IMMS Flashcards
1
Q
cholesterol in cell membrane role
A
supports fluidity
2
Q
proteins in cell membrane role
A
as transporters
3
Q
glycolipids and glycoproteins in cell membrane role
A
involved in cell signalling
4
Q
tight junction role
A
seals neighbouring cells together in epithelial sheet to prevent leakage of molecules between them
5
Q
adherens junction role
A
joins an actin bundle in one cell to a similar bundle in neighbouring cell
6
Q
desmosome role
A
joins intermediate filaments in one cell to those in a neighbour
7
Q
gap junction role
A
allows passage of small water-soluble ions and molecules
8
Q
hemidesmasome role
A
anchors intermediate filaments in a cell to basal lamina
9
Q
steroid hormone response is
A
slow
10
Q
peptide hormone response is
A
fast
11
Q
example of steroid hormone
A
sex hormones - oestrogen, testosterone
12
Q
example of peptide hormone
A
insulin
13
Q
homeostasis definition
A
maintenance of a constant internal environment
14
Q
autocrine signalling
A
chemical is released from cell into ECF then acts upon same cell that secreted it
15
Q
paracrine signalling
A
chemical messengers involved in communication between cells, released into ECF
16
Q
example of paracrine signalling
A
ACh at neuromuscular junction
17
Q
endocrine signalling
A
secretion into blood, longer distance, systemic communication
18
Q
exocrine signalling
A
secretion into ducts then into organs
19
Q
proportions of water in body
A
1/3rd extracellular
2/3rd intracellular
20
Q
how much water in intracellular vs extracellular
A
28L intracellular
14L extracellular
21
Q
breakdown of extracellular fluid
A
1L transcellular
3L plasma
10L interstitial
22
Q
ECF contains
A
glucose urea Cl- HCO3- Na+
23
Q
main cation in ICF
A
K+
24
Q
main cation in ECF
A
Na+
25
osmolality definition
concentration of solutes in plasma per kilogram of solvent
26
osmolarity definition
concentration of solutes in plasma per litre of solution
27
osmotic pressure definition
measure of how easily a solution can take in water
28
oncotic pressure
form of osmotic pressure exerted by proteins pulling fluid into a solution (albumin)
29
oedema
increased movement of fluid from plasma to interstitial space
30
monosaccharide
sugar that cannot be hydrolysed
31
oligosaccharide
3-10 monosaccharides
32
glycosidic bonds formed by
condensation reaction of 2 monosaccharides water produced as byproduct
33
triglyceride made up of
3 fatty acids 1 glycerol
34
ATP
adenosine triphosphate
35
basal metabolic rate (BMR)
measure of energy required to maintain non-exercise bodily functions
36
1st step of glycolysis
glucose to glucose 6 phosphate by hexose kinase
| 1 atp to adp
37
2nd step glycolysis
glucose 6 phosphate to fructose 6 phosphate by phosphohexose isomerase
38
3rd step glycolysis
fructose 6 phosphate to fructose 1,6 bisphosphate by phosphofructokinase
1 atp to adp
39
4th step glycolysis (1)
fructose 1,6 bisphophate to dihydroxyacetone phosphate by triose phosphate isomerase
40
4th step glycolysis (2)
fructose 1, 6 bisphosphate to 3 phosphoglyceraldehyde x2 by fructose bisphosphate aldolase
41
5th step glycolysis
3 phosphoglyceraldehyde x2 to 1,3 bisphosphoglyceraldehyde x2 by glyceraldehyde-3-phosphate dehydrogenase
2NAD+ and 2Pi to 2NADH
42
6th step glycolysis
1,3 bisphosphoglyceraldehyde x2 to 3 phosphoglycerate x2 by phosphoglycerate kinase
2adp to 2atp
43
7th step glycolysis
3 phosphoglycerate x2 to 2 phosphoglycerate x2 by phosphoglycerate mutase
44
8th step glycolysis
2 phosphoglycerate x2 to phosphoenolpyruvate x2 by enolase
45
9th step glycolysis
phosphoenolpyruvate x2 to pyruvate x2 by pyruvate kinase
| 2adp tp 2atp
46
mneumonic for krebs cycle
can i keep selling socks for money officer
47
intermediated of krebs cycle
```
citrate
isotrate
alphaKetoglutarate
succinyl coA
succinate
fumerate
malate
oxoalacetate
```
48
enzymes of krebs cycle
```
aconitase
isocitrate dehydrogenase
alphaKetoglutarate dehydrogenase
succinyl coA synthetase
succinase dehydrogenase
fumarase
malate dehydrogenase
citrate synthetase
```
49
enzyme of krebs cycle mneumonic
can anthony drink down seven drinks 'fore dying
50
oxidative phosphorylation takes place in
inner mitochondrial membrane
51
explain oxidative phosphorylation
H+ pumped into intermembrane space via proton pumps
form electrochemical gradient
electrons transferred to O2 (final electron acceptor)
O2 split to form water
52
1 NADH is equal to
3ATP
53
1 FADH is equal to
2ATP
54
total atp from 1 molecule of glucose is
34 - 38 ATP
55
examples of fatty acids
linoleic acid
oleic acid
palmitic acid
arachidonic acid
56
fatty acid (beta) oxidation definition
catabolic process by which fatty acids are broken down in mitochondria to produce acetyl coA which enters krebs
57
where does beta oxidation take place
mitochondrial matrix
58
carnitine shuttle
acyl coA too big to transport into mitochondria
carnitine acyltransferase 1 on outer mitochondrial membrane removes CoA and ads carnitine
becomes acyl carnitine - transported into matrix
in matric carnitine acyltransferase 2 removes carnitine adds coA
acyl coA is oxidised to form acetyl coA
59
each round of fatty acid beta oxidation produces
1NADH
1FADH2
1 Acetyl CoA
60
can fatty acids act as nervous system fuel source
no FA cannot get through BBB
61
where does the krebs cycle take place
mitochondrial matrix
62
beta oxidation is dependent on
oxygen
good blood supply
adequate mitochondria number
63
ketogenesis is caused by
during high rates of fatty acid oxidation too much acetyl CoA is produced
this overwhelms the Krebs cycle and so you get ketone body formation
64
3 ketone bodies
acetone
acetoacetate
B-hydroxybutyrate
65
where does ketogenesis occur
in hepatocytes in the liver
66
3 causes of disease
genetic
multifactorial
environmental
67
ketone bodies used as fuels
- b-hydroxybutyrate oxidised to acetoacetate
- acetoacetate activated to acetoacetyl coA
- cleaved by thiolase enzyme to form acetyl coA
- can enter krebs
68
karyotype definition
number and appearance of chromosomes in a cell
69
G1 phase
not visible
rapid growth
protein synthesis of spindle proteins
70
cell cycle phases
G1 S G2 M
71
S phase
DNA doubles
histone proteins double
centrosome replication
double the DNA by the end of phase
72
G2 phase
energy stores accumulate
| mitochondria and centrioles double
73
what happens in prophase
chromatin condenses into chromosomes
| centrosomes nucleate microtubules and move to opposite poles
74
what happens in prometaphase
nuclear membrane breaks down
chromatids attach to microtubules
cell no longer has nucleus
75
what happens in metaphase
chromosomes line up along equator
76
what happens in anaphase
sister chromatids separate and pushed to opposite poles as spindle fibres contract
77
what happens in telophase
nuclear membrane reform
chromosomes unfold into chromatin
cytokinesis begin
78
what happens in cytokinesis
cell organelle evenly distributed
| cell divides into 2 daughter cells with nucleus and 46 chroms each
79
clinical significance of cytokinesis
downs syndrome occurs here
80
how is genetic diversity introduced in meiosis
metaphase 1 = random assortment
| prophase 1 = crossing over
81
what is non-disjunction
failure of chromosome pairs to separate in meiosis 1 or sister chromatids to separate in meiosis 2
82
example of non disjunction disorders
downs syndrome = 1 extra
| turners syndrome = only 1 X
83
what is gonadal mosaicism
when there are 2 different populations of cells in the gonads
one normal population one mutated
all gametes from the mutated line are effected
84
allele definition
one of several alternative forms of a gene at a specific locus
85
polymorphism
frequent hereditary variations at locus
| not mutation = doesnt cause problems
86
autozygosity
homozygous by descent
| = inheritance of same mutation from 2 branches of same family
87
penetrance definition
proportion of people with gene/genotype who show expected phenotype
88
what is lyonisation
process of X chromosome inactivation
89
what is knudson's 2 hit hypothesis
genes can be inherited or acquired
sporadic cancer requires 2 acquired mutations
inherited cancer requires 1 acquired mutation
higher chance of inherited cancer
90
what are peroxisomes
small membrane bound organelles containing enzymes which oxidase long-chain fatty acids
91
lactose made up of
glucose and galactose
92
sucrose made up of
glucose and fructose
93
maltose made up of
glucose and glucose
94
chiral centre is
carbon surrounded by 4 different groups
95
purine bases
adenine
| thymine
96
pyrimidine bases
cytosine
| guanine
97
glutamic acid charge
negative
98
primary structure of protein held together by
covalent bonds
99
bonds in secondary protein structure
hydrogen bonds between amino acids
100
bonds in tertiary protein structure
ionic bonds
disulphide bridges
van der Waal forces
101
what is an isoenzyme
enzymes have different structure and sequence but catalyse same reactions
102
what is sickle cell anaemia
genetic disorder characterised by hard sticky sickle-shaped RBC created by a mutation in Hb
103
role of antibodies
bind to antigens on toxins or proteins
| label for destruction by immune system
104
what is the specificity of antibodies determined by
the variable region
105
features of prokaryote
no nuclear membrane
| dna arranged in single chromosome
106
DNA in the mitochondria is
purely maternal
107
DNA polymerase role
reads template strand from 3' to 5'
| thus DNA is synthesised on daughter strand from 5' to 3'
108
why is DNA synthesised from 5' to 3'
because phosphate at 5' is used for energy for reaction to occur
109
topoisimerase role
unwinds double helix by relieving the supercoils
110
DNA helicase role
separates DNA apart
breaks H bonds between bases
exposes nucleotides
111
DNA polymerase role
reads 3' to 5' and synthesises DNA on daughter strand
| starts at a primer
112
single strand binding protein role
keeps 2 strands apart during synthesis to prevent annealing
113
primase enzyme role
RNA polymerase that synthesises short RNA primers needed to start the strand replication process
114
RNAse H role
removes RNA primers that began DNA strand synthesis
115
how is DNA replication completed
ligase enzymes join together short DNA pieces = Okazaki fragments
116
what are transcription factors
proteins which bind to promotor regions
117
what is a promotor
specific sequence of nucleotides that act as binding sites at the 5' end
118
where does a transcription complex form
around the TATA box
119
start codon
AUG
120
stop codons
UGA, UAG, UAA
121
where is mRNA made
the nucleus
122
what is an exon
contain the coding sequence
123
what is splicing
the removal of introns from pre-mRNA
124
what is exon shuffling
exons can be joined together in different order following splicing
allows new proteins to be made
125
degenerate but unambiguous definition
amino acids specified by more than one codon but each codon only specifies one amino acid
126
factors that turn off gene expression
activation of repressors (inhibitors of RNA polymerase binding)
enzymes no longer activated
transcription and processing proteins no longer produced
127
what is an out of frame deletion
