From which animals was insulin extracted before genetic engineering?

Insulin was extracted from the pancreases of cattle and pigs slaughtered for meat. The first experiments on insulin used dogs.

Why did animal insulin cause problems for some patients?

Animal insulin differs slightly from human insulin in its amino acids. Some patients made antibodies against it or had allergic reactions.

Why was extracting insulin from animal pancreases difficult?

Each pancreas holds only a tiny amount of insulin, so huge numbers were needed. The hormone had to be separated from many other proteins, and supply depended on slaughter.

CCEA A-Level Life and Health Sciences 0008

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Genetics, Stem Cell Research and Cloning

Insulin, factor VIII and chymosin from genetically modified microbes

3 things to know
A2 5

Overview

Insulin and diabetes, animal insulin and its problems, making human insulin with reverse transcriptase, Humulin and yeast, factor VIII and haemophilia, and rennet and chymosin in cheese making.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What type of molecule is insulin, and where in the body is it made?

Key term

What is the underlying fault in diabetes mellitus that insulin treatment corrects?

Key term

Why is insulin given by injection rather than swallowed as a tablet?

Questions from this subtopic

Each one with the model answer underneath.

1
What type of molecule is insulin, and where in the body is it made?
Model answer
Insulin is a protein hormone made of two short polypeptide chains. Insulin is made by beta cells in the islets of Langerhans in the pancreas.
2
What is the underlying fault in diabetes mellitus that insulin treatment corrects?
Model answer
Diabetes mellitus involves a deficiency of insulin or a poor response to it. Blood glucose cannot be brought down to normal, and injected insulin replaces what is missing.
3
Why is insulin given by injection rather than swallowed as a tablet?
Model answer
Insulin is a protein, so protease enzymes in the gut would digest it. Injected insulin reaches the blood intact.
4
From which animals was insulin extracted before genetic engineering?
Model answer
Insulin was extracted from the pancreases of cattle and pigs slaughtered for meat. The first experiments on insulin used dogs.
5
Why did animal insulin cause problems for some patients?
Model answer
Animal insulin differs slightly from human insulin in its amino acids. Some patients made antibodies against it or had allergic reactions.
6
Why was extracting insulin from animal pancreases difficult?
Model answer
Each pancreas holds only a tiny amount of insulin, so huge numbers were needed. The hormone had to be separated from many other proteins, and supply depended on slaughter.

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