Brainscape's Knowledge GenomeTM

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


See full index

BC3004: Cell Signalling > Polypeptides: Growth Hormones, Insulin, Glucagon > Flashcards

Polypeptides: Growth Hormones, Insulin, Glucagon Flashcards

1
Q

What is the typical length of polypeptide signalling molecules?

A

30-200 amino acids

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

Are polypeptide signalling molecules hydrophobic or hydrophilic?

A

Hydrophilic

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

What receptors do polypeptide signalling molecules bind to?

A

Cell surface receptors
* do NOT cross plasma membrane

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

TRUE OR FALSE:
Polypeptide signalling molecule effects on target cells are immediate and generally short-lived

A

True

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

What is the lifespan of Polypeptide signalling molecules?

A

Short lifespan i.e. minutes

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

How are Polypeptide Signalling Molecules functionally subdivided?

A
  • Polypeptide hormones
  • Polypeptide growth / differentiation factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some examples of Polypeptide Hormones?

A
  • Insulin
  • Glucagon
  • Gastrin
  • Vasopressin
  • Adrenocorticotropic Hormone (ACTH)
  • Follicle Stimulating Hormone (FSH)
  • Luteinising Hormone (LH)
  • Thyroid Stimulating Hormone (TSH)
  • Parathyroid Hormone
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some examples of Growth Factors?

A
  • Epidermal Growth Factor (EGF)
  • Insulin-like Growth Factor 1 (IGF-1)
  • Interleukins (ILs)
  • Nerve Growth Factor (NGF)
  • Erythropoietin (Epo)
  • Platelet Derived Growth Factor (PDGF)
  • Somatotropin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the FIVE characteristics of Polypeptide Growth Factors/Hormones?

A
  1. Produced as a longer precursor form (on the RER)
  2. Have an N-terminal signal sequence
  3. Sometimes glycosylated and / or contain di-sulfide bridges
  4. Secreted via the secretory pathway
  5. Interact with cell surface receptors, which are typically tyrosine kinase receptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How long is Epidermal Growth Factor (EGF)?

A

53 amino acids

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

How many intramolecular disulfide bonds are contained in EGF?

A

Three

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

What does EGF stimulate?

A
  • Cell growth
  • Differentiation
  • Survival
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What anti-cancer drug targets EGF?

A

Herceptin

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

How do Polypeptide Signalling Molecules respond to ligand binding?

A

Directly modify cellular proteins

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

What happens after ligand binding in the EGF receptor?

A

Autophosphorlyation of activated receptor and phosphorylation of other cellular proteins

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

What type of activity do EGF receptors display when activated?

A

Protein kinase activity (addition of phosphate groups)

17
Q

What part of the protein is a phosphate group added to during phosphorylation?

A

Hydroxyl group (OH) of a Serine / Threonine or a Tyrosine

18
Q

Where does Autophosphorylation occur after ligand binding to the EGF receptor?

A

Tyrosines

19
Q

What is the function of the N-Terminal Signal Sequence on Polypeptide pre-hormones?

A

Targets them to the lumen of the Rough ER and to the secretory pathway

20
Q

Where in the cell are mature hormones generated from pro-hormones?

A

Golgi apparatus

21
Q

What is the mechanism of action for the Synthesis and Secretion of hormones?

A
  1. Pro-hormone translated on RER by ribosomes
  2. Enters ER lumen (signal sequence)
  3. Vesicles bud off the ER
  4. Vesicles go to Golgi and dock
  5. Enters Golgi
  6. Undergoes post-translational modification to form mature hormone (growth factor)
  7. Vesicles leave Golgi and go to Plasma Membrane (secretory pathway)
  8. Exocytosis from cell
22
Q

How are Polypeptide Hormone Precursors post-translationally modified?

A
  • Proteolytic cleavage
  • Disulfide bridge formation
  • Glycosylation
23
Q

What does hormone / neurotransmitter stimulation cause?

A

Exocytosis of polypeptide hormone into the blood

24
Q

How long do released polypeptides remain active in the blood?

A

Seconds to minutes

25
Q

How are released polypeptides degraded?

A

By the blood or tissue proteases

26
Q

What cellular functions are affected by Polypeptide Hormones?

A
  • Uptake and mobilisation of glucose
  • Storage / mobilisation of fat
  • Secretion of cellular products
27
Q

What cellular function is affected by Growth Factors?

A

Growth / differentiation of cells

28
Q

How does Insulin and Glucagon work?

A

Acts antagonistically to regulate blood glucose concentrations

29
Q

How does Insulin affect blood glucose levels?

A

Decreases blood glucose levels by stimulating its uptake into cells and its storage as glycogen

30
Q

How does Glucagon affect blood glucose levels?

A

Increases blood glucose by stimulating the activation of glycogen phosphorylase and glycogen synthase for the conversion of glycogen to glucose

31
Q

What is Diabetes?

A

A reduced ability to regulate blood glucose levels

32
Q

What is Type II Diabetes?

A
  • Insulin-resistant diabetes (non-insulin dependent)
  • Results from mutated insulin receptors
33
Q

What is Type I Diabetes?

A
  • Insulin-dependent
  • Insulin β-cells in pancreas are destroyed
  • Autoimmune disease
34
Q

What is Hypoglycemia?

A

Deficiency of glucose

BC3004: Cell Signalling (18 decks)

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