Chapter 17 - Photosynthesis

Question 1

why are leaves different colours

Answer 1

photosynthetic pigments absorb different wavelengths of light

Question 2

what are photosystems made up of

Answer 2

• reaction Centre (primary pigment) and light harvesting system (accessory pigment)

Question 3

What is the importance of C-H bonds

Answer 3

• non polar
• low energy to break bonds
• store a lot of energy
• lots of energy is released

Question 4

Inter-relationship between photosynthesis and respiration

Answer 4

• photosynthesis uses light energy to synthesise organic molecules (glucose) and the energy is stored in the C-H bonds
• respiration breaks down the organic molecules into inorganic molecules releasing energy from C-H bonds using it to synthesise ATP

Question 5

Adaptations of chloroplasts

Answer 5

• large surface area of grana to maximise absorption of light energy
• thylakoids contain pigments, photosystems and electron transport chains

Question 6

Adaptations of chloroplasts

Answer 6

• large surface area of grana to maximise absorption of light energy
• thylakoids contain pigments, photosystems and electron transport chains

Question 7

What wavelength of light does chlorophyll best absorb

Answer 7

-red and blue

Question 8

What wavelength of light does chlorophyll best absorb

Answer 8

-red and blue

Question 9

Uses of Triose phosphate

Answer 9

• synthesis of complex molecules: amino acids, glucose, lipids
• regeneration of RuBP using ATP

Question 10

Uses of Triose phosphate

Answer 10

• synthesis of complex molecules: amino acids, glucose, lipids
• regeneration of RuBP using ATP

Question 11

Light intensity as a limiting factor of photosynthesis

Answer 11

• increasing light intensity increases rate of photo ionisation and photolysis so more NADPH and ATP are produced

Question 12

Carbon dioxide concentration as a limiting factor of photosynthesis

Answer 12

• increase in carbon dioxide concentration increases rate of GP production from RuBP

Question 13

Temperature as limiting factor of photosynthesis

Answer 13

• increasing temperature increases enzyme activity (eg. RuBisCo) increasing rate
• extreme high temperatures cause enzymes and proteins in ETC to denature decreasing rate

Question 14

Where does the light dependent stage of photosynthesis occur

Answer 14

Thylakoid membrane

Question 15

Where does the light independent stage occur

Answer 15

In the stroma