Unit 2 - Intro to Photosynthesis

Question 1

Photosynthesis Chemical equation

Answer 1

6CO2 + 6H2O =(water synthesis) glucose + 6O2

Question 2

Process of Photosynthesis two main steps?

Answer 2

1) Photo light dependent rxn
2) Synthesis light-independent reaction of Calvin cycle

Question 3

Photo light dependent rxn

Answer 3

• light energy is captured by pigment mols
• energy is used to make ATP and NADPH

Question 4

Synthesis Light Independent Reaction or Calvin cycle

Answer 4

• free energy or ATP and electrons of NADPH r used to synthesize sugars such as glucose from CO2
• process is also called CO2 fixation

Question 5

Light

Answer 5

• only 5% of the light that hits the earths surface is converted to organic compounds by photosynthesis

Question 6

Light travels in…

Answer 6

wave packets called photons

Question 7

Light from the sun is a…

Answer 7

mixture of photons of different energies (called wavelengths measured in nanometers (nm)

Question 8

where r photons captured in plants

Answer 8

plastids ie chloroplasts

Question 9

Chloroplasts functions

Answer 9

• photosynthesis factories for plants and algae
• store excess glucose as starch

Question 10

Chloroplasts structure

Answer 10

• 2 membranes (like mitochondria)
• interior space filled w stroma
  in stroma r thylakoids (membrane-bound sacs)
• thylakoid membrane contains light-gathering pigments

Question 11

Thylakoids Structure

Answer 11

1) grana
2) lamelae
3) lumen

Question 12

Grana

Answer 12

stack of thylakoids (60 grana per chloroplast with 30-50 thylakoids each)

Question 13

Lamellae

Answer 13

unstacked thylakoids that link grana together

Question 14

Lumen

Answer 14

interior of the thylakoid, water-filled

Question 15

Pigments Chlorophyll

Answer 15

• green plants algae and cyanobacteria contain chloroplasts w the pigments chlorophyll a and b.

Question 16

Both a and b structures

Answer 16

absorb blue and red light and reflected green light

Question 17

chlorophyll a is used…

Answer 17

to transfer energy from light into chemical energy

Question 18

chlorophyll b

Answer 18

is an accessory pigment

Question 19

Chlorophylls a and b side groups contain:

Answer 19

a = CH3 groups
b = CHO groups

Question 20

Accessory Pigments

Answer 20

in addition to chlorophyll b there r other accessory pigments. Their job is to absorb light that can damage chlorophyll and lose it as heat instead

Question 21

Carotenoids

Answer 21

appear yellow and orange + had double and single bonds
ie. carrots

betacarotene = protects ur eyes

Question 22

Xanthaphylls

Answer 22

reflect yellow light also found in the thylakoid

Question 23

what waste is produced during photosynthesis

Answer 23

water

Question 24

what is the useful production from photosynthesis

Answer 24

glucose

Question 25

what is the name of the pigment needed for photosynthesis

Answer 25

chlorophyll a

Question 26

in which organelle is this pigment found

Answer 26

chloroplast

Question 27

photoexcitation

Answer 27

- electrons in chlorophyll r normally at ground state (lowest energy level)

Question 28

excitation (photoexcitation)

Answer 28

the energy from a photon of light excites the electrons to a higher potential energy level but as electrons return to ground state they release energy

Question 29

primary electron acceptors

Answer 29

isolated chlorophyll mol fluoresce when their e- return to ground state, but in a photosynthetic membrane

Question 30

Photosystem

Answer 30

protein-based complex composed of clusters of pigments that absorb light energy

Question 31

antenna complex

Answer 31

has chlorophyll mol and accessory pigments in a protein matrix; the pigments absorb light E and transfer it to the reaction centre.

Question 32

reaction centre

Answer 32

a protein complex that contains chlorophyll A whose e- get excite then transferred to primary electron acceptors

Question 33

Antenna complex

Answer 33

pigment mol (chlorophyll b, carotenoids etc) captures the inital photons of light and transfers the energy between accessory pigments unitl it reaches... the reaction centre

Question 34

reaction centre

Answer 34

a protein complex composed of chlorophyll a, whose electrons get excited and then r transferred to the primary electron acceptor

Question 35

Photosystems

Answer 35

two e- from the reaction centre r excited and jump up in energy level. These electrons r captured by an electron carrier

Question 36

PI (P700) and PII (P680)

Answer 36

depending on the chlorophyll in the reaction centre they can absorb different wavelengths of light. there r two photosystems present in the thylakoid membrane: Photosystem 1 and Photosystem 2

Question 37

Photosystem 1 (P700)

Answer 37

the reaction centre can absorb wavelengths of 700nm

Question 38

Photosystem 2 (P680)

Answer 38

the reaction centre can absorb wavelengths of 680nm

Question 39

Engelmann Experiment: do plants absorb certain colours?

Answer 39

he tested this using algae in different colours of light and aerobic bacteria - spirogyra algae is long with spiral chloroplast

Question 40

Splitting Light

Answer 40

Engelmann then split the light into colours (ROYGBIV) and shined it on the spirogyra (there was enough CO2 for photosynthesis

Question 41

other accessory pigments in leaves

Answer 41

they maximize absorption of wavelengths. AUTUMN -cooler temps, chlorophylls is destroyed -other hidden colours show