IMMS

Question 1

what is mosaicism

Answer 1

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

Question 2

what is gonadal/germline mosaicism

Answer 2

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

Question 3

what is heterochromia

Answer 3

variation in colouration

Question 4

when does crossing over occur

Answer 4

prophase 1

Question 5

what happens in prometaphase

Answer 5

• nuclear membrane breaks down
• microtubules invade nuclear space
• chromatids attach to microtubules

Question 6

purposes of mitosis (3)

Answer 6

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

Question 7

dominant characteristics

Answer 7

manifest themselves in a heterozygous state

Question 8

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

Answer 8

translation

Question 9

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

Answer 9

transcription

Question 10

where are ribosomes formed

Answer 10

in the nucleus

Question 11

what causes sickle cell anemia

Answer 11

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

Question 12

in hypoxia, the abnormal HbS …

Answer 12

polymerises

Question 13

the HbS structural change causes sickling by …

Answer 13

binding to the cytoskeleton

Question 14

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

Answer 14

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

Question 15

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

Answer 15

bone

Question 16

sickle cell disease can be treated with hydroxyurea because it …

Answer 16

increases the synthesis of HbF (foetal Hb)

Question 17

what is an oligosaccharide

Answer 17

a few units of a monosaccharide

Question 18

bond between amino acids

Answer 18

peptide bond ( between amino and carboxyl groups )

Question 19

what breaks peptide bonds

Answer 19

proteolytic enzymes eg proteases and peptidases

Question 20

whats a proteoglycan

Answer 20

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

Question 21

how to form an ester

Answer 21

lipid and alcohol

Question 22

steroids

• regulate
• are used in

Answer 22

• regulate cell differentiation

- are used in cell signalling

Question 23

whats the steroid nucleus

Answer 23

cholesterol

Question 24

what are eicosanoids

Answer 24

chemicals synthesised from 20 carbon acids which cause inflammation

Question 25

define a base

Answer 25

proton acceptor

Question 26

how many litres of water in a 70kg man - intracellular? - extracellular total? - interstitial? - plasma fluid?

Answer 26

42L TOTAL - intracellular 28L - extracellular total 14L - interstitial 11L - plasma fluid 3L

Question 27

is there more sodium in or outside the cell?

Answer 27

outside

Question 28

is there more potassium in or outside the cell?

Answer 28

inside

Question 29

what is used in calculating serum osmolarity?

Answer 29

sodium, glucose, BUN (blood urea nitrogen)

Question 30

what is insensible fluid loss?

Answer 30

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

Question 31

what is sensible fluid loss?

Answer 31

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

Question 32

albumin effect on oncotic pressure?

Answer 32

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

Question 33

what influences the amount of ADH released?

Answer 33

plasma osmolarity

Question 34

osmolality definition and units

Answer 34

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

Question 35

where is aldosterone made

Answer 35

adrenal cortex

Question 36

what does aldosterone do

Answer 36

- 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

Question 37

what is the principal site of renin production?

Answer 37

juxtaglomerular cells

Question 38

what causes renin to be produced?

Answer 38

decrease in perfusion pressure indicating fall in ECF volume

Question 39

what does renin do?

Answer 39

converts angiotensinogen (produced by liver) to produce angiotensin I

Question 40

what does acetyl cholinesterase (ACE) do?

Answer 40

converts angiotensin I to angiotensin II

Question 41

where is acetyl cholinesterase (ACE) produced?

Answer 41

lungs

Question 42

what does angiotensin II do?

Answer 42

- 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

Question 43

where is ADH made

Answer 43

hypothalamus (but released from posterior pituitary)

Question 44

what do eicosanoids do and what are they made from

Answer 44

cause inflammation and are made from 20 carbon acids

Question 45

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

Answer 45

3

Question 46

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

Answer 46

ester bond

Question 47

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

Answer 47

glycosidic bond

Question 48

what is the p53 gene

Answer 48

tumor supressor gene

Question 49

what does topoisomerase do

Answer 49

unwinds the dna

Question 50

what does dna polymerase do

Answer 50

reads the existing dna to create 2 new strands

Question 51

what does dna helicase do

Answer 51

opens/unzips the dna

Question 52

what direction does dna replication go in

Answer 52

5' to 3'

Question 53

what does primase do

Answer 53

make the primers involved in dna synthesis

Question 54

what does it mean by the genetic code being degenerate

Answer 54

many amino acids are specified by more than one codon

Question 55

what is the central dogma

Answer 55

dna--> rna--> protein

Question 56

kDA unit??

Answer 56

kilodaltons

Question 57

what is special about retroviruses eg HIV

Answer 57

they can do reverse transcription

Question 58

what is transcription

Answer 58

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

Question 59

what is rRNA

Answer 59

it combines with proteins to form 80s ribosomes

Question 60

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

Answer 60

they dont involve the centromere

Question 61

deficiency in folic acid leads to ??

Answer 61

fragile x syndrome

Question 62

what is the end of the chromosome called

Answer 62

telomere

Question 63

what is a de novo mutation

Answer 63

a mutation in the germ cells

Question 64

what is penetrance

Answer 64

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

Question 65

what is an autosome

Answer 65

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

Question 66

what is homozygous

Answer 66

presence of identical alleles at a given locus