Biochemistry Question Review

Question 1

Where would you find hydrophilic and hydrophobic amino acids in cells?

Answer 1

You would find hydrophilic AA in the cytosol and hydrophilic in the phospholipid bilayer

Question 2

What Amino acids undergo phosphorylation by protein kinase enzymes?

Answer 2

Serine, Threonine and Tyrosine due to hydroxyl groups on side chains

Question 3

Vmax is?

Answer 3

When an enzyme is working at maxium velocity

Question 4

What is the Michaels-Menten Equations?

Answer 4

E+S⇔ES⇒E+P

V₀=(V_max [S])/(K_m + [S])

V_max=[K]K_cat

V=(K_cat[E][S])/(K_m+[S])

V=((K_cat)/(K_m))•[E][S} _{Only at low substrate concentrations}

Question 5

What are the units for V_max?

Answer 5

Moles of enzyme per second

Question 6

What is K_cat and what are the units?

Answer 6

Rate of Catalytic conversion of a substrate

Units: Number of substrate molecules turned over per enzyme/ second

Question 7

What is K_m?

Answer 7

Michael’s constant

The substrate concentration at which half of the enzyme’s active sites are full

Question 8

At certain conditions, a High K_m can indicate?

Answer 8

The high K_m can indicate that the enzyme has a lower affinity for it’s substrate because it requires a higher substrate concentration

Question 9

What is the one type of inhibition that does not bind to the allosteric site?

Answer 9

Competitive Inhibition-the inhibitor binds to the active site

Question 10

Competitive Inhibition can be overcome by?

Answer 10

Adding more substrate

Question 11

In Competitive inhibtion what are the differences in V_max and K_m?

Answer 11

In Competitive inhibition:

V_max is not altered

K_m is higher because substrate concentration has to be high to reach max velocity

Question 12

In Non-competitive Inhibition, what is the difference to V_max and K_m?

Answer 12

In Non-competitive Inhibition:

V_max is lower because less enzyme is available to react

K_m remains the same

Question 13

In mixed inhibition, what are the differences to V_max and K_m?

Answer 13

In mixed inhibition:

V_max is lower

If inhibitor is bound to enzyme K_m is higher

If inhibitor is bound to substrate K_m is lower

Question 14

In Uncompetitive Inhibition, what are the differences in V_max and K_m?

Answer 14

In Uncompetitive Inhibition:

V_max is lower

K_m is lower

Question 15

A good way to remember if a passage is talking about an enzyme is to?

Answer 15

Look at the ending, if it ends in -ase it’s an enzyme

Question 16

How do enzymes work in a reaction?

Answer 16

They increase reaction rates by facilitating the formation on a more stable transition state between reactants and products. This increased stability decreases the activation energy.

Question 17

How is Delta G affected by enzymes?

Answer 17

Delta G is not affected by enzymes because they only stablize transition states

Question 18

List the weight of the nucleotides from largest to smallest?

Answer 18

Largest

deoxyguanosine monophosphate (dGMP)

deoxyadenosine monophosphate (dAMP)

deoxythymine monophosphate (dTMP)

deoxycytidine monophosphate (dCMP)

Smallest

Question 19

What Enzymes facilitate the dephosphorylation of ATP in Glycolysis?

Answer 19

Hexokinase/Glucokinase

PFK-1 (and if stimulated by insulin-PFK-2, because PFK-1 will be inactivated)

Question 20

What Enzymes facilitate the phosphorylation of ADP in Glycolysis?

Answer 20

Phospholglycerate kinase

Pyruvate kinase

Question 21

What Enzyme is involved in the reduction of NAD⁺ to NADH in Glycolysis?

Answer 21

Glyceraldehyde-3-P dehydrogenase

It occurs during the step of Glyceraldehyde 3-P→1,3 Bisphosphoglycerate

Question 22

NADH is oxidized in what step of Glycolysis (assuming anerobic respiration)?

Answer 22

In the step of Pyruvate →Lactate by lactate dehydrogenase

Question 23

What are the irreversable steps of glycolysis?

Answer 23

3 irreversible steps in glycolysis:

hexokinase (Glucose→Glucose 6-P);

phosphofructokinase (Fructose 6-P → Fructose 1,6-BisP);

pyruvate kinase (Phosphoenolpyruvate→Pyruvate)

Question 24

What is alternitive splicing?

Answer 24

Rearrangement of introns and exon elements that are joined by splicing to alter mRNA coding sequences

Question 25

A splice acceptor site is where?

Answer 25

The splicing site is at the end of intron 3'

Question 26

What is the mneumonic for remembering nonpolar AA?

Answer 26

**G**randma **A**lways **V**isits **L**ondon **I**n **M**ay **F**or **W**inston's **P**arty

Question 27

What is the mneumonic for remembering Polar AA?

Answer 27

**S**anta's **T**eam **C**rafts **N**ew **Q**uilts **Y**early

Question 28

What is the mneumonic for remembering electrically charged AA?

Answer 28

**D**ragons **E**at **K**nights **R**iding **H**orses

Question 29

What is a signal sequence?

Answer 29

A specific AA sequence that directs protiens in translation to the RER

Question 30

NADH is?

Answer 30

The reduced form of nicotinamide adenine dinucleotide

Question 31

What is chemosmosis?

Answer 31

The movement of ions across a semi-permeable membrane bound structure, down electrochemical gradient Ex: The energy from H+ down the concentration gradient is used to make ATP via ATP synthase

Question 32

Where does NAD+/NADH appear in: Glycolysis Kreb's Cycle ETC

Answer 32

**Glycolysis**: Reduced during the reaction from Glyceraldehyde 3-P to 1,3 Bisphosphotglycerate **Kreb's:** 1. Reduced in reaction from isocitrate to alpha ketoglycerate 2. Reduced in reaction from alpha ketoglycerate to succinyl CoA 3. Oxidized in reaction from malate to oxaloacetate **ETC:** Oxidized by complex 1

Question 33

What is FAD+/FADH and where does it appear in: Kreb's Cycle ETC

Answer 33

Flavin adenine dinucleotide **Krebs**: Reduced in reaction from succinate to fumerate **ETC**: oxidized by complex 2

Question 34

Steriods are defined by what type of structure?

Answer 34

Their 3 ring structure

Question 35

Increasing neuron-firing threshhold would have what impact on action potiential?

Answer 35

Increasing neuron-firing threshold would make it harder to generate an A.P

Question 36

What do transcription factors do?

Answer 36

Bind to DNA and recruit RNA polymerase

Question 37

What is the function of RNA polymerase?

Answer 37

It is a multi-unit enzyme that synthesizes RNA molecules from a template of DNA during transcription

Question 38

If an inhibitory protien is degraded, leading to constant activiation on the pathway what does this tell us about the pathway?

Answer 38

That there is a promoter in the pathway, since the inhibitory protien degraded and cannot bind to the promoter, the pathway will be continuously activated.

Question 39

What are oligosaccarides?

Answer 39

Carbohydrates

Question 40

What is the initial filtration step in the glomerulous?

Answer 40

The initial filatration step occurs primarily through passive flow due to pressure difference created by blood pressure.

Question 41

Nucelotides are linked to each other by phospodiester bonds. Phosphodiester bonds link?

Answer 41

The 3' sugar base of one nucleotide and the 5'phosphate of another nucleotide

Question 42

Aldoserone is responsible for the __________ of K+ ions.

Answer 42

Aldoserone is responsible for the **excretion** of K+ ions.

Question 43

\_\_\_\_\_\_\_\_\_\_\_ decreases cellular concentrations of glucose.

Answer 43

**Insulin** decreases cellular concentrations of glucose.

Question 44

Screated proteins such as insulin are cleaved into mature form where?

