Biochem

Front 1

A girl who has repeatedly had hypoglycemic episodes presents with:
-hypoglycemia
-ketonuria
-ketonemia along with an appropriately low insulin level

Blood Alanine is abnormally low; however, infusion of alanine produces a rapid rise in blood glucose. What is the most likely defect?

Back 1

Protein Catabolism in muscle

Front 2

Under fasting conditions, what is the primary substrate for Gluconeogenesis?

Back 2

Alanine derived from muscle protein

Front 3

What 2 AA's are predominantly present in Histones?

Back 3

Lysine & Arginine = positively charged & bind tightly to negatively charged DNA

Front 4

What does Pyruvate Kinase deficiency cause?

Back 4

Hemolytic Anemia

*normally converts PEP -> Pyruvate in Glycolysis

Front 5

What is the most important buffer WITHIN cells? Extracellularly?

Back 5

Within = Phosphate

EC = Bicarbonate

Front 6

Women on a fat-free diet notices that her "hair is falling out"...what is this due to?

Back 6

Vitamin A

Front 7

Vitamin that is a lipid antioxidant that is important in the stabilization of cell membranes

Back 7

Vitamin E

Front 8

From which intermediate in the glycolytic pathway does the Pentose Phosphate Pathway shunt?

Back 8

Glucose-6-Phosphate

Front 9

What is the purpose of the Pentose Phosphate Pathway?

Back 9

Alternative route for the oxidation of glucose
-supplies NADPH = for fatty acid & cholesterol synthesis
-supplies Pentoses = synthesis of Nucleotides & some coenzymes

Front 10

Proteins destined for the Cytosol & organelles are synthesized where?

Back 10

"free" ribosomes

Front 11

Proteins destined to be secreted from a cell are synthesized where?

Back 11

RER

**vs. cytosol-bound proteins = "free" ribosomes

Front 12

A 25-year old woman with Type I Diabetes Mellitus has maintained good glycemic control for several years. Recently she has gained 10 lbs. & joined a group exercise program. By the end of her first 1-hr aerobics session, she is dizzy, nauseated, & feels faint. Which underlying mechanism is the most likely explanation for this episode?

Back 12

Translocation of GLUT4 to the cell membranes of Myocytes due to increased AMP associated with exercising muscle

*this is INDEPENDENT of Insulin

Front 13

What is the mechanism by which cells secrete plasma proteins?

Back 13

Constitutive Exocytosis
-also involved with supplying the PM with newly synthesized lipids & proteins

Front 14

An infant PKU would be expected to be deficient in which of the following nonessential AA's?

Back 14

Tyrosine

Front 15

WHat structure is common to all Sphingolipids?

Back 15

Ceramide

Front 16

What is involed in the oxidation of Fatty Acids...it is important in transferring FA's from the Cytoplasm into the Mitochondria

Back 16

Carnitine

Front 17

9 year old girl with mental retardation has elevated levels of Isoleucine, Leucine, & Valine. What enzyme is deficient & what is the disease?

Back 17

Branched Chain Ketoacid Dehydrogenase

Maple Syrup Disease

*I Love Vermont Maple Syrup

Front 18

What enzyme is deficient in Homocystinuria? What cofactor is needed?

Back 18

Cystathionine Synthase

B6

Front 19

Urea cycle enzyme deficiency associated with Hyperammonemia

Back 19

Ornithine Transcarbomoylase deficiency

Front 20

Glycogen storage disease caused by Glucose-6-Phosphatase deficiency

Back 20

von Gierke

Front 21

2 month old has severe fasting hypoglycemia, hepatomegaly, & lactic acidosis

Back 21

von Gierke disease = Glucose-6-phosphatase deficiency

Front 22

A 2-year-old child is brought to the pediatrician b/c of hematuria. Examination reveals HTN & an abdominal mass. A tumor is localized to the right kidney & biopsy reveals a stroma containing smooth & striated muscle, bone, cartilage, & fat, with areas of necrosis. What disease & what chromosome?

