported molecules (membrane proteins which regulate the passage of substances in and out of the cell)

Question 23

What is the outer membrane of the chloroplast?

Answer 23

Permeable to molecules ie H2O and CO2

Question 24

Describe the light dependent reaction

Answer 24

Light energy is absorbed by PSII and excites electrons
Electrons enter the ETC and move along electron carries in a series of REDOX reactions losing energy in the process
This energy is used to synthesis ATP (photophosphorylation)
Electrons from PSII replace those lost from PSI
Water is split by photolysis and the electron replaces the one lost from PSII
Electron from ATV combine with H+ ions from water and NADP producing reduced NADP

Question 25

What is the role of ATP?

Answer 25

ATPase catalyses the breakdown of ATP to ADP and Pi

Question 26

Describe the light independent reaction

Answer 26

CO2 combines with RuBP catalysed by Rubisco
6C compound is unstable so breaks into 2 GP molecules
GP reduced to form GALP - H is from the oxidation of red NADP and ATP provides energy by breaking down
2/12 GALPs form glucose
10/12 GALPS recreate RuBP which is phosphorylated using ATP