Topic 5- Energy transfers in organism

Question 1

where does glycolysis occur?

Answer 1

in the cytoplasm

Question 2

what two types of respiration does glycolysis occur in?

Answer 2

aerobic and anaerobic

Question 3

describe the process of glycolysis

Answer 3

1) 2 molecules of ATP hydrolysed to produce 2 ATP and 2 inorganic phosphate
2)phosphorylation of glucose to glucose phosphate
3)glucose phosphate split into triose phosphate
4)triose phosphate oxidised producing pyruvate
5)co enzyme NAD reduced to produce NADH
6)4 molecules of ATP produced through substrate-level phosphorylation

Question 4

what reactions make up the process of aerobic respiration?

Answer 4

glycolysis, link reaction, krebs cycle, oxidative phosphorylation

Question 5

what is the net gain of ATP in glycolysis?

Answer 5

2

Question 6

where does the link reaction occur?

Answer 6

mitochondrial matrix

Question 7

describe the process of the link reaction

Answer 7

1) pyruvate actively transported into the mitochondrial matrix
2)pyruvate is converted into acetate
3)molecule of carbons dioxide is produced through pyruvate decarboxylation and pyruvate is oxidised
4)hydrogen lost reduces NAD to NADH
5)acetate + CoA produced acetyl CoA

Question 8

what is the overall equation for the link reaction?

Answer 8

pyruvate + NAD +CoA —>CO2 + NADH+ acetyl CoA

Question 9

where does the krebs cycle occur?

Answer 9

mitochondrial membrane

Question 10

how many times does the krebs cycle repeat?

Answer 10

twice

Question 11

what is the net gain of ATP from the krebs cycle?

Answer 11

2

Question 12

describe the krebs cycle

Answer 12

1)acetyl CoA loses the CoA and binds to oxaloacetate to form citrate (6c)
2)citrate is decarboxylated twice producing 2 carbon dioxide molecules
3)citrate is also dehydrogenated twice producing 2 NADH
4)the 4c compound created undergoes substrate level phosphorylation producing ATP
5)co enzymes, NAD and FAD, are reduced
6) cycle repeats again for each molecule of glucose

Question 13

where does oxidative phosphorylation occur?

Answer 13

between the matrix and inter membrane space

Question 14

how much ATP is produced from oxidative phosphorylation?

Answer 14

over 30 molecules

Question 15

describe the process of oxidative phosphorylation

Answer 15

1)NADH and FADH travel towards the inner mitochondrial membrane
2)electrons donated to proteins in the membrane, producing NADH, FAD and protons when NADH and FADH2 are oxidised
3)electrons move along electron transfer chain through a series of redox reactions
4)as they travel, electrons provide the proteins with energy
5)energy is used to transport protons from the matrix to inter membrane space through active transport
6)this maintains a proton gradient
7)electrons at the end of the chain react with oxygen and protons to produce water
8)oxygen is known as the final electron acceptor
9)protons in the inter membrane space diffuse back into the matrix via ATP synthase in a process known as chemiosmosis
10)supplies ATP synthase with energy which is used to catalyse the production of ATP

Question 16

where does the whole process of anaerobic respiration occur?

Answer 16

in the cytoplasm

Question 17

what happens after glycolysis when anaerobic respiration occurs in animals?

Answer 17

lactate fermentation

Question 18

what happens after glycolysis when anaerobic respiration occurs in yeast/plants?

Answer 18

ethanol fermentation

Question 19

describe ethanol fermentation

Answer 19

1)pyruvate decarboxylated to form ethanal, losing carbon dioxide
2)NADH oxidised to NAD, reducing the ethanal to ethanol as it gains the hydrogen
3)the regenerated NAD is repeatedly used in glycolysis so ATP can continue to be made

Question 20

describe lactate fermentation

Answer 20

1)NADH oxidised to NAD
2)pyruvate gains hydrogen reducing it to lactate
3)regenerated NAD repeatedly used in glycolysis so that ATP can continue to be made

Question 21

describe t he structure of chloroplasts

Answer 21

-contain stacks of thylakoids, also known as grana
-thylakoids contain different types of pigments: chlorophyll A, chlorophyll B, carotenoids and xanthophyll
-each pigment absorbs a different wavelength of light

Question 22

what factors effect the rate of photosynthesis?

Answer 22

light intensity
carbon dioxide concentration
temperature

Question 23

what happens to the rate of photosynthesis when light intensity increases?

Answer 23

rate of light dependent reaction increases
more ATP/NADPH produced
rate of light independent reaction increases

Question 24

what happens to the rate of photosynthesis when carbon dioxide concentration increases?

Answer 24

increased conversion of RuBP to GP

Question 25

what happens to rate of photosynthesis when temperature increases?

Answer 25

increases rubisco activity until it is denatured leading to decreased activity
molecules in the thylakoid membrane stop working

Question 26

how can the limiting factors of photosynthesis be overcome?

Answer 26

using artificial lighting, carbon dioxide waste and using greenhouses

Question 27

what are the adaptations of chloroplasts?

