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BioMed Flashcards

1
Q

Structure of a standard eukaryotic cell

A

> diverse in shape, structure and function

> Plasma membrane

> Nucleus

> Mitochondria

> Internal membrane bound organelles

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2
Q

Describe structure and function of cytoskeleton

A

> Helps cells maintain their shape and internal structures

> Provides mechanical support that lets cells carry out division and movement

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3
Q

Difference between prokaryotes and eukaryotes

A

> Prokaryotes: no nucleus, contains plasmids, usually unicellular, about 1-10 micrometers

> Eukaryotes: contains nucleus, usually multicellular, 10-100 micrometers

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4
Q

Primary structure of protein

A

Sequence of amino acids

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5
Q

Secondary structure of protein

A

Folding; alpha helix and beta pleated sheet

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6
Q

Tertiary structure of protein

A

3D shape; Defined by the hydrophilic and hydrophobic interactions between R groups of amino acid chains.

di-sulphide bridges

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7
Q

quaternary structure of a protein

A

A number of polypeptide chains linked together, and sometimes associated with non-protein groups to form a protein.

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8
Q

What is the action of oxidoreductases? Examples?

A

Reduction and oxidation reactions

Examples:

Dehydrogenase

Oxidase

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9
Q

What is the action of Transferases? Examples?

A

Transfer of amino, carboxyl, acyl, carbonyl, methyl, phosphate

Examples:

Transaminase

aldolase

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10
Q

What is the action of hydrolyses? Examples?

A

Change of bonds coupled with inserting water

Examples:

Esterase

Peptidase

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11
Q

What is the action of lyases? Examples?

A

Cleavage of C-C, C-S, C-N but not peptide bonds

Examples:

Decarboxylase

Aldolase

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12
Q

What is the action of isomerases? Examples?

A

Rearrangement of bonds

Examples:

Epimerase

Mutase

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13
Q

What is the action of ligases? Examples?

A

Formation of bonds between carbon and oxygen, sulphur, and nitrogen

Examples:

Synthetase

Carboxylase

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14
Q

What is Km? What does low km mean? high?

A

> the michealis constant

> Enzyme binds to the substrate tightly and works fast even at a low substrate concentration

> Enzyme binds to substrate weakly and requires a high concentration of substrate to work fast

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15
Q

What is Vmax?

A

Maximum possible rate of reaction

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16
Q

What are allosteric regulators

A

Bind to a regulatory site other than the active site and changes the enzyme activity by altering the proteins tertiary or quaternary structure

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17
Q

What are the 6 ways you can regulate enzyme activity

A

> feedback loops (short term)

> Feed forward activation (short term)

> allosteric regulation (short term)

> phosphorylation-dephosphorylation sequence (short term)..aka post-translational modification

> proteolysis (long term)

> Changes in gene expression (long term)

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18
Q

What enzyme does phosphorylation require? dephosphorylation?

A

> Kinase

> Phosphotases

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19
Q

What do irreversible inhibitors do?

A

Form covalent bonds

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20
Q

What happens to km and Vmax in competitive inhibitors

A

Km= increases

Vmax=unchanged

> More substrate required to saturate enzyme

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21
Q

What happens to km and Vmax in non-competitive inhibitors

A

km=unchanged

Vmax=decreases

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22
Q

What is an isoenzyme

A

Different enzymes the catalyze the same reaction but are subject to different regulatory controls (ex: DAHP synthase for aromatic amino acids)

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23
Q

mnemonic to remember classes of enzymes?

A

Over The Hills Live Intelligent Ladies

Oxidoreductases, Transferases, Hydrolyses, Lyases, Isomerases, Ligases

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24
Q

3 main uses of lipids

A

> storage of energy

> forming membranes

> signalling between and within cells

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25
Q

What are the two essential fatty acids?

A

linoleic acid and linolenic acid

> must be taken in from the diet

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26
Q

What does the delta sign mean when naming fatty acids? Omega sign? What does the first number mean? The second?

A

> delta=where double bonds are in relation to the carboxylic end

> Omega= where the double bonds are in relation to the omega end

> 1st number=number of carbons

> 2nd number=number of double bonds

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27
Q

What is the other name for a triglyceride? describe it

A

> Triacylglycerol

> 3 fatty acids join onto a glycerol molecule in the formation of an ester bond

> Main storage form of lipids found in adipose tissue surrounding visceral organs and subcutaneous fat

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28
Q

What are the two types of phospholipids? Give an example of each

A

> Glycerophospholipids
Example:Phosphatidylserine
Sphingolipids
Example:Sphingomyelin

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29
Q

What is cholesterol based on and what does it do?

