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first year med > principles > Flashcards

principles Flashcards

1
Q

what can be said about the affinity of a low Km?

A

higher affinity - only need small amount for reaction to successfully occur

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2
Q

what are collaterals?

A

alternative vascular routes, small branches that form to bypass area of narrowing in the main artery to maintain blood flow

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3
Q

where are lipids produced?

A

SER

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4
Q

describe the histological features of skeletal muscle, epithelium, cardiac muscle and dense irregular connective tissue

A

epithelium - avascular, form cohesive sheets, lines abdominal cavity

skeletal muscle - long elongated cells, multiple nuclei

cardiac muscle - striated and branched, single cell nucleus

dense irregular connective tissue - bundles of collagen fibres arranged in random directions

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5
Q

which cells produce myelin for the CNS?

A

oligodendrocytes

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6
Q

which cells produces myelin for the PNS?

A

schwann cells

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7
Q

what are chondrocytes?

A

resistant cells within cartilage

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8
Q

what happens when a stop codon is reached by a ribosome (in site A)?

A

a termination protein binds to the codon and is used to release the growing peptide from the P site tRNA

the ribosome is likely to dissociate

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9
Q

is the Km for a competitive inhibitor high or low?

A

higher

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10
Q

what effect does heat exposure have on muscle tone?

A

decreases muscle tone

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11
Q

heritable mutation in mitochondrial DNA can only be transmitted from affected mother to her children

True or false?

A

true

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12
Q

x-linked conditions only transmit male to male

true or false?

A

FALSE !!!

NO male to male transmission

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13
Q

what letter represents the long arm of the chromosome?

A

long arm = q

short arm = p

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14
Q

what antibiotics target the cell wall?

A

penicillin’s
glycopeptides - vancomycin
cephalosporins

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15
Q

what antibiotics target nucleic acid synthesis?

A

metronidazole

ciprofloxacin

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16
Q

what antibiotics target protein synthesis?

A

aminoglycosides - gentamicin
tetracyclines - deoxycycline
macrolides - erythromycin

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17
Q

what can happen if c-myc is persistently expressed?

A

rapid proliferation of tumour cells

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18
Q

how can intracellular calcium contribute to cell death?

A

increases mitochondrial permeability

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19
Q

what 2 cell types are predominantly found in granulation tissue?

A

endothelial cells and myofibroblasts

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20
Q

what is pinocytosis?

A

internalisation of fluids (and particles within) into cells through invagination of the cell membrane

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21
Q

what are papillomas?

A

benign epithelial tumours growing exophytically (outwardly)

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22
Q

what do you put in a yellow sharps bin with a blue lid?

A

medicine vials with residual medicines

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23
Q

what do you put in a red bag?

A

soiled laundry

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24
Q

what does ABCDE stand for?

A 
A - airway
B - breathing
C - circulation
D - disability (glucose monitoring is integral)
E - evidence, environment, exposure
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25
Q

what are isozymes?

A

isoforms of enzymes - catalyse the same reaction but have different properties and structure (diff. amino acid sequence)

useful for diagnoses from blood

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26
Q

whats an apoenzyme? holoenzyme?

A

apoenzyme = enzyme without a cofactor

holoenzyme = apoenzyme + apoenzyme (enzyme with cofactor)

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27
Q

what are foam cells?

A

macrophages stuffed with lipids

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28
Q

pol I + III synthesise all mRNA

True or false

A

FALSE

pol II synthesises all mRNA

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29
Q

which transcription factor is required for all pol II transcribed genes?

A

TFIID

TFIID remains at promotor during transcription initiation - allows transcription at low basal rates

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30
Q

which enzyme catalyses peptide bond formation between amino acids in P + A sites?

A

peptidyl transferase

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31
Q

how do free ribosomes in the cytosol make proteins and where are they for?

A

post-translational

  • cytosol
  • nucleus
  • mitochondria
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32
Q

how do bound ribosomes on the RER make proteins and where are they for?

A

co-translationally - moved while still being made

plasma membrane
ER
golgi
secretion

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33
Q

what happens in missense mutations?

A

change of amino acid

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34
Q

what happens in nonsense mutations?

A

creates new termination codons

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35
Q 
where does supplied energy come from during activity of:
4 secs
15 secs
4 mins
77 mins
4 + days
A 
4 secs = ATP
15 secs = phosphocreatinine
4 mins = free circulating glucose
77 mins = glycogen stores
4 + days = fat stores
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36
Q

what are the 3 control points in glycolysis and what do they control?

A

control points = enzymes catalysing irreversible reactions

helokinase = substrate entry
phosphofructokinase = rate of flow
pyruvate kinase = product exit

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37
Q

what products and how much does each turn of the TCA cycle make?

A

1 GTP
1 FADH2
3 NADH

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38
Q

energy released by electrons in oxidative phosphorylation is used to efflux protons (H+) into matrix from innermembrane space

true or false

A

FALSE

… into innermembrane space from matrix

this sets up H+ electrochemical gradient which ATP synthase (integral) uses to drive ATP formation

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39
Q

what is a baby called between 2-8 weeks?

A

embryo

8 weeks + = foetus
0 - 3 weeks = conceptus

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40
Q

when does oogenesis start?

A

in DEVELOPMENT

begin meiosis but arrest in prophase until puberty

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41
Q

what happens during cleavage?

A

period of rapid cell division - no increase in size

formation of morula then blastocyst (days 1-4)

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42
Q

whats a teratogen?

A

agent that causes abnormality following foetal exposure

eg alcohol

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43
Q

what is the fate of the trophoblast?

A

cells eventually become foetal/embryonic part of placenta

splits into:

  • cytotrophoblast - inner part of trophoblast
  • syncytiotrophoblast - invasive layer (into endothelium)
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44
Q

what is the fate of the ectoderm?

A

skin and nervous system

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45
Q

what is the fate of the mesoderm?

A

paraxial mesoderm= axial skeleton, skeletal muscle, back dermis

intermediate mesoderm = urogenital systems

lateral plate mesoderm:

  • somatic layer - most of dermis, lining of body wall
  • visceral layer - Cardio, smooth muscle
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46
Q

what is the fate of the endoderm?

A

lining of:

  • gut tube
  • respiratory tract
  • bladder + urethra
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47
Q

what are the first cells to move through primitive streak in gastrulation?

A

cardiac progenitors - derived from mesoderm

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48
Q

what is a normal respiratory rate?

A

12-20 breaths per min

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49
Q

why does arterial pressure not fall to zero during diastole?

A

elastic recoil

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50
Q

what are the4 types of shock?

A

hypovolaemic - loss of blood volume

cardiogenic - sudden severe impairment of cardiac function (heart attack)

obstructive - obstruction to circulation (PE, tension pneumothorax)

distributive - excessive vasodilation + abnormal distribution of blood flow

  • neurogenic - spinal cord injury
  • vasoactive - septic shock
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51
Q

what is secondary active transport and what are the 2 mechanisms?

A

transfer of solute across membrane always coupled with transfer of ion that supplies driving force

  1. symport (co-transport) - solute and ion move in same direction
  2. antiport (exchange/counter transport) - move in opposite directions
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52
Q

what is the threshold potential for an action potential?

A

-60mV

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53
Q

list strategies to increase passive current speed in axons

A

increase axon diameter
decrease leak of current across axon = myelin

myelinated axons = saltatory conduction

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54
Q

hepatic portal system

A

returns blood from the digestive tract and the spleen to the liver

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55
Q

subclavian vein

A

paired, large vein, responsible for draining blood from the upper extremities to RA

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56
Q

Morulla

A

spherical shape ball of cells, without a cavity, 3-4 days after fertilisation

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57
Q

acrosome

A

cap-like saccular organelle in the anterior half of the sperm head that contains enzymes

58
Q

vascular, typically polarised forming cohesive sheets, lines body surfaces

A

epithelium

59
Q

long elongated cells, each having multiple nuclei

A

skeletal muscle

60
Q

Packed, extracellular bundles of collagen fibres which are arranged in random directions

A

dense irregular connective tissue

61
Q

cardiac muscle

A

striated cells that are branched and have single nucleus

62
Q

CNS glial cells

A

astrocytes, microglia and oligodendrocytes

63
Q

astrocytes

A

number of functions including sipporting and maintaining homeostasis in extracellular environment

64
Q

difference between microglial cells and oligodendrocytes

A

oligodrendrocytes produce myelin

65
Q

phosphorylating ADP to ATP in animal cells

A

oxidative phosphorylation and substrate level phosphorylation

66
Q

Oxidative phosphorylation

A

oxidation of NADH and FADH2 to NAD+ and FADH is coupled with pumping protons out of mitochondrial matrix, which in turn is coupled with phosphorylation of ADP to ATP via ATP synthase

67
Q

substrate level phosphorylation

A

phosphate group is directly transferred to ADP forming ATP usually derived from intermediate metabolite

68
Q

Quaternary structure

A

relative orientation of one polypeptide to another polypeptide in a multisubunit protein

69
Q

rate of reduction of pyruvate to lactate

A

matched by NADH regeneration by glyceraldhyde 3-phosphate dehydrogenase

70
Q

TATA box

A

type of promoter sequence (30 base pairs) upstream of the transcription start site which specifies where transcription begins

71
Q

RNA polymerase

A

enzyme that is responsible for copying a DNA sequence into an RNA sequence during transcription

72
Q

GPCRs

A

integral membrane protein, single polypeptide
extraceullular NH2, intracellular COOH
7 transmembrane

73
Q

binds to intracellular receptor that then activates gene expression in the nucleus

A

steroid hormone

74
Q

which substance within the cell directly stimulates protein kinase A?

A

cyclic AMP

75
Q

which conducts ions quicker, ligand-gated ion channels or carrier molecules?

A

ligand gated ion channels

76
Q

how is signalling terminated in the G-protein cycle?

A

the hydrolysis of GTP to GDP at the alpha subunit

77
Q

which foetal cells is the placenta derived from?

A

trophoblast

78
Q

what type of molecules target ligand gated ion channels and how fast are they transferred?

A

example = nicotinic acetylcholine receptor

‘fast’ neurotransmitters (milisecond)
targeted by hydrophilic signalling molecules –> acetylcholine, amino acids

GPCR = slow neurotransmitters (seconds)

79
Q

what type of receptor is mainly targeted by hydrophilic protein mediators such as insulin and growth factors?

A

kinase-linked receptors

work on timescale of hours

80
Q

how do steroid hormones enter the cell?

A

diffusion

81
Q

what is the apparent volume of distribution (Vd) and what is indicated by a high/low Vd?

A

theoretical volume that the total amount of administrated drug would have to occupy to provide the same conc as it currently is in the blood plasma - allows determine optimal dose to get target plasma conc

small Vd = drug in just plasma
large Vd = drug in plasma + tissue

** drug with high Vd will require higher dose **

82
Q

what factors can increase Vd?

A

liver failure
renal failure
pregnancy

83
Q

what factors decrease Vd?

A 
dehydration
large molecule - confined to plasma
high plasma protein
hydrophilic
high charge
84
Q

mechanism of action of macrolides?

A

inhibits protein synthesis by acting on 50s subunit of ribosomes

85
Q

what is the main source and function of tumour necrosis factor alpha?

A

source = macrophages

function = inducing fever + neutrophil chemotaxis

86
Q

give examples of tumour suppressor genes?

A 
BRCA2
BRCA1
p53
NF1
APC
VHL
PTEN
87
Q

is c-MYC an oncogene or tumour suppressor gene?

A

oncogene

88
Q

what is the function of the RER?

A

translation + folding of new proteins

manufacture of lysosomal enzymes

89
Q

examples of gram positive rods

A

clostridium

listeria monocytogenes

90
Q

list the steps of phagocytosis

A

macrophages express PRRs
receptor binding to PAMPs signals formation of phagocytic cup
cup extends around target + pinches off - forming phagosome
fusion with lysosomes to form phagolysosome - kills
debris released

pathogen derived peptide expressed on cell surface receptors (MHC-II molecules)
pro-inflammatory mediators released - TNF alpha

91
Q

what does degranulation involve?

A 
release of preformed proinflammatory substances eg
histamine
nitric oxide
prostaglandins
proinflammatory cytokines - TNF alpha
92
Q

what type of cytokines do virally infected cells produce?

A

interferons- IFNalpha

93
Q

what is the fate of inactive C3 post cleavage via C3 convertase?

A

-> C3a + C3b = fully active

C3b - unstable protein, will degrade unless bound, opsonin, can bind to ligands on pathogen surface - stabilises it
-> involved in generating enzyme complex to cleave C5

C3a - amplify acute inflammation via positive feedback loop (with C5a also)

94
Q

how does MAC kill pathogens and how is it formed?

A

extracellular salts/water enters pore via osmosis - causing pathogen to swell + burst

formed via interactions between C5b + other complement cascade proteins

95
Q

what type of cell links the innate and adaptive immune response? what is it’s main function?

A

dendritic cells

innate - activated in response to acute inflammation signals
adaptive - activates T cells

main function = process / present antigens on their surface for T cells

96
Q

what cell is responsible for immune responses in the extracellular body fluids?

A

B cells

97
Q

what are B cell receptors composed of?

A

b cell receptors = antibodies (Ig…)

4 polypeptide chains - 2 light, 2 heavy chains

98
Q

how are protein antigens broken down into peptide antigens?

A

via proteases

99
Q

what type of cells to MHC-I present peptide antigens to?

A

CD8+

100
Q

where do B + T cells wait in the lymph node while waiting to be activated?

A

B cells - in stromal cells (edge of lymph node)

T cells - in middle

101
Q

what is a germinal centre reaction?

A

b cells clonally proliferate + differentiate into long lived plasma cells that secrete high affinity antibodies - also long-lived memory b cells

102
Q

B cells need help from T cells in the germinal centre in order to respond to protein antigens

true or false ????? :o

A

true dat

they then differentiate into plasma cells which produce + secrete antigen-specific antibodies

103
Q

which part of the antibody is responsible for the effector function?

A

mediated by heavy chain constant region - Fc region

104
Q

define agglutination

A

clumping together of particles caused by antibody molecules binding to antigens on the surface of 2 adjacent particles, cells, pathogens, antigens

–> increases efficacy f pathogen elimination by enhancing phagocytosis

105
Q

what cells secrete growth factor IL-2?

A

CD4+ TH0

stimulates own + antigen activated CD8+ proliferation + differentiation

CD8+ aren’t good at making IL-2 (need it to become cytotoxic T cells) -> rely on it coming from CD4+

106
Q

what do TH1 cells do?

A

provide proinflammatory signals that activate macrophages

107
Q

what are macrophages role in the resolution of the immune system?

A

switch to anti-inflammatory - secrete anti-inflammatory mediators that initiate repair + wound healing

phagocytose any apoptotic cells killed by cytotoxic T cells

108
Q

right shift of oxyhaemoglobin dissociation

A 
decrease pH - acidic
increased [H+]
increased CO2
increased [2, 3 - DPG]
increased temp
109
Q

what do you call a high grade dysplasia?

A

carcinoma in situ (CIS)

affects whole of epithelium
last stage before becoming invasive

110
Q

name some benign tumours of the mesenchymal (connective tissue)

A 
fat = lipoma
bone = osteoma
cartilage = enchondroma
smooth muscle = leiomyoma
blood vessels = haemongioma
111
Q

how do WBCs move along the endothelium in acute inflammation?

A

weak bonds between
selectins + glycoproteins
ICAM + integrins

chemokines activate strong bonds - stops + flattens against vessel wall

112
Q

what are the 3 types of necrosis?

A

coagulative - ghost outline, no nucleus

liquefactive - post stroke leaves hole in brain

caseous (cheesy) - granuloma formation, associated with TB

113
Q

what is the main protein responsible for apoptosis?

A

caspases

114
Q

which cell most commonly initiates apoptosis via extrinsic pathway?

A

T - lymphocytes

–> have surface molecule called FAS ligand (FASL)

pathway begins when FASL binds to FAS receptors on target cell

115
Q

what are anti-apoptotic proteins

A

BCL-2 + BCL-x

in healthy cell - anti-apoptotic bind to pro-apoptotic blocking their action

116
Q

name pro-apoptotic proteins

A

BAX + BAK

117
Q

how is the caspase cascade activated in damaged cells?

A

BCL-2 + BCL-x are blocked so BAX + BAK free to punch channels in mitochondria
–> allows mitochondrial substances (eg cytochrome C) to leak into cytoplasm

leaked cytochrome C binds to APAF-1 proteins to create a compound that activates the caspase cascade

118
Q

which cyclin dependant kinase is responsible for activating the retinoblastoma protein? what does this activation cause?

A 
CDK4 phosphorylates (activates) Rb
--> CDK4 is activated by cyclin D

Rb inhibits E2F - E2F starts cell division
when Rb is phosphorylated by CDK4, Rb can’t bind to E2F so carries on green lighting cell division

119
Q

in what stage of the cell cycle is p53 involved?

A

G2

–> checks for mistakes, repair attempted or destroyed

120
Q

what is virchows triad?

A

where thrombosis is favoured

sites of endothelial injury
turbulent blood flow
hypercoagulable blood

121
Q

what vitamins are fat soluble?

A

vitamin A, D, E, K

122
Q

name the enzyme that attacks cell walls

A

lysozyme

123
Q

define specificity

A

how well test detects NOT having the disease
–> ‘true’ negatives

speciFicity - Fuck no

124
Q

define sensitivity

A

how well the test detects having the disease when it is present
–> ‘true’ positives - proportion with false neg

125
Q

what part of the antigen binds to the antibody?

A

epitope

126
Q

what is the positive predictive value (PPV)?

A

how reliable the test result is when it shows the disease is present

no. positive test + have disease / no. with positive test

127
Q

what can a vitamin C deficiency cause?

A

scurvy

gingivitis

128
Q

what can a vitamin A deficiency cause?

A

night blindness (nyctalopia)

vitamin A = retinol

  • converted into retinal - important visual pigment
  • important in epithelial differentiation
  • antioxidant
129
Q

what can a vitamin D deficiency cause?

A

rickets, osteomalacia

130
Q

what is the difference between foetal + adult haemoglobin?

A

foetal haemoglobin has gamma subunits instead of beta subunits causing it to have a high affinity for oxygen that adult Hb

131
Q

which cranial nerves carry parasympathetic fibres only?

A 
oculomotor nerve (II)
facial nerve (VII)
glossopharyngeal nerve (IX)
vagus nerve (X)
132
Q

define neoplasia

A

new growth which is not in response to a stimulus

133
Q

define proto-oncogenes

A

normal genes which stimulate cell division

134
Q

Hallmarks of cancer

A 
Evading growth suppressors
Resisting cell death 
Sustaining proliferative signalling 
Enabling replicative immortality
Avoiding immune destruction
135
Q

Boyle’s law

A

At any constant temperature the pressure exerted by a gas varies inversely with the volume of the gas

136
Q

La Place’s Law

A

The smaller the alveoli the higher the tendency to collapse

137
Q

Dalton’s law

A

the total pressure exerted by a gaseous mixture= the sum of the partial pressures of each individual component of the mixture

138
Q

Henry’s law

A

The O2 dissolved in blood is proportional to partial pressure

139
Q

Bohr effect

A

Increased release of O2 by conditions at the tissues (a shift of the curve to the right)

140
Q

Haldane effect

A

Removing O2 from Hb increases the ability of Hb to ick-up CO2 and CO2 generate H+

141
Q

Ductus venosus

A

Allows oxygenated blood from the placenta to bypass the hepatic circulation

first year med (15 decks)

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