Answer 27

1)thylakoid membrane provides large surface area
2)proteins hold grana for maximum light absorption
3)ATP synthase and selectively permeable membrane for ATP synthesis
4)DNA and ribosomes for synthesis of required proteins

Question 28

where does the light dependent reaction occur?

Answer 28

thylakoid membrane between the stroma and thylakoid space

Question 29

describe the light dependent reaction

Answer 29

1)light energy absorbed by chlorophyll
2)photoionisation- energy transferred to electrons causing them to be in an excited state.this makes them leave the chlorophyll
3)photolysis- light splits water into electrons, protons and oxygen
4)electrons move down the electron transfer chain through a series of redox reactions, providing energy to the proteins so that protons can be actively transported into the thylakoid space
5)this maintains a proton gradient between the stroma and thylakoid space
6)electrons at the end of the chain react with NADP and protons to produce NADPH
7)protons diffuse back into the stroma through ATP synthase in a process called chemiosmosis
8)ATP synthase supplied with energy which is used to catalyse the production of ATP

Question 30

where does the light independent reaction occur?

Answer 30

in the stroma

Question 31

describe the light independent reaction

Answer 31

1)carbon dioxide enters stroma and reacts with ribulose biphosphate forming two molecules of glycerate-3-phosphate, catalysed by rubisco
2)glycerate-3-phosphate reduced to 2 molecules of triose phosphate when NADPH is oxidised, requiring ATP
3)roughly 80% of triose phosphate is converted to ribulose biphosphate using ATP
4)other 20% converted to organic substances like glucose, amino acids and glycerol

Question 32

what is biomass?

Answer 32

the dry mass per given area per given time or the mass of carbon per given area per given time

Question 33

what type of store does biomass contain?

Answer 33

chemical energy store

Question 34

what is a chemical energy store?

Answer 34

energy stored in the bonds of chemical compounds, which is produced during photosynthesis

Question 35

what equation is used to calculate heat released per unit mass?

Answer 35

(specific heat capacity of water x water vol. x temp.change) / mass of dry biomass

Question 36

what is gross primary production?

Answer 36

chemical energy store in plant biomass in a given area or volume

Question 37

what is net primary production?

Answer 37

chemical energy store left when respiratory losses have been taken into account

Question 38

how do you calculate net primary production?

Answer 38

NPP=GPP— R

Question 39

how do you calculate net product of consumers?

Answer 39

N=I—(F+R)
I: energy ingested
F:losses from excretion
R:respiratory losses

Question 40

what is primary/secondary productivity?

Answer 40

biomass in a given area at a given time

Question 41

how is % efficiency calculated?

Answer 41

(energy available after transfer/energy available before transfer) x 100

Question 42

how can % efficiency be increased?

Answer 42

1)simplifying food webs
2)reduce respiratory losses

Question 43

what are the 4 key parts of the nitrogen cycle?

Answer 43

nitrogen fixation
ammonification
nitrification
denitrification

Question 44

what is nitrogen fixtation?

Answer 44

~ carried out by mutualistic nitrogen fixing bacteria found in root nodules or free living nitrogen fixing bacteria found in soil
~mutualistic nitrogen fixing bacteria have a symbiotic relationship with plants
~nitrogen gas converted into nitrogen containing compounds

Question 45

what is ammonification?

Answer 45

nitrogen compounds in waste products and dead organisms converted into ammonia by saprobionts, forming ammonium ions

Question 46

what is nitrification?

Answer 46

nitrifying bacteria convert ammonium ions into nitrites before a different nitrifying bacteria converts nitrites to nitrates. this requires oxygen.

Question 47

what is denitrification?

Answer 47

denitrifying bacteria use nitrates during respiration which produces nitrogen gas that returns to the atmosphere. this occurs in anaerobic conditions

Question 48

what is mycorrhizae?

Answer 48

the relationship between roots + fungi
1)increases root surface area for water and mineral uptake
2)fungi act as sponges and hold onto water which can be useful in times of drought

Question 49

describe the phosphorus cycle

Answer 49

1) weathering of rocks slowly releases phosphate ions into the soil and water sources
2)plants absorb phosphate ions through the roots and algae absorbs it from the water
3)phosphate ions transferred to consumers during feeding
4)saprobionts break down waste products and dead organisms releasing phosphate ions into soil/water
5)phosphate ions either taken up by producers again or are trapped in sediments which may turn back into rock again

Question 50

what is the role of fertiliser?

Answer 50

replace nutrients lost due to harvesting crops and removing livestock

Question 51

what are the 2 types of fertilisers?

Answer 51

natural fertilisers made of organic matter or artificial fertilisers made from inorganic matter

Question 52

describe the process of eutrophication

Answer 52

1) leaching- fertilisers moved into nearby bodies of water by rainwater or water from irrigation systems
2)algal bloom- leaching causes rapid growth of algae on the surface
3)aquatic plants and algae die- sunlight blocked by algae meaning aquatic plants can’t photosynthesise, algae also die as nutrients runs out
4)saprobionts increase in number- as plants die, numbers of saprobionts increase to break down the dead matter
5)decrease in dissolved oxygen- saprobionts use up oxygen during respiration
6)aerobic organisms die as dissolved oxygen concentration decreases