Metabolism And Digestion

Question 1

What happens to the digested carbs in the liver?

Answer 1

Glucose may oxidise in the form of ATP for metabolic activity in the liver
Some glucose remain circulating to maintain a BM of 3.5 - 8 mmol/L
If excess, might convert to insulin/glycogen in liver and skeletal muscles

Question 2

What is the lock and key hypothesis of enzyme action?

Answer 2

Enzymes are folded into complex 3D shapes that allow smaller molecules to fit. The place where the molecules fit is the active site, the shape of the active site matches the shape of its substrate molecules

Question 3

What are the 3 phases of gastric secretion?

Answer 3

Cephalic phase - extrinsic stimulation of secretion by sight, smell, taste
Gastric phase - food in the stomach
Intestinal phase

Question 4

What is glycolysis?

Answer 4

Breakdown of glucose by enzymes releasing energy and pyruvic acid

Question 5

What is glycogenesis?

Answer 5

Formation of glycogen from sugar

Question 6

What is glyconeogenesis?

Answer 6

Metabolic pathway that results in the generation of glucose from certain non-carb carbon substrates

Question 7

What are the 4 main functions of the digestive system?

Answer 7

Breaks down the food
Absorbs water
Excretes cholesterol
Synthesis vitamins

Question 8

What are triglycerides?

Answer 8

A type of fat found in the blood

Question 9

How does insulin and glucagon play a part in carbohydrate metabolism?

Answer 9

It lowers blood glucose by increasing glucose transport in muscle and adipose tissue and stimulates the synthesis of glycogen, fat and protein

Question 10

What is protein metabolism?

Answer 10

The creation of proteins and amino acids, known as anabolism
As well as the breakdown of proteins, known as catabolism
Process: transcription, translation and post-translation

Question 11

How are carbs digested?

Answer 11

Mouth - saliva releases amylase which begins the breakdown of the sugars in carbs
Stomach - the carbs travel through oesophagus into the stomach and is now known as chyme. The stomach makes acid to kill bacteria in the chyme
Small intestine, pancreas, liver - goes into duodenum, this causes release of pancreatic amylase.chyme breaks down into maltose. The wall of the small intestine begins to make lactase, sucrose and Maltese. These enzymes break down the sugars into monosaccharides. Then absorbed into the small intestine. Then processed even more by liver and stored as glycogen. Insulin is released from pancreas
Colon - anything left is broken down by intestinal bacteria