Biochemistry 1- Boards And Beyond

Question 1

What is the mutation in alpha 1 antitrypsin deficiency

Answer 1

Mutation in AAT gene

Question 2

What is the definition of expressivity

Answer 2

Variations in phenotype of gene

Question 3

What is the definition of pleiotropy

Answer 3

One gene= multiple phenotypic effects and traits

Question 4

What is the mutation in lynch syndrome (HNPCC)

Answer 4

Germaine mutation in DNA mismatch repair genes

Question 5

What are some main criteria of McCune-Albright Syndrome

Answer 5

Affects many endocrine organs, precocious puberty (menstruation may occur 2 years old), fibrous growth in bones, skin pigmentation (cafe-au-lait spots)

Question 6

What is the mutation in McCune-Albright syndrome

Answer 6

Somatic mutation of GNAS gene

Question 7

What stage do primary oocytes arrest in until puberty

Answer 7

In prophase of meiosis I until puberty

Question 8

Where do secondary oocytes arrest until fertilization

Answer 8

Metaphase 2

Question 9

What are the Acrocentric chromosomes

Answer 9

13, 14, 21, 22

Question 10

What are some classic examples of incomplete dominance

Answer 10

Achondroplasia, familial hypercholesterolemia

Question 11

What are some classic examples of X-linked recessive

Answer 11

Hemophilia A and B

Question 12

What is the classic example of X-linked dominant

Answer 12

Fragile X syndrome

Question 13

What are some common findings with Edward syndrome (trisomy 18)

Answer 13

Poor intrauterine growth, abnormally shaped head, low set ears, small jaw and mouth, rocker bottom feet, GI defects

Question 14

What are some common characteristics of Patau syndrome (trisomy 13)

Answer 14

Severe intellectual disability, severe structural malformations, eye abnormalities, cleft lip and palate, post-axial polydactyly

Question 15

What is the repeat associated with fragile X syndrome

Answer 15

CGG repeats

Question 16

What chromosome is the frataxin gene involved in friedreichs ataxia on

Answer 16

9

Question 17

What repeat is associated with huntington’s disease

Answer 17

CAG repeat

Question 18

What expansion is associated with Myotonic dystrophy

Answer 18

CTG expansion

Question 19

What is the disorder classified as deletion of part of short arm (p) of chromosome 5

Answer 19

Cri-du-chat syndrome

Question 20

What is the disorder caused by partial deletion on long arm of chromosome 7

Answer 20

Williams syndrome

Question 21

What are some characteristics of Williams syndrome

Answer 21

Elfin-facial appearance (small nose, chin; wide mouth), intellectual disability, well-developed verbal skills, extremely friendly with strangers, supravalvular aortic stenosis

Question 22

What is the goal of purine synthesis

Answer 22

Create AMP and GMP

Question 23

What is step one and 2 of purine synthesis

Answer 23

Step one is create PRPP; step 2 is create IMP

Question 24

What are the nitrogen sources of purine synthesis

Answer 24

Aspartate, glycine, glutamine

Question 25

What is the rate limiting step of purine synthesis

Answer 25

Glutamine-PRPP-amidotransferase

Question 26

What is the classic presentation of lesch-Nyhan syndrome

Answer 26

Male child with motor symptoms, self-mutilation, gout

Question 27

What is step one and 2 of pyrimidine synthesis

Answer 27

Step one is make carbamoyl phosphate; step 2 is make orotic acid

Question 28

What is the defect with orotic aciduria

Answer 28

UMP synthase

Question 29

What are some key findings with orotic aciduria

Answer 29

Orotic acid in urine, megaloblastic anemia (but no B12/folate response), growth retardation

Question 30

What occurs with there is ornithine transcarbamylase deficiency

Answer 30

Increased carbamoyl phosphate

Question 31

What 2 monosaccharides make up lactose

Answer 31

Galactose and glucose

Question 32

What 2 monosaccharides make up sucrose

Answer 32

Fructose and glucose

Question 33

Where is GLUT-1 and is it insulin dependent or independent

Answer 33

Brain, RBC; independent

Question 34

Where is GLUT-4 and is it insulin dependent or independent

Answer 34

Fat tissue, skeletal muscle; insulin dependent

Question 35

Where is GLUT-2 and is it insulin independent or dependent

Answer 35

Liver, kidney, intestine, pancreas; independent

Question 36

What inhibits glucokinase in glycolysis

Answer 36

F6P

Question 37

What does glucokinase deficiency result in medically

Answer 37

Hyperglycemia

Question 38

What is the rate limiting step of glycolysis

Answer 38

Phosphofructokinase

Question 39

What are key regulators of phosphofructokinase in glycolysis

Answer 39

Citrate, ATP

Question 40

What are key inducers of phosphofructokinase in glycolysis

Answer 40

AMP, fructose-2,6-bisphosphate

Question 41

What type or heredity is pyruvate kinase deficiency

Answer 41

Autosomal recessive

Question 42

What must be present in order for pyruvate carboxylase to be active

Answer 42

Acetyl CoA

Question 43

What is the first step in gluconeogenesis and what is the required cofactor

Answer 43

Pyruvate carboxylase; biotin

Question 44

What are some clinical signs of biotin deficiency

Answer 44

Dermatitis, glossitis, loss of appetite, nausea

Question 45

What is the rate limiting step of gluconeogenesis

Answer 45

Fructose-1,6-bisphosphatase 1

Question 46

Where do you get glucose-6-phosphatase for the conversion of glucose-6-phosphate to glucose in gluconeogenesis

Answer 46

Endoplasmic reticulum

Question 47

How does thyroid hormone effect gluconeogenesis

Answer 47

Increases it

Question 48

What is deficient in Von Gierke's disease

Answer 48

Glucose-6-phosphatase

Question 49

Describe the presentation of von gierkes disease

Answer 49

Presents in infancy (2-6 months), severe hypoglycemia between meals (seizures), No effect on muscle

Question 50

What is deficiency in pompe's disease

Answer 50

Acid alpha glucosidase deficiency

Question 51

What is the clinical presentation of pompes disease

Answer 51

Presents in infancy, enlarged muscles (cardiomegaly, enlarged tongue), hypotonia, death from heart failure

Question 52

What is deficient in cori's disease

Answer 52

Debra Ching enzyme

Question 53

What is the clinical presentation of cori's disease

Answer 53

Similar to type 1 (von gierkes) except milder hypoglycemia, no lactic acidosis (cori cycle intact), muscle involvement

Question 54

What is deficient in McArdle disease

Answer 54

Muscle glycogen phosphorylase

Question 55

What is the clinical presentation of McArdles disease

Answer 55

Presents in adolescence/early adulthood; exercise intolerance, fatigue, cramps; myoglobinuria and CK release; urine may turn dark after exercise

Question 56

Where does the HMP shunt occur (Pentose phosphate pathway)

Answer 56

Cytosol

Question 57

What is the first enzyme involved in the oxidative reactions of the HMP shunt

Answer 57

Glucose-6-phosphate dehydrogenase

Question 58

What is the required cofactor for transketolase

Answer 58

Thiamine (B1)

Question 59

What are the 3 key enzymes in the respiratory burst

Answer 59

NADPH oxidase, superoxide dismutase, myeloperoxidase

Question 60

What are the 5 organisms that cause almost all Chornic granulomatous disease infections

Answer 60

Staph aureus, pseudomonas, serratia, nocardia, aspergillosis

Question 61

What are bite cells in G6PD deficiency

Answer 61

Phagocytic removal by splenic macrophages

Question 62

What are Heinz bodies of G6PD deficiency

Answer 62

Oxidized Hgb precipitated in RBCs

Question 63

What is deficient in essential fructosuria

Answer 63

Fructokinase

Question 64

What is deficiency in hereditary fructose intolerance

Answer 64

Aldolase B

Question 65

What is teh clinical presentation typically seen with hereditary fructose intolerance

Answer 65

Baby just weaned from breast milk, failure to thrive, hypoglycemia (seizures), enlarged liver

Question 66

What is deficient in classic galactosemia and what is the typical clinical presentation

Answer 66

Deficiency of galactose-1 phosphate uridyltransferase; presents in infancy shortly after consumption of milk; liver failure, jaundice, hepatomegaly

Question 67

What are the 5 cofactors required for pyruvate dehydrogenase complex

Answer 67

NAD+, FAD+, coenzyme A, thiamine, lipoid acid

Question 68

What 4 enzymes is thiamine a cofactor for

Answer 68

Pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, alpha-ketoacid dehydrogenase, transketolase

Question 69

What is FAD+ synthesized from

Answer 69

riboflavin (B2)

Question 70

What are the key lab findings with PDH complex deficiency

Answer 70

Elevated alanine; lactic acidosis

Question 71

Where do all reactions of the TCA occur

Answer 71

Mitochondria

Question 72

What is the rate limiting enzyme in the TCA cycle

Answer 72

Isocitrate dehydrogenase (isocitrate to alpha-ketoglutarate)

Question 73

What is another name for complex 1 of the Electron transport chain

Answer 73

NADH dehydrogenase

Question 74

What are the key intermediates of complex 1 of ETC

Answer 74

Flavin mononucleotide (FMN) and iron sulfur compounds (FeS)

Question 75

What is another name for complex 2 of the ETC

Answer 75

Succinate dehydrogenase (also part of TCA cycle)

Question 76

What is another name for complex 3 of ETC

Answer 76

Cytochrome bc1 complex

Question 77

What is the rate limiting step of fatty acid synthesis

Answer 77

Acetyl-CoA converted to malonyl CoA (via acetyl-CoA carboxylase)

Question 78

What activates fatty acid breakdown

Answer 78

Glucagon and epinephrine

Question 79

What are some characteristics of the infantile phenotype of primary systemic carnitine deficiency

Answer 79

Encephalopathy, hepatomegaly, hyperammonia, hypoketotic hypoglycemia, low serum carnitine

Question 80

What are the 3 major Ketone bodies

Answer 80

Acetone, acetoacetate, 3-hydroxybutyrate

Question 81

Where does the conversion of ethanol to acetaldehyde via alcohol dehydrogenase occur

Answer 81

Cytosol

Question 82

Where does the conversion of acetaldehyde to acetate via aldehyde dehydrogenase occur

Answer 82

Mitochondria

Question 83

What is the trigger for all biochemical problems related to ethanol

Answer 83

Increased NADH

Question 84

What is inadequate in kwashiorkor and marasmus

Answer 84

In kwashiorkor it is inadequate protein intake; in marasmus it is inadequate overall energy intake (insufficient total calories)

Question 85

What type of disorders of hypoketotic hypoglycemia

Answer 85

Mitochondrial disorders

Question 86

What are lab findings that suggest inborn errors of metabolism

Answer 86

Hypoglycemia, kerosine, hyperammonemia, lactic acidosis

Question 87

What glycogen storage diseases have no hypoglycemia

Answer 87

McArdles disease (type 5), pompes disease (type 2)

Question 88

What is deficient in maple syrup urine disease

Answer 88

Alpha ketoacid dehydrogenase

Question 89

What is elevated in all mitochondrial disorders

Answer 89

Alanine

Question 90

What are the lab findings with PDH complex deficiency

Answer 90

Elevated alanine, lactic acidosis, no hypoglycemia