Turco 4

Question 1

Galactose source

Answer 1

From lactose…broken down by lactase

Question 2

Is galactose pathway necessary for life?

Answer 2

No

Question 3

Galactose metabolism

Answer 3

Lactose broken to galactose and glucose by lactase
Galactose phosphorylated by galactokinase into gal-1-P
G-1-P reacts with uridyl transferase which uses UDP-Glc to make Glc-1-P
Glc-1-P becomes G-6-P and goes to glycolysis

Question 4

Epimerase

Answer 4

Takes UDP-Glc to UDP-Gal and vice versa

Question 5

Where does galactose metabolism occur?

Answer 5

Liver and brain

Question 6

How does galactose enter mucosa/blood

Answer 6

Mucosa via active transport - use sodium symporter

Blood via passive transport

Question 7

Lactose intolerance mech

Answer 7

Lactase is defective…genes go from euchromatin to nanochromatin and get shut down…not lethal

Question 8

Lactose intolerance manifestations

Answer 8

Diarrhea - lactose can’t be absorbed and draws H2O
Bloating and cramps - Normal flora uses lac operon and cleaves lactose…ferments because no oxygen…makes methane via anaerobic fermentation

Question 9

Galactosemia from

Answer 9

Any non-lactase enzyme mutation

Question 10

Epimerase deficiency

Answer 10

Benign…can still make UDP-Gal via normal metabolism

Question 11

Uridyl transferase def

Answer 11

Severe - liver cirrhosis and mental retardation

Liver cirrhosis leads to hypoglycemia, bleeding problems, jaundice, ammonia problems

Question 12

Galactokinase def

Answer 12

Cataracts but not other problems because when galactokinase is deficient, galactose never enters cell and is not trapped

Question 13

Both uridyl transferase and galactokinase will present with

Answer 13

Sugar in the urine

Question 14

Mech of galactose related cataracts

Answer 14

Galactose becomes galactitol using aldose reducatase (uses NADPH)

Question 15

Diabetic cataracts

Answer 15

SLower forming…glucose moves into lens and forms sorbitol…we have mech to turn sorbitol over

Question 16

Fructose source

Answer 16

Sucrose or directly from fruit/honey

Question 17

Fructose transport into muscoa

Answer 17

Passive

Question 18

Fructose metabolism

Answer 18

Sucrose broken into glucose and fructose by sucrase
Fructose made into F-1-P by fructokinase
Aldolase B takes F-1-P to glyceraldehyde and DHAP

Question 19

Where does fructose metabolism occur?

Answer 19

Liver and kidney

Question 20

Fructose and reproduction

Answer 20

Higher in seminal fluid..defects in fructose metabolism maybe infertility???

Question 21

Essential fructosuria

Answer 21

Fructokinase def

Benign and get fructosuria…may get a little dehydration

Question 22

Hereditary fructose intolerance

Answer 22

Aldolase B deficiency

Builds up in liver and kidney…hypoglycemia, jaundice, ammonia probs, kidney failure, bleeding

Question 23

Hereditary fructose intolerance mechanism

Answer 23

Depletes liver of Pi by trapping it as F1P and causing liver damage…severe hypoglycemia

Question 24

Diagnosis of hereditary fructose intolerance

Answer 24

Done after child is eating solids because sucrose not consumed prior to that

Question 25

Vomiting and hereditary fructose intolerance

Answer 25

Result of ammmonia problems

Question 26

Tx for hereditary fructose intoleracne

Answer 26

Dietary restrictions

Question 27

Fructose and cataracts

Answer 27

No association because no aldehyde group so cannot be reduced by aldose reductase…NO CATARACTS

Question 28

Splenda

Answer 28

Chlorinated sucrose…can cook with this…can’t be absorbed

Question 29

Equal

Answer 29

Aspartame….aspartic acid and phenylalanine dipeptide…made into methyl ester @ carboxyl end…can’t cook with this

Question 30

Side effects of equal

Answer 30

Body cleaves dipeptide and makes methanol…would have to drink a ton of this to make enough to be toxic