Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > 11. Photosynthesis > Flashcards

11. Photosynthesis Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Give adaptations of the leaf for photosynthesis

A
  • Large surface area for light absorption
  • Leaf arrangement that minimises overlap and shadowing
  • Thin for gas exchange
  • Transparent cuticle and epidermis to let light through to mesophyll cells
  • Long, narrow upper mesophyll cells packed with chloroplasts
  • /Numerous stomata for gas exchange
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Give the equation for photosynthesis

A

6CO2 + 6H20 —> C6H12O6 + 6O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Give the 3 main stages of photosynthesis

A
  1. Capturing light energy
  2. The light-dependent reaction: electron flow created by light, produces reduced NADP, ATP and oxygen
  3. The light-independent reaction: protons used to produce sugars/organic molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Give the structure of chloroplasts

A
  • The grana- stacks of thylakoids containing chlorophyll, where light-dependent stage takes place
  • The stroma- fluid filled matrix where light-independent stage takes place
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe Oxidation

A

When a substance gains oxygen or loses hydrogen/electrons. Oxidation results in energy being given out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define ‘Photoionisation’

A

The chlorophyll molecule becomes ionised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe the process of producing ATP by the chemiosmotic theory

A
  • Protons (H+) are pumped from the stroma into thylakoids using proton pumps in the thylakoid membrane.
  • The energy to drive this process comes from electrons released when water molecules are split by light- photolysis
  • The photolysis of water produces protons, increasing proton concentration in thylakoid
  • This creates a concentration gradient of protons across the thylakoid membrane with high concentration in thylakoids and low concentration in stroma
  • The protons can only cross the thylakoid membrane through ATP synthase channel proteins.
  • This changes the structure of the enzyme which then catalyse the combination of ADP and an inorganic phosphate to form ATP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the photolysis of water

A

The loss of electrons when light strikes a chlorophyll molecule leaves a shortage of electrons. If the chlorophyll molecule is to continue absorbing light energy, these electrons must be replaced. The replacement electrons are provided from water molecules that are split using light energy.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Give the products of the light-dependent reaction

A
  • Reduced NADP
  • ATP
  • Oxygen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is reduced NADP produced in the light-dependent reaction?

A

The protons that pass out of the thylakoid through ATP synthase channels are taken up by the electron carrier NADP. On taking up protons the NADP becomes reduced.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why is reduced NADP important to the plant?

A

Source of chemical energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How are chloroplasts adapted to their function of capturing sunlight for the light-dependent reaction?

A
  • Thylakoid membranes provide a large surface area for attachment of chlorophyll, electron carriers and enzymes.
  • A network of proteins in the grana hold the chlorophyll in a manner allowing maximum light absorption
  • The granal membranes have ATP synthase channels to catalyse ATP production, selectively permeable to establish a proton gradient
  • Chloroplasts contain both DNA and ribosomes to quickly manufacture proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

State where in a plant cell the electron carriers involved in the light-dependent reaction are found

A

On the thylakoid membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe what happens in the photolysis of water

A

Water molecules are split to form electrons, protons and oxygen, as a result of light exciting electrons in chlorophyll.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the products of the light-independent reaction?

A

Sugars and organic products

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the Calvin Cycle/ Light-independent reaction

A
  1. Carbon dioxide diffuses into the leaf through stomata and dissolved in water around mesophyll cells. It diffuses into the stroma of the chloroplast.
  2. In the stroma, the carbon dioxide reacts with 5-carbon compound ribulose bisphosphate, catalysed by the enzyme rubisco
  3. The reaction produces 2 molecules of the 3-carbon glycerate 3-phosphate
  4. Reduced NADP reduces glycerate 3-phosphate to triose phosphate using ATP
  5. The NADP is reformed and goes back to the light-dependent reaction to be reduced again by protons
  6. Some triose phosphate are converted to organic substances: starch, cellulose, lipids, glucose etc.
  7. Most of triose phosphate is used to regenerate ribulose biphosphate using ATP from light-dependent reaction
17
Q

How is the chloroplast adapted to carrying out the light-dependent reaction?

A
  • The fluid of the stroma contains enzymes needed for reaction
  • The stroma fluid surrounds the grana so the products of the light-dependent reaction readily diffuse into the stroma
  • Contains both DNA and ribosomes so can manufacture proteins
18
Q

Which factors affect photosynthesis?

A
  • Temperature
  • Light intensity
  • CO2 concentration
19
Q

What is the limiting factor?

A

The least favourable factor, limits the rate at which photosynthesis takes place. Changing only the levels of the other factors won’t affect the rate of photosynthesis.

20
Q

What experiment can you use to measure rate of photosynthesis?

A

Potometer

21
Q

Describe the role of ribulose bisphosphate in the Calvin Cycle

A

It combines with a molecule of CO2 to produce 2 molecules of glycerate-3-phosphate

22
Q

State how the reduced NADP from the light-dependent reaction is used in the light-independent reaction

A

It is used to reduce glycerate-3-phosphate to triose phosphate

23
Q

Apart from reduced NADP, which other product of the light-dependent reaction is used i the light-independent reaction?

A

ATP

24
Q

Light is not required for the Calvin cycle to take place. Explain therefore why the Calvin cycle cannot take place for long in the absence of light

A

The Calvin cycle requires both ATP and reduced NADP in order to operate. Both are the products of the light-dependent reaction, which needs light. No light means no ATP or reduced NADP are produced and so the Calvin cycle cannot continue once ATP or reduced NADP have been used up.

25
Q

What is an electron carrier?

A

A chain of carrier molecules along which electrons pass releasing energy in the form of ATP as they do so

Biology (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions