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FAB Flashcards

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1
Q

Deficient enzyme in Phenylketonuria (PKU)

A

Phenylalanine hydroxylase (PAH)

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2
Q

PKU presentation?

A

Seizures, albinism and a musty odor” to the baby’s sweat and urine. If untreated develops microcephaly and impairment of cerebral function.”

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3
Q

PKU Gene?

A

PAH gene is located on chromosome 12 in the bands 12q22-q24.1

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4
Q

What does phenylalanine hydroxylase do?

A

Converts the amino acid phenylalanine into the amino acid tyrosine

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5
Q

PKU treatment?

A

special diet low in phenylalanine

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6
Q

Why consuming alcohol in a fasting state can make you hypoglycemic?

A

Because alcohol metabolism changes the NADH/NAD+ ratio. Important steps in gluconeogenesis use NAD+.

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7
Q

Fatty liver mechanism in kwashiorkor?

A

Low protein intake leads to reduced production of VLDLs thus accumulating fatty acids within the liver.

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8
Q

Edema, irritability, anorexia, ulcerating dermatoses, and an enlarged fatty liver. Kwashiorkor or Marasmus?

A

Kwashiorkor

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9
Q

Tissue and muscle wasting and variable edema. Kwashiorkor or Marasmus?

A

Marasmus

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10
Q

Alcoholic develops a rash, diarrhea and altered mental status. What is the most likely cause?

A

Vitamin B3 deficiency

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11
Q

Enzyme deficient in Alkaptonuria?

A

homogentisate 1,2-dioxygenase

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12
Q

Black spots in the sclera of the eye and urine turns brown when left exposed to open air. Name the disease.

A

Alkaptonuria

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13
Q

What accumulates in Alkaptonuria?

A

homogentisic acid in tissues

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14
Q

What does homogentisate 1,2-dioxygenase do?

A

Catalyzes the conversion of homogentisate to 4-maleylacetoacetate. Involved in the break down of the amino acids tyrosine and phenylalanine.

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15
Q

Distinctive characteristic of _________ is that ear wax exposed to air turns red or black after several hours because of the accumulation of homogentisic acid.

A

Alkaptonuria

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16
Q

Genetic disorder characterized by high cholesterol levels, specifically very high low-density lipoprotein (LDL)

A

Familial hypercholesterolemia

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17
Q

What disease is caused by a mutation of the LDLR gene that encodes the LDL receptor protein?

A

Familial hypercholesterolemia

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18
Q

Common places cholesterol accumulates in patients with Familial hypercholesterolemia?

A

Eyelids (xanthelasma palpebrarum), the outer margin of the iris (arcus senilis corneae) and in the form of lumps in the tendons of the hands, elbows, knees and feet, particularly the Achilles tendon (tendon xanthoma).

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19
Q

Can Familial Hypercholesterolemia lead to atherosclerosis?

A

Yes.

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20
Q

Enzyme deficient in McArdles disease?

A

myophosphorylase

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21
Q

Exercise intolerance with myalgia, early fatigue, painful cramps, weakness of exercising muscles and myoglobinuria. Name the disease.

A

McArdle’s disease.

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22
Q

McArdle’s disease treatment?

A

Vitamin B6 appears to impart greater resistance to fatigue.

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23
Q

What does Myophosphorylase do?

A

Involved in the breakdown of glycogen to glucose for use in muscle. Removes 1,4 glycosyl residues from outer branches of glycogen and adds phosphate to form glucose-1-phosphate.

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24
Q

Chronic pancreatitis with pancreatic insufficiency. What vitamins are likely deficient?

A

A,D,E,K

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25
What are the fat soluble vitamins?
A,D,K,E
26
What are the water soluble vitamins?
Vitamin C, Thiamine (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid, Biotin, Folate, Cobalamin (B12), Pyridoxine (B6)
27
Higher toxicity. Water or fat soluble vitamins?
Fat soluble vitamins because they accumulate in fats.
28
Which B vitamin is stored in the liver?
B12
29
Vitamin A (retinol) deficiency.
Night blindness, dry skin
30
Vitamin B1 (thiamine) deficiency.
Beriberi and Wernicke-Korsakoff syndrome.
31
Weight loss, emotional disturbances, impaired sensory perception, weakness and pain in the limbs, and periods of irregular heart rate.
Beriberi
32
Folic acid deficiency.
Microcytic megaloblastic anemia,
33
Biotin deficiency?
Dermatitis, enteritis. Caused by antibiotic use and ingestion of raw eggs.
34
Vitamin C (ascorbic acid) deficiency?
scurvy, anemia, bruising, poor wound healing.
35
Vitamin D deficiency?
Rickets in children, osteomalacia in adults and hypocalcemic tetany.
36
Vitamin E deficiency?
Increased fragility of erythrocytes, neurodysfunction.
37
Vitamin K deficiency?
Hemorrhage
38
zinc deficiency?
Delayed wound healing, hypogonadism.
39
3 D's: Dermatitis, Diarrhea, Dementia.
Pellagra.
40
Vitamin B2 (riboflavin) deficiency?
Angular stomatitis, Cheilosis, corneal vascularization.
41
Vitamin B3 (niacin) deficiency?
Pellagra.
42
Vitamin B5 (pantothenate) deficiency?
Dermatitis, enteritis, alopecia, adrenal insufficiency.
43
Vitamin B6 (pyridoxine) deficiency?
Convulsions, hyperirritability, peripheral neuropathy.
44
Vitamin B12 (cobalamin) deficiency?
Microcytic megaloblastic anemia, neurologic symptoms, glossitis.
45
Limiting reagent in ethanol metabolism?
NAD+
46
What does alcohol dehydrogenase do?
Converts Ethanol to acetaldehyde.
47
What does acetaldehyde dehydrogenase do?
Converts acetaldehyde to acetate.
48
Hepatocellular steatosis mechanism in alcoholics?
Ethanol metabolism causes the NADH/NAD+ ratio to go up causing diversion of pyruvate to lactate and oxaloacetate to malate thereby inhibiting gluconeogenesis. Also this elevated NADH/NAD+ ratio inhibits glycolysis and stimulates fatty acid synthesis.
49
What histones form the nucleosome core?
H2A, H2B, H3, H4
50
Histone H1 function?
Does not make the nucleosome bead/core. It sits on top of the structure, keeping in place the DNA that was wrapped around the nucleosome.
51
Is Heterochromatin transcriptionally active?
No.
52
Is Euchromatin transcriptionally active?
Yes.
53
What nucleotides have 1 ring?
Adenine and Guanine.
54
What nucleotides have 2 rings?
Uracil, Cytosine and Thymine.
55
How many hydrogen bonds compose the G-C bond?
3 hydrogen bonds.
56
How many hydrogen bonds compose the A-T bond?
2 hydrogen bonds.
57
Which bond melts at a higher temperature the A-T bond or the G-C bond?
G-C bond.
58
What are the amino acids necessary for purine synthesis?
Glycine, Aspartate, Glutamine.
59
Nucleotides (base + ribose + phosphate) are linked by?
3' to 5' phosphodiester bond.
60
Substituting purine for purine and pyrimidine for pyrimidine.
TransItion
61
Substituting purine for pyrimidine or vise versa.
TransVersion
62
What are the generic code features?
Unambiguous, Degenerate/Redundant, Commaless non-overlapping, Universal.
63
Why is the generic code unambiguous?
Each codon specify only one amino acid.
64
Why is the generic code degenerate/redundant?
More than one codon may code for the same amino acid.
65
Why is the generic code commaless, non-overlapping?
Read from a fixed starting point as a continuous sequence of bases.
66
Why is the generic code universal?
Genetic code is conserved throughout evolution.
67
What are the mutations in DNA?
Silent, Missense, Nonsense, Frame shift.
68
What is a DNA silent mutation?
Mutations that do not result in a change to the amino acid sequence of a protein.
69
What is a DNA missense mutation?
A point mutation in which a single nucleotide is changed, resulting in a codon that codes for a different amino acid.
70
What is a DNA nonsense mutation?
A point mutation in a sequence of DNA that results in a premature stop codon.
71
What is a DNA frame shift mutation?
Mutation caused by insertion or deletion of a number of nucleotides that is not evenly divisible by three.
72
Genome has multiple origins of replication.
Eukaryotic DNA replication.
73
Single origin of replication, continuous bidirectional DNA synthesis on leading strand and discontinuous on leading strand.
Prokaryotic DNA replication.
74
Create a nick in the helix to relieve super coils.
DNA topoisomerases.
75
Makes a RNA primer on which DNA polymerase III can initiate replication.
Primase.
76
Elongates the chain by adding deoxynucleotides to the 3' end until it reaches primer of preceding fragment. 3' -> 5' exonuclease activity proofreads each added nucleotide.
DNA polymerase III.
77
Degrades RNA primer and fill in the gap with DNA.
DNA polymerase I.
78
Links together two DNA strands that have double strand break.
DNA ligase.
79
Mutated in xeroderma pigmentosa.
Nucleotide excision repair.
80
Nucleotide excision repair mechanism?
Specific endonucleases release the oligonucleotide containing damaged bases. DNA polymerase and ligase fill in and reseal the gap.
81
Base excision repair mechanism?
