Topic 6

Question 1

characteristics of chemolithotrophy?

Answer 1

only occurs in prokaryotes
evolved when organic molecules weren’t abundant

Question 2

which primary electron donors does chemolithotrophy use?

Answer 2

H2S, Fe, H2, NH3

Question 3

what does chemolithotrophy not require?

Answer 3

glycolysis
fermentation
bridge reaction
Krebs cycle

Question 4

what does chemolithotrophy require?

Answer 4

ETC
oxidative phosphorylation

Question 5

why aren’t all metabolic pathways equal?

Answer 5

using different primary electron donors or final electron acceptors generate a proton gradient in which can differ in strength
-organic electron acceptors hold more potential energy and generate greater PMF than inorganic
-oxygen is the strongest final electron acceptor and will generate a greater PMF

Question 6

strength of PMF for aerobic respiration?

Answer 6

greatest PMF—> most ATP

Question 7

strength of PMF for aerobic respiration?

Answer 7

less PMF—> less ATP

Question 8

strength of PMF for chemolithotrophy?

Answer 8

least PMF—> least ATP

Question 9

how do reduction reactions work?

Answer 9

-polar covalent bonds in the reactant are broken
-nonpolar covalent bonds in the products are formed
-bonding electrons between carbon and oxygen in CO2 have moved closer to the C atoms in glucose so CO2 is reduced
-bonding electrons between the oxygen and hydrogen in H2O have moved farther away from the O atoms in O2 so water is oxidized

Question 10

what are membranes in the chloroplast?

Answer 10

outer
inner
thylakoid

Question 11

what are the two spaces in the chloroplast?

Answer 11

stroma
lumen

Question 12

what is the electromagnetic spectrum?

Answer 12

waves of different solar energy exist as photons and can be visible

Question 13

which part of the electromagnetic spectrum is important in photosynthesis?

Answer 13

400-700

Question 14

what happens when a photon hits an object?

Answer 14

it can be:
reflected (bounces back)
transmitted (pass through)
absorbed (electrons gain energy of the photon)

Question 15

what is pigment?

Answer 15

molecules efficient at absorbing photons

Question 16

how do pigments work?

Answer 16

their chemical structure allows their electrons to absorb solar energy and move to a higher level
-they absorb specific wave lengths which must match exactly the energy needed to raise an electron to a higher level

Question 17

what do blue pigments do to electrons?

Answer 17

raise them 2 levels

Question 18

what do green pigments do to electrons?

Answer 18

wont raise an electron

Question 19

what do red pigments do to electrons?

Answer 19

raise them 1 level

Question 20

where are photosynthetic pigments?

Answer 20

embedded in the thylakoid membrane

Question 21

what are the main pigments for phototrophs?

Answer 21

chlorophylls

Question 22

what do chlorophylls do?

Answer 22

captures energy for photosynthesis

Question 23

what are carotenoids?

Answer 23

accessory pigments that extend the wavelength for energy absorption

Question 24

how are pigment molecules organized?

Answer 24

into photosystems which are light harvesting systems

Question 25

what is a reaction center?

Answer 25

a collection of proteins that interact with pigments

Question 26

what is clustered around reaction centers?

Answer 26

antenna pigments

Question 27

what do antenna pigments do?

Answer 27

channel energy to the reaction centre when excited

Question 28

how do reaction centres reduce a primary electron acceptor?

Answer 28

light is absorbed by an antenna pigment -energy is transferred by inductive resonance to the reaction centre -the reaction centre's special chlorophyll donates an excited e- to the primary e- acceptor

Question 29

characteristics of a light dependent reaction?

Answer 29

solar energy is used to make ATP and NADH linear electron transport

Question 30

what pigment does photosystem 2 use?

Answer 30

P680

Question 31

what pigment does photosystem 1 use?

Answer 31

P700

Question 32

how does photosystem 2 generate PMF

Answer 32

P680 reduces the primary e- acceptor which passes the e- to plastoquinone -Pq reduces the cytochrome complex and release the H+ to the lumen -cytochrome reduces Plastocyanin

Question 33

what is plastoquinone?

Answer 33

a hydrophobic electron taxi that grabs an electron from the stroma when reduced

Question 34

what is plastocyanin?

Answer 34

a hydrophilic electron taxi

Question 35

how does P680 replace its electron?

Answer 35

by oxidation of H2O

Question 36

How does photosystem 1 produce NADPH?

Answer 36

P700 reduces the primary electron acceptor which passes the electron to ferredoxin -NADP+ reductase reduces NADP+ to NADPH in the stroma

Question 37

what is ferredoxin?

Answer 37

a hydrophilic electron taxi that reduces NADP+ reductase

Question 38

how does P700 replace its electron

Answer 38

by accepting electrons from plastocyanin

Question 39

what does electron flow through both photosystems produce?

Answer 39

a strong proton electrochemical gradient across the thylakoid membrane

Question 40

how is the strong proton electrochemical gradient formed?

Answer 40

H+ released in the lumen by oxidation of H2O H+ pumped from stroma to lumen H+ are used in the stroma to reduce NADP+

Question 41

what is photophosphorylation?

Answer 41

using solar energy to generate PMF to power ATP synthase for chemiosmosis

Question 42

where is ATP generated during photophosphorylation?

Answer 42

the stroma side of the thylakoid membrane

Question 43

what are the three steps of the Calvin cycle?

Answer 43

carboxylation/fixation reduction regeneration

Question 44

why do we need cyclic electron transport?

Answer 44

because the Calvin cycle needs more ATP than linear electron transfer makes

Question 45

what happens in cyclic electron transport?

Answer 45

ferredoxin reduces Pq instead of NADP+ reductase electrons flow normally to P700 to generate PMF

Question 46

what is the product of photosynthesis?

Answer 46

G3P

Question 47

where is G3P formed?

Answer 47

calvin cycle

Question 48

what is G3P converted to?

Answer 48

glucose

Question 49

uses for G3P glucose?

Answer 49

used in glycolysis and aerobic respiration linked into polymers of starch or cell walls used in synthesis of macromolecules (amino acids, fatty acids, nucleic acids)

Question 50

characteristics of cyanobacteria?

Answer 50

responsible for oxygenation of earth photosynthetic mechanicm similar to chloroplasts (ps1, ps2, calvin cycle)

Question 51

characteristics of anoxygenic photosynthesis?

Answer 51

only prokaryotes before oxygen and organic molecules were abundant first metabolism to use ETC only uses cyclic electron flow does not split H2O does not produce oxygen