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Biochemistry Flashcards

(110 cards)

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1
Q

Components of the nucelosome

A

DNA wrapped around a large histone
H1 histone linker connects them
DNA negative with phosphate groups
Histone are LARGe and positive from lysine and arginine

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2
Q

What is heterochromatin

A

Highly condensed (HeteroChromatin)
Dark, less visible on EM
Deactivates transcription

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3
Q

What is Euchromatin

A

Euchromatin is expressed
Active, more visible on EM
Transcriptionally active

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4
Q

What is visible and non-visible on EM stain

A

Euchromatin visible
Heterochromatin less visible (dark)

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5
Q

Function of DNA methylation

A

Adds methyl groups to DNA which changes the expression of DNA without altering the sequence
Deactivates DNA

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6
Q

Condition with dysregulated DNA methylation

A

Fragile X syndrome

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7
Q

What is histone acetylation

A

Acetylation makes DNA active
Activates transcription

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8
Q

What is histone deacetylation

A

Removal of acetyl groups - deactivates DNA, by reducing transcription

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9
Q

What condition is associated with histone acetylation

A

Thyroid fisorders
Thyroid hormone synthesis can be altered by acetylation

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10
Q

What condition is associated with histone deacetylation

A

Huntingtons disease

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11
Q

What amino acids are purine and pyramidines

A

Purines - A, G
Pyramidines - C, U, T

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12
Q

Deamination reaction of;
Guanine, cytosine, 5 methylcystine, adenine

A

Cystosine - uracil
Guanine - xanthine
Adenine - hypoxanthine
5 methylcystine - thymine

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13
Q

Drugs that affect pyramidine synthesis

A

Leflunomide - dihydrooate dehydrogenase
5- flurouracil - thymidylate synthesis

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14
Q

Drugs affecting purine synthesis

A

5 mercaptopurine - de novo purine synthesis
Mycophenalate and ribavirin - inosine monophosphate dehydrogenase

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15
Q

Drugs that affect both purine and pyramidine synthesis

A

Methotrexate, TMP, pyramethamine - dydrofolate reductase
Hydroxyurea - ribonucleotide reductase

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16
Q

Condition caused by impaired nucleotide excision repair

A

Xeroderma pigmentosum

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17
Q

Types of DNa repair and where they occur in the cell cycle

A

Nucleotide excision repair - G phase
Base excision repair - throughout
Mismatch repair - S phase

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18
Q

Condition caused by impaired DNA repair - non homologous end joining

A

Ataxia telangectasis

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19
Q

Condition caused by impaired DNa repair - homologous recombination

A

BRCA 1 and 2 + fanconi syndrome

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20
Q

Function of helicase

A

Helicase halves DNA at replication fork

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21
Q

Function of primase

A

Primes RNA for DNA to initiate replicarion

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22
Q

Function of telomerase

A

Adds TTAGGG to avoid loss of materal with duplication
Telomerase TAG’s for Greatness and Glory

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23
Q

Types of DNA repair

A

Single stranded
- nucleotide excision repair (G phase)
- base excision repair (throughout)
- mismatch repair (S phase)
Double stranded
- homologous recombination
- non-homologous end joining

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24
Q

What is a transition mutation

A

Purine - purine or pyramidine to pyramidine change

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25
Silent mutation
Same codon
26
Missense mutation
Changed amino acid
27
Nonsense mutation
Stop in codon, non functioning protein
28
Condition caused by missense mutation
Sickle cell
29
Conditjons caused by frameshift mutation
Cystic fibrosis, taysaxhs, duchenne muscular dystrophy
30
Conditiond caused by splice site mutation
Marfans, beta thalassaemia, gauchers
31
RNA polymerases - eukaryotes
RNA polymerase I - rRNA RNA polymeraze II - mRNA, miRNA, snRNA RNA polymerase III - tRNA, 5s RNA rNA MIght Maintain Small Nucleus by 5pm Tonight
32
RNA polymerases - prokaryotes
1 RNA polymerase - all kinds of
33
Sequence of protein synthesis
Initiation - elongation - termination
34
What are the 2 types of post translational modifications
Trimming Covalent alterations
35
Trypsinogen to trypsin is what type of post translational modification
Trimming
36
Phosphorylation is what type of post translational modification
Covalent alteration
37
pathophysiology of Lesch Nyhan syndrome
defective purine salvage (utilizes folate/vitamin D) absent HGPRT
38
features of lesch nyhan syndrome
caused by absent HGPRT Hyperuriciaemia Gout Pissed off (self mutilation) Rred/orange crystals in urine Tense muscles (dystonia) also megaloblastic anaemia due to low folate and b12
39
phases of the cell cycle are regulated by what?
cyclins, cyclin dependant kinases, and tumour suppressor genes
40
where does n-linked glycosylation occur?
rough endoplasmic reticulum 'N-linked eNdoplasmic'
41
function of rough endoplasmic reticulum
site of synthesis of secretory (exported) proteins, N-linked oligosaccharides, lysosomal and other proteins
42
function of smooth endoplasmic reticulum
site of steroid synthesis and detoxification of drugs and poisons 'gets rid of bad stuff to make it smooth and nice' (lacks surface ribosomes which makes it smooth)
43
what cells are rich in smooth endoplasmic reticulum?
hepatocytes and steroid hormone producing cells of the adrenal cortex and glands (function is for steroid synthesis and detoxification of drugs and poisons)
44
what are the vesicular tracking proteins
carry material from ER to golgi appartatus or from golgi to ER COPI - retrograde (golgi to ER) COPII - antegrade (ER to golgi) 2 steps forward, 1 step back clathrin - trans golgi
45
pathophysiology of adrenoleukodystrophy
x-linked recessive disorder of beta-oxidation due to mutation of the ABCD1 gene of peroxisomes results in a build of VLCFA in adrenal glands
46
what type of immune responses are proteasomes responsible for?
MHC-1 mediated
47
function of cystoskeleton filaments; microfilaments intermediate filaments microtubules
microfilaments - muscle contraction intermediate filaments - maintains cell structure microtubules - movement, cell division
48
pathophysiology of primary cilliary dyskinesia
autosomal recessive Dynein arm defect
49
features of primary ciliary dyskinesia
situs inversus hearing loss recurrent chest infections infertility - ectopic pregnancys
50
how does digoxin affect ATP pump
inhibits atp pump so directly inhibits Na/Ca exchange resulting in increased Ca = increased cardiac contractility
51
Na and K movement in Na/K Atp pump
3 K in 2 Na out
52
4 types of collagen and where each are most commonly found
1 - skeletal, skin, tendon, Late wound repair 2 - cartillage, vitreous humour 3 - arteries, skin, uterus, foetal, Early wound repair 4 - basement membrane (glomerulus, cochlea), lens 5 - interstitial tissue, placenta
53
what type of collagens are involved in early and late wound repair
early type 3 collagen late type 1 collagen
54
type of collagen affected in ehlors danlos syndrome
classical type (skin and joint symptoms) -> type V vascular type (SAH, aneurysms) -> type III
55
whats the genetic term to describe the BRCA 1gene
incomplete penetrance (not everyone with the BRCA1 gene will develop ovarian or breast cancer)
56
whats the genetic term to describe huntingtons disease
anticipation increased severity or earlier onset with each succeeding generation
57
what is allelic heterogenicity and a condition it is found in
different alleles in the same locus result in the same disease beta-thalassaemia
58
what conditions are an example of imprinting
prader willi and angleman syndrome
59
in prader willi, disease occurs when maternal or paternal derived gene is silenced or mutated?
paternal
60
in angleman syndrome, disease occurs when maternal or paternal derived gene is silenced or mutated?
maternal
61
chromosome involved in prader willi and angleman syndromes?
chromosome 15
62
chromosome affected in haemochromatosis
6
63
chromosome affected in ADPKD and huntingtons
4
64
chromosome affected in renal cell carcinoma and von hippel lindau
3
65
chromosome affected in williams syndrome and CF
7
66
chromosome affected in wilsons disease and patau syndrome
13
67
what chromosome is affected in FAP
5
68
chromosome affected in BRCA 2
13
69
chromosome affected in marfans syndrome
15
70
what part of the brain is affected in wernickes-korsakoffs syndrome
dorsal nucleus of thalamus
71
FAD and FMN are derived from what vitamin
B2 (riboflavin)
72
NAD and NADP are derived from what vitamin
B3 (niacin)
73
what vitamin is a component of coenzyme A (COA)
B5
74
what vitamin is a component of pyridoxal phosphate (PLP)
pyridoxine (B6)
75
features of zinc deficiency
delayed wound healing suppressed immunity male hypogonadism reduced adult hair anosmia acrodermatitis enteropathica (occurs at openings i.e. perianal)
76
antedote for alcohol overdose and mode of action
fomepizole (competitive inhibitor of alcohol dehydrogenase)
77
mode of action of disulfiram
inhibits acetaldehyde deydrogenase which increases acetaldehyde = increased hangover symptoms
78
resting phase of cell cycle
G0
79
what phase of the cell cycle determines the length of the cycle
G1 phase
80
what phase of the cell cycle is the shortest
mitosis
81
what phase of the cell cycle does DNA, RNA and histone synthesis occur
S phase
82
what are the 2 main regulators of Ca in the body
PTH and calcitriol (active form of vit D)
83
what enzyme is responsible for the phsophorylation of glucose to glucose-6-phosphate
glucokinase
84
rate limiting enzyme of glycolysis
phosphofructokinase-1 (fructose-6-P to fructose-1,6,biphosphate) glucokinase/hexokinase (glucose to glucose-6-P)
85
rate limiting enzyme of cholesterol synthesis
HMG-COA reductase
86
rate limiting enzyme of ketogenesis
HMG-COA synthase
87
rate limiting enzyme of lipolysis (fatty acid oxidation)
carnitine acyltransferase I
88
rate limiting enzyme for HMP shunt (hexose monophosphate shunt)
glucose-6-phosphate dehydrogenase
89
vitamin C is responsible for production of what proteins and enzyme?
proline and lysine in collagen synthesis dopamine beta-hydroxylase (dopamine to NE)
90
what vitamin helps absorption of iron suplements?
ascorbic acid (vit C)
91
NAD and NADP are derived from what vitamin ? are they used in anabolic or catabolic processes ?
vitamin B3 (niacin) NAD - catabolic NADP - anabolic (fatty acid and steroid synthesis)
92
function of glucokinase and where is it found
converts glucose to glucose-6-phosphate found in liver hexokinase converts this in other tissues
93
what enzyme catalyses glucose to glucose-6-phosphate
glucokinase in liver and b cells in pancrease hexokinase in other tissues
94
feedback inhibitor for glucokinase and hexokinase
both convert glucose to glucose-6-phosphate glucokinase inhibited by fructose-6-phosphate hexokianse inhibited by glucose-6-phosphate
95
is glucosekinase and hexokinase induced by insulin
glucoskinase yes hexokianse no
96
does PFK or FBP increase during gluconeogenesis?
FBP increases in gluconeogenesis PFK decreases FaBien the Peasant works hard when starving Prince FederiK only works when fed
97
what cofactor does arsenic inhibit ? what is the function of this cofactor ?
lipoic acid cofactor for 3 enzymes in the mitochrondri that link glycolysis to TCA cycle
98
cofactors required in the pyruvate dehydrogenase complex in the mitochondria (pyruvate +NAD +CoA -> NADH + acetylCoA + C02)
The Lovely Coenzymes For Nerds Thiamine (B1) Lipoic acid CoA (B5 pantothenic acid) FAD (B2 riboflavin) NAD (B3 niacin)
99
in pyruvate dehydrogenase deficiency, what lab serum lab finding would there be?
increased serum alanine
100
gluconeogenesis irreversible enzymes
pathway produces fresh glucose pyruvate carboxylase phosphoenolpyruvate carboxylase fructose-1,6, biphosphatase 1 glucose 6 phosphate
101
main inhibitory neurotransmitter in the brain
GABA (glycine in spinal cord)
102
main inhibitory neurotransmitter in the spinal cord
glycine (GABA in brain)
103
Glycine can be synthesised from what essential amino acid
serine
104
glycine causes inhibition through what receptors
NMDA (prevents glutamate-mediated depolarisation via NMDA receptors at post synaptic terminal)
105
glycine is used as an intermediate in the synthesis of what proteins
porphyrins and purines
106
G-6-P deficiency results in a build up of what amino acid
glutathione
107
features of hartnup disease
rare secondary form of pellagra sun exposed dementia diarrhoea dementia (incl nystagmus, ataxia, )
108
hartnup disease results in elevated level of what amino acid in the urine
tryptophan (due to reduced abroption in the kidney and gut)
109
hartnup disease results in what vitamin deficiency
niacin (B3) due to tryptophan deficiency
110

General Principles (13 decks)

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