Photosynthesis

Question 1

What is photosynthesis

Answer 1

It is the process by which green plants and certain other organisms transform light energy into chemical energy

Question 2

What is the photosynthesis reaction

Answer 2

Carbon dioxide + Water → Glucose + Oxygen + Water

Question 3

What are chloroplasts made of

Answer 3

• Double phospholipid bilayer
  forming inner and outer
  membrane
• Inside the inner membrane
  is a third network of
  membranes called the
  thylakoid
• Thylakoid membrane forms
  disc like stacks called granum

Question 4

What is the function of the chloroplast

Answer 4

• Site of photosynthesis
• Capture sun’s energy and
  use it to convert carbon
  dioxide and water into
  sugar/glucose and oxygen

Question 5

What is chlorophyll

Answer 5

• Chlorophyll is needed to make food in plants
• Chlorophyll is a green pigment located within the thylakoid membrane
  of chloroplasts
• Chlorophyll has many pigments and may also show as other colours in
  plant leaves

Question 6

What is glucose

Answer 6

• Glucose is stored chemical energy
• Plants and animals use it during
  respiration to produce ATP
  molecules (energy)
• Glucose is also used to make
  cellulose and starch, which allow the
  plant to grow and repair

Question 7

What are the 2 phases of chlorophyll production

Answer 7

• Glucose is produced in two
  phases inside the
  chloroplast:
• Phase 1: light dependent
  (needs sunlight)
• Phase 2: light
  independent (doesn’t
  need sunlight)

Question 8

What is phase 1 - light dependent

Answer 8

• Occurs in the thylakoid membrane/grana of the chloroplast
• Energy from sunlight is used to split water molecules (H2O) into
  hydrogen ions and oxygen
• Oxygen diffuses out of the leaf as a waste product
• Phase 1 also produces ATP (energy molecule) using an enzyme called
  ATP synthase
• Hydrogen ions are carried to the next phase by a carrier molecule
  called NADP + which can store the hydrogen and transport it to the
  stroma for the next phase
• NADP+ 🡪 NADPH2

Question 9

What is the reaction of Phase 1

Answer 9

Water –> (light) oxygen+hydrogen

Question 10

What is phase 2 - light independent

Answer 10

• Occurs in the stroma of the chloroplast
• Also called the Calvin Cycle
• Hydrogen ions produced in Phase 1 are moved into the stroma of the
  chloroplast by the carrier molecules NADP+
• Carbon dioxide from the air and hydrogen from Phase 1 are used to produce
  glucose
• This occurs in a series of reactions that use ATP and enzymes
• End product is glucose
• More oxygen is produced as a waste product and diffuses out of the stomata
• Light independent reactions do not happen at night! They still need the
  products from Phase 1!

Question 11

What is the reaction of phase 2

Answer 11

Hydrogen + carbon dioxide 🡪 glucose

Question 12

How is photosynthesis linked to cell transport

Answer 12

Carbon dioxide needed for
photosynthesis diffuses into the
leaf through the stomata at the
bottom

• Oxygen diffuses out of the
  stomata as a waste product
• Glucose leaves chloroplast by
  facilitated diffusion
• Water is absorbed from the soil
  by cells in the roots through
  osmosis

Question 13

What are adaptations of a chloroplast

Answer 13

The chloroplast is specifically adapted to increase the rate of
photosynthesis for the plant and maximise glucose production

Question 14

What are factors affecting photosynthesis

Answer 14

• Photosynthesis requires reactants, sunlight (for energy in Phase 1) and
  enzymes
• Factors that affect enzyme activity can also affect the rate of
  photosynthesis (ex. temperature, pH, cofactors, inhibitors)
• Environmental conditions such as light intensity, carbon dioxide, and
  water availability can also affect the rate of photosynthesis