Back 22

Wilm's tumor

Chr. 11

Front 23

Chromosome that is the site of a tumor suppressor gene involved in the pathogenesis of colon CA & Familial Adenomatous Polyposis

Back 23

Chr. 5 = APC tumor suppressor

Front 24

Chr. that contains the Retinoblastoma gene. What other cancer is the person susceptible to?

Back 24

Chr. 13

Osteosarcoma

**Chr. 13 is also site of BRCA-2

Front 25

What 3 important genes are contained on Chr. 17?

Back 25

p53

Neurofibromatosis-1

BRCA-1

Front 26

What chr. is NF-2 gene on?

Back 26

22

Front 27

Syndrome characterized by bronchiectasis, sinusitis, & situs inversus

Back 27

Kartagener syndrome = absence of inner or outer dynein arm

Front 28

Sphingomyelinase deficiency that results in progressive neurodegeneration, hepatosplenomegaly, & cherry-red spot on retina

Back 28

Niemann-Pick disease

Front 29

HExosaminidase A deficiency that occur commonly in Ashkenazi jews

Back 29

Tay-Sachs

Front 30

Fibrillin deficiency resulting in a person who is tall & thin, fingers are spider-like (arachnodactyly). Displaced lens of the eye & aortic dilation leading to aortic aneurysm

Back 30

Marfin Syndrome

Front 31

Liver & Steroidogenic tissues have this receptor that recognizes HDL & mediates transfer of Cholesterol into these tissues

Back 31

Scavenger Receptor SR-B1

Front 32

This acts as a carrier of "activated carboxyl" groups for 3 key enzymes that catalyze carboxylation reactions. Symptoms of deficiency include dermatitis & enteritis

Back 32

Biotin

Front 33

Dermatitis, diarrhea, & dementia

Back 33

Pellagra = niacin deficiency

Front 34

Vitamin deficiency that leads to convulsions, hyperirritability. It's deficiency is can be induced by Isoniazid or Oral Contraceptives

Back 34

B6 = Pyridoxine

Front 35

Vitamin deficiency in which person presents with lesions of the lips, mouth, skin, & genatalia

Back 35

Riboflavin = B2

Front 36

What does the Nucleolus manufacture?

Back 36

rRNA = ribosomal RNA = protein production capability

Front 37

Where does Uric Acid come from?

Back 37

Purines

Front 38

What are Glucose molecules complexed with during Glycogen synthesis?

Back 38

UDP

Glucose-1-Phosphate + UDP -> UDP-Glucose + PPi

Front 39

When is GTP made in the TCA cycle?

Back 39

Succinyl-CoA -> Succinate

Front 40

What is Hereditary Fructose Intolerance due to a deficiency of? What 2 sugars should the patient avoid?

Back 40

Aldolase B

Fructose & Sucrose & Sorbital

Front 41

In the Citric Acid Cycle, Succinate Thiokinase catalyzes the cleavage of the Succinyl-CoA thioester bond with formation of a high-energy compound. What is this compound & what biochemical pathway is it used in?

Back 41

GTP

Elongation of the Polypeptide chain

Front 42

What AA has the best buffering capacity?

Back 42

Histidine = pKa is within range of the pH range

Front 43

What AA can be a precursor of Niacin?

Back 43

Tryptophan

Front 44

Disease that presents as muscle weakness & can also cause cataracts, testicular atrophy, heart disease, dementia, & baldness. What disease & what chromosome?

Back 44

Myotonic Dystrophy

Chr. 19

Front 45

In what Carbon form does Glucose enter the TCA cycle?

Back 45

Acetyl-CoA

Front 46

Explain the timeline & processes involved in energy usage & production in a marathon runner

Back 46

ATP stores are used up in 1 second

Creatine phosphate will be the primary source of energy for the next 3-4 seconds

Glycolysis occurs after this

After extended periods of time = Gluconeogenesis & Lypolysis

Front 47

Which enzyme in the TCA cycle would need Riboflavin to be active?

Back 47

Succinate Dehydrogenase = needs FAD

Front 48

What type of Amino Acids are present on the surface of protein molecules?

Back 48

Hydrophilic = Aspartate, Glutamate, Lysine, & Arginine (Histidine possibly)