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Flashcards in Biochem Deck (51):
1

What are organic compounds that activate enzymes showing Michaelis Menten kinetics called? Examples?

Cofactors, eg Mg+

2

What equation is equal to pH?

-log[H+]

3

Describe the quaternary structure bonding of a protein

Requires bonds to form between the side chains of the amino acids that are part of two separate protein molecules. The type of bonds formed are the same as those formed in the tertiary structure.

4

Side chain of CYSTEINE

-CH2SH
Special

5

Side chain of ALANINE

-CH3
Non polar

6

Side chain of ASPARTIC ACID

-CH2COOH
Polar acidic

7

Side chain of SERINE

-CH2OH
Polar uncharged

8

Side chain of LYSINE

(CH2)4-NH3+
Polar basic

9

Stages between a keratin molecule and a keratin filament

1 a-keratin molecule
2 Dimer
3 Protofilament
4 Protofibril
5 a-keratin filament

10

What groups are attached to the centra carbon atom in an amino acid?

-NH2
-H
-COOH

11

What are the most abundant proteins in muscle?

Actin and myosin

12

How many katals of enzyme activity is the amount required to catalyse the conversion of 1 mole of a substrate to the product in 1 second?

1

13

In the presence of a competitive inhibitor is the km increased, decreased or unchanged?

Increased

14

In the presence of a competitive inhibitor is the Vmax increased, decreased or unchanged?

Unchanged

15

How does temperature affect the activity of an enzyme reaction?

Denaturing effect
Kinetic effect

16

Name two properties of competitive inhibitors

They can be overcome by increasing the substrate concentration.
They have a similar shape to the substrate.

17

Name a competitive inhibitor

Malonate

18

Name a non-competitive inhibitor

Mercury ions

19

Name an irreversible inhibitor

Penicillin

20

Name an inhibitor that acts as a nerve poison (irreversible)

DFP

21

Name two properties of irreversible inhibitors

They usually prevent the substrate entering the active site.
They usually bond to the side chain of either serine or cysteine at the enzyme active site.

22

Name two properties of allosteric enzymes

They show sigmoidal rather than hyperbolic (Michaelis Menten) kinetics.
They must contain two or more sub-units.

23

How does a change in the pH affect bonding in enzymes?

Effect the electrostatic (ionic) bonding in the tertiary structure of enzymes

24

Is the -OH group in a-glucose above or below the ring?

Below

25

Which types of glycosidic bond are found in glycogen?

a1-4
a1-6

26

When a -NH2 group replaces an -OH group it is called _________

Glucosamine

27

When a -COOH group replaces the -OH group on C6 it is called __________

Glucuronic acid

28

When an -H replaces an -OH group it is called _______

Deoxyglucose

29

Why does cellulose form long straight chains?

Because every alternate glucose unit inverts

30

What molecules unbranched and highly branched molecules are starch made up of?

Amylose
Amylopectin

31

What are the names for a carbon atom with 4 different atoms or groups attached to it by a covalent bond?

Asymmetric
Chiral

32

What are functions of carbohydrates?

Cell recognition
Energy store
Structural component

33

Which of the following monosaccharides are the components of lactose?

Glucose
Galactose

34

What carbonyl groups are found in monosaccharides?

Aldehyde
Ketone

35

What is the most abundant protein in most vertebrates?

Collagen

36

What is the Km?

Michaelis constant

37

What is the michaelis constant?

An indication of the affinity of an enzyme for it's substrate

38

At ____ concentrations of a substrate, the rate of an enzyme reaction is directly proportional to the substrate concentration if the concentration of the enzyme remains constant.

Low

39

Cellulose forms long straight chains because every alternate glucose unit _______

Inverts

40

What is a common non-reducing disaccharide?

Sucrose

41

What is an epimer?

An isomer of a monosaccharide where the only difference is the side of the central carbon backbone that the -OH and -H point on one carbon atom only

42

Which type of glycosidic bond is found in cellulose?

B1-4

43

Name the polysaccharide found in bacterial cell walls

Peptidoglycan

44

What is the protein in muscle which binds to and acts as a store of oxygen

Myoglobin

45

Which of the following is the polysaccharide found in insect exoskeletons?

Chitin

46

What is the name of the enzyme that converts pyruvate to lactate?

Lactate dehydrogenase

47

What does alchohol dehydrogenase convert acetylaldehyde to?

Ethanol

48

What toxic substance does alcohol dehydrogenase catalyse the conversion of methanol to

Formaldehyde

49

Which enzyme catalyses the major control point in glycolysis?

Phosphofructokinase (PFK)

50

How many molecules of ATP are produced form ADP by substrate level phosphorylation when glucose is converted to pyruvate by glycolysis?

4

51

What is the net yield of ATP form anaerobic glycolysis per glucose

2