Biochem

Question 1

Smooth Endoplasmicreticulum involved in synthesis of what?

Answer 1

Hormones and phospholipids

Question 2

small nuclear ribonucletides (snRNPs) are involved in what?

Answer 2

RNA splicing/Spliceosome

Question 3

What process is INCREASED in Leysch Neyhan disease? What are key enzymes/substrates?

Answer 3

De Novo Purine synthesis is INCREASED

PRPP synthetase/PRPP amidotransferase have INCREASED activity

Glycine, Aspartate, and Glutamine are substartes

Question 4

Review Fructose metabolism…

Answer 4

Fructose is metabolized by FRUKTOKINASE/ALDOSE B/HEXOKINASE

Can BYPASS PFK-1 in Glycolytic Pathway

Question 5

Which biochemical processes take place in cytoplasm? In mitochondria?

Answer 5

Hexose Monophosphate Pathway - transketolase enzyme (CYTOSOL)

B-oxidation, Fatty acid synthesis, Krebs cycle, Ketogenesis (MITOCHONDRIA)

Question 6

Compare Glucokinase and Hexokinase…

Answer 6

Glucokinase has LOWER affinity for glucose, allows it to act as “glucose sensor” bc it relies more on Blood Glucose Concentration.

Present in Panc Beta Cells and Liver

Question 7

Which amino acid becomes essential in Homocystinuria?

Answer 7

Cysteine

Question 8

Which enzyme is impaired in pt with RIBOFLAVIN nutritional defiency?

Answer 8

SUCCINATE DEHYDROGENASE.

Riboflavin (B2) is a precursor for FAD and FMN, which are cofactors for SUCCINATE DEHYDROGENSAE (Complex II) in the electron transport chain.

Question 9

Glycogenolysis is stimulated by what in SKELETAL MUSCLE?

Answer 9

Increased intrancellular Calcium.

The Ca activates Phosphorylase Kinase, which activates glycogen phosphorylase, which leads to glycogen breakdown. Hence, muscle contraction is linked to increased breakdown of glycogen for fuel.

Question 10

Psyc Pt with “weird eating habits” has papilledema, headaches, nausea, dry skin, and heptatosplenomegaly……too much of what vitamin?

Answer 10

VITAMIN A

Vit A can be acute, chronic, or teratogenic, may lead to cirrohsis and hepatotoxicity. Also alopecia, dry skin and vision problems.

Question 11

Sickle cell results from what type of amino acid substitution?

Answer 11

VALINE(hydrophobic) for GLUTAMIC ACID (hydrophilic)

Question 12

Niacin is synthesized from what?

Answer 12

Tryptophan!!

Question 13

IP3 is generated from what? Leads to what? Activates what?

Answer 13

generated from PLC, leads to increased intracellular Ca, which activates PKC, which leads to SMOOTH MUSCLE contraction

Question 14

WHich step in TCA cycle leads to generation of GTP? What can the GTP be used for?

Answer 14

GTP created from conversion of Succinyl CoA to Succinate by Succinate Thiokinase

The GTP may be used by PEPck to create Pyruvate from oxaloacetate

Question 15

Homocystinuria most commonly caused by defect in what enzyme? What is an essential cofactor for the enzyme?

Answer 15

Cystathionine Beta Synthetase (CBS)

Pyroxidine (B6) is an essential cofactor.

Cysteine becomes essential amino in these pts.

Pyroxidine is also supplemented.

Question 16

MEN 1

Answer 16

Primary Hyperpara (Hypercalicemic)
Pituitary Tumors (Prolactin) 
Pancreatic tumors (especially gastrinoma)

Question 17

MEN 2A

Answer 17

Medullary Thryoid Cancer
Pheochrom
Parathyroid Hyperplasia

Question 18

MEN 2B

Answer 18

Medullary Thyroid Cancer
Pheochrom
Mucosal Neuromas/Marafinoid Habitus

Question 19

Treatment of Adrenal Hyperplasia/21 Hydroxylase def is what?

Answer 19

Glucocorticoids, which directly inhibit ACTH release

Question 20

What accounts for highest mortality in Diabetics?

Answer 20

MI/Cardiovascular disease (stroke is second)

Question 21

What is most effective/fastest acting when trying to raise BG in a patient with acute hypoglycemia?

Answer 21

Intramuscular Glucagon (then buccal/sublingual glucose or sucrose)

Question 22

How to gluccocorticoids influence gluconeogensis?

Answer 22

They INCREASE it

Question 23

What is the difference bt a gastric ULCER and EROSION?

Answer 23

EROSION = to muscularis mucosa but not beyond

ULCER= Beyond musc. mucosa and into submucosal layers

Question 24

INTERNAL hemmoroids, describe, where does blood supply come from ?

Answer 24

Non painful, Superior Rectal Vein which drains to Internal Iliac and Inferior Mesenteric

(EXTERNAL are painful, derive from INF rectal vein, which drains directly to internal pudendal)

Question 25

Describe manifestation of Zollinger Ellison Syndrome?

Answer 25

Caused by gastrinoma, DISTANT DUODENAL ULCER, High-normal gastrin levels that RISE in response to SECRETIN

Question 26

How is unabsorbed Copper eliminated in body?

Answer 26

SECRETED into BILE and then stool

Question 27

Review important structures that are associated with the different segments of the Duodenum…!!

Answer 27

!!!

Question 28

What affect does citrate have on Glycolysis?

Answer 28

Strong allosteric INHIBITOR of PFK1, and so it INHIBITS glycolysis

Question 29

What is regenerated by ANAEROBIC glycolysis (ie strenuous excerice)?

Answer 29

NAD+, which helps drive glycolysis.

IF lactate dehydrogenase is inhibited, then NAD+ is depleted and glycolysis is inhibited

Question 30

Describe pathological findings of Hashimotos?

Answer 30

Mononuclear infiltrate, with well developed germinal centers.

Question 31

Describe path findings of Medullary Thryoid Cancer?

Answer 31

Nests of polygonal cells with Congo-red positive deposits

Question 32

Which type of colon polyps are MORE likely to be malignant?

Answer 32

SERRATED and ADENOMATOUS ( VILLOUS more then TUBULAR)

Question 33

Galactosemia

Answer 33

Deficiency of Galactose -1-phosphate uridyl transferase (GALT). Which converst galactose 1-p to UDP galactose and Glucose 1P

Look at pic on phone.