Topic 5 - Energy Transfers In And Between Organsims

Question 1

What is the thylakoids job in photosynthesis?

Answer 1

Folded membranes which contain photosynthetic pigment and electron carrier proteins are embedded within these membranes which are both involve in LDR.

Question 2

What is the Stromas role in photosynthesis?

Answer 2

Fluid centre which contains enzymes involved in the LIR.

Question 3

What are the inner and outer membranes jobs?

Answer 3

Control what can enter and leave the organelle.

Question 4

What is the light dependent stage of photosynthesis?

Answer 4

– the light dependent reaction occurs on the thylakoid membrane or grana.
– LDR is the first stage of photosynthesis and it requires light. Light energy and water are used to create ATP and reduce NADP which are needed for the independent stage.

Question 5

The 4 stages of the light dependent stage

Answer 5

1. Photolysis
2. Photoionisation of chlorophyll
3. Chemiosmosis
4. Production of ATP and rescued NADP

Question 6

What is photolysis of water?

Answer 6

• Light energy is absorbed by chlorophyll and splits into oxygen, hydrogen and electrons.
• The hydrogen is picked up by NADP to form NADPH and is used in the light independent reaction.
• The electrons are passed along a chain of electron carrier proteins.
• The oxygen is either used for respiration or diffuses out of the leaf through the stomata.

Question 7

What is photo ionisation of chlorophyll?

Answer 7

• light energy is absorbed by the chlorophyll and the energy result in the electrons becoming excited and raising up an energy level to leave chlorophyll.
• Therefore the chlorophyll has been ionised by light.
• Some of the energy from the released electrons is used to make ATP and reduced NADP in chemosmosis.

Question 8

What is chemosmosis?

Answer 8

The movement of protons across the membrane to generate ATP.
-Light energy excite electrons, and electrons move through the electron transport chain pumping hydrogen irons into the thylakoid space Creating a gradient.
- Hydrogen ions diffuse back into the stoma through ATP synthase producing ATP.

Question 9

What is the light independent reaction?

Answer 9

Also known as the Calvin cycle and occurs in the stroma. The fluid contains the enzyme RuBisco which catalyses this reaction. This stage is temperature sensitive due to the fact it involves enzymes.

Question 10

What does the light independent reaction use?

Answer 10

Carbon dioxide, reduced NADP and ATP to form a hexose sugar.

Question 11

Explain what is the light independent reaction/calvin cycle?

Answer 11

– Carbon dioxide react with ribulose bisphosphate to 2 molecules of glycerine 3-phosphate a carbon 3 comp. This reaction is catalysed by the enzyme RuBisco.
– GP is reduced to triose phosphate using energy from ATP and accepting a hydrogen from reduced NADP.
– Some of the carbon from TP leaves the cycle each turn to be converted into useful organic substances.
– The rest of the molecule is used to regenerate RuBP with the energy from ATP.
– Whilst glucose is the product this monosaccharide can join to form disaccharides such as sucrose and polysaccharides such as cellulose and starch. It can also be converted into glycerol and therefore combine with fatty acids to make lipids for the plant.

Question 12

What are the limiting factors of photosynthesis?

Answer 12

Temperature, light intensity, and carbon dioxide concentration.

Question 13

What can farmers do to limit the factors affecting photosynthesis?

Answer 13

These range from growing plants under artificial lighting to maximise the light intensity. Heating a greenhouse to increase the temperature of burning fuel, such as paraffin burners, to release more carbon dioxide.

Question 14

What do farmers have to consider when trying to limit limiting factors of photosynthesis?

Answer 14

The extent each technique is used needs to be considered in terms of profit. If extra growth from photosynthesis is minimal, it will not be cost-effective to pay for heating/lighting/fuel.

Question 15

Where does glycolysis occur>

Answer 15

Cytoplasm

Question 16

Where does the link reaction occur?

Answer 16

Mitochondrial matrix

Question 17

Where does the Krebs cycle occur?

Answer 17

Mitochondrial matrix.

Question 18

Where does oxidative phosphorylation occur?

Answer 18

Mitochondrial inner membrane-cristae.

Question 19

What is glycolysis?

Answer 19

Respiration produces ATP
Glycolysis is the first stage of anaerobic and aerobic respiration
It occurs in the cytoplasm and is an anaerobic process

Question 20

What are the three key stages of glycolysis?

Answer 20

1. Phosphor relating glucose to glucose phosphate using ATP.
2. The production of triose phosphate
3. Oxidation of triose phosphate to produce pyruvate with a net gain of ATP and reduced NAD.

Question 21

After glycolysis has finished, there are pyruvate and NADH what is done with these two?

Answer 21

Pyruvate and NAD are actively transported from the cytoplasm into the mitochondrial matrix.

Question 22

What happens in the link reaction?

Answer 22

– The pyruvate made in glycolysis is oxidised to acetate.
– NAD picks up the hydrogen and becomes reduced NAD.
– Acetate then combined with co-enzyme A to produce acetyl co-enzyme A.

Question 23

What happens in the Krebs cycle?