A

> Based on steroid structure

>Decreases membrane fluidity as it packs between other lipids

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30
Q

Name four lipid derivatives

A

> Vitamin D
Steroid hormones
Bile salts
Eiosanoids

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31
Q

Describe vitamin D

A

> Synthesised from 7-dehydricholesterol by sunlight

>Required for calcium absorption and bone formation

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32
Q

Describe steroid hormones and give three examples

A

> derived from cholesterol

>cortisol, oestrogen, progesterone

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33
Q

Describe bile salts

A

> synthesised from cholesterol in the liver

>secreted from the duodenum to aid absorption of dietary fats

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34
Q

Describe eiosanoids and give two examples

A

> derived from arachidonic acid
Involved in inflammation response and vascular contraction
prostaglandins and thromboxanes

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35
Q

3 main uses of a carbohydrate

A

> energy storage
structure
recognition and adhesion

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36
Q

What do monosaccharides consist of

A

aldehyde or ketones and at least two alcohol groups

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37
Q

What is the structure of an aldehyde?Ketone?

A

> double bonded oxygen and a hydrogen and an r group (on end)

>Double bonded oxygen with two r groups (in the middle)

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38
Q

What are the 3 monosaccharides?

A

glucose, fructose & ribose

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39
Q

What is sucrose broken down into? by what enzyme?Lactose?Maltose?

A

> glucose & fructose by sucrase
Glucose & galactose by lactase
glucose & glucose by maltase

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40
Q

What are glycosaminoglycans? what is their role

A

> large negatively charged heteropolysaccharides

>roles in the extracellular matrix, acting as lubricants and shock absorbers

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41
Q

What are the four types of phospholipid movements in the membrane?

A

> lateral diffusion
flexion(movement/bending of tail)
rotation(turning around of tail)
flip-flop(rarely occurs-only with help of flippase enzyme, its when they swap from top layer to bottom layer/vice versa)

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42
Q

Give some examples of small non-polar molecules and how they cross the membrane

A

> Cross by simple diffusion

>O2,CO2,N2,steroid hormones

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43
Q

Give some examples of small uncharged polar molecules and how they cross the membrane

A

> Can diffuse but not as easily as small non-polar molecules

>H2O, ethanol, glycerol

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44
Q

Can ions diffuse across the membrane?

A

no

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45
Q

What do transporters allow

A

Active or passive diffusion

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46
Q

What are the two types of active transport and what are they driven by

A

Primary active transport driven by ATP

Secondary active transport driven by co-transport of Na+

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47
Q

What do channels allow for? What type of gated are they

A

facilitated diffusion

ligand-gated or voltage-gated

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48
Q

Where are ligand-gated ion channels found? what else are they called

A

> Found at neuromuscular junctions

>Ionotropic receptors or ion-channeled coupled receptors

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49
Q

What do G-protein coupled receptors include?

A 
Receptors for:
adrenaline
glucagon
odour molecules
acetylcholine
rhodopsin (photoreceptor in retina)
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50
Q

Explain what happens in a g-protein coupled receptor

A

> Ligand binding site causes activation of associated g protein
activated G protein stimulates enzymes that produce second messages (cAMP)
Causes signal amplification

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51
Q

What is anabolic? catabolic?

A

> where the body builds and repairs muscle tissue

>where the body breaks down the tissue to replenish depleted energy levels

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52
Q

When does a reaction occur spontaneously?

A

when Gibbs free energy is negative

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53
Q

What is Gibbs free energy measured in?

A

in kJ/mol

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54
Q

What food molecules are oxidised to release energy?

A

carbon-based food molecules

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55
Q

What are activated carriers

A

biomolecules that store energy in the form of transferrable chemical groups

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56
Q

What is NADP+ usually used in

A

Anabolic pathways

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57
Q

What usually happens to FAD

A

usually covalently linked to enzymes and acts as a coenzyme

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58
Q

What is the net result of glycolysis & what does it require

A

2 pyruvate, 2 ATP, 2NADH

requires 2ATP

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59
Q

What is the Krebs cycle also known as & where does it occur

A

TCA or citric acid cycle

Occurs in the mitochondrial matrix

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60
Q

Net result of Krebs cycle

A

3NADH, 1FADH2, & 1GTP

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61
Q

Name some short term ways to control the metabolism

A

Binding of allosteric inhibitors to alter enzyme activity

Covalent modification such as phosphorylation

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62
Q

Name some long term ways to control the metabolism

A

Changes in gene expression to alter total amount of enzymes

Changes in proteolysis to alter total amount of enzymes

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63
Q

Percentage of ECF and ICF in the body

A

20% ECF

40%ICF

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64
Q

Conc. of sodium ions in mmol/L in the ECF & ICF? potassium? calcium?

