Unit 3 part 1

Question 1

What is a risk factor?

Answer 1

Anything that increases the chance of getting a disease e.g diet, smoking, occupation

Question 2

What are risk factors that are associated with lung disease

Answer 2

Occupation, smoking, air pollution, infections and genetics

Question 3

What is correlation?

Answer 3

This is where a change in one of two variables is reflected by a change in the other variable

Question 4

What is a cause?

Answer 4

A factor which is directly a cause of a disease. (Only true if there is compelling experimental evidence by scientists)

Question 5

What is relative risk?

Answer 5

Measured by comparing the likelihood of harm occurring into those exposed to hazard compared with those who are not exposed.

Question 6

What is digestion?

Answer 6

The process in which large molecules are hydrolysed by enzymes to produce smaller molecules that can be absorbed and assimilated

Question 7

Where does digestion of carbohydrates begin?

Answer 7

In the mouth

Question 8

What enzyme does saliva contain?

Answer 8

Salivary amylase

Question 9

What does salivary amylase do?

Answer 9

Hydrolyses starch into maltose

Question 10

How does chewing aid digestion?

Answer 10

It breaks down food into smaller pieces increasing the surface area so hydrolysis by enzyme is more rapid

Question 11

What enzyme does the pancreas release?

Answer 11

Releases pancreatic juice in the small intestine which contains pancreatic amylase (and others)

Question 12

Where does the complete hydrolysis of starch occur in?

Answer 12

In the ileum, where the enzyme maltose hydrolyses starch into alpha glucose

Question 13

Where are maltase and disaccharidases released from?

Answer 13

Released into the lumen from part of the cell membrane of the epithelial cells known as membrane-bound disaccharidases.

Question 14

What are the disaccharidases

Answer 14

Maltase
Lactase
Sucrase

Question 15

What do the disaccharides hydrolyse into e.g maltose into?

Answer 15

Maltose - two alpha glucose molecules
Lactose- glucose and galactose
Sucrose- glucose and fructose

Question 16

What are lipids hydrolysed into?

Answer 16

Glycerol,fatty acids and monoglycerides

Question 17

Where is lipase secreted?

Answer 17

In the pancreas into the small intestine

Question 18

What bonds do lipase hydrolyse?

Answer 18

Ester bonds of triglycerides

Question 19

How does bile salts increase rate of hydrolysed of lipids by lipase

Answer 19

Bile salts emulsify lipids causing them to form small droplets which increases the surface area of lipids which speeds up the hydrolysis by lipase

Question 20

Where are bile produced, stored and released from?

Answer 20

Produced in the liver
Stored in the gall bladder
Released by the bile duct

Question 21

What enzymes hydrolyse proteins

Answer 21

Endopeptidase
Exopeptidase
Dipeptidase

Question 22

What are amino acids?

Answer 22

Small soluble molecules which are absorbed in the ileum

Question 23

Where does hydrolyses of protein begin and by which enzyme?

Answer 23

In the stomach by endopeptidase

Question 24

How does endopeptidase hydrolyse protein?

Answer 24

It hydrolyses internal peptide bonds between the amino acid of proteins to form small polypeptides and peptides

Question 25

What is the endopeptidase in the stomach of humans and it’s optimum pH

Answer 25

Pepsin pH -1-2

Question 26

What secrets exopeptidase and what how does the enzyme hydrolyse proteins?

Answer 26

Pancreas secrets it It hydrolyses the peptide bonds at either end of a polypeptide so individual amino acids of dipeptides are removed

Question 27

How does dipeptidase hydrolyse dipeptides?

Answer 27

Hydrolyses peptide bonds of dipeptides into individual amino acids.

Question 28

What are dipeptidases?

Answer 28

Membrane bound enzymes in the folded cell membrane of epithelial cells of the ileum

Question 29

What are the adaptations of the ileum

Answer 29

Large surface are due to long length and presence of microvilli and villi Villi contains capillaries that absorb monosaccharides and amino acids maintaining a high diffusion gradient Wall of each villus contains a single layer of epithelial cells providing a short diffusion pathway for absorption Large number of mitochondria present to supply ATP for active transport.

Question 30

Explain absorption of digested lipids

Answer 30

Question 31

How are amino acids and monosaccharides absorbed in the illeum

Answer 31

Initially, monosaccharides and amino acids acids will be at a higher concentration than the epithelium cells so they are absorbed into the epithelium down a concentration gradient by facilitated diffusion Eventually, the concentration of amino acids in the epithelial cells increase above that in the lumen so co transport absorbs these molecules against the concentration gradient.

Question 32

Explain Rate of uptake of glucose by co transport

Answer 32