Answer 44

In the endomembrane system →all protein modification occurs in the E.R or the golgi

Question 45

What are the chances of disease with: Autosomal Dominate Autosomal Recessive X-linked Dominate X-linked recessive

Answer 45

What are the chances of disease with: **Autosomal Dominate**: 50/50 Chance of disease **Autosomal Recessive:** Have to have two copies of gene for disease. 25% chance of being unaffected 50% chance of being a carrier 25% chance of being affected **X-linked Dominate:** All affected fathers will have affected daughters If son is affected, mother will always be affected **X-linked recessive:** Affected father will not have affected sons, and tends to skip a generation

Question 46

What are the purines?

Answer 46

Adeneine and Guanine

Question 47

What are the pyrimidines?

Answer 47

Cytosine, Thymine and Uracil

Question 48

Proteases do what?

Answer 48

catalyze the hydrolysis of protiens to peptides, oligopeptides and AA

Question 49

What are the steps of apoptosis?

Answer 49

1. Cell Shrinks 2. Cell Fragments 3. Cytoskeleton collapses 4. Nuclear envelope dissasembles 5. cells release apotitic bodies

Question 50

Only ____________ perform alternitive splicing.

Answer 50

Only **Eukaryotes** perform alternitive splicing.

Question 51

Bacterial genes are often found in operons and these genes?

Answer 51

These genes have a single promoter and are transcribed as a group

Question 52

What is alternitive splicing?

Answer 52

Alternitive splicing allows a single gene to code for multiple protiens via creating new mRNA to code for these proteins.

Question 53

An inotropic agent or Inotrop is?

Answer 53

A medicine that changes the force of your hearts contractions Positive inotropes strengthen the force of a heartbeat, while negative inotropes weaken it

Question 54

What is the Cori Cycle?

Answer 54

Otherwise known as the Lactic Acid cycle, it produces lactic acid in anaerobic conditions in muscle and then lactate is transportaed to the liver. In the liver it is converted to glucose and then glucose is transported back to the muscle

Question 55

Osmotic pressure is directly _________ to solute concentrations.

Answer 55

Osmotic pressure is directly **proportional** to solute concentrations.

Question 56

What is a Palindromic DNA sequence?

Answer 56

Nucleic Acid sequences where the one strand matches it's complementary strand when read in the same direction. Important for enzymes such as restriction enzymes because they have to recognize specific sequences and these palindromic sequences higher the chance that both strands of DNA are cut

Question 57

What is the final reaction of the ETC?

Answer 57

2 *e*^- + H⁺ + 1/2O₂ → H₂O

Question 58

ETC: Complex I is named and catalyzes the oxidation of?

Answer 58

Complex I is the NADH Dehydrogenase Synthase that oxidizes NADH to NAD+

Question 59

ETC: Complex II is named and catalyzes the oxidation of?

Answer 59

Complex II is the Succinate Dehydrogenase Complex. It participates in the catalyzation of succinate to fumerate in the Krebs cycle producing FADH, and it oxidizes FADH to FAD+

Question 60

ETC: Complex III is named what and contains?

Answer 60

Complex III is named Cytochrome Reductase Q and contains Fe 2+ ⇔Fe 3+

Question 61

ETC: Complex 4 is named what and contains?

Answer 61

Complex 4 is named Cytochrome C oxidase and contains both heme and copper complexs.

Question 62

What is the total amount of ATP produced through Glycolysis, Krebs and ETC?

Answer 62

32 Atp

Question 63

What are imprinted genes?

Answer 63

Genes whose expression is determined by the parent who contributed them Violates rule of inheritance because both alleles in a heterozygote are expressed

Question 64

The optimum temperature for an enzyme is?

Answer 64

37º C

Question 65

Osmotic pressure is defined as?

Answer 65

The pressue that needs to be applied to a solution to prevent inward flow of water across a semipermeable membrane. Osmotic pressure causes water to move into a solution with the highest concentration of solutes

Question 66

Osmosis is?

Answer 66

The movement of water molecules from an area of low concentration of solute to an area of high concentration of solute