Exam 2: Metabolism

Question 1

Anabolism

Answer 1

The synthesis of complex molecules from simpler ones

Question 2

Metabolism

Answer 2

Chemical processes that occur within a living organism in order to maintain life

Question 3

Catabolism

Answer 3

The breakdown of complex molecules into simpler ones

Question 4

Oxidoreductase

Answer 4

A class of enzyme that catalyzes oxidation-reduction reactions

Question 5

Transferase

Answer 5

A class of enzymes that catalyzes the transfer of chemical groups between molecules

Question 6

Hydrolase

Answer 6

A class of enzyme that catalyzes hydrolysis of molecules

Question 7

Lyase

Answer 7

A class of enzyme that catalyzes the breaking of various chemical bonds by means
other than hydrolysis and oxidation

Question 8

Isomerase

Answer 8

class of enzyme that catalyzes the conversion of a molecule from one isomer to
another

Question 9

Ligase

Answer 9

A class of enzymes that catalyzes the joining of two large molecules by forming a new
chemical bond

Question 10

Enzyme

Answer 10

A substance produced by a living organism that acts as a catalyst to bring about a
specific biochemical reaction.

Question 11

Apoenzyme

Answer 11

An enzyme that requires a cofactor but does not have one bound

Question 12

Holoenzyme

Answer 12

An apoenzyme together with its cofactor(s)

Question 13

Allosteric site

Answer 13

Relating to or denoting the alteration of the activity of a protein through the binding of
an effector molecule at a specific site.

Question 14

ooxidation-reduction reactions

Answer 14

Transfer of electrons from an electron donor to an electron acceptor
Reactions always occur simultaneously
Cells use electron carriers to carry electrons (often in H atoms)
ex: lactate dehydrogenase

Question 15

Function and role of enzymes

Answer 15

organic catalysis that increases the likelihood of a reaction
rate is influenced by: temperature, pH, enzyme and substrate concentrations, and presence of inhibitors

Question 16

six classification of enzymes

Answer 16

Oxidoreductase
Transferase
Hydrolase
Lyase
Isomerase
Ligase

Question 17

Enzyme Inhibition

Answer 17

Influences on the rate of enzymatic reactions Race To Pass Evan’s Poop
1. Rate of enzymatic Reactions
2. Temp
3. pH
4. Enzyme and substrate concentration\
5. Presence of inhibitors
Inhibitors
- Substances that block an enzymes’ active site
- Do not denature enzymes
- Allosteric inhibitors vs allosteric activators
Inhibitors A is the substrate for enzyme 2 and inhibitor b is the substrate for enzyme 3 and the end product is an inhibitor - negative feedback cycle

Question 18

Cellular respiration

Answer 18

Cellular respiration is the complete process of breaking down glucose to produce ATP
* Resultant pyruvic acid completely oxidized to
produce ATP by series of redox reactions
* Three stages of cellular respiration
– Synthesis of acetyl-CoA
– Krebs cycle
– Final series of redox reactions
(electron transport chain)

Question 19

result of cellular respiration

Answer 19

Synthesis of acetyl-CoA Results in:
- Two molecules of acetyl-CoA
- Two molecules of CO2
- Two molecules of NADH
Krebs cycle results in:
- Two molecules of ATP
- Two molecules of FADH2 ( Electron transport chain)
- Six molecules of NADH ( electron transport chain)
- Four molecules of CO2
electron transport chain results in:
- Total of ~34 ATP molecules formed from one molecule of glucose

Question 20

glycolysis

Answer 20

– Occurs in cytoplasm of most
cells
– Involves splitting of a six-
carbon glucose into two
three-carbon sugar molecules
– Substrate-level
phosphorylation
* Direct transfer of phosphate
between two substrates
– Net gain of two ATP
molecules, two molecules of
NADH, and precursor
metabolite pyruvic acid
– Divided into three stages involving 10 total steps
* Energy-investment stage
* Lysis stage
* Energy-conserving stag

Question 21

the krebs cycle

Answer 21

Occurs in cytosol of prokaryotes
and in matrix of mitochondria in
eukaryotes
* Generates electron carriers
* Great amount of energy remains
in bonds of acetyl-CoA
– Transfers much of this energy to
coenzymes NAD+ and FAD
* Six types of reactions in Krebs
cycle
– Anabolism of citric acid
– Isomerization reactions
– Hydration reaction
– Redox reactions
– Decarboxylations
– Substrate-level phosphorylation

Question 22

result of krebs cycle

Answer 22

Results in:
– Two molecules of ATP
– Two molecules of FADH2
– Six molecules of NADH
– Four molecules of CO2

Question 23

electron transport chain

Answer 23

– Most significant production of ATP occurs from series
of redox reactions known as an electron transport
chain (ETC)
– Series of carrier molecules that pass electrons from
one to another to final electron acceptor
– Energy from electrons used to pump protons (H+)
across the membrane, establishing a proton gradient
– Located in cristae of eukaryotes and in cytoplasmic
membrane of prokaryotes
– Use of electrochemical
gradients to generate ATP
– Cells use energy released in
redox reactions of ETC to
create proton gradient
– Protons flow down
electrochemical gradient
through ATP synthases that
phosphorylate ADP to ATP
– Called oxidative
phosphorylation because
proton gradient created by
oxidation of components of
ETC

Question 24

result of electron transport chain

Answer 24

– Total of ~34 ATP molecules
formed from one molecule of
glucose

Question 25

Compare and contrast cellular respiration and fermentation. Discuss the steps involved in each

Answer 25

Cellular respiration and fermentation are both processes used by cells to generate energy in the form of ATP, but the key difference is that cellular respiration requires oxygen while fermentation does not, leading to a significantly higher ATP yield in cellular respiration and different end products depending on the process involved; both processes begin with glycolysis, but cellular respiration continues through the Krebs cycle and electron transport chain, while fermentation uses alternative pathways to regenerate electron carriers and produce byproducts like ethanol or lactic acid.

Question 26

Discuss commercial products produced by fermentation process

Answer 26

a. Some cells cant carry out cellular respiration
-Aerobic bacteria with no oxygen
-Genes do not encode for process
b. Cells require constant source of NAD+ for glycolysis
-Can’t be obtained simply using glycolysis and krebs Cycle
-Can’t be obtained without ETC
c. Fermentation pathways provide cells with alternate source of NAD+
- Partial oxidation of sugar ( or other metabolites ) to release energy using organic molecules from within the cell ( endogenous) as final electron acceptor
D. Uses an endogenous electron acceptor
- Usually an intermediate of the pathway used to oxidize the intermediate of the pathway used to oxidize the organic energy source e.g. pyruvate
e. Does not involve the use of an electron transport chain nor the generation of a proton motive force
f. ATP synthesized only by substrate -level phosphorylation
- glycolysis

commercial products: Alcohol, cheese, yogurt, soy sauce, swiss cheese, nail polish remover…

Question 27

Identify when oxidative phosphorylation and substrate level phosphorylation occur during glucose metabolism

Answer 27

1. Both processes can occur in the mitochondria, but only substrate-level phosphorylation takes place in the cytoplasm (except in the case of prokaryotes).
2. Substrate level phosphorylation occurs after the 6 carbon glucose is split into two 3-ring carbon sugar molecules - it is the direct transfer of phosphate between two substrates and gains net gain of 2 ATP 2 NADH and precursor between 2 substrate
3. Oxidative phosphorylation is the fourth step of cellular respiration and produces the most energy in cellular respiration.
4. It is the process where electron transport from the energy precursors from the citric acid cycle (step 3) leads to the phosphorylation of ADP, producing ATP. This also occurs in the mitochondria.