Which one of the following statements regarding insulin hormone is correct?
- A.Insulin is a protein hormone which is not produced in human body.
- B.Insulin is a steroid hormone which is produced in human body.
- C.Insulin is a cholesterol-driven hormone given to human.
- D.Insulin is a protein hormone which is produced in human body.
Correct answer
Explanation
The correct answer is D. Insulin is a protein (peptide) hormone made in the human body by the beta cells of the islets of Langerhans in the pancreas.
Insulin is a small protein of 51 amino acids in two chains, A and B, joined by disulphide bridges. It lowers blood sugar by helping cells take up glucose and by making the liver and muscles store it as glycogen; glucagon, made by the alpha cells, does the opposite. When the body makes too little insulin or cannot use it, the result is diabetes mellitus. Insulin was isolated by Frederick Banting and Charles Best in 1921, and since the 1980s human insulin for patients has been produced by genetically engineered bacteria.
A is wrong: insulin is produced in the human body, by the pancreas.
B is wrong: insulin is not a steroid; steroid hormones include cortisol, oestrogen and testosterone.
C is wrong: insulin is not made from cholesterol; steroid hormones are.
Exam tip: Insulin — beta cells, lowers sugar; glucagon — alpha cells, raises sugar; both are peptide hormones.
Practice Questions
View allConsider the following animals :
1. Hedgehog
2. Marmot
3. Pangolin
To reduce the chance of being captured by predators, which of the above organisms rolls up/roll up and protects/protect its/their vulnerable parts?
- A.1 and 2
- B.2 only
- C.3 only
- D.1 and 3
Show answer
Hedgehogs and pangolins curl into a tight ball when threatened, covering the soft belly and face with spines or scales; marmots do not.
Read the full explanation →Which one of the following is used in preparing a natural mosquito repellent?
- A.Congress grass
- B.Elephant grass
- C.Lemongrass
- D.Nut grass
Show answer
Lemongrass and its close relative citronella grass yield aromatic oils that keep mosquitoes away, so they are the base of many natural repellents.
Read the full explanation →Which one of the following devices is non-ohmic ?
- A.Conducting copper coil
- B.Electric heating coil
- C.Semi conductor diode
- D.Rheostat
Show answer
A diode does not obey Ohm's law: the current through it is not proportional to the voltage across it. An ohmic conductor gives a straight-line graph of current against voltage, so its resistance stays constant at a fixed temperature.
Read the full explanation →What is the formula mass of anhydrous sodium carbonate? (Given that the atomic masses of sodium, carbon and oxygen are 23 u, 12 u and 16 u respectively)
- A.286 u
- B.106 u
- C.83 u
- D.53 u
Show answer
Anhydrous sodium carbonate is Na₂CO₃, and 2 × 23 + 12 + 3 × 16 = 106 u. Formula mass is the sum of the atomic masses of all the atoms in one formula unit of an ionic compound.
Read the full explanation →Which one of the following minerals is used as a fuel in nuclear power stations ?
- A.Bauxite
- B.Quartz
- C.Feldspar
- D.Pitchblende
Show answer
Pitchblende, or uraninite, is the chief ore of uranium, the fuel used in most nuclear power stations. Pitchblende is a heavy, black mineral made mostly of uranium oxide.
Read the full explanation →