Photosynthesis 3.2

Question 1

What is the equation for photosynthesis?

Answer 1

6CO2+ 6H2O  C6H12O6 + 6O2

Question 2

What is the definition of photosynthesis?

Answer 2

Photosynthesis is the process by which green plants are able to use light energy to convert carbon dioxide into carbohydrates.

Question 3

Why do plants get rid of their leaves in the winter?

Answer 3

As the leaves aren’t receiving much sunlight so they would take the plants nutrition.

Question 4

What characteristic of the leaf allows it to absorb as much sunlight as possible?

Answer 4

Thin and large surface area allows sunlight to penetrate the leaf as much as possible.

Question 5

What characteristic allows the leaf to diffuse carbon dioxide?

Answer 5

Stomatal pores, air spaces in spongy mesophyll and spaces between the palisade cells.

Question 6

What is needed for the light dependent stage of photosynthesis to occur?

Answer 6

Light energy my be harvested by the plant.

Question 7

Where are chlorophylls and carotenoids found?

Answer 7

The thylakoid membranes of the chloroplast.

Question 8

What are groups of chlorophylls and carotenoids called?

Answer 8

An antenna complex.

Question 9

What is a photon?

Answer 9

A quantum of light energy.

Question 10

What are the two stages of photosynthesis?

Answer 10

Light dependent and light independent.

Question 11

What is the light dependent stage?

Answer 11

The stage that requires light.

Question 12

What is the light independent stage?

Answer 12

The stage that is able to take place in the dark.

Question 13

Where does the light stage take place?

Answer 13

The internal membranes of the chloroplasts-thylakoids.

Question 14

What are the functions of the light stage?

Answer 14

Production of reduced NADP using hydrogen obtained by splitting water.
Synthesis of ATP.

Question 15

What is the first reaction of the light dependent stage?

Answer 15

Splitting water molecules by light (photolysis), to produce hydrogen ions and electrons. Oxygen is produced as a waste product.

Question 16

What is the second reaction of the light dependent stage?

Answer 16

Synthesis of ATP from ADP and Pi. This type of phosphorylation is known as photophosphorylation as light energy is involved.

Question 17

What is the third reaction of the light dependent stage?

Answer 17

The combination of hydrogen ions and electrons with NADP to produce NADPH2.

Question 18

What are the two ways phosphorylation can occur?

Answer 18

Non-cyclic processes – both ATP and NADPH2 are made.
Cyclic processes – only ATP is made.

Question 18

Why is light harvested?

Answer 18

To energy levels of the electrons.

Question 19

What is non-cyclic phosphorylation?

Answer 19

The phosphorylation of ADP to ATP using the energy from sunlight called photophosphorylation.

Question 20

Where does non-cyclic phosphorylation take place?

Answer 20

In both photosystems I and II.

Question 21

Where does cyclic phosphorylation take place?

Answer 21

In photosystem I.

Question 22

How many ATP molecules are formed in non-cyclic phosphorylation?

Answer 22

1

Question 23

How many NADPH2 molecules are formed in non-cyclic phosphorylation?

Answer 23

2

Question 24

What is the Calvin cycle?

Answer 24

A metabolic pathway.

Question 25

What is the main purpose of the Calvin cycle?

Answer 25

To convert carbon dioxide into carbohydrates- glucose, fructose...

Question 26

Describe the structure of a chloroplast.

Answer 26

Double membrane, grana connected by intergranal lamellae and stroma.

Question 27

Where are chloroplasts located in an angiosperm leaf?

Answer 27

Mesophyll layers.

Question 28

What is a photosynthetic pigment?

Answer 28

A molecule present in chloroplasts that absorbs certain wavelengths.

Question 29

Examples of photosynthetic pigments:

Answer 29

Chlorophyll a and b, beta carotene and xanthophyll's.

Question 30

What is an absorption spectra?

Answer 30

A graph showing the wavelengths of light absorbed by a pigment.

Question 31

What is an action spectra?

Answer 31

A graph of the rate of photosynthesis against each wavelength of light absorbed by a pigment.

Question 32

What is an action spectra?

Answer 32

A graph of the rate of photosynthesis against each wavelength of light absorbed by a pigment.

Question 33

What is photolysis?

Answer 33

The splitting of a molecule of water in the presence of light that occurs during the light dependent stage of photosynthesis. This produces protons, electrons and oxygen: H2O-->2H+ + 2e- + 1/2O2

Question 34

What happens to the products of photolysis?

Answer 34

Hydrogen is used in proton pumping and to reduce NADP, e- replaces electrons lost from chlorophyll a in photosystem II and oxygen is a by-products which is used for respiration or diffuses out of the leaf as waste gas.

Question 35

How does the electron transfer chain result in the production of reduced NADP?

Answer 35

NADP acts as a final electron acceptor and is subsequently reduced.

Question 36

What is a limiting factor?

Answer 36

A variable that limits the rate of a particular reaction.

Question 37

Factors that limit the rate of photosynthesis.

Answer 37

Light intensity- light dependent stage Light wavelength- absorption by chlorophyll CO2 levels- light-independent stage Temperature- enzyme-controlled reactions pH- enzyme-controlled reactions.

Question 38

What does nitrogen deficiency in plants cause?

Answer 38

Stunted growth and chlorosis (yellowing of the leaves)

Question 39

Describe the role of magnesium in plant metabolism.

Answer 39

Synthesis of chlorophyll.

Question 40

What does magnesium deficiency in plants cause?

Answer 40

Chlorosis.