Exam 4- Chapter 6 Part 2

Question 1

What is the difference between anaerobic and aerobic respiration

Answer 1

anaerobic uses terminal electron acceptors other than oxygen and produces less ATP

Question 2

Why does anaerobic respiration yield less ATP

Answer 2

Redox potential of electron acceptors are less positive than that of oxygen
The differential is not as large

Question 3

Fermentation

Answer 3

like glycolysis but with extra steprs to recycle NAD+ by getting rid of electrons carried by NADH

Question 4

Why do organisms ferment?

Answer 4

Do not encode genes to use ETC
Can use ETC sometimes but live in environments where terminal acceptor is not available

Question 5

importance of fermentation

Answer 5

allows organisms to adjust to changes in their environment

Question 6

Why does fermentation generate less energy than aerobic and anaerobic respiration?

Answer 6

does not use ETC
relies solely on glycolysis (substrate-level phosphorylation)
substrate is only partially oxidized

Question 7

What is used as the electron acceptor in fermentation

Answer 7

endogenous acceptor
pyruvate or derivative

Question 8

Respiration VS Non-Respiration

Answer 8

respiration invovles ETC and exogenous acceptor
non-respiration uses endogenous acceptor and no ETC

Question 9

Homo-lactic acid fermentation

Answer 9

uses lactic acid dehydrogenase
generates 2 lactic acid and nets 2 ATP

Question 10

What organisms carry our homo-lactic acid fermentation

Answer 10

Lactic acid bacteria (gram-positive microbes)

Question 11

Hetero-lactic acid fermentation

Answer 11

Uses pentose phosphate pathway
generates both lactic acid and ethanol
nets 1 ATP

Question 12

Penetose phosphate pathway

Answer 12

Energy investment phase yields a 5-carbon sugar which is then broken into a 3-carbon and a 2-carbon

Question 13

What does 3-carbon lead to

Answer 13

broken down into lactic acid using pathway similar to Embden-meyerhof
1 ATP

Question 14

What does 2-carbon lead to

Answer 14

Ethanol
purpose is to recycle carriers
no ATP generated

Question 15

What organisms carry out hetero-lactic acid fermentation?

Answer 15

LAB Leuconostoc

Question 16

Alcohol fermentation

Answer 16

Produces ethanol and CO2
Eventually comes to an end when the concentration of end products gets too high and kills organisms
Nets 2 ATP

Question 17

What organisms carry out alcohol fermentation?

Answer 17

yeasts
some bacteria

Question 18

Mixed acid fermentation

Answer 18

Different end products dependent on the acid

Question 19

Why have mixed acid fermentation

Answer 19

many acids dont let the concentration of end products get too high and kill organisms

Question 20

What organisms carry out mixed acid fermentation

Answer 20

several bacteria
fungi

Question 21

What mixed acid fermentation processes have been adapted for commercial use?

Answer 21

acetone production
butanol production

Question 22

Metabolism of polysaccharides

Answer 22

Partially broken down into smaller subunits by secreted enzymes outside the cell
Smaller subunits are broken down by the usual pathways in the cell

Question 23

metabolism of Proteins/Amino acids

Answer 23

Protease breaks polypeptides into individual amino acids
Amino group is detached from individual amino acids leaving an organic acid
Organic acid is used in TCA

Question 24

metabolism of Lipids

Answer 24

Lipases separate fatty acid tails off of glycerol
Beta-oxidation pathway cleaves fatty acids into smaller chunks at the beta carbon
Chunks are sent to TCA

Question 25

Why is metabolism of lipids tightly regulated

Answer 25

Don't want to catabolize the cells' lipids, as they are only found in the plasma membrane If these lipids are catalyzed the cell wont be a cell anymore

Question 26

Chemolithotrophy

Answer 26

Electrons are released from an inorganic molecule energy source, then transferred to the terminal electron acceptor in ETC

Question 27

Why does chemolithotrophy generate less ATP

Answer 27

no substrate phosphorylation electron carriers are more positive than organic molecules- smaller differential

Question 28

T/F chemolithotrophy makes less ATP than fermentation

Answer 28

FALSE

Question 29

Photophosphorylation

Answer 29

ATP synthesis and the light reaction used in conjunction with ATP Light reaction captures light and uses it to create PMF

Question 30

Site of light capture in eukarya

Answer 30

photosystem in specialized thylakoid cells Light is harvested by pigments

Question 31

What pigments to plants use

Answer 31

Chlorophyll A and B

Question 32

What pigments do cyanobacteria use?

Answer 32

chlorophyll a only

Question 33

what are photosystems composed of

Answer 33

numerous antennae that absorb light energy

Question 34

How do photosystems work?

Answer 34

light energy is passed to eelctron in reaction center An electron is sent onto the electron transport system

Question 35

Anoxygenic photosynthesis

Answer 35

H2O is used as an electron source and O2 is not produced Only 1 photosystem used

Question 36

Why is O2 not produced in anoxygenic photosynthesis

Answer 36

wavelength does not have enough energy

Question 37

What is used to generate reducing power for anoxygenic photosynthesis

Answer 37

bacteriochlorophylls

Question 38

What organisms carry out anoxygenic photosynthesis

Answer 38

green bacteria phototrophic puple bacteria heliobacteria

Question 39

oxygenic photosynthesis

Answer 39

oxygen is generated and released into environment as a byproduct because H2O is split to donate electrons uses both photosystems

Question 40

What organisms carry out oxygenic photosynthesis

Answer 40

photosynthetic eukaryotes cyanobacteria

Question 41

chlorophylls

Answer 41

major light absorbing pigments different chlorophylls have different absorption peaks

Question 42

Accessory pigments

Answer 42

transfer light energy to chlorophylls absorb different wavelengths of light than chlorophylls

Question 43

Examples of accessory pigments

Answer 43

carotenoids Phycobiliproteins

Question 44

Bacteriorhodopsin-based phototrophy

Answer 44

invovles bacteriorhodopsin to generate a proton motor force still uses ATP synthase Does not include ETC

Question 45

What is an example of a bacteriorhodopsin-based phototroph

Answer 45

Halobacterium

Question 46

WHy does bacteriorhodopsin-based phototrophy still exist

Answer 46

archaea live in extreme environments and ont have substrates to use anything else

Question 47

Anabolism

Answer 47

energy from catabolism is used for biosynthetic pathways using carbon source and inorganic molecules to synthesize new organelles and cells

Question 48

How do cells form macromolecules

Answer 48

generate precursors from major metabolic pathways utilize precursors to build common building blocks uses building blocks to form polymers and macromolecules

Question 49

Turnover

Answer 49

continual degradation and resynthesis of cellular constituents by nongrowning cells

Question 50

Why is metabolism carefully regulated

Answer 50

for the rate of turnover to be balanced by the rate of synthesis

Question 51

Biosynthesis efficiency

Answer 51

1. large molecules are made from small molecules 2. many enzymes do double duty (amphibolic) 3. some enzymes function in one direction only 4. anabolic pathways are irreversible (biosynthesis is coupled with ATP) 5. catabolism and anabolism are physically separated 6. catabolism and anabolism use different cofactors 7. Large assemblies form spontaneously from macromolecules by self-assembly

Question 52

Precursor metabolites

Answer 52

anything used to build precursors critical step in anabolism

Question 53

How are carbon skeletons used

Answer 53

precursor metabolites starting substrates for biosynthetic pathways

Question 54

Two pathways for biosynthesis

Answer 54

Salvage pathway De novo synthesis

Question 55

Salvage pathway

Answer 55

take things they find in environment and build onto it

Question 56

De novo synthesis

Answer 56

build any molecules they need from scratch