Photosynthesis

Question 1

Why is energy important ?

Answer 1

• Living thinsg need energy for biological processes to occur
• Plants need energy for things like photsynthesis,active transport(minerals to move via their roots),Dna Replication and cell divsion
• Animals need energy for things like muscle contraction,maintence of body temperature,active transport,DNA replication and cell division.
• Micro-organisms need energy for things liuke DNA replication,cell division,protein syntheisi and seomtimes motility.
• Without these organisms would die

Question 2

What is photosynthesis?

Answer 2

• Photosynthesis is the process where theenergy from light is used to make glucose from water and carbon dioxide. The light energy is converted into chemial energy in the from of glucose.
• Energy is stored in the plant until the plants relase it by repiration. Animals cant make their own fodd so they eat plants to gain the energy
• Photosynthesis equation:
• 6CO2 + 6H2O → C6H12O6 + 6O2.

Question 3

What is respiration ?

Answer 3

• Living things release energy from glucose. The energy is used to power all the biological processes in the cell.
• There are two types:
• Aerobic - using oxygen
• Anaerobic - without oxygen
• Equation: C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 4

What is ATP?

Answer 4

• ATP is the immediate source of energy in a cell
• It is made from a nucleotide base, adenine, riobse sugar, 3 phosphate groups
• It carries energy to the celll where it is needed
• ATP is synthesised from ADP and inorganic phosphate using energy from an energy-releasing reaction,e.g the breakdown of glucose in respiration.The energy is stored as chemical energy in the phosphate bond.
• The enzyme ATP synthase catalyzes this reaction
• This process is known as phospholyration
• ATP goes back to where is needed in the cell

Question 5

What are ATP’s properties ?

Answer 5

• ATP releases a small amount of energy at the time so no energy is wasted
• A small soluble molecule so it can be easily transported arpund the cell
• It can be easily broken down so it can be released
• It can transfer energy to another molecule by transferring one of its phosphate groups
• ATP can pass out the cell, so the cell always ha s an immediate supply of energy

Question 6

What is a a compensation point ?

Answer 6

• Both processes can occcur at the same time at different rates (photosynthesis and respiration). The rate at which photosynthesis takes place is partly dependent on the light intensity of the envrionment tahst the plant is inn .
• Theres a particular level of light intensity at which the rate of photosynthesis exactly matches the rate of respiration. This is called the compensation point for light intensity.

Question 7

What are the choloroplasts?

Answer 7

• Photsynthesis takes place in the cholroplasts of plant cells. They are small flattened organelles , found in plant cells .

Question 8

Draw the structure of chlolorplast ?

Answer 8

CHECK GOOGLE IF YOUR CORRECT !!!!!

Question 9

What do cholroplasts contain?

Answer 9

• They contain phosynthetic pigments (e.g chlorophyll a , b carotene )
• These are coloured substances that absorb the light energy needed for photsynthesis
• The pigments are found in the thylakoid membrane- they are attcahed to proteins. The protein and pigement is called photsystem.

Question 10

What are the two types of photsynthetic pigements a photosystem contains?

Answer 10

• Primary acessory pigments - are reaction centres where the electrons are excited during LDR - in most it only contains chlorphyll a
• Acessory pigments make up light-harvesting systems , these surrond reaction centres and transfer light energy to them to boost the energy availablefor electron excitement to take place.

Question 11

What is a coenzyme?

Answer 11

• It is a molecule that aids the function of an enzyme.They usually work by transferring a chemical group from one molecule to another
• A coenzyme used in photosyntheis is NADP. NADP transfers hydrogen from one molecule to another-this means it can reduce or oxidise a molecule.

Question 12

What are the stages of photosynthesis?

Answer 12

• The light-dependent reaction
  -The light-independent reaction (calvin cycle)

Question 13

Draw and explain LDR diagram

Answer 13

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Question 14

Describe the reaction involving glycerate 3-phosphate in the Calvin cycle. Include details about the fate of the products produced in this reaction.

Answer 14

In the Calvin cycle, glycerate 3-phosphate is converted into triose phosphate (TP), which has three carbons. This reaction requires reduced NADP and ATP from the light-dependent reaction.
NADP, ADP and produced in this reaction return to the thylakoid membrane to be used up in the light-dependent reaction to produce new molecules of reduced NADP and ATP