Mock Exam 3 Questions 17-30

Chemo =

cannot obtain energy from sunlight

• relies on chemical compounds for energy (H2S)

Litho =

uses inorganic substance as an electron souce

Auto =

using a single-carbon molecule (CO2)

The EM pathway is the most common way to

break down and start to oxidize glucose

• found in all domains of life

The ED pathway is only used by

certain bacterial species

Both the ED and EM pathway can be used to make

NADH and ATP

The EM pathway yields

a net 2 ATP

The ED pathway yields

a net 1 ATP

The ED pathway leads to the production of

glyceraldehyde 3-phosphate

• can then be used in the EM pathway

The ED pathway also produces a special intermediate

2-keto-3-deoxy-6-phosphogluconate (KDPG)

• NOT found in the EM pathway

The PPP (hexose monophosphate pathway) is a major source of

NADPH

• used as a reducing power in biosynthesis

The PPP is used to

oxidize glucose 6-phosphate and eventually produce ribulose 5-phosphate

The PPP produces

2 unique carbon skeletons

• E4P (later used in shikimate pathway)

• R5P

E4P is used to make

aromatic amino acids

The citric acid cycle is an

amphibolic pathway

• composed of catabolic and anabolic pathways

The citric acid cycle is common in

aerobic bacteria

• used to fully oxidize our carbon source (not NAD+)

Glucose produces

two molecules of pyruvate

• is then fed into the citric acid cycle

The citric acid cycle occurs

twice per glucose

One major enzyme used in the citric acid cycle is

pyruvate dehydrogenase

• used to convert pyruvate to acetyl-CoA

Pyruvate kinase is used in

glycolysis to convert PEP to pyruvate

How many net ATP molecules are generated directly from the TCA cycle if two molecules of glucose are used for aerobic respiration?

4 ATP

The TCA cycle yields

1 ATP for each turn

The oxidation of a single glucose requires

two turns of the TCA cycle

There are four total turns of the

TCA cycle

• each turn yields 1 ATP

The ETC is used to make most of the ATP via

OP during respiration

ETC electron carries go from

the most negative to the most positive reductionm potentials

Transmembrane proteins job is to

transport electrons across different membranes

The prokaryotic ETC

may be branched or shorter than the mitochondrial ETC

The ETC in prokaryotes yields

a lower P/O ratio than eukaryotes

Fermentation is the process of

partially oxidizing the energy source

• because its only partially oxidized, it will not yeild as much ATP as respiration

There is no ETC used in

fermentation so no OP

In fermentation, an endogenous electron acceptor such as

pyruvate may be used

Fumarate reductase is not used in

fermentation

• its an enzyme present during anaerobic respiration

E. coli =

mixed acid fermentation

Bacillus spp. =

lactic acid fermentation

E. aerogenes =

butanediol fermentation

P. denitrificans =

butanediol fermentation

• non-fermenting bacterium

S. cerevisiae = 

alcoholic acid fermentation

E. coli

• performs glycolysis in the cytoplasm

• is a facultative anaertobe

• lacks teichoic acids

E. coli is an example of a

pathogenic microbe

• chemoorganotroph

Which carbon skeleton is formed from the enzyme PDH?

acetyl-CoA

Archaea can perform

aerobic and anaerobic respiration

• cannot use PPP to produce carbon skeletons

In the ETC, archaea have a shorter ETC than

eukaryotic ETC

Archaea are generally

extremeophiles that live in environments generally unsuitable for humans

Archaea have a cell wall composed of

only L-amino acids

Theoretically, _____ is the net yield that ATP can be produced during respiration in eukaryotes

32

• actual number is closer to 30

Why does anaerobic respiration produce less ATP than aerobic respiration?

anaerobic respiration involves electron acceptors with a lower redox potential than oxygen

The Calvin-Benson cycle (reductive pentose phosphate cycle) is a form of

carbon fixation used by prokaryotes and eukaryotes that is used to make glyceraldehyde 3-phosphate

In the carboxylation phase,

RuBisCO is used to produce 3-phosphoglycerate