Metabolic Diseases

Question 1

what causes lactose intolerance?

Answer 1

adults have a low level of lactase, causing the lactose eaten to be ingested into the gut where it is broken down by microorganisms, which produce lactic acid

Question 2

how do the organisms that ferment lactose cause water to be drawn into the intestine?

Answer 2

they produce lactic acid which is osmotically active and so causes water to be drawn in

Question 3

what organisms ferment the lactose?

Answer 3

small microorganisms such as lactobacillus

Question 4

how do the symptoms of lactose intolerance occur?

Answer 4

the gases cause bloating and the water drawn into the intestine causes diarrhoea

Question 5

what is galactosemia?

Answer 5

term used to describe people suffering from failure to metabolise galactose

Question 6

what enzyme is needed to metabolise galactose?

Answer 6

galactose-1-phosphate uridyl transferase

Question 7

how does the lack of this enzyme effect the eye?

Answer 7

a lack of the enzyme means galactose is reduced in the presence of aldose reductase, to galactitol, which causes water to be drawn into the eye causing cataracts

Question 8

what are the symptoms of galactosemia?

Answer 8

failure to thrive, vomiting, diarrhoea following the ingestion of milk

Question 9

what are the more extreme symptoms of galactosemia?

Answer 9

enlargement of the liver resulting in jaundice and sometimes cirrhosis of the liver and mental retardation

Question 10

how is galactosemia treated?

Answer 10

removal of galactose from the diet and lactose of sufferers

Question 11

what symptoms may sufferers still experience after removal of galactose from the diet?

Answer 11

CNS development issues

Question 12

what can CNS issues due to galactosemia cause?

Answer 12

poor language skill development and ovarian failure in females

Question 13

how does glycolysis differ in cancer cells?

Answer 13

enhanced rate of glucose uptake and so a faster rate of glycolysis

Question 14

what do cancer cells do to challenge what we know about anaerobic glycolysis?

Answer 14

they metabolise glucose to lactate even in the presence of oxygen

Question 15

what causes a change in environment due to the glycolysis in cancer cells?

Answer 15

the glycolysis results in an acidic environment due to the secretion of lactic acid

Question 16

what effect does the now acidic cancer cell have?

Answer 16

the acidic environment facilitates tumour invasion into surrounding tissue and prevents the immune system from attacking the tumour

Question 17

what substrate concentration increases in a cancer cell due to increased rate of glycolysis?

Answer 17

glucose-6-phosphate

Question 18

what does an increased amount of glucose-6-phosphate cause?

Answer 18

provides a substrate for another metabolic pathway as well as glycolysis, that provides molecules for growth such as nucleotides

Question 19

what does anaerobic exercise activate?

Answer 19

hypoxia-inducible transcription factor (HIF-1)

Question 20

what causes hypoxia?

Answer 20

a lack of oxygenation

Question 21

what is the similarity between cancer cells and body cells?

Answer 21

the enhanced ability to generate ATP anaerobically

Question 22

what advantage does HIF-1 provide?

Answer 22

allows athletes to generate ATP anaerobically in response to hypoxia