Answer 23

Acetyl co-enzyme A react with a 4 carbon molecule releasing coenzyme A and producing a 6 carbon molecule that enters the Krebs cycle.
In a series of redox reactions, the Krebs cycle generates reduce co-enzymes and ATP by substrate level phosphorylation and carbon dioxide is lost.

Question 24

What is the stages of oxidative phosphorylation?

Answer 24

The electron transport chain
Movement of protons across the inner mitochondrial membranes
Catalysed by ATP synthase.

Question 25

What is anaerobic respiration?

Answer 25

– In the absence of oxygen respiration occurs anaerobically it occurs in the cytoplasm of the cell only. – The pyruvate produced in glycolysis is reduced to form ethanol and carbon dioxide lactate by gaining the hydrogen from reduced NAD. – This oxidises NAD so they can be reused in glycolysis and ensure more ATP is continued to be produced

Question 26

What are the producers of any ecosystem?

Answer 26

Plants – in a food web they are able to produce their own carbohydrates using carbon dioxide in the atmosphere or water.

Question 27

How is energy lost between each trophic level?

Answer 27

Respiration and excretion the remaining energy is used to form biomass.

Question 28

What is the biomass?

Answer 28

Measured in terms of mass of carbon or dry mass of tissue given area.

Question 29

What is gross primary production?

Answer 29

The chemical energy stored in plants biomass in a given area of volume. It is the total energy resulting from photosynthesis.

Question 30

What is net primary product?

Answer 30

The chemical energy store in the plants by a must taking into account energy that will be lost due to respiration.

Question 31

What is the formula for net production of consumers and what are the symbols mean?

Answer 31

N = I - (F + R) I = the chemical energy stored in ingested food F = chemical energy to the environment in faeces and urine R = respiratory losses

Question 32

What is nitrogen?

Answer 32

The air is 78% nitrogen however plants and animals cannot obtain nitrogen through gas exchange. Nitrogen gas contains a triple bond. Micro organisms are needed to convert nitrogen gas into nitrogen containing substances that plants and animals can absorb.

Question 33

Which biological molecules contain nitrogen?

Answer 33

Proteins, ATP and nucleic acidS

Question 34

What are the processes in the nitrogen cycle?

Answer 34

1. Siaprobiotic nutrition and microbes. 2. Ammonification. 3. Nitrification. 4. Nitrogen fixation. 5. Denitrification

Question 35

What is phosphorus used for in organisms?

Answer 35

DNA/RNA ATP Phospholipid bilayer It is therefore an essential element of life

Question 36

What is the phosphorus cycle?

Answer 36

This cycle is different to the carbon and nitrogen in that phosphorus is not found as a gas and therefore not in the atmosphere. Instead, it is mainly found as a phosphate ion in mineral form in sedimentary rocks.

Question 37

What Is mycorrhizae?

Answer 37

Fungal associations between roots and beneficial fungi

Question 38

Why are mycorrihzae beneficial for plant growth?

Answer 38

1. The fungi increase the surface area for water and minimal absorption. 2. The. Mycorrhizae act like a sponge so hold water and minerals around the roots. 3. This makes plants more drought resistant unable to take up more organic ions. Part in the nutrient cycle is therefore improving the uptake of relatively scarce ions such as phosphate ions.

Question 39

What is the phosphorus cycle?

Answer 39

- Plants and absorb phosphate ions from the oceans and the soil through their root hair cells. - Animals will then eat the plants. - when animals excrete it will release phosphate ions back into the ocean and the soil. - some of the excretion and decomposition from animals is broken down and the roads into the oceans and soil. - deposition of phosphate ions occurs to build up rocks. - phosphate ions in soil will compact to make sedimentation. - sedimentary rocks can be eroded to at least the phosphate back into the sea and the soil.

Question 40

What are fertilisers?

Answer 40

Fertilisers are added to soil to replace the nitrate and phosphate ions lost when plants are harvested and removed from nutrient cycles as crops.

Question 41

What are the two types of fertiliser?

Answer 41

Natural – manure Artificial – inorganic chemicals

Question 42

What are the advantages and disadvantages of natural fertilisers?

Answer 42

Natural fertilisers are cheaper and often free if the farmers own animals. However, the exact minerals and proportions cannot be controlled.

Question 43

What are the advantages and disadvantages of artificial fertilisers?

Answer 43

Artificial fertilisers are chemicals created to contain exact proportions of minerals. Organic substances are more water soluble and therefore more of these ions dissolve in the water surrounding the soil.

Question 44

What is the environmental impact of artificial fertilisers?

Answer 44

Leaching: when water soluble compounds are washed away often into rivers or ponds. If the nitrogen fertiliser leaches into waterways it causes eutrophication.

Question 45

What is eutrophication?

Answer 45

When nitrates leached from fertilised fields stimulate growth of algae in ponds. The excessive growth of algae creates a blanket on the surface of the water which blocks out light. As a result, plants below cannot photosynthesise and therefore they die. This result in an increased in bacteria which are always firing and using up oxygen within the water . Eventually, fish and other aquatic organisms died due to the lack of dissolved oxygen in the water.