DEFINITIONS💔💔

Question 1

What is nutrition

Answer 1

Nutrition is the process by which organisms obtain food and energy for growth, repair and maintenance of the body.

Question 2

What is assimilation

Answer 2

Nutrients used by cells provide energy and make cytoplasm for growth of the cell.

Question 3

What is peristalsis

Answer 3

The rhythmic, wave like muscular contractions in the wall of the alimentary canal

Question 4

Functions of liver

Answer 4

1. bile production
2. deamination of amino acids into urea
3. detoxification
4. convert excess glucose into glycogen
5. breakdown of hormones

Question 5

Different digestions

Answer 5

1. starch —> maltose —> glucose
2. protein —> polypeptides —> amino acids
3. fats —> fatty acids + glycerol

Question 6

Harmful effects of alcohol consumption on digestive system

Answer 6

1. Alcohol stimulates acid secretion in the stomach leading to an increased risk of gastric ulcers
2. Excessive alcohol may lead to cirrhosis of the liver where liver cells are destroyed and replaced with fibrous tissue. This may then lead to haemorrhage in the liber, liver failure and death.

Question 7

What is homeostasis

Answer 7

The maintenance of constant internal environment.

Question 8

Factors needed in the negative feedback process

Answer 8

1. Set point that needs to be maintained
2. Stimulus
3. Receptors (that detect the stimulus)
4. Control centre
5. Corrective mechanism (effector is the thing that carries out the corrective mechanism and causes a final response.)

Question 9

What is a hormone

Answer 9

A chemical messenger produced in minute quantities by an endocrine gland.

Question 10

Effects of insulin

Answer 10

1. Increases rate of glucose uptake by cells
2. Makes cell membrane more permeable to glucose
3. Stimulates liver and muscle cells to convert glucose to glycogen for storage
4. Increases use of glucose for tissue respiration

Question 11

Effects of glucagon

Answer 11

1. Converts glycogen to glucose in the liver cells
2. Converts amino acids and fats to glucose in the liver cells

Question 12

Effects of antidiuretic hormone (ADH)

Answer 12

Regulates water potential of blood in body through osmoregulation, increases reabsorption of water in the nephrons.

Question 13

What is deamination

Answer 13

Excess amino acids are transported to the liver by blood where they are deaminated. Part of the amino acid molecule is removed and converted to urea which is removed by the kidneys.

Question 14

Why is urea harmful

Answer 14

Abnormally high urea concentration in the blood may cause abdominal pain, nausea or vomiting.

Question 15

What is the human urinary system?

Answer 15

It consists of:
1. A pair of kidneys
2. A pair of ureters
3. Urinary bladder
4. Urethra

Question 16

How is urine formed

Answer 16

1. Ultrafiltration in the Bowman’s capsule to form glomerular filtrate
2. Selective reabsorption in the proximal convoluted tubule

Question 17

What is ultrafiltration

Answer 17

It is the first stage of urine formation. Small molecules are filtered out of the blood by the glomerulus into the Bowman’s capsule.

Question 18

Selective reabsorption is?

Answer 18

• The second stage of urine formation, useful substances eg amino acids and glucose are reabsorbed into the blood capillaries again.

Question 19

What is active transport

Answer 19

Net movement if particles from a region of lower concentration to a region of higher concentration, against concentration gradient, with the requirement of ENERGY.

Question 20

What is osmoregulation

Answer 20

The maintenance of a blood water potential by controlling the water potential and solute concentration in the blood involving the kidneys and skin.

Question 21

What is water potential?

Answer 21

The tendency of water molecules to move from one place to another. (Eg dilute = higher water potential, concentrated = lower water potential)