OCR F214 Photosynthesis

F214 Module 3: Photosynthesis
4.3.1 Photosynthesis

(a) define the terms autotroph and heterotroph
Autotrophs organisms that use light energy or chemical energy and inorganic molecules (carbon dioxide and
water) to synthesise complex organic molecules.
Heterotrophs organisms that ingest or digest complex organic molecules, releasing the chemical potential
energy stored in…

F214 Module 3: Photosynthesis

(f) define the term photosynthetic pigment
Photosynthetic pigments molecules that absorb light energy. Each pigment absorbs a range of wavelengths in
the visible region and has its own distinct peak of absorption. Other wavelengths are reflected. They appear to us
as the colour of the light…

F214 Module 3: Photosynthesis
5. The hydrogen ions made in the photolysis of water combines with electrons to form hydrogen atoms . The
NADP combines with hydrogen to form reduced NADP .
6. As the protons move across the thylakoid membrane by chemiosmosis through ATP synthase, causing
photophosphorylation producing ATP…

F214 Module 3: Photosynthesis
Electrons ­ replace those lost by the oxidised chlorophyll and to reduce chlorophyll a.
Oxygen ­ used by the plant in aerobic respiration but much of it diffuses out of the leaves , through stomata ,
into the air.
(k) outline how the products of the…

F214 Module 3: Photosynthesis
Most triose phosphate is recycled to ribulosebisphosphate. 5 out of 6 molecules of TP (3C) are recycled by
phosphorylation , using ATP from the lightdependent reaction , to 3 molecules of RuBP (5C).

(o) describe the effect on the rate of photosynthesis, and on levels of…

F214 Module 3: Photosynthesis
involved in electroncarriers ) also
photophosphorylation = denature .
more ATP . o Oxygen more successfully
3. Splits water molecules to competes for rubisco and
produce protons involved stops it from accepting CO 2.

in photophosphorylation = o More water loss from
more ATP . stomata…

F214 Module 3: Photosynthesis











Using Changes in Density of Leaf Discs:
1. Use a drinking straw to cut several leaf discs .

2. Place 5/6 discs in a 10cm3 syringe and halffill the syringe with dilute sodium hydrogencarbonate solution.
3. Hold the syringe upright , place your finger over the…