IMMS Flashcards

1
Q

what is mosaicism

A

cells within the same person have different genetic makeup (can be somatic or germline/gonadal)

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2
Q

what is gonadal/germline mosaicism

A

where more than one set of genetic information is found specifically within the gamete cells

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3
Q

what is heterochromia

A

variation in colouration

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4
Q

when does crossing over occur

A

prophase 1

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5
Q

what happens in prometaphase

A
  • nuclear membrane breaks down
  • microtubules invade nuclear space
  • chromatids attach to microtubules
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6
Q

purposes of mitosis (3)

A
  • growth
  • replacing dead cells
  • producing 2 daughter cells which are genetically identical to the parent cell
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7
Q

dominant characteristics

A

manifest themselves in a heterozygous state

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8
Q

the process in which mRNA is used to specify the amino acids required for protein formation is known as

A

translation

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9
Q

the process by which DNA is transcribed / copied into mRNA which then leaves the nucleus

A

transcription

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10
Q

where are ribosomes formed

A

in the nucleus

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11
Q

what causes sickle cell anemia

A

mutation which causes the substitution of an amino acid in the beta globin chain

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12
Q

in hypoxia, the abnormal HbS …

A

polymerises

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13
Q

the HbS structural change causes sickling by …

A

binding to the cytoskeleton

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14
Q

in sickle cell anemia, capillary occlusion is now thought to occur by …

A

endothelial damage causing multicellular (platelets, white cells) aggregates which occlude the capillary

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15
Q

in patients with SCD (sickle cell) an acute pain crisis is typically caused by capillary occlusion in the …

A

bone

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16
Q

sickle cell disease can be treated with hydroxyurea because it …

A

increases the synthesis of HbF (foetal Hb)

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17
Q

what is an oligosaccharide

A

a few units of a monosaccharide

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18
Q

bond between amino acids

A

peptide bond ( between amino and carboxyl groups )

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19
Q

what breaks peptide bonds

A

proteolytic enzymes eg proteases and peptidases

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20
Q

whats a proteoglycan

A

long unbranched polysaccharide radiating from a core protein (when sulphated they absorb a lot of water)

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21
Q

how to form an ester

A

lipid and alcohol

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22
Q

steroids

  • regulate
  • are used in
A
  • regulate cell differentiation

- are used in cell signalling

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23
Q

whats the steroid nucleus

A

cholesterol

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24
Q

what are eicosanoids

A

chemicals synthesised from 20 carbon acids which cause inflammation

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25
Q

define a base

A

proton acceptor

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26
Q

how many litres of water in a 70kg man

  • intracellular?
  • extracellular total?
    • interstitial?
    • plasma fluid?
A

42L TOTAL

  • intracellular 28L
  • extracellular total 14L
    - interstitial 11L
    - plasma fluid 3L
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27
Q

is there more sodium in or outside the cell?

A

outside

28
Q

is there more potassium in or outside the cell?

A

inside

29
Q

what is used in calculating serum osmolarity?

A

sodium, glucose, BUN (blood urea nitrogen)

30
Q

what is insensible fluid loss?

A

insensible fluid loss is loss that is not easily measured e.g. sweating, water lost from respiration, evaporation during abdominal surgery

31
Q

what is sensible fluid loss?

A

sensible fluid loss is that which is easily measured e.g. urine output, vomit, fluid in surgical drains

32
Q

albumin effect on oncotic pressure?

A

albumin increases oncotic pressure so fluid diffuses from the interstitial fluid into the blood

33
Q

what influences the amount of ADH released?

A

plasma osmolarity

34
Q

osmolality definition and units

A

the measure of how much substance has dissolved into another substance in mOsmKg-1

35
Q

where is aldosterone made

A

adrenal cortex

36
Q

what does aldosterone do

A
  • steroid hormone released from the adrenal cortex in response to stimulation by angiotensin II
  • it promotes sodium reabsorption and potassium secretion in the distal tubules of the kidneys therefore increases water reabsorption
37
Q

what is the principal site of renin production?

A

juxtaglomerular cells

38
Q

what causes renin to be produced?

A

decrease in perfusion pressure indicating fall in ECF volume

39
Q

what does renin do?

A

converts angiotensinogen (produced by liver) to produce angiotensin I

40
Q

what does acetyl cholinesterase (ACE) do?

A

converts angiotensin I to angiotensin II

41
Q

where is acetyl cholinesterase (ACE) produced?

A

lungs

42
Q

what does angiotensin II do?

A
  • increases sympathetic activity e.g. vasoconstriction
  • acts on posterior pituitary gland to secrete ADH when severely volume depleted
  • acts on adrenal gland to stimulate release of aldosterone
43
Q

where is ADH made

A

hypothalamus (but released from posterior pituitary)

44
Q

what do eicosanoids do and what are they made from

A

cause inflammation and are made from 20 carbon acids

45
Q

A and T nucleotides have how many hydrogen bonds between them?

A

3

46
Q

what is the bond within a nucleotide that joins the phosphate to the sugar

A

ester bond

47
Q

what is the bond within a nucleotide that joins the sugar to the base

A

glycosidic bond

48
Q

what is the p53 gene

A

tumor supressor gene

49
Q

what does topoisomerase do

A

unwinds the dna

50
Q

what does dna polymerase do

A

reads the existing dna to create 2 new strands

51
Q

what does dna helicase do

A

opens/unzips the dna

52
Q

what direction does dna replication go in

A

5’ to 3’

53
Q

what does primase do

A

make the primers involved in dna synthesis

54
Q

what does it mean by the genetic code being degenerate

A

many amino acids are specified by more than one codon

55
Q

what is the central dogma

A

dna–> rna–> protein

56
Q

kDA unit??

A

kilodaltons

57
Q

what is special about retroviruses eg HIV

A

they can do reverse transcription

58
Q

what is transcription

A

when the dna is copied into mrna which then leaves the nucleus

59
Q

what is rRNA

A

it combines with proteins to form 80s ribosomes

60
Q

what does it mean when chromosome defects are described as paracentric eg inversions

A

they dont involve the centromere

61
Q

deficiency in folic acid leads to ??

A

fragile x syndrome

62
Q

what is the end of the chromosome called

A

telomere

63
Q

what is a de novo mutation

A

a mutation in the germ cells

64
Q

what is penetrance

A

the % of individuals with a specific genotype showing the expected phenotype

65
Q

what is an autosome

A

any chromosome other than sex chromosomes that occur in pairs in diploid cells

66
Q

what is homozygous

A

presence of identical alleles at a given locus