BioChem Intel Deck I Fill in blanks

Question 1

What enzyme is responsible for leukotriene productions?

What is a Leukotriene?

Answer 1

Arachidonate 5-lipoxygenase

any of a group of biologically active compounds, originally isolated from leukocytes. They are metabolites of arachidonic acid, containing three conjugated double bonds.

Question 2

The disease characterized by increased leukotriene synthesis is?

This disease cannot be treated with?

It should be treated with ?

Answer 2

Asthma

Cannot be treated with aspirin or (NSAIDs),

Inhibitors of 5-Lipoxygenase and antagonists of leukotriene receptors.

Question 3

What enzyme is deficient in hereditary fructose intolerance?

Answer 3

Aldolase B

Question 4

What metabolites accumulate and what are the symptoms of the above disease?

Aldolase B Deficency

Answer 4

Frutose 1-phosphate accumulates. ATP falls and AMP rises – hyperuricemia and lactic acidosis, hypoglycemia, impaired protein synthesis (f.e. decrease in blood clotting factors), impaired glycogenolysis. Diagnosis: fructose in urine.

You need Aldolase B to convert it into glyceraldehyde and dihydroxyacetonephosphate (DHAP).

Question 5

Respiratory distress syndrome is seen most frequently in Preterm infants and it is caused by:

Answer 5

Insufficient production of Pulmonary Lung surfactant

Question 6

Malignant carcinoid tumor is associated with increased synthesis of?

Answer 6

Vasoactive hormones (mainly serotonin)

Question 7

What are the two biochemical functions of Thiamine?

Answer 7

The formation or degradation of Alpha-ketols by (Transketolase), and in the oxidative decarboxylation of alpha-keto acids (Pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex).

Question 8

What is Nitrogen Balance?

Answer 8

Difference between consumed and excreted nitrogen

Question 9

Where are HDLS formed and what is their function?

Answer 9

HDL particles are formed in the blood and within the liver and intestine. These high density Lipids are added to an apolipoprotein made by the liver and intestine and secreted into the blood.

• scavenge and removes bad cholesterol (LDLs) and send them to liver to be reporcessed or converted to bile to be secreted out of the system.
• maintains blood vessel walls by maintence in cleaning the surface in a anti athersclerosis prevention module.

Question 10

Describe the Apolipoprotein Supply:

C-11 and APO E

Answer 10

They provide apolipoproteins Apo C-11 (activator of lipoprotein lipase) which is: a water-soluble enzyme that hydrolyzes triglycerides in lipoproteins, such as those found in chylomicrons and very low-density lipoproteins (VLDL), into two free fatty acids.

Apo E (required for endocytosis of lipoproteins) is a class of proteins involved in the metabolism of fats in the body.

remeber: Apoliprotein are proteins that bind lipids (oil-soluble substances such as fat and cholesterol) to form lipoproteins. They transport the lipids through the lymphatic and circulatory systems because we know the lipid components of lipoproteins are insoluble in water

Question 11

What is the relationship of HDL’s and Reverse cholesterol Transport?

Answer 11

They transport cholesterol from peripheral tissues back to the liver (for bile acid synthesis or cholesterol disposal via the bile), and to steroidogenic cells for hormone synthesis.

HDL’s take up CE;s and unesterfied cholesterol from non heptatic tissues. The esterfication is catalyzed by LCAT (activated by HDL and Apo A-1). These esters are either returned to liver, or exchanged for triglycerides with VLDLs.

Question 12

Faulty collagen synthesis is resulting from inherited defects causes several disease. List some that you learned during the course.

Answer 12

Ehlers-Danlos syndrome, Osteogenesis Imperfecta.

Question 13

List 5 essential amino acids

Answer 13

Histidine, Leucine, Isoluciene, Methionone, Phelaline, Theronine, Tryptophan, and Valine

Question 14

The predominantt nitrogen metabolite excreted in urine in humans is?

Answer 14

Urea

Question 15

What protein serves as the primer for glycogen synthesis?

Answer 15

Fragments of glycogen or glycogenin (if glycogen is abscent)

Question 16

Name the 3 major apolipoproteins and list their function

Answer 16

Apo A-1 major one of HDL, it activates LCAT

Apo B-100: VLDL, IDL, LDL is recognised by receptors for endocytosis

Apo A-4: is thought to act primarily in intestinal lipid absorption.

Apo C-II: activates lipoprotein lipase in capillaries (transferred from circulating HDLs to other lipoproteins)

Apo E: liver cells have these receptors.

Apo B types: form low-density lipoprotein LDL (sometimes referred to as “bad cholesterol”) particles. These proteins have mostly beta-sheet structure and associate with lipid droplets irreversibly. Most of the other apolipoproteins

(Apo -A) form high-density lipoprotein (“good cholesterol”) particles. These proteins consist of alpha-helices and associate with lipid droplets reversibly. During binding to the lipid particles these proteins change their three-dimensional structure. There are also intermediate-density lipoproteins formed by Apolipoprotein E.

Question 17

In fasting, which molecule allosterically stimulates glycogen breakdown in the muscle?

Answer 17

AMP ( allosteric activator of glycogen phosphorylase )

Question 18

The name of glycogen storage disease type 1 is?

The enzye deficient is?

What are the symptoms?

Answer 18

Von Gierke Disease

glucose-6-phosphatase

sever fasting hypoglycemia, fatty liver, progressive renal disease, growth retardation, delayed puberty, lactic acidemia, hyperlipidemia, hyperurecemia

Question 19

What step follows glutamate formation during amino acid catabolism?

Answer 19

Oxidative glutamate deamination in which the amino group is liberated as free ammonia (catalysed by glutamate dehydrogenase)

Question 20

Pellagra is a disease which results from a deficiency of?

Answer 20

Niacin, which has clinical features of dermatitis, diarrhea, dementia.

Question 21

Statins are drugs used in?

Answer 21

to treat Hypercholesterolemia by inhibiting cholesterol synthesis. (reversible, competitve inhibitors of HMG CoA reductase)

Question 22

What enzyme liberates arachidonic acid from the plasma membrane?

Answer 22

Phospholipase A2

Question 23

Cellular cAMP levels can be increased by inhibiting what enzyme?

Answer 23

cAMP phosphodiesterase

Question 24

What is glycogen storage disease type V?

Answer 24

Mc Ardle Syndrome

Question 25

What is the main organ and enzyme affected in this disease?

Answer 25

Skeletal muscle; skeletal muscle glycogen phosphorylase (other name: myophosphorylase)

Question 26

By what mechanism does Oligomyocin poison oxidative phosphorylation?

Answer 26

Oligomycin inhibits the ATP synthase, by closing ion channels and preventing proton re entry into mitochondrial matrix

Question 27

Allopurinol is used to inhibit?

Answer 27

Xanthine oxidase, which catalyses the oxidation of hypoxanthine to xanathine and oxidation of xanthine to uric acid (part of degradation of purine nucleotides)

Question 28

Classical galactosemia is caused by inherited deficiency of?

What are toxic metabolites responsible for this disease?

Answer 28

Galactose-1-phosphate uridylyltransferase:

Galactitol and Galactose-1-phosphate