Photosynthesis

Question 1

Phosphorylation

Answer 1

Adding phosphate to a molecule

Question 2

Photophosphorylation

Answer 2

Adding phosphate using light

Question 3

Photolysis

Answer 3

Splitting a molecule using light

Question 4

Hydrolysis

Answer 4

Splitting a molecule using water

Question 5

Reduced

Answer 5

Gaining electrons or gained hydrogen

Question 6

Oxidised

Answer 6

Lost electrons or gained oxygen

Question 7

Photosynthesis Definition

Answer 7

The process where energy from light is used to break H2O and store hydrogen as glucose. It occurs in the chloroplast

Question 8

Photosynthesis Equation

Answer 8

6CO2 + 6H20 + ENERGY = C6H12O6+6O2

Question 9

ATP as an Energy store

Answer 9

During respiration, glucose is broken down

This releases energy that creates synthesis of ATP º

Question 10

How is ATP synthesise?

Answer 10

• Phosphorylation of ADP occurs
  Inorganic phosphate is added to ADP+Pi to form ATP.
  Energy is released when ATP is hydrolysed to ADP

Question 11

Structure of a Chloroplast

Answer 11

• A double membrane called chloroplast envelope
• Thylakoid membranes - Stack to form grana and have a large surface area.
• Lamellae - Joins the grana together
• Photosynthetic pigments - Absorb light and attach to proteins to form photosystems
• Stroma - Contains enzymes and sugars for L.I.R
• Starch grains - store carbohydrates
• Ribosomes - Protein synthesis

Question 12

Absorption of light

Answer 12

White light is a mix of different colours. Each colour has a different wavelength

• Blue: 450nm
• Red: 650nm

Question 13

Chromatography Practical

Answer 13

1) Cut fresh leaf tissue and grind with sand
2) Put the sample in a test tube with propanone and shake
3) Add distilled water and shake
4) Add petroleum ether so solvents separate
5) Draw a pencil line on chromatography paper and allow the solvent to travel up the paper
6) The pigment will be left behind

Question 14

The light-dependent Reaction

Answer 14

• This occurs in the grana inside the chloroplast

- This uses light to form ATP, NADPH

Question 15

Non-cyclic phosphorylation

Answer 15

1) Light absorbed in PSII, electrons excite and move to higher energy level. These move down the E.T.C to PSI
2) Photolysis of water - Produces H*, E- and O2. Electrons then replace those in PSII
3) The electrons lose energy moving down the chain. Protons transporter to thylakoid creating a proton gradient. Protons move into the stroma via ATP synthase, Energy synthesises ATP
4) Light absorbed at PSI excites electrons to a high level, Electrons are transferred to NADP to form NADPH

Question 16

Cyclic phosphorylation

Answer 16

This only produces small amounts of ATP

1) Electrons move to a high level
2) cycle back to PSI by moving down a small section of the E.T.C to produce small amounts of ATP

Question 17

Light Independent Reaction

Answer 17

This occurs in the stroma of the chloroplast

Question 18

The Calvin Cycle

Answer 18

1) Co2 combines with RuBP, this is catalysed by RUBISCO enzyme
2) 2 x Glycerate 3 phosphate (GP) are formed
3) ATP and NADP reduce GP to TP or GALP
4) Some GALP is used to make other organic compounds
4) The rest is regenerated to form RuBP again