Biochemistry Flashcards

1
Q

What are nucleotides?

A

Compound = nitrogen containing base + sugar + phosphate

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2
Q

Which end of DNA are new nucleotides added to?

A

3”

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3
Q

What are ZDV & AZT?

A

Retrovirals (used to treat HIV)

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4
Q

What are Okazaki fragments?

A

Short DNA formed on a lagging strand in DNA replication

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5
Q

What does helicase do?

A

Unwind DNA strand (stop it rewinding)

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6
Q

In which direction is the leading strand formed in?

A

3” - 5”

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7
Q

In which direction is the lagging strand formed in?

A

5” - 3”

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8
Q

What do enzymes do?

A

Catalyse a reaction so it reaches equilibrium faster

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9
Q

Do enzymes alter the position of equilibrium?

A

No

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10
Q

What are the 2 types of co factors?

A

Metal ions

Coenzymes

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11
Q

What is an apoenzyme?

A

Enzyme without cofactor

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12
Q

What is holoenzyme?

A

Enzyme with cofactor

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13
Q

Where do substrates bind to enzymes?

A

Active site

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14
Q

What factors affect enzyme activity?

A

Temperature
pH
Concentration (enzyme or substrate)

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15
Q

What are isozymes?

A

Isoforms of enzymes

Catalyse same reaction but have different shape & properties

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16
Q

What does increased CK show?

A

Muscle damage (skeletal)

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17
Q

What are Zymogens?

A

Inactive precursors of enzymes

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18
Q

What does the Michaelis-Menten equation show?

A

Kinetics of an enzyme reaction

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19
Q

What is Vmax?

A

Maximal rate of reaction (with unlimited substrate)

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20
Q

What is Km?

A

Michaelis constant

Conc of S when 1/2 Vmax

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21
Q

Mechanisms of enzyme control

A
Allosteric 
Regulation of transcription 
Reversible covalent modification 
Irreversible covalent modification 
Degradation
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22
Q

What is Allosteric control?

A

Altered enzyme activity by means of conformation induced by different molecules

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23
Q

Do Allosteric enzymes follow Michaelis-Menten kinetics?

A

NO

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24
Q

What shape is the curve of an allosteric enzyme?

A

Sigmoid

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25
Q

What is cooperativity?

A

Influence that binding of a ligand to one promoter has on the binding of a ligand to another promoter in an oligomennorhea phase

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26
Q

What are nucleosides?

A

Compound = nitrogen based base + sugar

E.g. Adenosine

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27
Q

4 types of amino acid

A

Polar
Non polar
Acidic
Basic

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28
Q

What is the Henderson-Hasselbach equation used for?

A

Calculate the properties of buffer solutions

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29
Q

What is a buffer solution?

A

A solution that’s pH remains constant when small amounts of acid or base are added

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30
Q

When does pH = pKa in a titration curve?

A

Point of inflexion

31
Q

What is the primary structure of a protein?

A

Sequence of amino acid residues (held together by covalent peptide bonds)

32
Q

What is the secondary structure of a protein?

A

Localised conformation of the polypeptide backbone

33
Q

What is the tertiary structure of a protein?

A

3D structure of an entire polypeptide, including all its side chains

34
Q

What is the quaternary structure of a protein?

A

Spatial arrangement of polypeptide chains in a protein with multiple subunits (NOT all the time)

35
Q

3 arrangements of secondary structure protein?

A

Alpha helix
Beta pleated sheets
Beta strands

36
Q

Which protein has a triple helix?

A

Collagen

37
Q

Why is collagen important?

A

Influences strength of connective tissue

Important for blood clotting

38
Q

Symptoms of scurvy?.

A

Bleeding gums

Skin discolouration

39
Q

Stages of catabolism

A

1) macromolecules -> monomeric units
2) monomeric units -> Acetyl-CoA + some ATP
3) Acetyl group -> Kreb cycle -> CO2 + H2O

40
Q

3 types of protein

A

Fibrous
Globular
Conjugated

41
Q

Which forces stabilise tertiary structures?