A

Sodium: ECF:140 ICF:10
Potassium: ECF:4 ICF:120
Calcium: ECF:1.25 ICF:0.0001

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65
Q

What are four important internal properties?

A

> temperature
pH
Glucose concentration
Oxygen levels

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66
Q

What is interstitial fluid? Plasma?

A

> thin layer of fluid which surrounds the bodies cells

>Colourless fluid part of blood, lymph in which fat globules are suspended

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67
Q

Define diffusion and bulk flow

A

> Net movement down a concentration gradient due to random motion of individual molecules
Movement of water and solutes together due to a pressure gradient

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68
Q

What law describes what happens when gases come into contact with fluids such as blood? Describe it

A

Henrys law

>Concentration of a gas in a liquid is directly proportional to the solubility and partial pressure of that gas

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69
Q

What are the two equations for pH

A

pH=-log10[H+]

pH=pKa+log10[A-]

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70
Q

Whats the equation for [H+]

A

[H+]=10^-pH

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71
Q

What is the equation for pKa

A

pKa=-logKa

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72
Q

What are the differences between acids and bases

A 
Acids:
Low pH
high conc of H+
release protons
Bases:
High pH
Low conc of H+
Accept protons
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73
Q

Difference between strong and weak acids

A

Strong acids almost completely dissociate whereas weak acids only partially dissociate
Strong acids have a low pKa, weak acids have a high pKa

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74
Q

What is pKa

A

The pH at which the acid is half dissociated

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75
Q

What does it mean when the pH=pKa

A

Then [A-]=[HA]

buffer resists any change (acid or base)

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76
Q

What does it mean when pH < pKa

A

Then [HA]>[A-]

buffer resists addition of base

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77
Q

what does it mean when pH>pKa

A

Then [HA] < [A-]

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78
Q

What is the typical blood pH? when is it considered alkaline? acidosis?

A

7.4
when it increases above 7.45
when it decreases below 7.35

79
Q

What are osmolyte particles

A

dissolved particles that determine osmotic pressure

80
Q

What is an osmole

A

osmole=6 x 10^23 osmolyte particles

81
Q

Define osmolarity & its equation

A

the number of osmolyte particles per volume of a solution

osmolarity=sum of molar conc x osmotic coefficient

82
Q

what is the reflection coefficient

A

degree to which a membrane is permeable to a solute

83
Q

Define hyposmotic, isosmotic, hyperosmotic

A

> solution contains lower conc. of impermeable solutes than the solution on the other side of the membrane
solution contains equal conc. of solute either side of the membrane
solution contains a higher conc. of impermeable solutes than the solution on the other side of the membrane

84
Q

Define tonicity

A

effect that a solution has on the cell volume

85
Q

what happens in a hypotonic solution? hypertonic?

A

> results in swelling and haemolysis

>results in creation or shrinking

86
Q

What is haemolytic

A

destruction or rupture of red blood cells

87
Q

What does paracrine mean

A

diffusion of a chemical signal in interstitial fluid to the neighbouring cells

88
Q

what does autocrine mean

A

cell signals to itself

89
Q

What are the three main types of receptors found on the cell membrane

A

receptors which are ion channels (ligand-gated)
receptors which are enzymes or directly bound to enzymes
receptors which act via G proteins

90
Q

What does tetrodoxin do

A

stop action potential

91
Q

What is saltatory conduction

A

when action potentials jump from one node to the next

accelerates action potential propagation & save energy

92
Q

What cell is the myelin provided by in the CNS

A

oligodendrocytes

93
Q

What cell is the myelin provided by in the PNS

A

Schwann cells

94
Q

What is a resting membrane potential

A

where ions are distributed asymmetrically across the plasma membrane

95
Q

what does a depolarised membrane mean

A

allows more cations to enter neurone

membrane potential decreases (becomes less negative)

96
Q

What is EPSP

A

excitatory postsynaptic potential
temporary depolarisation of postsynaptic membrane caused by flow of positively charged ions into the postsynaptic cell as a result of opening of ligand-sensitive channels

97
Q

What is IPSP

A

inhibitory postsynaptic potential
temporary hyperpolarisation of postsynaptic membrane caused by flow of negatively charged ions into the postsynaptic cell

