Ecosystems rely on energy transfer T5/photosynthesis. Flashcards

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1
Q

Name the two elements needed to make proteins that are not present in glucose.
(2)

A
  • Nitrogen

- Sulfur

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2
Q

Name the two elements needed to make nucleic acids that are not present in glucose.
(2)

A
  • Nitrogen

- Phosphorus

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3
Q

Which molecule provides the source of hydrogen for photosynthesis?

A

-H20

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4
Q

What is the source of energy for photosynthesis?

A

-Light

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5
Q

Which molecule provides the hydrogen for the light independent reactions?

A

-Reduced NADP

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6
Q

Which molecule provides the energy for the reduction of carbon dioxide to glucose in the light-I reactions?

A

-ATP

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7
Q

Where does the light-dependant reaction take place?

A

The thylakoid membranes of chloroplasts.

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8
Q

Where does the light-independent reaction take place?

A

The chloroplast stroma.

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9
Q

Plant fibres and oil-based plastics have both been used to make ropes.
Describe one advantage and one disadvantage of using ropes made from plant fibres rather than ropes made from oil-based plastics.
(2)

A
  • Advantage: is sustainable /biodegradable / can decompose.

- Disadvantage: less strong /can decompose/ is biodegradable.

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10
Q

Plant cell walls contain cellulose. Name the monomer that makes up cellulose.
(1)

A

Beta-glucose

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11
Q

How are the beta-glucose monomers held together in a cellulose molecule?
(1)

A

-By glycosidic bonds in an unbranched chain.

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12
Q

Photosynthesis is a two-stage process by which plants fix carbon dioxide.
Describe the light-dependent reactions of photosynthesis.
(5)

A
  • Use of light energy to excite electrons in chlorophyll/ photosystem 1 and 2/electrons promoted to higher energy level.
  • Photolysis of water to produce oxygen, electrons and hydrogen ions.
  • Electrons used in the electron transport chain/ to replace those lost by chlorophyll/ electrons used in redox reactions/ move along electron carrier proteins.
  • Generation of ATP/ photo-phosphorylation.
  • Reduction of NADP.
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13
Q

Describe the structure of a cellulose cell wall.

3

A
  • Cellulose molecule is a polymer/ chain of beta-glucose molecules.
  • Cellulose molecules held together by hydrogen bonds as microfibrils.
  • Microfibrils arranged in parallel/ criss cross.
  • Ref. to hemicelluloses.
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14
Q

Write an equation summarising:

  • The splitting of water
  • The reduction of NADP
A

a) H20=2H and 2e- and 1/2 O2

b) 2H+ and 2e- and NADP = reduced NADP

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15
Q

Which enzyme catalyses the breakdown of ATP to ADP?

1

A

-ATPase

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16
Q

Why can the Clavin cycle be described as using carbon fixation?

A

-In the Calvin cycle, the inorganic carbon in CO2 is incorporated into organic molecules. The Carbon is fixed in organic molecules making it available to other organisms. These compounds can store energy.

17
Q

Name a substance that has been phosphorylated in the light independent reaction.
-Name a substance formed by reduction.
(1)

A
  • RuBP

- GALP

18
Q

Describe how a plant converts glucose into sucrose.

A

-A glucose molecule is converted into fructose, which joins with a glucose molecule in a condensation reaction to form the disaccharide sucrose.

19
Q

Describe how a plant produces cellulose using the glucose formed in photosynthesis.
(3)

A
  • B-glucose molecules join together, 1,4 glycosidic bonds form between adjacent B glucose molecules.
  • Straight chains of B-glucose form cellulose.
  • Hydrogen bonds form between the cellulose molecules, forming microfibrils.
20
Q

What additional elements are involved in the formation of i) amino acids and ii) nucleic acids, explain how in each case the plants obtains these elements.

A

i) Amino acids - nitrogen and sulfur; obtained from nitrate and sulfate ions absorbed by the plant roots.
ii) Nucleic acids - nitrogen in nitrogenous bases and phosphorus in phosphate group; obtained from nitrate and phosphate ions absorbed by the plant roots.

21
Q

What’s the overall reaction of photosynthesis?

A

6CO2 + 6H2O > (energy from light in the presence of chlorophyll) > C6 H12 O6 + 6O2

22
Q

Plants produce ATP in their chloroplasts during photosynthesis. They also produce ATP during respiration. Explain why it is important for plants to produce ATP during respiration in addition to during photosynthesis.
(5)

A
  • In the dark no ATP production in photosynthesis;
  • Some tissues unable to photosynthesise/produce ATP;
  • ATP cannot be moved from cell to cell/stored;
  • Plant uses more ATP than produced in photosynthesis;
  • ATP for active transport;
  • ATP for synthesis (of named substance)
23
Q

Light energy is absorbed by the chlorophyll. After the absorbed energy excites the electrons, what state is the chlorophyll considered to be in?

A

Photo ionised

24
Q

Which photosystem is involved in cyclic phosphorylation?

A

PS1

25
Q

What is starch made up of.

A

Polysaccharides branched amylopectin and unbranched amylose.