hormonal communication

Question 1

What hormone is released by beta cells in the pancreas when blood glucose concentration is too high?

Answer 1

Insulin

Insulin increases glucose uptake by liver and muscle cells and promotes glycogenesis.

Question 2

What process involves the conversion of glucose to glycogen?

Answer 2

Glycogenesis

Glycogenesis occurs in liver and muscle cells in response to insulin.

Question 3

What is the role of glucagon when blood glucose levels are low?

Answer 3

Increases conversion of glycogen to glucose (glycogenolysis)

Glucagon also promotes gluconeogenesis from amino acids and lipids.

Question 4

What is the primary cause of Type 1 diabetes?

Answer 4

Inability to produce enough insulin or producing ineffective insulin

• This can be due to damage to beta cells in the islets of langerhans by the antibodies of the persons’s immune system. (autoimmune disease)
  -genetic
  -triggered by virus / environmental factor)

Question 5

List three risk factors for developing Type 2 diabetes.

Answer 5

• Age over 40
• Family history of Type 2 diabetes
• common in males
• common in ethnic groups such as asian , african
• being overweight
• high blood pressure

Question 6

What dietary changes can help control Type 2 diabetes?

Answer 6

• Decrease starch intake
• Increase cellulose/fiber intake

• Starch has the greatest effect on blood glucose concentration.
• fat+protein have no effect on blood glucose

Question 7

What does a diabetic patient risk if not taking medication due to glucose uptake issues?

Answer 7

Fatigue

Insufficient glucose uptake leads to low ATP production.
+ glucose is not stored as it is not converted into glycogen

Question 8

Why is fasting required before a diabetes test?

Answer 8

To restore normal blood glucose concentration

This allows insulin to act fully before testing.

Question 9

How is the Glycaemic Index (GI) of a food determined?

Answer 9

By calculating iAUC for the test food and dividing it by iAUC for glucose

The result is multiplied by 100.

Question 10

What is HbA1C and what does it measure?

Answer 10

A form of heamoglobin that indicates the mean concentration of blood glucose over 8 to 12 weeks

• glucose combines w/ Hb to form HbA1C
• HbA1C cannot accurately measure glucose levels beyond 12 weeks.
• bc erythrocytes have a limited life span of 8-12 weeks + then broken down in the liver by kupffer cells

Question 11

What is gestational diabetes similar to, and how does it differ?

Answer 11

Similar to Type 2 diabetes

In gestational diabetes, insulin is produced but liver cells do not respond to it.

Question 12

What is the function of protein kinase in glucose metabolism?

Answer 12

• Protein kinase activates glycogen phosphorylase, so stimulates conversion of glycogen to glucose,
• and inhibits of glycogen synthase, preventing conversion of glucose to glycogen

Question 13

True or False: Different tissues respond to adrenaline in the same way.

Answer 13

False

Different types of adrenaline receptors lead to varied responses.

Question 14

What are the two main functions of the pancreas?

Answer 14

• Endocrine gland (releases hormones)
• Exocrine gland (secretes enzymes)

The pancreas monitors blood glucose concentration.

Question 15

List two advantages of using genetically modified (GM) bacteria for insulin production.

Answer 15

• Plentiful supply of insulin
• Ethical and no religious objections

Question 16

What is the advantage of using stem cells for diabetes treatment?

Answer 16

Provides a permanent cure by allowing insulin production

Stem cells can differentiate into beta cells.

Question 17

Describe the process of insulin secretion after glucose enters the beta cell.

Answer 17

ATP production closes potassium channels–> so k+ions builds up inside the cell–> opening VG calcium channels–> ca ions enter the cell by diffusion –> leading to insulin vesicle exocytosis

Insulin secretion continues as long as blood glucose remains high.

Question 18

What is the delay in insulin increase after blood glucose rises attributed to?

Answer 18

Time required for beta cells to depolarize and produce insulin

This results in a lag between glucose and insulin fluctuation.

Question 19

How do plant and mammalian hormones differ in their production and transport?

Answer 19

• Mammal hormones are made in endocrine glands
• Plant hormones are made in many tissues
• Mammal hormones move in blood, plant hormones in xylem/phloem

Question 20

What is a common feature of both plant and animal hormones?

Answer 20

Hormones bind to receptors, triggering a cascade of events

Small concentrations of hormones can have significant effects.

Question 21

Fill in the blank: Steroid hormones can diffuse through cell membranes because they are _______.

Answer 21

[fat soluble / non-polar / uncharged / hydrophobic]

This allows them to move directly through the phospholipid bilayer.