Specific glycosylases recognize and remove damaged bases, AP endonuclease cuts DNA at apyrimidinic site, empty sugar is removed and DNA polymerase and ligase fill in and reseal the gap.
82
Mismatch repair mechanism?
Unmethylated, newly synthesized string is recognized, mismatched nucleotides are removed and the gap is filled and resealed.
83
Mutated in hereditary nonpolyposis colon cancer.
DNA mismatch repair.
84
Double strand non homologous end joining.
Brings together two ends of DNA fragments.
85
In what direction are DNA and RNA synthesized?
5' -> 3'
86
In what direction are proteins synthesized?
5' -> 3'
87
What are the types of RNA?
mRNA. tRNA, rRNA
88
What is the largest type of RNA?
mRNA
89
What is the most abundant type of RNA?
rRNA.
90
What is the smallest type of RNA?
tRNA
91
What are the RNA polymerases for eukaryotes.
RNA polymerase I, II, and III.
92
What does RNA polymerase I make?
rRNA.
93
What does RNA polymerase II make?
mRNA.
94
What does RNA polymerase III make?
tRNA.
95
What inhibits RNA polymerase II ?
alpha-amanitin.
96
What are the RNA polymerases for prokaryotes?
RNA polymerase makes all 3 kinds of RNA.
97
What are the mRNA start codons?
AUG and rarely GUG.
98
What are the mRNA stop codons?
UGA, UAA, UAG.
99
Site where RNA polymerase and other transcription factors bind to DNA from AT rich upstream sequence with TATA and CAAT boxes (gene locus).
Promoter site.
100
Stretch of DNA that alters gene expression by binding transcription factors
Enhancer.
101
Site where negative regulators bind.
Operator.
102
What is an exon?
Exons contain the actual genetic information coding for protein.
103
What is an intron?
Introns are intervening non-coding segments of DNA.
104
What is RNA splicing?
Modification of an RNA after transcription, in which introns are removed and exons are joined.
105
First step in mRNA splicing?
Primary transcript combines with snRNPs (small nuclear ribonucleoproteins) to form spliceosome.
106
Second step in mRNA splicing?
Lariat intermediate is generated.
107
Third step in mRNA splicing?
Lariat is released to remove intron and exons are joined.
108
RNA processing step 1?
Capping on 5' end (7 methyl-G).
109
RNA processing step 2?
Polyadenylation on 3' end
110
RNA processing step 3?
Splicing out of intros.
111
Steps in protein synthesis?
Initiation, elongation, termination.
112
Protein synthesis: Initiation.
A ribosome attaches to the mRNA and stars to code the FMet codon (AUG, GUG or UUG).
113
Protein synthesis: Elongation.
tRNA brings the corresponding amino acid to each codon as the ribosome moves down the mRNA strand.
114
Protein synthesis: Termination.
Reading of the final mRNA codon which ends the synthesis of the peptide chain and releases it.
115
What are the protein post translational modifications?
Trimming, Covalent alterations, proteasomal degradation.
116
Posttranslational modification: Trimming.
Removal of N- or C- terminal pro-peptides from zymogens togenerate mature proteins.
117
Posttranslational modification: Covalent alterations.
Phosphorylation, Glycosylation, Hydroxylation.
118
Posttranslational modification: Proteosomal degradation.
Attachment of ubiquitin to defective proteins to tag them for break down.
119
Enzyme regulation methods?
Enzyme concentration alterations, covalent modification, proteolytic modification, allosteric regulation, pH, temperature and transcriptional regulation.
120
What are the cell cycle phases?
G1, S phase, G2, Mitosis.
121
What are the cells that remain in the G0 phase and regenerate from stem cells?
Neurons, skeletal and cardiac muscles, RBCs.
122
What are the cells that enter the G1 state from G0 when stimulated?
Stable cells: Hepatocytes, Lymphocytes.
123
What are the cells that never go to G0 and divide rapidly with a short G1?
Labile cells: Bone marrow, gut epithelium, skin, hair follicles.
124
Where in the cell are N-Linked oligosaccharides added to proteins?
RER.
125
What do Nissl-bodies synthesize?
Enzymes and peptide neurotransmitters.
126
Cells rich in RER?
Mucus secreting goblet cells of the small intestine and anti-body secreting plasma cells.
127
Cell site where steroid synthesis and detoxification of drugs and poisons take place?
SER.
128
Cells rich in SER?
Hepatocytes, steroid hormone producing cells of the adrenal cortex are rich in cells.
129
Failure of addition of mannose-6-phosphate to lysosome proteins, enzymes are secreted outside the cell instead of being targeted to the lysosome.
I-cell desease also refered to as mucolipidosis II (ML II).
130
Coarse facial features, clouded corneas, restricted joint movement, and high plasma levels of lysosomal enzymes. Often fatal in children.
I-cell disease.
131
Kartagener's syndrome.
Immotile cilia due to dynein arm defect. Results in male and female infertility, bronchiectasis and recurrent sinusitis.
132
Plasma membrane composition?
Asymmetric fluid bilayer. Cholesterol 50%, phospholipids 50%, sphingolipids, glycolipids and proteins.
133
Major component of RBC membranes, of myelin, bile and surfactant.
Phosphatidylcholine.
134
Where is the ATP site on a sodium pump?
Cytoplasm side.
135
How many K and how many Na does a sodium pump move for each ATP?
3 Na+ go out and 2 K+ come in.
136
How does Ouabain work?
Inhibits the sodium pump. Binds to K+ site.
137
What drugs inhibit the Na+ K+ ATPase causing an increase in cardiac contractility.
Cardiac glycosides.

Biochemistry (2 decks)

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