Photosynthesis

Question 1

What is autotrophic nutrition?

Answer 1

Converting light energy to chemical energy which is used to make complex organic molecules from simple inorganic molecules.

Question 2

What is photoautotroph?

Answer 2

An organism which uses light for autotrophic nutrition.

Question 3

What is a heterotroph?

Answer 3

An organism that digests complex organic molecules to smaller inorganic molecules to be used as substrate in respiration for energy.

Question 4

What is the compensation point?

Answer 4

When the rate of respiration and photosynthesis is the same.

Because Photosynthesis only occur during the day, while plants respire constantly.

Question 5

What is the compensation period?

Answer 5

Time it takes for the compensation points to be reached again.

Question 6

Essential structure of chloroplasts

Answer 6

Outer and inner membrane
Stroma
Granum ( Thylakoids stacked on each other)
Intertribal lamellae connects grana
Starch grains 
Ribosomes
DNA

Question 7

Where does the first stage of photosynthesis occur?

Answer 7

Grana

Question 8

How are chloroplasts adapted to its function?

Answer 8

Contain lots of grana with lots of thylakoid which increases the surface area for photosystems and for electron carriers and ATP synthase.

Question 9

Where does the second stage of photosynthesis occur?

Answer 9

Stroma

Question 10

What is the cytoplasm of a chloroplast called and what can be found inside?

Answer 10

Stroma

- enzymes for 2nd stage
- starch grains
- DNA
- ribosomes

Question 11

What is the Photosynthetic pigments?

Answer 11

Lots of photosystems on Thylakoid’s membrane.

Question 12

Describe the structure of a Photosystem

Answer 12

A funnel shape, the sides containing chlorophyll and accessory pigments which work together to absorb certain wavelengths of light.
The end of the funnel contains the primary pigment reaction centre ( usually chlorophyll a)

Question 13

What wavelengths do Chlorophyll a absorb and what colour are they?

Answer 13

Green

Photosystem I = P700 (700nm)
Photosystem II = P680 (680nm)

Question 14

What range of wavelength does Chlorophyll B absorb and what is its colour?

Answer 14

400-500nm and around 650nm

Yellow green

Question 15

What are the two accessory pigments

Answer 15

Carotenoids

Xanthophylls

Question 16

What colour is the carotenoids? And the wavelengths they absorb

Answer 16

Yellow and orange

400-500nm

Question 17

What wavelengths do Xanthophylls absorb and what colour?

Answer 17

Blue and green

375-550nm

Question 18

Compare and contrast the principles of a respirometer and a photosynthometer

Answer 18

Respirometer - measures O2 absorbed by movement of fluid in capillary tube due to pressure change in the tube as CO2 produced is absorbed in soda lime or NaOH so less air in tube.

Photosynthometer - measures volume of air bubble produced from plant in the capillary tube which can be moved to be measured with ruler.

Both need to use volume = ( length of air bubble or distanced moved by air bubble divided ) x pi r^2