Sign In

Quick Biochemistry - Hormone Metabolism (Section 5)

1
How does the thyroid gland acquire circulating iodine?
Answer
(C)
Via active transport
2
How are thyroid hormones primarily carried within the bloodstream?
Answer
(D)
Mostly bound to TBG, partially free, and sometimes bound to TBPA
3
If thyroxine binding globulin and thyroxine binding pre-albumin are at maximum capacity for thyroxine, how is excess hormone transported?
Answer
(A)
By albumin
4
Where are the receptors for thyroid hormones located?
Answer
(C)
Inside the cells
5
What is the primary effect of thyroxine binding to its receptors?
Answer
(D)
Enhancement of transcription
6
Which thyroid hormone exhibits the highest potency?
Answer
(C)
T3
7
Which thyroid hormone is found in the greatest quantity in the bloodstream?
Answer
(D)
T4 bound to TBG
8
What controls the release of thyroid hormones?
Answer
(D)
All of the above
9
What are typical signs of an overactive thyroid gland?
Answer
(A)
Enlarged thyroid, sensitivity to heat, weight loss, and rapid heart rate
10
Which of the following is NOT a common characteristic of hyperthyroidism?
Answer
(D)
Low metabolic rate
11
Which of the following is NOT a potential symptom of myxoedema?
Answer
(C)
Rapid heart rate
12
What condition can potentially lead to cognitive impairment?
Answer
(A)
Cretinism
13
Where is parathyroid hormone (PTH) produced?
Answer
(A)
Chief cells of the parathyroid glands
14
How many amino acid units make up the PTH molecule?
Answer
(B)
84
15
Which part of the PTH molecule is crucial for its function?
Answer
(A)
The first 34 amino acids
16
What is the approximate lifespan of PTH in the body?
Answer
(B)
A few minutes
17
What is the intracellular signaling molecule activated by PTH?
Answer
(A)
Cyclic AMP
18
Which of the following effects is NOT caused by PTH?
Answer
(D)
Increased phosphate reabsorption in the kidney
19
What primarily controls the release of PTH?
Answer
(D)
Plasma calcium levels
20
What impact does a high level of PTH have on blood composition?
Answer
(C)
Increased calcium and decreased inorganic phosphorus
21
Muscle spasms associated with a medical condition may occur
Answer
(D)
After a surgical procedure involving the parathyroid glands
22
Which element facilitates the formation of insulin crystals?
Answer
(C)
Zinc
23
Approximately how much insulin is secreted each day?
Answer
(D)
40-50 units
24
In which of the following scenarios is the number of insulin receptors reduced?
Answer
(A)
Obesity
25
Where are the locations for insulin interaction on the cell?
Answer
(A)
a-subunits of insulin receptor
26
Where are the a-Subunits of the insulin receptor located?
Answer
(A)
Outside the cell membrane
27
Where are the ẞ-Subunits of the insulin receptor located?
Answer
(C)
Across the cell membrane
28
Which part of the insulin receptor contains the tyrosine kinase domain?
Answer
(B)
B-Subunits
29
The attachment of insulin to its receptor leads to activation of
Answer
(D)
Tyrosine kinase
30
What is the subunit composition of the insulin receptor?
Answer
(B)
Two a-and two ẞ-subunit
31
Which type of cell generally does *not* require insulin to facilitate glucose uptake?
Answer
(D)
Liver cells
32
What is a known effect of insulin on metabolic processes?
Answer
(C)
Gluconeogenesis
33
Which of the following processes is stimulated by insulin?
Answer
(A)
Glycogenesis
34
What biological processes are amplified by the presence of insulin?
Answer
(D)
All of these
35
Insulin is associated with a reduction in the production of which of these substances?
Answer
(C)
PEP carboxykinase
36
Under which of these circumstances is diabetes mellitus *least* likely to develop?
Answer
(B)
Tumour of β-cells
37
Which of these scenarios may lead to a hypoglycemic coma?
Answer
(D)
After overdose of insulin
38
What molecule acts as a signaling molecule for glucagon's effects within a cell?
Answer
(A)
Cyclic AMP
39
How many amino acids make up the glucagon peptide?
Answer
(A)
29
40
When does the release of glucagon typically increase?
Answer
(D)
When blood glucose is low
41
What is the primary physiological action of glucagon, in terms of carbohydrate metabolism?
Answer
(C)
Stimulating glycogen breakdown in the liver
42
Which substance is NOT produced using tyrosine as a starting material?
Answer
(A)
Melatonin
43
From which compound is dopamine derived during its biosynthesis?
Answer
(A)
Dihydroxyphenylalanine
44
Which substance can effectively penetrate the blood-brain barrier?
Answer
(C)
Dopa
45
In what type of cells is epinephrine primarily produced?
Answer
(D)
All of these
46
What is the immediate precursor in the pathway for epinephrine synthesis?
Answer
(B)
Norepinephrine
47
What is considered to be the major breakdown product of catecholamines?
Answer
(D)
Vanillylmandelic acid
48
Which enzyme plays a crucial role in the breakdown of catecholamines?
Answer
(C)
Monoamine oxidase
49
Which type of receptor does norepinephrine primarily interact with?
Answer
(A)
a-Adrenergic receptors
50
Which adrenergic receptor subtypes are primarily linked to the activation of a stimulatory G-protein?
Answer
(D)
B₁-and B₂-adrenergic receptors