Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Principles 2018 > Biochemistry > Flashcards

Biochemistry Flashcards

1
Q

What is oxidation?

A

Loss of electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is reduction?

A

Gain of electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the most oxidisable state of carbon?

A 
Alkane 
Alcohol
Aldehyde
Carboxylic acid
Carbon Dioxide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some functions of biomolecules?

A 
Information storage
Structural
Energy generation
Energy currency/storage
Recognition/communication/specificity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the four major classes of biomolecules?

A

Peptides and proteins
Lipids
Nucleic acids
Carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the first law of thermodynamics?

A

Energy is neither created nor destroyed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the second law on thermodynamics?

A

When energy is converted from one form to another, some of that energy becomes unavailable to do work

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What changes are involved in reactions?

A

Enthalpy

Entropy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is enthalpy?

A

Heat content

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is entropy?

A

Randomness, disorder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the equation for free energy change?

A

(energy of the products) – (energy of the reactants)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is an exergonic reaction?

A

total free energy of the product(s) is less than the total free energy of the reactant(s)
Delta G is NEGATIVE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is an endergonic reaction?

A

otal free energy of the product(s) is more than the total free energy of the reactant(s)

Delta G is POSITIVE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is delta G?

A

Change in free energy under standard conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What reactions can occur spontaneously?

A

Exergonic reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the stability of ATP?

A

negative charges close together in ATP put a strain (electrostatic repulsion) on the molecule that makes it less stable than ADP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Do cells store ATP?

A

No not really, constantly regenerated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define metabolism?

A

all the reactions taking place in the body, divided into catabolism and anabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe glycolysis?

A

Initial breakdown of glucose for the generation of ATP

Early steps use two ATP molecules

Later steps generate four ATP molecules

Net gain of two ATP molecules per glucose molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe gluconeogenesis?

A

Making new glucose from non-carbohydrate precursors, e.g. pyruvate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are control points in metabolic pathways?

A

Reactions with large delta G values

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How is flux through control points controlled?

A

Altering the activity of the enzyme

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is significant about the structure of water?

A

Water is polar;

  • electrons are shared unequally
  • depends on electronegativity of atoms

Water molecule is bent

  • forms a dipole
  • tetrahedral shape
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Which substances dissolve in water?

A

Ionic and polar substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is a hydrogen bond?

A

Covalent bond between hydrogen and a more electronegative atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Are hydrogen bonds stronger than covalent bonds?

A

Individually they are weaker, can be strong collectively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is the hydrophobic effect?

A

Oil and water don’t mix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Define amphipathic?

A

Hydrophilic and hydrophobic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Describe the structure of amphipathic molecules?

A

Polar (hydrophilic) head

Non-polar (hydrophobic) tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What do amphipathic molecules form in water?

A

Micelles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What lipids are found in cell membranes?

A
  • structural (lipid bilayer)

- precursors of signalling molecules (DAG, IP3)

32
Q

What is the roll of proteins in cell membranes?

A

confer selectivity
involved in recognition
and more

33
Q

What does D and L polypeptides refer to?

A

stereochemistry of amino acids
D and L forms are
sterioisomers: non-superimposable mirror images

34
Q

What do all amino acids contain?

A 
-a-carbon group bonded to;
>an amino group (-NH2)
>a carboxyl group (-COOH)
>a hydrogen (-H)
>a side chain (-R)
35
Q

What is the exception to the stereoisomer rule?

A

Glycine

36
Q

How are peptide bonds formed?

A

by hydrolysis

37
Q

Describe peptide bonds

A
  • Partial double bond character
  • Planar
  • Strong and rigid
38
Q

Describe an acid

A

Can donate a protein

39
Q

Describe a base

A

Can accept a proton

40
Q

What is pH?

A

Measurement of home many protons in a solution?

41
Q

What is a buffer?

A

Solution to control the pH of a reaction mixture

42
Q

What does a titration curve plot?

A

pH as a function of base added to an acid

43
Q

What is a zwitterion?

A

Amino acids without charged side groups (no net charge)

44
Q

How can proteins act as buffers?

A

Several of the amino acid side chains can be ionised

45
Q

What can cause the ionisation of a protein?

A

A change in pH

46
Q

Describe primary protein structure?

A

the sequence of amino acid residues

47
Q

Describe secondary protein structures?

