BIOCHEM

Question 1

What kind of bond is used for Glycogen?

Answer 1

ALPHA 1,4 glycosidic bond

Question 2

What sugars make up UDP-glucose ?

Answer 2

glucose (hexose) and ribose (pentafurnaose, that has C2 and C3 OH Groups that are cis and C3 and C4 groups that are trans

Question 3

In glycogen, what kind of bonds form due to branching?

Answer 3

Alpha 1, 6 glycosidic bonds

Question 4

Which molecules have dissociate the most vs least? high dissociation states

Answer 4

STRONG ACIDS dissociate the MOST
Molecules with High Negative charges, dissociate the Least

Question 5

Describe the emission for gamma decay, Beta - decay, Beta plus and nuclear fission

Answer 5

Gamma decay : emission of PHOTONS
Beta - decay: emission of an ELECTRON
Beta + decay: emission of a PROTON
Nuclear Fission: emission of a NEUTRON

Question 6

which genomic regions are rich in repeats?

Answer 6

Heterochromatin, telomeres and centromeres

Question 7

What are the bonds found in DNA?

Answer 7

N-glycosidic linkage between deoxyribose and the nitrogenous base; van der Waals and hydrophobic interactions between bases.

Question 8

Distinguishes between partial penetrance and full penetrance

Answer 8

Partial penetrance: when an individual may or may not develop disease
full penetrance: an individual will develop disease

Question 9

How can you achieve most specific binding of DNA to a ligand?

Answer 9

To achieve the most specific binding possible , the biochemist should aim to have MANY DNA molecules for each ligand (LARGE DNA TO LIGAND ratio)
If there are many ligand molecules and DNA is the limiting factor, the ligand might bind less specifically

Question 10

What is the environment of DNA?

Answer 10

DNA has a inner region that is hydrophobic due to nitrogen bases and outer region that is hydrophilic (with region surrounding DNA and hydrophilic phosphate backbone)

Question 11

which pathway is NADPH generated and what is its role?

Answer 11

NADPH is produced in Pentose Phosphate pathway.
NADPH is a reducing agent and it participates in reduction reactants

Question 12

In order to replicate itself, what does a rapidly dividing cell need?

Answer 12

rapidly dividing cell needs precursors for DNA synthesis, such as pentose rings. these precursors are need for DNA synthesis to occur.

Question 13

what conditions occur for lactic acid production ?

Answer 13

Lactic acid production occurs under ANAEROBIC conditions , where you regenerate NAD+ needed for glycolysis

Question 14

What happens to NADH under aerobic conditions ?

Answer 14

under aerobic conditions, NADH is converted to NAD+ through Electron transport chain, where O2 is the final electron acceptor

Question 15

What happens when there is a competitive inhibitor ?

Answer 15

-Km increases
-Vmax stays the same
competitive inhibitor interferes with enzyme interacting with substrate.
-the inhibitor also slows down the rate that substrate converts into product (hence substrate increases, while product decreases)

Question 16

Where does ketogenesis occur?

Answer 16

mitochondria of liver cells

Question 17

What occurs in individuals with Ketoacidosis ?

Answer 17

Individuals with Ketoacidosis:
- will have low blood pH (increase H+)
-increased respiratory rate (ventilation) which will allow more CO2 to be expelled in order to increase blood pH
-also bicarbonate excretion will decrease (so you can reabsorb more)

Question 18

What changes occur in an individual with untreated type 1 diabetes ?

Answer 18

Individual with untreated type 1 diabetes:
-Excess glucose in blood. This glucose cannot enter cells to be used for energy
-This causes increased use of fatty acid oxidation (breakdown) and protein catabolism for energy
-leads to increased Acetyl coA and and increased Ketone bodies to be used by brain for energy in absence of glucose.
-This increased FA oxidation and ketogenesis caused decreased blood pH leading to need for Increased ventilation to excrete CO2 and bring blood pH back to normal

Question 19

which energetic processes occur in the mitochondria ?

Answer 19

-Citric acid cycle
- electron transport
-oxidative phosphorylation

Question 20

What must happen for Krebs cycle to occur?

Answer 20

Kreb cycle occurs in the mitochondrial matrix
-NAD and FAD get reduced
-Two GTP molecules are produced per glucose
(oxygen is indirectly required for krebs to occur)

Question 21

which process requires oxygen for it to occur

Answer 21

Oxygen is required in the ELECTRON TRANSPORT CHAIN for NADH and FADH2 to be oxidized

Question 22

what is product of both glycolysis and electron transport chain ?

Answer 22

ATP

Question 23

In anaerobic conditions what process can occur and how many ATP are produced. How many ATP would be produced for 3 molecules of glucose ?

