Lecture 8- Photosynthesis

Question 1

What are photoautotrophs?

Answer 1

Organisms that can make their own energy using light and carbon dioxide

Question 2

True or false: Photosynthesis is an exergonic process

Answer 2

False; photosynthesis is an endergonic process

Question 3

In which organelle does photosynthesis take place?

Answer 3

Chloroplast

Question 4

Where do the light-independent reactions take place?

Answer 4

In the stroma

Question 5

What are heterotrophs?

Answer 5

Organisms that obtain their carbon from organic sources

Question 6

Where is chlorophyll located in a chloroplast?

Answer 6

Thylakoid membrane

Question 7

True or false: Under normal conditions, electrons in photosynthesis undergo a cyclic flow

Answer 7

False; under normal circumstances, electrons in photosynthesis undergo linear flow

Question 8

What is a photon?

Answer 8

Small particle of light energy

Question 9

Which enzyme is primarily responsible for ATP synthesis in photosynthesis?

Answer 9

ATP synthase

Question 10

Why are leaves green?

Answer 10

Chlorophyll reflects green light

Question 11

What does the wavelength of a photon tell us about it?

Answer 11

The shorter the wavelength, the more energy & the longer the wavelength, the less energy

Question 12

What are the three simplified steps of the light-dependent reactions?

Answer 12

Split water and release atmospheric oxygen → reduce NADP+ to NADPH → generate ATP from ADP

Question 13

Which pigment is present in photosystem two (PSII)?

Answer 13

P680

Question 14

Which molecules undergo redox in photosynthesis?

Answer 14

Water is oxidized and carbon dioxide is reduced

Question 15

True or false: ATP synthase requires energy in the form of ATP to synthesize ATP from ADP

Answer 15

False; the synthesis of ATP from ADP through ATP synthase is driven by an electrochemical gradient (facilitated diffusion)

Question 16

What is the cytoplasm of a chloroplast called?

Answer 16

Stroma

Question 17

What are the three stages of the Calvin cycle in order?

Answer 17

Carbon fixation → reduction → regeneration

Question 18

The reaction between carbon dioxide and RuBP takes place in which stage of the light-independent reactions? Which enzyme catalyzes this reaction?

Answer 18

Carbon fixation & RuBisCo

Question 19

Which enzyme is responsible for reducing NADP to NADPH?

Answer 19

NADP reductase

Question 20

Where do the light-dependent reactions take place?

Answer 20

Thylakoid membrane

Question 21

Which pigment is present in photosystem one (PSI)?

Answer 21

P700

Question 22

What are the reactants of the carbon fixation stage of the light-independent reactions?

Answer 22

Carbon dioxide and RuBP

Question 23

What is the second stage of the Calvin cycle? What occurs during this stage?

Answer 23

Carbon reduction & ATP/NADPH are used to convert 3-Phosphoglycerate (PGA) to glyceraldehyde-3-phosphate (G3P)

Question 24

In the first step of the Calvin cycle, carbon fixation, carbon dioxide and RuBP react to form what?

Answer 24

3-Phosphoglycerate (PGA)

Question 25

Which molecule(s) are reduced during the Calvin cycle?

Answer 25

PGA

Question 26

What are the sources of electrons for PSII and PSI?

Answer 26

PSII electrons from water & PSI electrons from PSII

Question 27

Where do protons go when water is split at PSII?

Answer 27

Protons create an acidic environment in the thylakoid lumen