A

the localised conformation of the polypeptide backbone

48
Q

Describe tertiary protein structure?

A

the three-dimensional structure of an entire polypeptide, including all its side chains

49
Q

Describe quaternary protein structure?

A

the spatial arrangement of polypeptide chains in a protein with multiple subunits

50
Q

How can polypeptides rotate?

A

Rotate around the angles between

  • the a carbon and the amino group
  • the a carbon and the carboxyl group
51
Q

What are the three types of secondary protein structure?

A

Alpha helix
Beta strands
triple helix

52
Q

Where is the collagen triple helix found?

A

Component of bone and connective tissue

53
Q

Are collagen triple helices water soluble?

A

No

54
Q

What bonds are involved in a collagen triple helix?

A

Repeating sequence of X-Y-Gly in all strands
>X = any amino acid
>Y = proline or hydroxyproline
>also contains hydroxylysine

Inter-chain H-bonds (no
intra-chain)
>involving hydroxylysine and hydroxyproline

Covalent inter- and intra-molecular bonds

55
Q

What changes in collagen structure with age?

A

Covalent cross linking increases

56
Q

What is the basis of scurvy?

A

The enzyme which hydroxylates proline requires ascorbic acid (vitamin C)

This results in weakened collagen

57
Q

What are the two forms of tertiary structure?

A

Fibrous proteins

Globular proteins

58
Q

Describe the structure of fibrous proteins?

A

polypeptide chains organized approximately parallel along a single axis
>consist of long fibers or large sheets
>tend to be mechanically strong
>insoluble in water and dilute salt solutions

59
Q

Give examples of fibrous proteins

A

Keratin of hair and wool

Collagen of connective tissue including cartilage, bones, teeth, skin, blood vessels

60
Q

Describe the structure of globular proteins?

A

folded to a more or less spherical shape
>soluble in water and salt solutions
>polar side chains are on the outside and interact with the aqueous environment by hydrogen bonding and ion-dipole interactions
>nonpolar side chains are buried inside
nearly all have substantial sections of alpha-helix and beta-sheet

61
Q

Give examples of globular proteins?

A

Myoglobin

Haemoglobin

62
Q

What forces stabilise tertiary structure?

A

-Covalent disulphide bonds
-Electrostatic interactions = salt bridges
-Hydrophobic interactions
-Hydrogen bonds
>backbone
>side chain
-Complex formation with metal ions

63
Q

Where are polar side groups usually locates on proteins?

A

The outside

64
Q

What hydrophobic interactions are present within proteins?

A

> Weaker attraction between water and hydrocarbon
Weaker attraction between hydrocarbon and hydrocarbon (van der Waals interactions)
Strong organizing influence – the hydrophobic effect

Amino acids with hydrophobic side-chains tend to cluster in the centre of globular proteins

65
Q

How does substitution of amino acids alter protein structure?

A

By changing the physiological pH you change interactions and bond formation

66
Q

Describe the physiological changes involved in sickle cell anaemia

A

Single nucleotide sequence change in coding region of the B chain of haemoglobin A, resulting in altered protein (valine instead of glutamic acid)

67
Q

What can misfolding of polypeptide chains cause?

A

Alzheimer’s, parkinson’s, CJD

68
Q

What is the folding of polypeptide chains aided by?

A

Chaperones

69
Q

What is mad cow disease caused by?

A

Caused by infection

70
Q

What is cruetzfeldt-jacob disease caused by?

A

Spontaneous or inherited mutations

71
Q

What are prion proteins?

A

Normal components of the brain

72
Q

What types of physical condition or chemical agent sill disrupt the various protein structures?

A 
-Heat
(increase in vibrations)
-Extremes of pH
(electrostatic interactions interrupted)
-Detergents, urea, guanidine hydrochloride
(disrupt hydrophobic interactions)
-Thiol agents, reducing agents
(reduce and thereby disrupt disuplhide bonds)
73
Q

Describe the structure of myoglobin?

A

Globular
-contains a haem group
> which contains an iron iron (prosthetic groups)

74
Q

What is the haem in myoglobin responsible for?

A

Binding oxygen

Storing oxygen in muscle

75
Q

Describe the structure of haemoglobin?

A
  • Four subunits
  • two a and two B
  • each contains a haem group
76
Q

What does binding of one oxygen to haemoglobin do?

A

Changes the affinity of the other subunits

Principles 2018 (34 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions