SCIENCE 2ND QUARTER: PHOTOSYNTHESIS

Question 1

What is photosynthesis?

Answer 1

• light/solar energy → chemical energy

Question 2

What is chloroplasts?

Answer 2

• contains chlorophyll

Question 3

What is Chlorophyll?

Answer 3

• the pigment that makes plants green.

Question 4

What are the major locations of photosynthesis?

Answer 4

• leaves

Question 5

What are the 2 stages of photosynthesis?

Answer 5

1. Light-Dependent Reactions
2. Light-Independent Reaction/Calvin Cycle

Question 6

Where do Light-Dependent Reactions take place?

Answer 6

• the thylakoid

Question 7

What is the first step in the Light-Dependent Reactions?

Answer 7

1. Light absorption in Photosystem II
   -Photons/light strike PSII - electrons get
   excited (electron excitation)

Question 8

What is the second step in the Light-Dependent Reactions?

Answer 8

2. ATP synthesis
   
   • Hydrogen ions go to ATP Synthase (enzyme)
     and convert ADP → ATP to Calvin Cycle

Question 9

What is the third step in the Light-Dependent Reactions?

Answer 9

3. Light absorption in Photosystem I
   
   • Photons/light strike PSI - electrons get
     excited again

Question 10

What is the fourth step in the Light-Dependent Reactions?

Answer 10

4. NADPH formation
   
   • NADP+ reductase converts NADP+ →
     NADPH

Question 11

Where does the Calvin Cycle take place?

Answer 11

• the stroma

Question 12

What is the first step in the Calvin Cycle?

Answer 12

1. Carbon fixation
   
   • CO2 binds to the RuBP sugars by the
     enzyme Rubisco
   • 6-carbon molecules → 2 3-carbon molecules
     (3-PGA)
   • 3-PGA - 3-phosphoglycerate

Question 13

What is the second step in the Calvin Cycle?

Answer 13

2. Reduction
   
   • 3-PGA → G3P
   • 6 ATPs → 6 ADPs
   • 6 NADPHs → 6 NADP+ & inorganic
     phosphate

Question 14

What is the third step in the Calvin Cycle?

Answer 14

3. Regeneration of RuBP
   
   • 1 G3P molecule - leaves the Calvin cycle and
     forms organic compounds e.g. glucose
   • Remaining 5 G3P molecule - regenerates
     RuBP so the Calvin cycle can continue