blood glucose regulation

Question 1

What is the metabolism?

Answer 1

Metabolism is a collection of thousands of coordinated chemical reactions which take place in the bodys cells to convert food into energy

Question 2

What controls the chemical reactions of the metabolism?

Answer 2

Special proteins called enzymes.

Question 3

What does food get broken down into when eaten?

Answer 3

When food is eaten, catalytic proteins in the digestive system (enzymes) break proteins down into amino acids, fats down into fatty acid and glycerol and carbohydrates down into simple sugars.

Question 4

What biomolecules are used as energy/energy stores?

Answer 4

Simple sugars, fatty acids and amino acids.

Question 5

What happens once the nutrients enter the cells?

Answer 5

Other enzymes work to speed up or regulate the reactions involved with metabolising these molecules.

Question 6

Where are the main places the energy is stored in the body from the processes?

Answer 6

In body tissues, especially in the liver, muscles and body fat.

Question 7

What is one of the major requirements for the metabolising processes?

Answer 7

Oxygen.

Question 8

What happens when large molecules are broken down in the presence of oxygen?

Answer 8

A large amount of energy released and is sometimes called oxidation.

Question 9

What is some of the energy from oxidation used for?

Answer 9

To transform adenosine diphosphate to adenosine triphosphate

Question 10

What is ATP’s main job?

Answer 10

ATP is the major means for transporting energy within the body and is needed for nearly every reaction in body e.g creation of new cells, the action of muscles, the polarising and depolarising of the nerve cell membrane all need ATP

Question 11

What are the two activities occurring in the process of metabolism?

Answer 11

The building of body tissues and energy stores and the breaking down of body tissues and energy stores to generate more fuel for the body functions.

Question 12

What is the process if metabolism that builds and stores called?

Answer 12

Anabolism.

Question 13

What does anabolism do?

Answer 13

Anabolism supports the growth of new cells, the macitence of body tissues and the storage of energy for the future.

Question 14

What occurs during anabolism?

Answer 14

During anabolism small molecules are changed into larger, more complex molecules of carbohydrate, protein and fat.

Question 15

What is anabolism dependent on?

Answer 15

It is oxygen dependent and requires the transformation of adenosine triphosate to adenosine diphosate by using the energy gained during the other form of metabolism

Question 16

What is catabolism?

Answer 16

Catabolism is the process which produces the energy needed for all the activity in the cells

Question 17

What happens during catabolism?

Answer 17

Cells break down large molecules, mostly carbohydrates and fats to release energy and turn ADP to ATP.

Question 18

What does the energy release in catabolism do?

Answer 18

Provides fuel for anabolism, heats the body, enables the muscles to contract and the body to move

Question 19

What does the pancreas do to help determine what main metabolic reaction will occur at specific times?

Answer 19

It secretes specific hormones which help determine the metabolic process that will occur.

Question 20

What are two main hormones included in regulating the concentration of glucose in the blood stream using negative feedback loops?

Answer 20

insulin and glucose

Question 21

What are the normal levels of blood glucose concentration?

Answer 21

Between 70-110 mg per 100cm cubed.

Question 22

What happens if the blood glucose concentration deviates out of its normal levels?

Answer 22

Corrective measures through either the release of glucose or insulin

Question 23

What would normally occur with blood glucose levels after eating?

Answer 23

More anabolic activity occurs as eating increases the level of glucose in the blood stream

Question 24

What does the pancreas do when it senses a raised level of glucose?

Answer 24

Releases the peptide hormone insulin from the beta cells of the islets of langerhans. The insulin is then transported through the blood stream and targets mainly liver and muscle cells.

Question 25

What happens once the insulin has reached its target cells?

Answer 25

It binds to specific insulin receptors and initiates two key intracellular processes.

Question 26

What is the first process the insulin binding to effectors causes?

Answer 26

An increase in the uptake of glucose into the target cell that insulin has attached to. Achieved from an intracellular cascade whereby cytoplasmic glucose transporter proteins are incorporated into the cell surface membrane, making the target cell much more permeable to glucose causing the blood glucose concentration to dramatically decrease as glucose moves into the cells through facilitated diffusion.

Question 27

What is the second process that occurs once the insulin has bonded to effectors?

Answer 27

Once glucose has entered the target cells cytoplasm the second process occurs. If energy is needed catabolic enzymes that break down the glucose during aerobic respiration to generate ATP will be stimulated. If energy isn’t needed, insulin will activate an enzyme called glycogen synthase which catalyses the anabolic conversion of excess glucose to glycogen which is a process called glycogenesis.

Question 28

What happens once blood glucose levels have returned to the ideal homeostatic range?

Answer 28

The beta cells of the pancreas respond by stopping any further insulin release.

Question 29

What happens if a person has Type 1 diabetes?

Answer 29

They lack insulin as a result of an autoimmune attack on their pancreatic cell beta cells

Question 30

What occurs when a person has type 2 diabetes?

Answer 30

The insulin is not able to attach to its cell surface receptors because their shape has been altered

Question 31

What is the result of type 1 or 2 diabetes on the persons homeostatic abilities?

Answer 31

They will lose the ability to build up stores of energy and glucose levels within the blood will rise rapidly, leading to many different complications

Question 32

What is the antagonist to insulin?

Answer 32

Glucagon

Question 33

What is glucagons role?

Answer 33

To raise glucose levels if the concentration in the blood stream drops below the ideal range

Question 34

How does glucagon raise blood glucose levels?

Answer 34

The alpha cells of the pancreatic islets will release the glucagon into the blood stream if the glucagon levels have dropped. Then this peptide hormone mainly targets metabolically active liver cells and once these target cells have been reached the glucagon will bind to specific receptors on the membrane surface. Glucagon will then initiate an intracellular cascade that can take on two forms with both thee roles being to release glucose into the blood stream

Question 35

What is the first way glucagon initiates an intracellular cascade to release glucose into the bloodstream?

Answer 35

The glucagon will stimulate phosphorylase enzymes that will catalyse the breakdown of glycogen to glucose in a process named glycogenolysis

Question 36

What is the second way glucagon initiates an intracellular cascade to release glucose into the bloodstream?

Answer 36

The glucagon will stimulate other enzymes that catalyse the conversion of other biomolecules into glucose in a process called gluconeogenesis

Question 37

What happens once enough glucose has entered the bloodstream?

Answer 37

The alpha cells of the pancreas respond by stopping any further glucagon release