3.2 Photosynthesis

Question 1

What is the equation for photosynthesis ?

Answer 1

Carbon dioxide + Water = Glucose + Oxygen

Question 2

Where does photosynthesis take place ?

Answer 2

In chloroplasts

Question 3

What do chloroplasts contain that enable photosynthesis ?

Answer 3

Photosynthetic pigments which absorb light energy at different wavelengths

Question 4

How can photosynthetic pigments be separated ?

Answer 4

Chromatography

Question 5

How are pigments identified in chromatography ?

Answer 5

By calculating Rf values to compare to values of known pigments

Question 6

How is Rf value calculated ?

Answer 6

Distance moved by pigment from origin % Distance moved by solvent front from origin

Question 7

What is absorption spectrum ?

Answer 7

A graph that shows how much light is absorbed by a pigment at different wavelengths of light

Question 8

What does a low absorbency of light mean ?

Answer 8

It has been reflected

Question 9

What does a high light absorbency mean ?

Answer 9

High rate of photosynthesis

Question 10

What is an action spectrum ?

Answer 10

Graph which shows the rate of photosynthesis at different wavelengths of light

Question 11

What is the benefit of a plant containing more than 1 pigment ?

Answer 11

Able to absorb more wavelengths of light = More light energy for photosynthesis

Question 12

What does Englemann’s experiment determine ?

Answer 12

Which wavelengths of light were used most for photosynthesis

Question 13

How is Englemanns experiment carried out ?

Answer 13

Algae was placed in suspension of motile aerobic bacteria, the light was refracted using a prism into rainbow colours

Question 14

What regions of the spectrum cause most photosynthetic activity ?

Answer 14

Blue and red

Question 15

What is light harvesting ?

Answer 15

The process of photosynthetic pigments absorbing light energy

Question 16

How is light harvesting achieved ?

Answer 16

By antenna complexes in the thylakoid membranes

Question 17

What is the name of the cell in Englemann’s experiment ?

Answer 17

Spirogyra cell

Question 18

What happens in light dependent cyclic photo phosphorylation ?

Answer 18

Light energy produces ATP
No splitting of water
Only product is ATP
Electrons keep travelling around

Question 19

Where does non cyclic photo phosphorylation occur ?

Answer 19

Chloroplasts

Question 20

Which photo system comes first in non cyclic photo phosphorylation?

Answer 20

2

Question 21

What is photolysis of water ?

Answer 21

Splitting of H2O into 2 electros, 2 H+ and 1/2 O2

Question 22

What are the products of non cyclic photo phosphorylation ?

Answer 22

NADPH2
ATP
Oxygen

Question 23

Where does the light independent stage (Calvin cycle) occur ?

Answer 23

Stroma of chloroplast

Question 24

What does the light independent stage use ?

Answer 24

Products of light dependent stage

Question 25

What are the 2 main minerals required in photosynthesis and plants ?

Answer 25

Nitrogen and magnesium

Question 26

What does nitrogen deficiency cause ?

Answer 26

Reduced growth and chlorosis

Question 27

What does magnesium deficiency cause ?

Answer 27

Chlorosis

Question 28

How is nitrogen processed in a plant ?

Answer 28

Taken up by roots as nitrates with are transported in the xylem and added to triose phosphate to produce amino acids which are transported in the phloem and used to make proteins and nucleic acids

Question 29

What is magnesium required for ?

Answer 29

By all tissues and to produce chlorophyll and activate ATPase

Question 30

Where is magnesium transported ?

Answer 30

Xylem

Question 31

What are the 4 limiting factors of photosynthesis ?

Answer 31

Carbon dioxide concentration Light intensity Temperature Water

Question 32

What does extremely high light intensity cause ?

Answer 32

Damage to photosynthetic pigments which decreases rate of photosynthesis at different

Question 33

What is the light compensation point ?

Answer 33

The light intensity at which a plant has no net gas exchange as the volume of gases used and produced in respiration and photosynthesis are equal.

Question 34

What does a lack of water cause ?

Answer 34

Cell plasmolysis Stomata closing Wilting Affected physical functions Reduced carbohydrate production

Question 35

What is the algal balls experiment measuring ?

Answer 35

The rate of photosynthesis by measuring the colour change of a pH indicator

Question 36

What causes an increase in pH in algal balls experiment ?

Answer 36

CO2 absorption from the solution where aquatic organisms photosynthesise

Question 37

What happens when CO2 dissolves in water ?

Answer 37

Carbonic acid produced disassociates releasing hydrogen ions, causing pH to lower CO2+H20 = H2CO3= H+HCO3

Question 38

What causes pH indicator to change colour in algal balls experiment ?

Answer 38

Photosynthesis removes CO2 from a solution so H+ ion concentration decreases and pH increases

Question 39

What colour represents low pH/ acidic ?

Answer 39

Yellow

Question 40

What colour represents high pH or alkaline ?

Answer 40

Blue

Question 41

How is a leaves large flat surface an advantage for photosynthesis ?

Answer 41

Allows absorption of maximum light energy

Question 42

How does a thin leaf (lamina) benefit photosynthesis ?

Answer 42

Allows CO2 and sunlight to reach mesophyll cells

Question 43

How are stomata pores an advantage for photosynthesis ?

Answer 43

Allow CO2 to enter the leaf

Question 44

How are air spaces in the spongy mesophyll layer an advantage for photosynthesis ?

Answer 44

They allow CO2 to diffuse through the leaf

Question 45

What is the benefits of the cubical and epidermal layers being transparent with thin cell walls ?

Answer 45

Light can penetrate through to the mesophyll layer

Question 46

What are the benefits of palisade cells being cylindrical and elongated to the surface of the leaf ?

Answer 46

Allows more cells to feet in the leaf and light only has to penetrate through cuticular and 1 epidermal cell before reaching the palisade cell

Question 47

What are the advantages of a palisade cells large vacuole ?

Answer 47

Pushes chloroplast to the outer layer of the cell resulting in no shading so greater light intensity

Question 48

Why do chloroplasts have a large surface area ?

Answer 48

To absorb maximum light intensity

Question 49

Why do chloroplasts move within the palisade layer ?

Answer 49

To get optimum light intensity