A
Covalent disulphide bridges 
Electrostatic interactions 
Hydrogen bonds 
Hydrophobic interactions 
Complex formation with metal ions
42
Q

What 4 things can disrupt protein structure?

A

Heat
Extremes of pH
Detergents (urea, guanidine hydrochloride)
Thiol agents, reducing agents

43
Q

Where does GLUT1 work?

A

Brain (low Km)

44
Q

Where do GLUT2 receptors act?

A
Liver (high Km) 
Beta cells (insulin dependent)
45
Q

Where does the GLUT3 receptor act?

A

Brain (low Km)

46
Q

Where does the GLUT4 receptor act?

A

Muscle (insulin-dependent)

Adipose tissue

47
Q

Where does the GLUT5 receptor act?

A

But (fructose transport)

48
Q

3 enzymes involved in glycolysis?

A

Hero kinase
Phospofructokinase
Pyruvate kinase

49
Q

What is the substrate for the TCA cycle?

A

Acetyl Co-A

50
Q

What is given off when pyruvate is converted to Acetly Co-A?

A

CO2

51
Q

What combines with Acetyl Co-A at the start of the TCA cycle?

A

Oxaloacetate

52
Q

How many GTP are produced in the TCA cycle?

A

1

53
Q

What are the 2 stages of oxidative phosphorylation?

A

Electron transport

ATP synthesis

54
Q

In oxidative phosphorylation what reduces O2 to H2O?

A

Electrons from NADH & FADH

55
Q

What does the P/O ratio measure?

A

The coupling of ATP to synthesis to electron transport

56
Q

How many ATP are made in total in the complete oxidation of glucose?

A

30-32 ATP molecules

57
Q

What type of diseases are OXOPHOS?

A

Degenerative diseases

58
Q

Examples of glycogen storage disease

A

McArdle’s disease
Andersen disease
Pompe disease

59
Q

Which enzyme marks muscle damage and what is its presentation?

A

CK

General aches/pains, crush injury, dark urine, poor exercise tolerance

60
Q

What enzymes indicate liver damage and what is its clinical presentation?

A

ALT, AST, GGT

Abdominal pain/tenderness, nausea/vomiting, jaundice

61
Q

What enzymes indicate pancreatic damage and what does it present as?

A

AMY, LIP

Acute abdominal pain, radiates to back

62
Q

What enzymes indicate cardiac damage and what is its clinical presentation?

A

CK, AST, LDH

Central chest pain, acute breathlessness, palpitations, cardiac arrest

63
Q

What does an increase in ALT usually indicate?

A

Drug overdose (or liver necrosis) - exclusive to liver

64
Q

What does GGT increase indicate?

A

GGT found in biliary tract and in liver

Increase shows alcohol excess

65
Q

What is lipase a good indicator of?

A

Pancreatic hepatitis

66
Q

What does reduced trope in show?

A

Had an MI

67
Q

Symptoms of hyperglycaemia?

A
Extreme thirst 
Dry mouth 
Blurred vision 
Drowsiness 
Frequent need to pass urine
68
Q

Symptoms of hypoglycaemia?

A
Feeling shaky and irritable 
Sweating 
Tingling lips 
Feeling weak 
Hunger 
Nausea
69
Q

Why do hypoglycaemic patients feel sick?

A

Lack of glucose -> breakdown fats to ketones -> acidosis

70
Q

What are chylomicrons?

A

A lipoprotein present in the blood after digested fat has been absorbed from the small intestine

71
Q

How do statins work?

A

Inhibit an enzyme involved in cholesterol synthesis in the liver

72
Q

How is Vmax determined from a Lineweaver-burk plot?

A

Intersection with the y axis

73
Q

How is Km determined from a lineweaver-burk plot?

A

Intersection with x axis