Photosynthesis

Question 1

What does life depend on?

Answer 1

light energy from sun thru photosynthesis

Question 2

what is the conversion of photosynthesis?

Answer 2

light energy to chemical energy (carbohydates)

Question 3

Yes or No

Is photosynthesis efficient?

Answer 3

No

Question 4

What can photosynthesis can carry out?

Answer 4

both photosynthetic and respiration process

Question 5

what does organisms require?

Answer 5

constant input of energy to offset entropy

Question 6

what are the two major metabolic pathways used to acquire energy?

Answer 6

1. respiration (heterotrophs/autotrophs)
2. photosynthesis (autotrophs)

Question 7

What happens in photosynthesis?

Answer 7

transforms light energy into usable energy in ATP or NADPH (in light or light-dependent reactions) then later stored in the chemical bonds of carbohydrates during carbon fixation or light-independent reactions

Question 8

What are the photosynthetic reactants?

Answer 8

1. light (energy source)
2. water (electron donor - oxidized)
3. CO2 is reduced (e- acceptor)

Question 9

What are the photosynthetic products?

Answer 9

1. Carbohydrates (sugars)
2. oxygen

Question 10

what plant is the most evolved?

Answer 10

angiosperms

Question 11

what structure has optimized light capture and gas exchange?

Answer 11

leaves

Question 12

how do leaves optimize light capture and gas exchange?

Answer 12

• thin cross-section
• flat surface
• cell organization that maximizes light capture

Question 13

what is the most active photosynthetic tissue?

Answer 13

mesophyll cells of leaves (palisade/spongy)

Question 14

what does mesophyll cells contain?

Answer 14

chloroplasts

Question 15

what does chloroplasts contain?

Answer 15

chlorophyll

Question 16

what are chlorophyll?

Answer 16

light absorbing green pigments

Question 17

what to examine to understand photosynthetic process?

Answer 17

1. Nature of light
2. Properties of pigments
3. Roles of pigments

Question 18

what light does reach earth in?

Answer 18

waves

Question 19

what is quanta?

Answer 19

different wavelengths contain different amounts of energy

Question 20

what are photons?

Answer 20

energy packets

Question 21

what does photosynthetic organism use special molecules called?

Answer 21

pigments

Question 22

what is the range of pigments absorb light in ?

Answer 22

visible spectrum from 400 to 700 nm

Question 23

What does chlorophyll absorbs?

Answer 23

blue (400-450nm) and red (650-700nm) wavelengths

Question 24

what does chlorophyll reflect?

Answer 24

green (500 - 550nm)

Question 25

what does it mean when it does not absorb colour?

Answer 25

reflecting colour

Question 26

what is the molecular structure of chlorophyll a and b?

Answer 26

porphyrin-like ring structure with central Mg ring contain loosely-bound electrons

Question 27

what is the absorption maximum of blue?

Answer 27

430nm

Question 28

what is the absorption maximum of red?

Answer 28

660nm

Question 29

What is absorb wavelengths of light not absorbed?

Answer 29

chlorophyll

Question 30

what is the carotenoids ?

Answer 30

accessory pigments

Question 31

what is the maximum absorption of carotenoids?

Answer 31

400-500nm

Question 32

what does carotenoids have?

Answer 32

- photo-protective role - protect against high light - have anti-oxidant properties protect against light damage

Question 33

What is bilin pigments?

Answer 33

- phycobilin - phycoerythrin

Question 34

what is the bilin pigment for?

Answer 34

accessory pigments

Question 35

what is the maximum absorption of bilin pigment?

Answer 35

400 - 500 nm

Question 36

what is absorbed by pigments in chloroplast?

Answer 36

sunlight energy

Question 37

what are the main pigments?

Answer 37

chlorophylls

Question 38

what is present in all photosynthetic organisms?

Answer 38

chlorophyll a

Question 39

what happens in chlorophyll absorption of blue light?

Answer 39

excites chlorophyll molecule to higher energy state than absorption of red light

Question 39

what happens in chlorophyll with absorption of light photons?

Answer 39

changes its energy state by altering distribution of electrons

Question 40

what happens when pigment absorbs light?

Answer 40

goes from ground state to an excited state (very unstable) - release as light and heat

Question 41

what happens when excited electrons fall back to the ground state?

Answer 41

photos are given off = fluorescence - light released is at lower energy level

Question 42

what happens in unstable high energy state?

Answer 42

chlorophyll gives up energy as heat to surrounding and drop to lower excited state

Question 43

what are the four routes to dissipate energy from lowest excited state in order to return to stable ground state?

Answer 43

1. heat (energy loss) 2. re-emit photon of longer wavelength (fluorescence) 3. energy transfer to another molecule (resonance transfer) 4. photochemistry (absorption with electron transfer)