Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > Cellular > Flashcards

Cellular Flashcards

1
Q

Carbamoyle Phosphate synthetase I and II

A

I: urea cycle
Mitochondria
Nitrogen source-ammonia

II: pyrimidine
Cytosolic
Nitrogen source: glutamine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Leflunomide

A

Inhibits dihyrdroorate dehydrogenase

Pyrimidine synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Methotrexate
TMP
Pyrimethamine

A

Inhibit dihydrofolate reductase
–> decreased THF, INDIRECTLY blocking dUMP conversion to TMP
(Same action as 5 FU, but FU works directly)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

5 fluorouracil

A

Forms 5 F dump
Inhibits thymidylate synthase
Decreased dTMP
(Same site of action as methotrexate, TMP and Pyrimethamine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Orotic Aciduria

A 
Deficiency in UMP synthase= Increased ortic acid in urine
Failure to thrive, developmental delay and MEGALOBLASTIC ANEMIA, refractory to Vit B12 and Folate supplementation 
NO HYPERAMMONEMIA (vs. ornithine transcarbomoylase) 
Tx: uridine supplementation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Purine synthesis rate limiting enzyme

A

Glutamine PRPP amino transferase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Azathioprine and 6 mercaptopurine

A

Inhibit de novo PURINE synthesis : block PRPP becoming IMP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

mycophenolate and ribavirin

A

Inhibit inosine mono phosphate dehydrogenase
Blocks conversion of IMP to GMP
PURINE synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

hydroxyurea

A

Inhibits ribonucleotide reductase
Pyrimidine synthesis
UDP does not become dUDP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Purine Salvage deficiencies

A

Adenosine deaminase deficiency

Leach Nyhan Syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Adenosine Deaminase deficiency

A

Increased dATP: toxicity in lymphocytes

Autosomal recessive SCID

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Leach Nyhan Syndrome

A

X linked, absent HGPRT(unable to salvage to GMP and IMP)
Excess uric acid production and de novo purine synthesis

S/s: self mutilation (lip biting), aggression, retardation, hyperuricemia, gout, dystonia
Tx: allopurinol
“Allie can’t salvage her friends. She’s a man so she bites her lip and does the robot. She ain’t retarded, she’s just pissed off.”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Fluoroquinolones

A

Topoisomerase II and topoisomerase IV inhibitors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Etoposide/teniposide

A

Eukaryotic topoisomerase II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

DNA polymerase III vs. polymerase I

A

Both: 5-3 synthesis and proofreads with 3-5 exonuclease
Prokaryotic
I: excises RNA primer with 5-3 exonuclease
III: does most of the transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Telomerase

A

Eukaryotes only
RNA dependent DNA polymerase
adds DNA to 3 end

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Example of missense mutations

A

Sickle Cell disease (substitution of glutamic acid with valine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Frameshift

A

Deletion or insertion of nucleotides NOT DIVISIBLE BY 3
Ex: Duchenne’s muscular dystrophy
Tay Sach’s disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Lac operon

A

Activated when glucose is absent and lactose is available
Low glucose: increased CAP and increased transcription
High lactose: binds repressor protein: increase transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Nucleotide excision repair

A

Endonuclease
Repairs bulky, helix distorting lesions
G1 phase of cell cycle
DEFECTIVE IN xeroderma pigmentosum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Base excision repair

A 
Spontaneous deamination 
Glycosylases remove base, creates an "AP" site
Nucleotides removed by Endonuclease
DNA poly fills gap 
Ligase seals
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Mismatch repair

A

Newly synthesized strand is recognized, mismatched nucleotides are removed
G2 phase of cell cycle
Defective in Lynch syndrome (HNPCC)

23
Q

Nonhomologous end joining

A

Repairs doubled stranded breaks
Mutated in ataxia telangiectasia (defect in ATM gene: failure to repair DNA double strand breaks: cell cycle arrest)
–cerebellar defects, spider angiomas, IgA deficiency
–increased AFP

Fanconi anemia (DNA repair defect causing bone marrow failure)

24
Q

Eukaryotic RNA polymerases

A

Poly I: rRNA
Poly II: mRNA
–inhibited by amanitin
Poly III: tRNA

25
Q

Prokaryotic RNA polymerase

A

1 polymerase makes all 3 types of RNA

Inhibited by Rifampin

26
Q

Splicing of pre mRNA: small nuclear ribonucleoproteins

A

Antibodies to snRNPs in Lupus

27
Q

Trna structure

A

5’ CCA 3’ end accepts amino acids

Cloverleaf

28
Q

Charging of tRNA

A

Aminoacyl -tRNA synthetase “matchmaker”

