Brainscape's Knowledge GenomeTM

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


See full index

BS1030: Biochemistry > CW7: Collagen, oestrogen receptor, and myoglobin > Flashcards

CW7: Collagen, oestrogen receptor, and myoglobin Flashcards

1
Q

What is the most abundant protein in mammals?

A

Collagen

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

What is the size and shape of collagen?

A

300 nm

Rod-shaped

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

In what structures does collagen provide tensile strength?

A

Skin, bone, teeth, cartilage, etc.

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

How many polypeptides form collagen? How many amino acids are in each polypeptide chain?

A

3 polypeptide chains of approx. 1000 amino acids each

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

What is the repeating pattern of collagen?

A

–(Gly-X-Y)– where X is usually proline and Y is often hydroxyproline

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

Why is glycine needed in the third position?

A

It has a small side chain (H) so allows for tight packing

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

How do people acquire scurvy?

A

Hydroxyproline (4-HyP) is formed from proline under the action of the enzyme prolyl hydoxylase

The additional –OH group allows cross-links to form between chains, adding tensile strength

Prolyl hydroxylase requires ascorbic acid (vitamin C) as a co-factor

Insufficient vitamin C means proline not converted to 4-HyP so no cross-links so weak collagen so scurvy!

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

What is the abbreviation for ‘oestrogen receptor’?

A

ER

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

Describe the structure and function of an oestrogen receptor.

A
  • Regulates the response to oestrogen
  • It is a soluble protein – nuclear hormone receptor
  • To achieve this effect it needs two key domains:
    • Ligand-binding domain (binds hormone; ligand = oestrogen)
    • DNA-binding domain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the role of the DNA-binding domain in the oestrogen receptor?

A

ER binds to specific DNA sequences (oestrogen response elements)

This affects the transcription of neighbouring genes, i.e. it switches them on or off

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

Why is hydroxyproline required at the third position?

A

Prolyl hydroxilase has a preference for hydroxylating a proline where there is a glycine just to the C-terminal side of the proline (N-terminal side of glycine)

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

What is oestrogen and where is it produced?

Is it hydrophilic or hydrophobic?

A

A hormone produced in the ovaries

It is hydrophobic so can cross membranes

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

How does tamoxifen work?

A

ER is overproduces in approx. 70% of breast cancers

Tamoxifen competes for binding to ER, but cannot activate it

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

Why was myoglobin one of the first proteins to be studied?

A

It is readily available

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

Where in the body is myoglobin mostly found? In what type of animals is it mostly found?

A

It is an oxygen-storing protein in muscles, especially in diving animals

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

How many amino acids are in myoglobin? What is this in kDa?

A

152 amino acids (18 kDa)

17
Q

How many subunits are in myoglobin? What is the name for this?

A

One – it is a monomer

18
Q

What is a prosthetic group? What is myoglobin’s prosthetic group?

A

A compound permanently associated with a protein that contributes to the protein’s function

Mb’s prosthetic group is haem with Fe2+

19
Q

Which binds oxygen: Fe2+ or Fe3+?

A

Fe2+ – it binds oxygen until it is oxygenated itself!

20
Q

Which type of motif is common in myoglobin?

A

Alpha helices

21
Q

Why does breathing in carbon monoxide lead to carbon monoxide poisoning and death?

A

CO is a poison to the system

It binds more strongly to Hb and Mb than O2 does

It is irreversible and leads to less Hb/Mb to carry oxygen so organs are starved of oxygen

22
Q

What type of structure is present in a haem prosthetic group?

A

Porphyrin ring

23
Q

Describe the haem prosthetic group.

A

It is a planar (flat) porphyrin ring structure with eight alpha helices (A-F, starting at the N-terminus)

24
Q

What is another name for His-E7 on the haem prosthetic group?

A

Distal histidine

25
Q

What is another name for His-F8 on the haem prosthetic group?

A

Proximal histidine

26
Q

What is the dissociation equilibrium constant for O2 binding to myoglobin?

A
27
Q

What is the equation for fractional saturation (Y) of myoglobin?

A
28
Q

What is the general equation for fractional saturation (Y)?

A
29
Q

How can the equation for the fractional saturation of myoglobin be rearranged so it is more like the Michaelis-Menten equation?

A
30
Q

What shape is the saturation curve for myoglobin?

A

Hyperbolic

BS1030: Biochemistry (21 decks)

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