Ch. 7 - Photosynthesis

Question 1

Photosynthesis (3)

Answer 1

• refers to the light dependent reactions and synthesis to the putting together of sugar (the 3C sugar G3P) during the Calvin Cycle
• all of our oil and gas originally from historic PS
• PS organisms trap solar energy into ATP and NADPH which they use to drive the production of carbohydrates (a way to convert solar into chemical energy)

Question 2

Photoautotroph

Answer 2

Organism that obtains energy from sunlight and carbon from CO2 by photosynthesis

Question 3

Heterotroph

Answer 3

Organism that cannot make its own organic food molecules and must obtain them from consuming other organisms or their organic products = a consumer or decomposer

Question 4

Cellular respiration and photosynthesis

Answer 4

• Glucose oxidized to CO2; oxygen reduced to water

- CO2 reduced to glucose; H2O oxidized to O2

Question 5

Mesophyll

Answer 5

Found in interior of leaf; each cell has ~30-40 chloroplasts

Question 6

Stoma/stomata

Answer 6

Tiny pores used for gas exchange

Question 7

Inner compartment

Answer 7

Filled with thick fluid - stoma (Calvin Cycle here)

Question 8

Thylakoids membrane

Answer 8

Contains pigments (light reactions here)

Question 9

Photosynthesis in 2 stages

Answer 9

• light dependent reactions (thylakoids membrane): some ATP is produced via photophosphorylation and NADP+ is reduced is NADPH
• Calvin Cycle

Question 10

NADP+

Answer 10

Nicotinamide adenine dinucleotide phosphate - same function as NAD+ in CR

Question 11

Electromagnetic spectrum (3)

Answer 11

• entire spectrum of radiation ranging in wavelengths form less than a nm to more than a km
• shorter wavelength > higher energy
• longer wavelength > lower energy

Question 12

Carotenoid pigments

Answer 12

Last longer in the fall, after green chlorophyll molecules have been broken down = beautiful fall colours

Question 13

Photon

Answer 13

Fixed quantity of light energy; the shorter the wavelength, the greater the energy

Question 14

Excited state of a photon (2)

Answer 14

• When a molecule absorbs a photon of light, its electrons are boosted to a higher energy level
• energy is quickly lost in the form of heat and light (longer, lower energy wavelength)

Question 15

Chlorophyll a (2)

Answer 15

• Absorbs mainly blue-violet light and red light

- looks blue-green because it reflects mainly green light

Question 16

Chlorophyll b (2)

Answer 16

• absorbs mainly blue and orange light and reflects (and appears) yellow-green
• broadens the range of light that a plant can use by conveying absorbed energy to chlorophyll a, which then puts the energy to work in the light-dependent reactions

Question 17

Photosystems (3)

Answer 17

• similar (but not identical to ETC in respiration)
• are sets of light absorbing pigments and their associated electron carriers
• consists of a number of light-harvesting complexes surrounding a reaction-centre complex

Question 18

Example of photosystem (2)

Answer 18

• in the thylakoids membrane light energy transfer between different pigment molecules to reach chlorophyll a
• chlorophyll a passes on excited electron to a primary electron acceptor

Question 19

light harvesting complex (2)

Answer 19

contains various pigment molecules bound to proteins

-function as a light-gathering antenna