IMMS Flashcards
Describe Peptide Hormones
Made from amino acids Water Soluble Binds to cell surface membrane Fast acting Premade and stored E.G. ADH, Insulin
Describe Steroid Hormones
Made from cholesterol Lipid Soluble, need transport protein to travel in blood Diffuses through cell surface membrane Slow acting Not premade E.g oestrogen, testosterone
How much of the water in average human is ICF
28L (66%)
How much water in an average human is ECF?
How is this distributed?
14L (33%)
Interstitial fluid 11L, Plasma 3L
Examples of sensible water loss
Urine/ vomit
Measurable
Examples of insensible water loss
Sweat, breath
Immeasurable
What cells in Kidney detect low NaCl
Macula Densa (in distal convoluted tubule)
What cells detect low Blood Pressure in the Kidneys
Juxtaglomeruler cells in afferent arteriole
What cells release renin
Juxtaglomeuler
What does ADH act on in the kidneys
AP-II protein in the collecting ducts
Increase permeability so more water retained
Where is ADH released from
Posterior Pituitary
Where is ADH made
Hypothalamus
Stored in pituitary
What is the affect of aldosterone
Increase Na+ reabsorption in ascending limb of loop of Henle
What is obligatory H2O movement
Water following the movement of Na+
Where is aldosterone released from
Suprarenal cortex
What is released by blood vessels (and myocytes of heart) when they become too dilated due to hugh blood pressure.
(High stress on walls)
Atrial natriuretic peptide
Is an antagonist to aldosterone so decreases blood pressure
Define osmolality
Conc. /kilo solution
Define osmolarity
Conc. /Litre of solution
Osmotic pressure
Pressure exerted by pure solvent on solution needed to prevent inward osmosis
(Solvent➡️ solution)
Oncotic pressure
Protein pressure (albumin) on capilly walls keeping fluid in
Hydrostatic pressure
Fluid pressure wanting to move out of capillary
What is it called when you have excess/ less Na+
Hyper/hyponatremia
Causes and symptoms of hypernatremia
Causes:- dehydration, ⬆️aldosterone, failing kidneys
Symptoms:- Oedema, ⬆️BP
Causes and symptoms of hyponatremia
Casues:- excess water, ⬇️aldosterone
Symptoms:- ⬇️BP, overhydrated intracellulary
What is excess/ less K+
Hyper/hypokalemia
Causes and symptoms of hyperkalemia
Causes:- Kidney failure, ⬇️aldosterone, alkalosis
Symptoms:- nerve and muscle issues
What is Excess/ less calcium
Hyper/hypocalcemia
Causes and symptoms of hypokalemia
Causes:- diarrhoea, ⬆️ aldosterone
Symptoms:- weakness, heart problems
What bond Binds carbohydrates
Glycosidic bonds
Describe triglycerides
Hydrophobic
Esterbond
Main energy source (9kcal/g) by fatty acid beta oxidation
Used for protection, lubrication, waterproofing
Phosolipids are amphipathic, what does this mean
A molecule with both hydrophilic and hydrophobic parts. (Negative head)
Describe nucleotide
Phosphate + pentose sugar + base
Phosphodiester bonds between 3’C + 5’C on sugar
Describe nucleoside
Pentose sugar + base (no phosphate)
What are purines and pyramidine
Purine have 2 rings A + G
Pyramidines have 3 rings C + T + U
1 purine will bind to one pyramidine
How many amino acids are there
20 naturally occuring, 8 are essential (must get through diet)
On which amino acids would you find disulfide bridges
S=S on cysteine
Compare adult and fetal haemoglobin
Adult is 2 alpha chains, 2 beta chain
Fetal is 2 alpha chains, 2 gama chains (⬆️O2 affinity)
Describe sickle cell anemia
Autosomal recessive disease
Mutated beta chain
Mutation occurs on 11p (small arm of chromosome 11)
GAG~ GTG (Substitution)
Valine coded for instead of Glutamic acid
Makes RBA have lower surface area (sickled)
RBA less flexible and more prone to damage
In DNA replication what unwinds the supercoil?
Topoisomerase
In DNA replication, what breaks the H bonds between strands
Helicase
Once the 2 strands are separated, what prevents them rejoining?
Single strand bases (SSBs)
Bind to exposed bases
What is the role of DNA polymerase
Forms phosphodiester bonds between between free nucleotides to form new strand
How does DNA polymerase read DNA and how does it synthesise it?
Reads 3⁰ to 5⁰
Synthesise 5⁰ to 3⁰
What is the role of DNA ligase
Joins ozaki fragments on the lagging strand by phosphodiester bonds
Where does transcription occur
Nucleus
What is the TATA box region
The promoter region for transcription.
Always starts with codon AUG (methionine)
Where does translation take place
Cytoplasm
Where does mRNA bind
Small subunit of ribosome
Where does tRNA bind
Large subunit of ribosome
What happens in G1 of the cell cycle
Organelles replicate
Not DNA
What is the G1 checkpoint
The cells checks for DNA damage pre DNA replication.
What happens if DNA damage is detected at the G1 checkpoint
Activates tumour suppressor gene p53 which leads to a cascade of events eventually ending either autolysis
What happens in the S phase of the cell cycle
DNA replication
What happens at the G2 checkpoint
Checks for DNA damage pre mitosis,
Damaged bases removed by glycosylases
In what phase of meisos does crossing over take place
Prophase 1
In what stage of meiosis does independent segregation occur
Metaphase 1
When will meiosis 2 take place in oogenesis
When the egg is fertilised
What is non-disjunction
Failure to separate in M1 or M2
What is gonadal mosaicism
Healthy patient has a mutated Germline
What is a polymorphism
Non pathogenic variations at a locus from a wild type (normal allele)
What is consanguinity
2 relatives union (reproductive)
Penetrance
% of people with expected phenotype from their genotype
Variable expression
Some genotypes may have different expressions
Late onset
Manifestation after birth later in life
vs at birth, congenital
Autozygosity
Same mutation from both sides of the family
Anticipation (in reference to genetic disorders)
Wider trinucleotide repeates of mutated sequence over generations
(Earlier and more severe each time)
E.g Huntingtons
What does Hemizygous mean
Genes come from an unpaid chromosome
E.g. men are hemizygous for genes on y
Lyonisation
1 female X randomly inactivated
Imprinting
1 allele suppressed (imprinted) of the 2 inherited
Sex limitation
Gene defect affects 1 sex only
What is the carrier frequency of cystic fibrosis in the UK
1/25
What js the defect that causes cystic fibrosis
Defect in gene F508
Most common auto recessive affecting whites in UK
What is the Hardy weinberg equation
p+q=1
p^2 + 2pq + q^2 = 1
p^2 = Homozygous dominant 2pq = heterozygous q^2 = homozygous recessive
What is the incidence of Cystic Fibrosis
1/2500
What is a tandem duplication mutation
Adjacent repeating bases
What is a non-tandmem mutation
Repeating bases at another locus
What is an inversion mutation
DNA segment reversed
Parametric:- outside centromere
Pericentric:- includes centromere
Translocation mutation
Exchange with non homologous chromosome
What does a karyotype show
Numerical configuration of chromosomes
What does an ideogram show
Distinct banding patterns of chromosomes
How many kcal/g are there in carb, protein, fat, alcohol
Carb=4
Protein=4
Fat=9
Alcohol=7
How grams of alcohol are there in 1 unit
8g
10ml
In the absorptive state, do you have higher or lower Insulin levels
Higher
Less glucagon
Where is fat stored
Adipocytes
Ito cells
Where are carbs stored
Skeletal muscle
As glycogen