98
Q

What does a hyperpolarised membrane mean

A 
allows efflux (flowing out) of cations or influx of anions
membrane potential increases (becomes more negative)
99
Q

Four steps in generating an action potential

A

initiation
upstroke
repolarisation
refractory period

100
Q

What happens in initiation of an action potential

A

stimulation results in a depolarisation of the membrane potential to a threshold value (between -50 to -60mV)

101
Q

What is summation

A

the additive effect of several electrical impulses on a neuromuscular junction

102
Q

What is a neuromuscular junction & what happens there

A

synaptic connection between the terminal end of a motor nerve and a muscle
nerve action potential, calcium entry into the presynaptic terminus, release of Ach quanta, diffusion of Ach across cleft

103
Q

What is the sympathetic nervous system? parasympathetic nervous system?

A

> fight or flight

>rest and digest

104
Q

What happens at the extreme in the SNS (sympathetic nervous system)

A

> heart rate increases
piloerection (hair stands up)
salivation in anticipation (Other digestion related things are stopped)
sweating
trachea & bronchi dilate (facilitate air flow)
arterioles redistribute blood for the vital organs

105
Q

What happens at the extreme in the parasympathetic nervous system

A

> Constriction of pupils
GI increases
trachea and bronchi constrict
decrease in heart rate & force of contraction

106
Q

what are three types of muscle

A

cardiac
skeletal
smooth

107
Q

Describe cardiac muscle

A

> generation of blood pressure
striated structure
Innervated in the ANS, involuntary

108
Q

Describe skeletal muscle

A

> voluntary muscle
striated structure
Innervated in the PNS, voluntary

109
Q

Describe smooth muscle

A

> contraction of smooth organs (stomach, blood vessels)
non-striated structure
Innervated by ANS, involuntary

110
Q

Function of skeletal muscle

A

> motor unit=consists of a motor neurone and innervated by muscle fibres

111
Q

How to distinguish if a sample is skeletal muscle

A

> Has large rod-like fibres
Has striations
nuclei at periphery (outer edges)
Each fibre singly innervated

112
Q

How are fibres activated in the cardiac muscle? How do you measure the force? What is the force per fibre increased by?

A

> by a spread of action potential
force=force per fibre x number of fibres
the sympathetic nervous system (beta 1 receptor) & hormones (thyroxine (T4) works by increasing beta 1 receptor density)

113
Q

How to distinguish if a sample is cardiac muscle

A

> intercalated discs separate cells
has one/two nuclei
has striations
(>cells are connected electrically)

114
Q

What is the force per cell modulated by in smooth muscle?

A

sympathetic nervous system (alpha or beta)

parasympathetic nervous system (muscarinic)

115
Q

How to distinguish if a sample is smooth muscle

A 
>very small cells
>single nucleus
>no striations
>cells are sometimes connected
>find them in hollow organs
116
Q

What is the I band? outer edge of A band? H zone? M line?

A

> thin (actin) filaments only
thin (actin) & thick (myosin) filaments overlap
thick (myosin) filaments only
thick (myosin) filaments linked by accessory proteins

117
Q

What are EMGs? What are they used for?

A

Electromyograms
can be used to monitor the levels of activation in the muscle cells in skeletal muscle
(sum of multiple motor unit action potentials (compound action potentials))

118
Q

Whats is the size (amplitude mV) of EMGs dependent on?

A

> Size of muscle
Depth of the muscle (distance between skin & muscle)
resistance between skin and recording electrodes

119
Q

What is the latency (delay) between stimulus and response in EMGs due to?

A

> Activation time of nerve
Conduction time in nerve
Transmission time across the neuromuscular junction
Conduction time within the muscle fibres

120
Q

Which way should the anode & cathode be placed in an EMG

A

cathode (negatively charged plate) should be placed nearer the hand than the anode (positively charged plate)

121
Q

define genome

A

genetic information fo an organism

122
Q

define gene

A

basic unit of inheritance (region of DNA that encodes for a function)

123
Q

what are the pyrimidines

A

uracil, thymine, cytosine

124
Q

What are the purines

A

adenine, guanine

125
Q

What bases pair with 2 bond/3 bonds

A

2 bonds=adenine & thymine

3 bonds=cytosine & guanine

126
Q

define intron

A

non-coding information

127
Q

define exon

A

required information(e.g. for protein coding sequence)

128
Q

What is pre-mRNA

A

introns & exons

129
Q

mRNA

A

post-splicing only exons

130
Q

What are telomeres

A

ends of the chromosomes

131
Q

Define pseudogene

A

a section of a chromosome that is an imperfect copy of a functional gene

132
Q

What is a tandem repeat

A

occur in DNA when a pattern of one or more nucleotides is repeated and the repetitions are directly adjacent to each other

133
Q

What is an interspersed genome-wide repeat?

A

identical or nearly identical DNA sequences that are scattered throughout the genome

134
Q

What happens during DNA synthesis

A

> unzipping pf the double helix by helicase (breaks hydrogen bonds between nucleotide bases)
strand in 3’-5’ (from unzipped end) is leading strand
strand in 5’-3’ is lagging strand
Leading strand:
Primer (short piece of RNA from enzyme primase) bind to end of leading strand
DNA polymerase binds to leading strand adding nucleotide bases in 5’-3’ direction (opposite of the leading strand)
called continuous replication
Lagging strand:
Numerous primers bind at various points
Okazaki fragments added in 5’-3’
called discontinuous replication
Both strands:
exonuclease strips away primers
DNA ligase seals up sequence

135
Q

What are the four types of DNA mutation

A

> insertion
deletion
double-strand breaks
point mutations

136
Q

What causes DNA mutations?

A 
>Uv light exposure
>cellular metabolism
>Ionising radiation
>chemical exposure
>replication errors
137
Q

What are the five repair pathways for DNA mutations?

A

> Base excision repair (recognises, removes and replaces damaged bases)
nucleotide excision repair (recognises damaged base, removes & replaces entire nucleotide)
mismatch excision repair (repairs replication errors made by DNA polymerases)
direct repair (repairs the damage itself)
double strand break repair

138
Q

What does UV radiation do in DNA damage

A

causes thymine to become covalently linked (forms a thymine dimer)

139
Q

What is mRNA

A

messenger RNA

copy of protein coding sequence

140
Q

What is rRNA

A

ribosomal RNA
component of ribosome
(when is acts as an enzyme its called a ribozyme)

141
Q

What is tRNA

A

transfer RNA

carries amino acids to ribosome

142
Q

What 3 RNA molecules are used for regulation of gene expression

A

miRNA
siRNA
lncRNA

143
Q

what is sRNA responsible for

A

splicing

144
Q

What is snoRNA responsible for

A

nucleotide modification of tRNA, rRNA

145
Q

What does peptidyl transferase do? what is it?

A

catalyses the formation of peptide bonds in protein synthesis (its an enzyme)

146
Q

What are the three types of RNA polymerase in eukaryotes and what do they do

A

I synthesises rRNAs
II synthesises mRNAs
III synthesis tRNAs and 1 rRNA

147
Q

What is the genetic code

A

(it is universal)

relationship between the sequences of bases in DNA and the sequence of amino acids in proteins

148
Q

What does tRNA do

A

reads the genetic code
when an amino acid is attached its called aminoacyl tRNA
`

149
Q

What are the five components needed for protein synthesis

A 
>Ribosome subunits
>mRNA
>aminoacyl tRNA
>protein factors
>GTP (guanine triphosphate)
150
Q

What are the three stages of protein synthesis

A

initiation
elongation
termination

151
Q

What happens in initiation of protein synthesis

A

formation of the 80s initiation complex

AUG is an initiator codon

152
Q

what happens in elongation of protein synthesis

A

aminoacyl tRNA enters A site
peptide bond formation
translocation (process that advances the mRNA–tRNA moiety on the ribosome, to allow the next codon to move into the decoding center)

153
Q

What happens in termination of protein synthesis

A

release factor binds
polypeptidyl-tRNA link hydrolysed
dissociation of compounds

154
Q

What is glycosylasation in protein synthesis

A

reaction in which a carbohydrate is attached to a hydroxyl or other functional group of another molecule

155
Q

What is phosphorylation in protein synthesis

A

amino acid residue is phosphorylated by a protein kinase by the addition of a covalently bound phosphate group

156
Q

What is proteolytic processing in protein synthesis

A

when a protease cleaves (splits/severs) one or more bonds in a target protein to modify its activity

157
Q

What is a homozygote? heterozygote?

A

Two identical forms of the particular gene

Two different forms of the particular gene

158
Q

What is a missense mutation

A

amino acid substitution

159
Q

What is a nonsense mutation

A

stop codon

160
Q

what is a silent mutation

A

substitution occurs but codes for the same amino acid

161
Q

What happens in mutations of promotors?

A

alters levels of transcription

162
Q

What happens in mutations of splicing?

A

low/no beta globin

163
Q

What happens in mutations in 5’-CAP site

A

reduced levels of translation

164
Q

What happens in mutations of Poly-A-tail signals

A

reduced levels of translation

165
Q

Define epigenetic code

A

defining code in every eukaryotic cell consisting of the specific epigenetic modification in each cell

166
Q

What is a single nucleotide polymorphism (SNP)

A

is a variation at a single position in a DNA sequence among individuals

167
Q

What are the stages of the cell cycle

A 
interphase
prophase
metaphase
anaphase
telophase
cytokineses
168
Q

What are the stages in interphase?

A

G1: (growth) increase supply of proteins, number of organelles (mitochondria and ribosomes)
S:DNA replication
G2: (growth) protein synthesis and rapid cell growth to prep cell for mitosis

169
Q

What happens in prophase

A

chromosomes visible condense
centromeres migrate to opposite poles
microtubule spindle forms between centrosome and kinetochore
nuclear membrane breaks down

170
Q

what happens during metaphase

A

chromosomes align along spindle equator

171
Q

What happens during anaphase

A

sister chromatids pulled apart to opposite poles

each daughter cell inherits one chromosome copy

172
Q

What happens during telophase

A

chromosomes de-condense

nuclear membrane reforms

173
Q

what happens during cytokinesis

A

membrane cleavage to form two identical daughter cells

174
Q

What regulates the cell cycle? How?

A

Cyclins
they bind and activate Cdks (Cyclin dependent kinases)
which directly/indirectly regulate expression or function of key proteins required at each stage of the cycle

175
Q

What are the checkpoints in the cell cycle

A

G1
G2
mitosis

176
Q

What are the steps in meiosis

A 
meiosis I:
prophase I
metaphase I
anaphase I
telophase I
meiosis II:
prophase II
metaphase II
anaphaseII
telophaseII
177
Q

What happens in the stages of meiosis

A

PI-chromosomes condense, nuclear membrane dissolves , homologous chromosomes form bivalents, crossing over occurs
MI-spindle fibres from opposing centromeres connect to bivalents (at centromeres) and align hem along middle of cell
AI-spindle fibres contract and pull bivalents apart, homologous chromosomes move to opposite poles
TI-chromosomes decondense, nuclear membrane may reform, cytokinesis occure
PII-Chromosomes condense, nuclear membrane dissolves, centrosomes move to opposite poles (perpendicular to before)
MII-Spindle fibres from opposing centrosomes attach to chromosomes (at centromere) and align them along the cell equator
AII-Spindle fibres contract and separate the sister chromatids, chromatids (now called chromosomes) move to opposite poles
TII-Chromosomes decondense, nuclear membrane reforms, cells divide (cytokinesis) to form four haploid daughter cells

178
Q

What is a karyotype

A

number and appearance of chromosomes of a cell

179
Q

What is heterochromatin? euchromatin?

A

dark bands

light bands

180
Q

What is anueploidy

A

abnormal number of (usually 1) chromosome

181
Q

what is a trisomy and which ones are compatible with life

A

additional chromosome
+18, +21, +13
can also have a trisomy of X

182
Q

What is a monosomy

A

loss of a chromosome

only loss of X is viable

183
Q

What is X-inactivation

A

called lyonisation in females

forms Barr bodies

184
Q

what is a Barr body

A

dark staining region in female cells

condesned inactive X chromosome

185
Q

What is a polygenic disease, give an example

A

impact of many genes each having limited individual impact (blood pressure)

186
Q

what is a multifactorial disease, give an example

A

interplay of environmental factors along with multiple genes (cancer, diabetes)

187
Q

what are totipotent stem cells

A

cells that can form all of the cell types in the body, plus the extra embryonic and placental cells

188
Q

What are pluripotent cells

A

can only make cells of the embryo proper, but that is all of the cells of the body

189
Q

what are multipotent cells

A

can only make cells within a certain germ layer and derivatives

190
Q

what are desmosomes

A

intercellular junctions that provide strong adhesion between cells and act as signalling centres

191
Q

what are tight junctions

A

they seal neighbouring cells in epithelial sheets to prevent leakage of molecules between cells

192
Q

What is necrosis

A

external injury
the cell swells and bursts spilling its contents over its neighbouring cells and invoking an inflammatory response that can be damaging

193
Q

what is apoptosis

A

programmed physiological cell death which by the cell dies neatly

FoM (4 decks)

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