Brainscape's Knowledge GenomeTM

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


See full index

Biology > Photosynthesis > Flashcards

Photosynthesis Flashcards

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

What is the role of thylakoids in chloroplasts?

A
  • Site of the light dependent reactions
  • Where photosynthetic pigments absorb light energy
  • For synthesis of ATP, Reduce NADP and O2 to be produced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the role of grana in the chloroplast?

A

Provide a large surface area for the absorption of light energy

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

What is the role of the starch grain in chloroplasts?

A
  • Excess carbohydrates produced stored as a startch grain

- Starch doesn’t affect water potential

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

What is the role of the double membrane in chloroplasts?

A

Controls movement of substances in and out of chlooplasts

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

Why are plants green?

A

Photosynthetic pigments absorb all wavelengths except green and reflect the green

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

What is an absorption spectrum?

A

A graph showing how much light energy is absorbed at different wavelengths by each photosythetic pigment

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

What are the two stages of photosynthesis?

A
  • Light dependent reaction (on thylakoid membranes producing Reduced NADP and ATP from light energy)
  • Light independent reaction (in stroma producing glucose from breaking down ATP and Reduced NADP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the adaptations of leaves for photosynthesis?

A
  • AIR SPACES in spongy mesophyll allowing CO2 to diffuse into photosynthesising cells
  • LARGE SA to capture as much light as possible
  • THIN to let light penetrate all the way through
  • STOMATAL PORES to allow CO2 through from diffusion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is an action spectrum?

A

A graph showing the ate of photosynthesis at different wavelengths

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where does photosynthesis occur?

A

In chloroplasts on the thylakoid membrane

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

What happened in the Engelmann’s experiment?

A
  • As the spiral chloroplasts of the bacteia photosynthesise oxygen is produced as a waste product
  • Mobile aerobic bacteria move towards the parts of the chloroplasts exposed to red and blue parts of the spectrum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the structure of photosystems?

A
  • Located in the thylakoid membranes
  • Antenna complex where clusters of photsythetic pigments are held
  • Reaction centre containing two molecules of chlorophyll a
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the adaptations of chloroplasts of photosynthesis?

A
  • More chloroplasts in palisade than spongy mesophyll so they are exposed to more light
  • Large SA allows more CO2 and light absorption
  • Thylakoid stacking maximises light catchment
  • Chloroplasts can move within palisade cells allows or maximum absorvtion of light and protection from bleaching
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the role of the stroma in the chloroplasts?

A
  • SIte of the light independent reaction
  • Holds reactants and products fo CO2 to boduuce glucose and ATP and Reduced NADP
  • Contains starch grains that store the products of photosynthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 2 types of photosystems?

A

Photosystem I has maximum absorption wavelength of 700nm and is used in both cyclic and non-cyclic photophosphorylation

Photosystem II has maximum absorption wavelength of 680nm and is used in only non-cyclic photophosphorylation

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

What is a photosystem?

A

A collection of accessory pigments in the antenna complex which absorb light at various wavelengths and transmit energy to the reaction centre

17
Q

When and where does photophosphorylation occur?

A

In the light dependent stage on the thylakoic membrane

18
Q

What happens in cyclic photophosphorylation?

A
  • Photon hits PSI and is absorbed by accessory pigments in the antenna complex and transfered to the primary pigment
  • Excites electrons to a higher energy level to an electron acceptor
  • Moves down electron transport chain and loses energy which is used to convert ADP + Pi to ATP
  • Electron returns to PSI
19
Q

What is chemiosmosis?

A
  • Energy released by the electron transport chain is used to pump protons from the stroma into the thylakoid space
  • This creats a proton concentration gradient
    Protons move back though ATP Synthetase
  • This energy released converts ADP + Pi to ATP
20
Q

What happens in non-cyclic photophosphorylation?

A
  • Photon hits PSII and excites electrons to a higher energy level to an electron acceptor
  • Moves down electron transport chain and loses energy which is used to convert ADP + Pi to ATP
  • Electron returns to PSI
  • Simultaneously light energy hits PSI and excites electron from chlorophyll a and then travels down the ETC
  • At the end joins to the terminal electron acceptor NADP to produce NADPH with H ions from photolysis
21
Q

What happens in photolysis?

A
  • Water splits into 1/2 O2 + 2e- + 2H+
  • The electrons replace those lost in PSII
  • Protons combine to make Reduced NADP
  • Oxygen is a waste product
22
Q

What does the electrochemical gradient produce?

A

A source of potential energy for the synthesis of ATP

23
Q

Describe/Draw the Calvin Cycle

A
  • Ribulose Bisphosphate and CO2 combine with RUBISCO making an unstable 6C Compound
  • This splits for two Glycerate-3-Phosphate
  • This becomes two Triose Phosphate with the breakdown of ATP and the oxidation of Reduced NADP
  • One carbon becomes glucose (fructose bisphosphate) the rest is converted into Ribulose Phosphate for the cycle to continue with the breakdown of ATP
24
Q

What stage of photosynthesis is the Calvin Cycle?

A

The light-independent stage

25
Q

What is chromatography?

A

A seperation technique to separate pigments in leaves

26
Q

What does an Rf value show?

A

How far a component has travelled compared to the solvent front

27
Q

What are the limiting factors for plant metabolism?

A

Inorganic nutrients: Nitrogen and Magnesium

28
Q

What happens with nitrogen defficiency?

A
  • Limits metabolism
  • Nitrogen is required to synthesise proteins and nucleic acids
  • Usually transported as nitrates on the xylem
  • Defficiency causes stunted growth of all organs, hinders cell division and chlorosis
29
Q

What happens with magnesium defficiency?

A
  • Limits metabolism
  • Transported as Mg2+ in xylem
  • Required in chlorophyll and for the activation of ATP Synthetase
  • Defficiency causes chlorosis as unable to photosynthesise
30
Q

What are the three limiting factors of photosynthesis?

A

Light intensity, carbon dioxide concentration, temperature

31
Q

What happens to the rate of photosynthesis as light intensity is increased?

A
  • As light increases so does the rate until it is no longer a limiting factor
  • It will plateau as all photosystems are used and there is saturation at about 1000 lux
32
Q

What happens to the rate of photosynthesis as carbon dioxide concentration is increased?

A
  • As concentration increases so does the rate until it is no longer a limiting factor
  • It will then plateau as something else is the limiting factor
33
Q

What happens to the rate of photosynthesis as temperature is increased?

A
  • Increase as temperatue increases as enzymes work best at warm temperature
  • Optimum temperature at 45 degrees
  • Then decrease as enzymes start to denature
34
Q

What is the compensation point?

A

Where rate of photosynthesis and rate of respiration are equal and there is no net gas exchange

35
Q

Why would the compensation point never be reached at night?

A

Light dependent reaction won’t take place at night so there is no photosynthesis

36
Q

What happens in photosystems?

A

Photons hit photosystems and excite pigments in the antenna complex these transfer enegy until it reaches the primary pigment in the reaction centre. The electrons ae raised to a higher energy level to electron acceptor

37
Q

What is the general formula for photosynthesis?

A

6CO2 + 6H2O –> C6H12O6 + 6O2

38
Q

Why is there more than one photosynthetic pigment?

A

To maximise the wavelength of light that can be absorbed for photosynthesis

39
Q

Name all the photsynthetic pigments

A

Chlorophyll a
Chlorophyll b
B-Carotene (carotenoid)
Xanthophyll (carotenoid)

Biology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions