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Flashcards in Photosynthesis Deck (17):
1

What is an autotroph?

An organism that uses light or chemical energy and inorganic molecules to synthesise complex organic molecules

2

What is a heterotroph?

An organism that invests and digests complex organic molecules to provide them with chemical energy

3

Define photosynthesis

The process by which light energy is used to form complex organic molecules in chloroplasts

4

What are photosynthetic pigments?

Molecules that absorb light energy at specific wavelengths (and reflect the others) in the thylakoid membranes

5

What is a primary pigment?

It is present in the reaction centre of every photosystem
- chlorophyll a: absorbs 450-480nm (blue) and 660-710nm (red) and reflects 480-710 (yellow/green)

6

What is an accessory pigment?

A pigment that absorbs different wavelength of light to primary pigments and passes the energy to the primary pigments in the reaction centre of a photosystem

7

What are examples of accessory pigments?

Chlorophyll b - blue/green reflected
Xanthrophyll
Carotene - orange/yellow reflected

8

What is Photosystem II?

Absorbs wavelengths of 480nm

9

What is Photosystem I?

Absorbs wavelengths of 700nm

10

What are light dependent reactions?

A reaction that takes place in the thylakoid membranes
- light energy is converted to chemical energy

11

What is photophosphorylation?

The formation of ATP in the presence of light energy which occurs in the thylakoid membranes

12

What is photolysis?

An enzyme catalysed reaction where water molecules are split in PSII using light energy

13

What are electron carriers?

Molecules that transfer electrons

14

What are electron acceptors?

Chemicals that accept electrons from other compounds

15

What are light independent reactions?

Reactions that take place in the stroma and chloroplasts which do not require light energy
-require NADP and ATP from the light dependent stage, where CO2 is also produced

16

What is a limiting factor?

The factor present in the lowest amount and thus limiting the rate of reaction
- CO2
- H20
- temp

17

What is the difference between cyclic and non cyclic photophosphorylation?

-cyclic involves only PSI
-photolysis of water does not occur
-NADPH is not produced (NAD coenzyme is not reduced)