Photo AI
Insulin and glucagon are hormones that control blood sugar levels in the body - OCR Gateway - GCSE Biology (Combined Science) - Question 13 - 2018 - Paper 8
Question 13
Insulin and glucagon are hormones that control blood sugar levels in the body. The diagram shows interactions between these two hormones. (a) (i) Complete the diag... show full transcript
Worked Solution & Example Answer:Insulin and glucagon are hormones that control blood sugar levels in the body - OCR Gateway - GCSE Biology (Combined Science) - Question 13 - 2018 - Paper 8
Step 1
Complete the diagram to show how insulin and glucagon work together to control blood sugar levels.
Answer
-
Top left box: When blood glucose levels rise (in response to insulin), the pancreas releases insulin. This causes target cells (like liver or muscle cells) to take up glucose.
-
Bottom right box: When blood glucose levels fall (in response to glucagon), the pancreas releases glucagon. This stimulates the liver to convert glycogen back into glucose and release it into the bloodstream.
Step 2
Explain why this type of control system is an example of negative feedback.
Answer
This control system is an example of negative feedback because it works to stabilize blood glucose levels. When glucose levels are high, insulin is released, which lowers blood glucose levels. Conversely, when glucose levels drop, glucagon is released to increase blood glucose levels. The system continuously monitors and adjusts hormone levels to maintain equilibrium.
Step 3
Write down the names of the two enzymes used in this process and explain what they do.
Answer
-
Restriction enzyme: This enzyme is used to cut the human insulin gene from the human DNA. It recognizes specific sequences within the DNA and makes precise cuts, allowing the gene to be isolated.
-
Ligase: This enzyme is used to join the insulin gene to the plasmid. It facilitates the formation of bonds between the DNA segments, ensuring that the insulin gene is properly inserted into the plasmid for transformation.