Photosynthesis

Question 1

list some metabolic activities

Answer 1

• active transport - which is essential for the uptake of nitrates by root hair cells and loading sucros into sieve tube cells
• anabolic reactions - building of polymers such as protein, polysaccharides, nucleic acid for growth and repair
• movement brought about by cilia, flagella or the contractile filaments in muscle cells

Question 2

what is respiration?

Answer 2

• the process by which organic molecules such as glucose are broken down into smaller inorganic molecules like co2 and water

Question 3

explain the process of chemiosmosis

Answer 3

• where ATP produced in respiration and photosynthesis is synthesised

Question 4

what ways do electrons get excited and raise to a higher energy level?

Answer 4

• electrons present in pigment molecules are excited by absorbing light from the sun
• high energy electrons are released when chemical bonds are broken in respiratory substrate

Question 5

explainthe interrelationship between the process of

photosynthesis and respiration

Answer 5

• photosynthesis is the reaction behind the production of biomass
• respiration is the process which organisms break down biomass to provide the ATP needed to drive the metabolic reactions that place in cells
• the raw materials for one are the products of the other

Question 6

what are light harvesting systems

Answer 6

• consists of chlorophyll b, xanthophylls and carotenoids
• the role of the light harvesting is to absorb light of different wavelengths using pigments and then the pigments transfer this energy down to the reaction centre where electrons are located and excited

Question 7

what colours does chlorophyll absorb

Answer 7

• blue and red

- reflects green light

Question 8

summarise the two stages of photosynthesis?

Answer 8

light- dependent stage:

                - energy from sunlight is absorbed and used to form ATP
                - Hydrogen from water is used to reduce coenzyme NADP to reduced NADP

light independent stage:

                       - hydrogen from reduced NADP and carbon dioxide is used to build organic molecules such as glucose
                        - ATP supplies the required energy