Brainscape's Knowledge GenomeTM

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


See full index

BCM210 > Topic 4 - Proteins > Flashcards

Topic 4 - Proteins Flashcards

1
Q

Less than 50 amino acids = a protein or a peptide?

A

Peptide

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

List the biological roles of proteins

A
  • Enzymes
  • Transport
  • Nutrient & storage
  • Contractile or motile
  • Structural
  • Defence
  • Regulatory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What determines protein function?

A

number of amino acids
amino acid composition
Number of aa chains
different aa’s in each chain

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

Non-amino acid parts of proteins are called…?

A

prosthetic groups

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

Proteins containing prosthetic groups (non-aa parts) are called…?

A

conjugated proteins

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

Identify the 4 levels of protein structure

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

Describe primary (covalent) structure of proteins

A

based on the linear sequence of amino acids.
Determines function & shape (protein configuration)

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

What is configuration (in relation to proteins)?

A

the AMINO ACID SEQUENCE (primary structure)

-covalent bonds have to be broken for change in configuration

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

What is conformation (in relation to proteins)? and how is it stabilised?

A

How the chain is ARRANGED

Stabilised by weak interactions

  • hydrogen bonds
  • Hydrophobic interactions
  • ionic interactions
  • disulfide bonds (outside cell)

ALL ARE VERY IMPORTANT

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

What is the purpose of disulfide bonds and where do they occur?

A

DO NOT OCCUR IN CELLS. ARE OUTSIDE CELLS

Used to make cells more robust

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

What is the driving force behind protein folding?

A

Minimising the number of hydrophobic amino acid R-groups exposed to water

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

Are peptide bonds covalent or non-covalent?

A

covalent

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

Describe seconday structure of proteins and name the two kinds of folding

A

How the primary sequence folds -spatial arrangement of aa’s that are close together in a peptide due to H-bonding

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

Describe the structure of the alpha helix (secondary structure)

A

commonly associated w/ globular proteins
right handed
simplest arrangement a polypeptide can make w/ a rigid (double) peptode bond
backbone wound around imaginary axis
R-groups protrude to outside
stabilised by H bonds

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

Describe the structure of Beta-pleated sheets (secondary structure)

A

Can be parallel or anitparallel
stabilised by h bonding b/w different strands

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

What is a beta turn and what is its purpose?

A

a connecting element b/w a-helix or b-sheet in globular proteins

used for change of direction (gly and pro often occur)

stabilised by H bonding

17
Q

Describe the tertiary structure of a protein and how it is stabilised

A

the overall 3D structure incl. assemblage of a-helix, b-sheet and connecting elements

forms fibrous (support) and globular (often enzymes) proteins

Maintained by weak interaction b/w R-groups =>H bonding b/w polar side chains, ionic interactions, hydrophobic interactions, Van der Waals & covalent cross-links (disulfide bonds)

18
Q

Describe the quaternary structure of a protein

A

proteins composed of multiple subunits (polypeptides). Polypeptides are held together by non-covalent interactions

19
Q

Describe protein denaturation, its effects and how it is caused

A

The unfolding of proteins

caused by changes in heat, pH & organic solvents

Causes loss of tertiary structure (disulphide bonds, aa side chain interactions) & secondary structure (folding). Most does NOT affect primary structure.

20
Q

How to hydrophobic effects allow proteins to spontaneously refold (renaturation)?

A

Hydrophobic aa’s want to release their ordered water

21
Q

Name the 3 kinds of proteins and give a brief description.

A
  1. Fibrous proteins =>long strands or sheets e.g. keratin, collagen
  2. Globular proteins =>chains folded into globular shape e.g. myoglobin (tertiary), haemoglobin (quaternary)
  3. Membrane proteins
22
Q

Describe the structure and function of keratin

A

fibrous protein

right handed a-helix as secondary structure

many cysteine residues, therefore disulfide linkages b/w chains (protofilaments).

23
Q

Describe the structure and function of Collagen

A

structural protein

right handed triple a-CHAIN

typically consists of Glycine, Alanine and Proline

assembly of collagen fibres requires vitamin C as a cofactor

24
Q

Describe the structure and function of Myoglobin

A

conjugated protein

single polypeptide chain w/ 8 a-helices

Oxygen storage

haem is its prosthetic group

25
Q

Describe the structure and function of Haemoglobin

A

globular, oxygen carrying protein
4 polypeptide chains
-2 a chains
-2 b chains

4 heme groups which bind O2

if 1 subunit chages shape for oxygen binding, so do all others (T-state to R-state)
T (tense) predominates in absence of O2. R favours binding of O2

26
Q

Describe the structure and function of Immunoglobins

A

B-cells secrete immunoglobins.

very specific (antigens/immunogens)

Y shaped structure w/ 2 identical heavy & light chains

BCM210 (18 decks)

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