base is lost within a codon so whole sequence shifts over and reading frame of gene is changed
catastrophic effects
128
what is an in frame deletion
complete codon is removed
| milder effects - late onset
129
what is a mis-sense mutation
point mutation in which single nucleotide change results in a codon that codes for a different amino acid (substitution)
can result in silent mutation/non-functional protein
130
what is a non-sense mutation
point mutation that produces a stop codon
| results in an incomplete/non-functional protein
131
example of a non-sense mutation disorder
duchennes muscular dystrophy
132
what is a splice site mutation
affects the removal of an intron
133
what is anticipation
when a disease will affect the future generation earlier and with greater severity than the past generation
e.g. huntingtons
134
role of a positive feedback loop
amplification of a signal
135
role of a negative feedback loop
inhibits a signal
136
what is a hormone
molecule that acts as a chemical messenger
137
peptide hormone properties
large
hydrophilic
bind to receptors on membranes
dissolved in blood when needed
138
steroid hormone properties
hydrophobic, lipid soluble
require transport proteins in blood
binds to receptors in cell - directly affects DNA
139
what is transcellular fluid composed of
CSF digestive juices mucus
140
3 ways to intake fluid
drinking
diet
IV
141
what are insensible losses
losses unaware of cannot be measured e.g. sweat, breath, vomiting, faeces
142
hydrostatic pressure definition
pressure difference between plasma and interstitial fluid
143
what happens when water is lost from ECF
ECF increase in osmolality
detected by osmoreceptors in hypothalamus
ADH released from post pituitary
increase water reabsorption from collecting duct
144
what happens when decreased renal bloodflow
renin released from jgc in kidney
renin = angiotensinogen to angiotensin 1
angiotensin 1 to angiotensin 2 by ACE
release of aldosterone from adrenal cortex
145
what does aldosterone do
increase Na+ reabsorption in kidneys in exchange for K+/H+ excretion
brings water into ECF
146
what is hyponatraemia
low sodium levels
| consequences = intracellular overhydration
147
what is serous effusion
excess water in a body cavity
148
what is oedema
excess water in intercellular tissue space
149
types of oedema (4)
inflammatory
venous
lymphatic
hypoalbuminaemic
150
what is hypernatraemia
high sodium
| consequences = intracellular dehydration
151
what is hyperkalaemia
high postassium
| consequences = risk of myocardial infarction
152
what is hypokalaemia
low potassium = weakness and cardiac dysrhythmia
153
what is hypercalcaemia
high calcium
| consequences = metastatic calcification
154
what is hypocalcaemia
low calcium
| consequences = spasms
155
3 types of endocytosis
phagocytosis
pinocytosis
receptor mediated
156
3 types of cell receptors
ion channel
g protein coupled
enzyme linked
157
how much energy per g of carbs
4kcal
158
how much energy per g of protein
4kcal
159
how much energy per g of alcohol
7kcal
160
how much energy per g of lipid
9kcal
161
BMR calculation
1kcal/kg body mass /hr
162
factors increase BMR (5)
```
high BMI
hyperthyroidism
exercise
low ambient temp
fever/infection
```
163
factors decrease BMR
age
female
starvation
hypothyroidism
164
what is daily energy expenditure DEE
energy needed to support BMR, physical activity, digestive energy
165
atp production at rest
30% carbs
| 70% lipids
166
where does glycolysis take place
cytosol
167
pyruvate to lactate in what conditions
in anaerobic conditions
168
pyruvate to lactate equation
2 pyruvate + 2APD + 2Pi = 2 lactate + 2ATP + 2H2O
169
why is glycolysis inhibited by acidosis?
phosphofructokinase-1 is pH dependent and is inhibited by acidic actions
170
AMP affect on glycolysis
AMP is an allosteric activator
| increases affinity of PFK-1 for fructose-6-phosphate
171
ATP affect on glycolysis
ATP is an allosteric inhibitor
decreases affinity of PFK-1 to fructose-6-phosphate
high ATP levels = slow reaction
172
before being oxidised, fatty acids must
be activated in the cytoplasm
173
activation of fatty acid equation
fatty acid + ATP + CoA = Acyl-CoA + pyrophosphate + AMP
174
when are fatty acids used as fuel
when hormones signal fasting or increased demand
175
electron transport chain is formed from
cytochromes and other proteins
176
role of ATP synthestase
forms a channel in the membrane to allow H to flow back into matrix via chemiosmosis
177
where are ketone bodies synthesised
mitochondrial matrix
178
what enzyme does the liver not have enough of and what are the consequences of this
succinyl CoA/acetoacetate CoA
cannot utilise ketone bodies as fuel
extrahepatic tissues have access to ketone bodies during prolonged starvation
179
what is diabetic ketoacidosis
reduced glucose supply so more fatty acid oxidation
increased ketone body production exceeds ability of peripheral tissues to oxidise
ketone bodies strong acids so lower ph of blood
180
what are the consequences of low blood pH
impairs ability of Hb to bind to O2
181
what is a reactive oxygen species (ROS)
reactive molecules and free radicals derived from O2
182
endogenous sources of ROS
NADPH and electron transport chain
183
exogenous sources of ROS
UV radiation
tobacco
drugs
184
fenton reaction
H2O2 + Fe2+ = Fe3+ + OH- + OH+
185
harber-weiss reaction
O2radical- + H2O2 + H+ = O2 + H2O + OHradical
186
what is respiratory burst
rapid release of oxygen species (superoxide radical/hydroxyl radical) from different types of cells during phagocytosis
187
name 3 enzymes that protect against oxygen toxicity
superoxide dismutase
catalase
glutathione peroxidase
188
name 3 antioxidant vitamins
vitamin E
vitamin C
carotenoids
189
name 3 diseases associated with free radical injury
parkinsons
emphysema
diabetes
190
2 other ways to protect against oxygen toxicity
cellular compartmentalisation
| repair
191
henderson hasselbalch equation
pH = pKa + log( [HCO3-] / [CO2] )
192
buffer definition
solution which resists changes in pH when small quantities of strong acids or base are added
193
normal pH range
7.35-7.45
194
the most important buffer system in the body is
carbonic acid and bicarbonate
195
3 systems for H+ concentration
blood/tissue buffering
excretion of CO2 by lungs
renal excretion of H+/regeneration of HCO3-
196
bicarbonate buffer equation
CO2 + H2O = H2CO3 = HCO3- + H+
197
3 biological buffers
protein
bicarbonate
haemoglobin
198
how do protein buffers work
If pH falls H+ binds to the amino group of the protein
If the pH rises H+ can be released from the carboxyl group of the protein
199
what occurs in the buffering of CO2
co2 from tissues diffuses into RBC
binds with Hb to form carbaminohaemoglobin
released at lungs and diffuses into alveoli
expired
200
what happens to the PaCO2 in respiratory acidosis
PaCO2 increases leading to an increase in H+ ions and so pH decreases
CO2 production is greater than CO2 elimination
201
causes of respiratory acidosis
inadequate ventilation due to airway obstruction - COPD/asthma
202
causes of respiratory alkalosis
CO2 elimination is more than O2 reabsorption
| hyperventilation in response to hypoxia
203
3 causes of metabolic acidosis
renal failure
loss of HCO3- ions
excess H+ production
204
2 causes of metabolic alkalosis
vomiting (excess H+ loss)
| increased HCO3- reabsorption
205
response in respiratory acid/alkalosis
rapid response limited effect
206
response in metabolic acid/alkalosis
delayed response greater effect
207
what is the anion gap
difference in serum concentration of cation and anions
208
type 1 collagen example
bone skin and teeth
209
type 2 collagen example
cartilage
210
type 3 collagen example
arteries liver kidneys spleen unterus
211
type 4 collagen example
basement membranes
212
type 5 collagen example
placenta
213
when does the trilaminar embryonic disc form
3rd week
214
what layer of trilaminar disc form epiblast
ectoderm
215
what cells does the epiblast give rise to
amnioblasts that line the amniotic cavity
216
what cells does the hypoblast give rise to
cells that line the blastocyst cavity - become endodermal cells
217
what is the chorion composed of
extra-embryonic mesoderm and 2 layers of trophoblast
218
what are the 2 differentiated layers of trophoblast
cytotrophoblast
| synctiotrophoblast
219
ectoderm becomes
structures outside the body:
CNS, PNS
epidermis of skin/hair/nails
pituitary/mammary/sweat glands
220
mesoderm becomes
```
3 parts:
paraxial plate
intermediate plate
lateral plate
= bones/muscles/heart and circulatory system/int sex organs
```
221
endoderm becomes
epithelial lining of GI/resp/urinary tracts
| parencyma of thyroid/parathryoid/liver/pancreas