Answer 23

For anaerobic conditions, only GLYCOLYSIS can occur. So for every molecule of glucose 2 Net ATP are made
-hence for 3 molecules of glucose (3 x 3 net atp) 6 ATP will be Made

Question 24

Describe what happens to the pH in the electron transport chain

Answer 24

In the electron transport chain, protons are pumped across the inner cell membrane, out of the matrix and into the inner membrane space, causing Increase in pH of the matrix

Question 25

Where does electron transport chain occur ?

Answer 25

inner membrane of mitochondria

Question 26

where does Krebs cycle and fatty acid oxidation occur?

Answer 26

Mitochondrial matrix

Question 27

What happens if electrons are blocked in one of the complexes (example complex 3 ) of electron transport chain ?

Answer 27

Inhibiting any part of the electron transport chain will halt the transfer of electrons.
Blocking electron transport at Complex III will result in a build-up of electrons at proteins earlier in the chain. Because these earlier proteins, including Complex I, cannot pass their electrons off, they will persist in the Reduced state
Proteins later in the chain can release their electrons, but cannot replenish them. These later proteins, including Complex IV, will persist in the oxidized state
Electrons meeting a roadblock at Complex III will never reach oxygen. Thus, oxygen consumption (reduction) will be decreased.

It is important to note that inhibiting the electron transport chain diminishes the proton gradient and compromises ATP synthesis. This is why antimycin is so toxic to cells

Question 28

What happens in individual with uncontrollable diabetes?

Answer 28

Uncontrollable diabetes :
results in hyperglycemia, due to either a relative or complete deficiency of insulin. This means the glucose in the blood cannot be transported into the cells. Thus, any processes that are dependent on glucose oxidation will be decreased and other processes to generate energy will be increased.
Fatty acid oxidation would be increased, as the cells would break down fatty acids to produce acetyl-CoA to feed into the Krebs cycle. This would result in an increase in acetyl-CoA
Since glycolysis is decreased, there would be a decrease in glucose-6-phosphate that is available for the pentose phosphate pathway (not an increase) and thus, a decrease in the amount of NADPH produced by the pentose phosphate pathway.

Question 29

what is purpose of pentose phosphate pathway ?

Answer 29

produce ribulose 5 phosphate that will be used to synthesize nucleotides and NADPH

Question 30

what happens to oxygen consumption and glucose consumption if electron transport chain is inhibited ?

Answer 30

Oxygen consumption will Decrease and glucose consumption will increase

In the absence of electron transport, oxygen is not needed (it is the final electron acceptor in the transport chain) so the consumption of oxygen would decrease.
Since the electron transport chain is not available to make energy (ATP) the cells will rely solely on anaerobic respiration – glycolysis.
Further, since the energy demands of the cells have not changed, and since glycolysis makes fewer ATP than electron transport, the rate of glycolysis will have to increase to keep the level of ATP normal. Thus, glucose consumption would increase.

Question 31

what is the most oxidized compound in glycolysis ?

Answer 31

PYRUVATE

Question 32

what would happen to individual that treated with drug promoting gluconeogenesis for a long time?

Answer 32

patient has increased serum glucose and decreased glycolytic activity.

Question 33

What would happen if pyruvate dehydrogenase complex is inhibited ?

Answer 33

if pyruvate dehydrogenase complex is inhibited, there would be LESS CO2 expired
-cellular respiration would be halted before decarboxylation (PDC) occurs
(PDC is when decarboxlation occurs and pyruvate converts to acetyl coA)

Question 34

What is used and produced for each round of Beta oxidation (fatty acid breakdown) ?

Answer 34

There is a removal of 2 carbons per round of beta oxidation until there are final 2 or 3 carbons left (depending on even or odd number of C’s in fatty acid)
-each beta oxidation round uses 1 water molecule
-for 1 water molecule used, produce 1 FADH2 and 1 NADH

Question 35

How many water molecules and FADH2 molecules would be produced if 11 carbon fatty acid chain?

Answer 35

11 C fatty acid chain (11 -2= 9-2= 7 -2 = 5 - 2 = 3
so 11 c will undergo 4 rounds of beta oxidation
for each round 4 molecules of water will be used and 4 FADH2 molecules produced

Question 36

what are the intermediates produced by liver in ketogenesis ?

Answer 36

• acetoacetate
• B-hydroxybutryate
  -Acetone

Question 37

which process allows for production of NADH during the protein catabolism ?

Answer 37

amino acid deamination

Question 38

what is produced in the oxidative phase of pentose phosphate pathway?

Answer 38

Ribulose 5 phosphate and 2 NADPH

Question 39

what inhibits the Krebs cycle?

Answer 39

Increased ATP levels and NADH levels inhibit Krebs cycle

Question 40

What increases glycogenolysis?

Answer 40

An overnight fast would lead to glucagon release, resulting in glycogenolysis by the liver and the release of glucose into the blood. Glycogenolysis is stimulated by the sympathetic nervous system (fight or flight),