Week 10

Question 1

What can lactose be broke down into?

Answer 1

Glucose and galactose

Question 2

What enzyme is used to break lactose down into its monosaccharides?

Answer 2

Lactase

Question 3

What causes Lactose intolerance?

Answer 3

Lack of lactase enzyme meaning the patient cannot metabolise lactase into glucose and galactose

Question 4

What microorganisms use lactose as an energy source and where are they found?

Answer 4

Lactobacillus in the gut.

Question 5

What do lactobacillus do to lactase?

Answer 5

They ferment Lactose into lactic acid, methane gas and hydrogen gas.

Question 6

What causes patients who are lactose intolerant to have diarrhoea?

Answer 6

Lactobacillus ferment lactose into lactic acid which is osmotically active and therefore draws water into the intestines.

Question 7

What symptoms are caused by lactobacillus in terms of lactose intolerance and why?

Answer 7

They produce methane and hydrogen gases which leads to painful distension and flatulence.

Question 8

What is distension?

Answer 8

Bloating

Question 9

What is another name for lactose intolerance?

Answer 9

Hypolactasia

Question 10

What are the symptoms of lactose intolerance?

Answer 10

Painful distension.
Gastrointestinal pain.
Flautlence.

Question 11

What is the failure to metabolise galactose Calle?

Answer 11

Galactosemia

Question 12

What is galactosemia?

Answer 12

Failure to metabolise galactose.

Question 13

What enzyme is lacking in sufferers of galactosemia?

Answer 13

Galactose-1-phosphatase uridyl transferase.

Question 14

How does galactosemia lead to cataracts forming ?

Answer 14

Lack of Galactose-1-Phosphate uridyl transferase means that Galactose is reduced to Galacticol in the presence of Aldose reductase.
Galacticol is osmotically active and causes water to be drawn into the lenses of the eye and cause cataracts.

Question 15

How can galactosemia be treated?

Answer 15

Removal of galactose and lactose from the diet of sufferers.

Question 16

What issues may still arise with sufferers of galactosemia even if they remove galactose and lactose from their diet?

Answer 16

Failures in the CNS leading to issues such as poor language development skills.
Ovarian failure.

Question 17

How does the rate of glycolysis vary in tumour cells compare with normal body cells?

Answer 17

Increases

Question 18

In what conditions can cancerous cells metabolise glucose to lactic acid?

Answer 18

Aerobic and anaerobic.

Question 19

What causes cancer tumours to be surrounded by an acidic environment ?

Answer 19

They carry out glycolysis producing lactic acid which is then secreted and causes a surrounding acidic environment.

Question 20

How is having a surrounding acidic environment beneficial t tumours?

Answer 20

It inhibits the immune system from attacking the tumour.

Question 21

What is HIF-1?

Answer 21

Hypoxia-inducible transcription factor 1

Question 22

What is the main similarity between tumour and body cells during anaerobic exercise?

Answer 22

Their enhanced ability to produce ATP.

Question 23

What are the advantages of ATP being produced aerobically and anaerobically?

Answer 23

Enhanced physical performance

Question 24

What process of metabolic control is the enzyme galactose-1-phosphatase uridyl transferase involved in?

Answer 24

Metabolism of galactose

Question 25

What is the role of HIF-1 in the control of metabolic processes?

Answer 25

Alters energy production from being aerobic via oxidative phosphorylation to being anaerobic.

Question 26

Why does initial tumour growth occur in the absence of oxygen and nutrients?

Answer 26

There are no ned blood vessels surrounding the tumour.

Question 27

What is the Warburg Effect?

Answer 27

Cancer cells have increased rates of glycolysis despite the presence of adequate oxygen levels.

Question 28

What are indicators that tumour cells are undergoing the Warburg Effect?

Answer 28

Alot of lactic acid produced. Reduced oxygen uptake by cells. Increased uptake of glucose by cells.

Question 29

Why do cancer cells use glycolysis despite there being enough oxygen present to undergo oxidative phosphorylation via respiration ?

Answer 29

Assures ATP synthesis when the tumour outgrows its oxygen supply. Metabolic intermediates of aerobic glycolysis provide raw materials for the synthesis of cellular components in tumour cells. Release of acid lowers environmental pH which favours tumour invasion and surprises the immune system.

Question 30

What the of glycolysis do tumour cells undergo?

Answer 30

Aerobic

Question 31

Why is it beneficial for tumours to be in an acidic environment ?

Answer 31

Acidic environments favour tumour invasion and suppress the immune system.

Question 32

What are the effects of over expression of HIF-1?

Answer 32

Increased transcription of genes that code for proteins that favour cancer. Increased Glucose uptake by regulating GLUT-1 expression. Increased glucose phosphorylation by upregulating hexokinase-2 expression. Loss of P53 function.

Question 33

What are the effects of loss of P53 function on glycolysis by over expression of HIF-1?

Answer 33

Greater glycolytic flux. Reduced pyruvate oxidation. Reduced ATP production by oxidative phosphorylation.