Responsible for accuracy of amino acid selection

29
Q

Pyrimidine base synthesis rate limiting enzyme

A

Carbamoyl phosphate synthetase II

30
Q

Eukaryotic vs. prokaryotic ribosomes

A

EUK: 40S + 60S = 80S
PRO: 30S + 50S = 70S

31
Q

Cell cycle phases

A 
Regulated by cyclins, CDKs and tumor suppressors 
G1 (growth) 
S (DNA synthesis) 
G2
M/MITOSIS
32
Q

P53 function

A

Tumor suppressor
Induces p21: inhibits CDK’s –> hypophosphorylated Rb
Rb then binds to and inactivates transcription factor E2F

33
Q

Permanent cells

A

Remain in G0, regenerate from stem cells

34
Q

Stable cells

A

Enter G1 from G0 when stimulated

Ex: hepatocytes and lymphocytes

35
Q

Nissl bodies

A

Rough ER in neurons

36
Q

I cell disease

A

Lysosomal storage disorder
Defect in N-acetylglucosaminyl-1-phosphotransferase
Golgi does not phosphorylate mannose residues –> proteins secreted extracellularly instead of being delivered to the lysosome.

S/s : coarse facial features, clouded corneas, restricted joint movement, high plasma levels of lysosomal enzymes

37
Q

Peroxisome

A

Catabolism of very long chain fatty acids, blanched chain fatty acids, amino acids and ethanol

38
Q

Vimentin stain

A

Mesenchymal tissue

Ex: fibroblasts, endothelial cells, macrophages

39
Q

Desmin

A

Muscle

Rhabdomyosarcoma

40
Q

Cytokeratin

A

Epithelial cells

Squamous cell carcinoma

41
Q

GFAP

A

Neuroglia

Astrocytoma, glioblastoma

42
Q

Neurofilaments

A

Neurons

Neuroblastoma

43
Q

Drugs that act on microtubules

A 
"Microtubules get constructed Very Poorly" 
Mebendazole
Griseofulvin
Colchicine
Vincristine/vinblastine
Paclitaxel
44
Q

Dynein vs. kinesin: molecular motor proteins

A

Dynein: retrograde to Microtubule- positive to negative
Kinesin: anterograde negative to positive

45
Q

Cilia structure

A

9 + 2 arrangement of Microtubule doublets

46
Q

Kartagener Syndrome

A

Immotile cilia due to dynein arm defect
Infertility due to immotile sperm and dysfunctional Fallopian tube cilia
Can cause bronchiectasis, recurrent sinusitis, situs inversus

47
Q

Na/K ATPase

A

2K in / 3 Na out

ATP binding site is on cytosolic side of the membrane

48
Q

Inhibitors of sodium potassium pump

A

Ouabain: binds to K site
Digoxin: directly inhibit Na/K ATPase: indirect inhibition of Na/Ca exchange –> increased cardiac contractility

49
Q

Collagen

A 
A strong, slippery, bloody BM
Type I: bone, skin, tendon 
Ex: osteogenesis imperfecta
II: cartilage 
III: reticulin: Blood vessels 
Ex: vascular Ehlers-Danlos 
IV: Basement membrane 
--Alport syndrome 
--targeted by autoantibodies in Goodpastures syndrome
50
Q

Collagen structure

A 
1. Gly-X-Y 
X and y are proline or lysine 
2. Hydroxylation: requires VIT C 
3. Glycosylation --form triple helix 
--osteogenesis imperfecta
4. Exocytosis and proteolytic processing
5. Cross linking 
--ehlers-dahlia and Menkes disease
51
Q

Osteogenesis Imperfecta

A 
Autosomal dominant 
Decreased production of type I collagen 
May be confused with CHILD ABUSE 
--multiple fractures
--BLUE SCLERAE
--hearing loss 
--tooth abnormalities
52
Q

Ehlers-Danlos

A 
Auto Dom or recessive
Faulty collagen synthesis
Hyperextensible skin
Tendency to bleed
Berry and aortic aneurysms 
Organ rupture
53
Q

Menkes disease

A

X linked recessive connective tissue disease caused by impaired copper absorption and transport due to defective Menkes protein
Brittle, kinky hair, growth retardation and hypotonia

Biochemistry (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions