IMMS Flashcards
What is the function of the golgi apparatus?
Processes and modifies ER products.
What generates the energy needed to phosphorylate ADP -> ATP?
The movement of H+ in and out of the mitochondrial matrix.
What is an example of type 4 collagen?
Basement membranes
How do HbS sub-units cause sickling?
They bind to the cytoskeleton which causes sickling.
What is the affect on HbS in hypoxia?
The HbS sub-units polymerise.
What is Knudson’s two hit hypothesis?
The idea that a sporadic cancer requires 2 acquired mutations whereas an inherited cancer requires only 1 acquired mutation and 1 inherited. Therefore you are more likely to develop an inherited cancer as the chance of one mutation is greater than the chance of 2.
Water distribution: How much water is there in the ICF?
28L
What is an example of type 3 collagen?
Arteries, liver, kidneys, spleen, uterus
How much energy do proteins provide?
4kcal/g
What happens in metaphase?
The chromosomes line up along the midline of the cell. The spindles attach to the centromeres.
What is the normal pH range of the human body?
7.35-7.45
What is mitosis used for?
Growth and repair.
Name 3 hormones involved in water homeostasis.
- Aldosterone.
- ADH - antidiuretic hormone.
- ANP - atrial natriuretic peptide.
List 2 causes of metabolic alkalosis.
Vomiting (loss of H+), increased reabsorption of HCO3-.
What are the 4 phases of the cell cycle?
G1, S, G2 and M
How does insulin increase the breakdown of glucose to pyruvate?
It stimulates PFK-1 indirectly through increasing fructose-2,6-bisphosphate levels and so increases the rate of glycolysis.
Why is sodium doubled in the plasma osmolality equation?
To account for negatively charged ions.
What condition is trisomy 21?
Down’s syndrome
What is the predominant electrolyte(s) in the ECF?
Na+, Cl-, HCO3-
A promoter sequence is coded in …
Single strand DNA.
Name 4 molecules you’d find in a plasma membrane.
- Cholesterol
- Glycoproteins
- Glycolipids
- Integral proteins
How much energy is stored as triglycerides?
15kg
How many genes are there in the human genome?
20,000.
What are the products of glycolysis?
2 ATP, 2 NADH, 2 Pyruvate
What enzyme does high insulin levels stimulate?
PFK-1 due to increasing fructose-2,6-bisphosphate levels.
What are desmosomes?
Attach cells via the intermediate filaments.
What can cause respiratory acidosis?
Inadequate ventilation due to airway obstruction (COPD, asthma).
What are removed in splicing of pre-mRNA?
Introns.
What is the cis face of the golgi apparatus?
The cis face is nearest the nucleus and receives ER vesicles.
What are the sub-units of haemoglobin?
2 alpha and 2 beta subunits.
Define sex limitation.
Both sexes have a gene but its expression is limited to only one of the sexes and it is turned off in the other.
What can cause respiratory alkalosis?
Hyperventilation in response to hypoxia.
CO2 elimination exceeds O2 reabsorption.
Give an example of an autosomal dominant condition.
Huntingtons disease.
What is the chorion composed of?
The extra-embryonic mesoderm and the 2 layers of trophoblast.
Briefly describe what happens in anaerobic respiration.
NAD is regenerated from NADH. Pyruvate, from glycolysis, forms lactate. Lactate dehydrogenase catalyses this reaction. NAD goes back to glycolysis so ATP can be produced.
How many hydrogen bonds form between cytosine and guanine?
3.
What is the predominant electrolyte(s) in the ICF?
K+
What is the definition of osmolarity?
The number of solute particles per L of fluid. (A high osmolarity has more solute particles per L).
What is the respiratory burst?
WBC’s using ROS in phagocytosis to damage the membrane of invading cells.
What is Mendel’s second law?
The law of independent assortment. The alleles of one gene sort into gametes independently of the alleles of another gene.
How many hydrogen bonds form between adenine and thymine?
2.
How much energy do lipids provide?
9kcal/g
Lipids have hydrophobic and hydrophillic parts. What is this called?
Amphipathic.
What is the role of cytochrome-C oxidase complex in oxidative phosphorylation?
It transports H+ out of the mitochondrial matrix.
What is multifactorial disease?
A disease due to genetic and environmental factors e.g. diabetes or schizophrenia.
Name 3 types of cell receptors.
- Ion channel receptors.
- G-protein coupled receptors.
- Enzyme linked receptors.
Would an X linked dominant condition be more common in males or females?
X linked dominant conditions occur twice as frequently in females as they do in males.
What does the trans face of the golgi do?
It sorts molecules into vesicles.
How long is pregnancy?
40 weeks.
What is a promoter sequence?
The promoter region controls when and where the RNA polymerase will attach to DNA so transcription can commence.
What 2 carbohydrates form lactose?
Glucose and galactose
What factors increase BMR?
Being overweight, pregnancy, low temperature, exercise, hyperthyroidism
What happens in prophase?
Chromatin condenses into chromosomes. Nuclear membrane begins to break down.
What type of cells are produced in mitosis?
2 diploid daughter cells which are genetically identical to the parent cells.
What is the affect on insensible losses if temperature increases by 1 degree?
Insensible losses will increase by 10%.
Define lyonisation.
One of the female X chromosomes becomes inactivated early in embryogenesis.
What 2 carbohydrates form maltose?
Glucose and Glucose
What is the function of gap junctions?
Conduct electrical signals.
Name 3 mechanisms by which a molecule can move across a plasma membrane.
- Diffusion - movement down a concentration gradient.
- Facilitated diffusion.
- Active transport - uses ATP, against concentration gradient.
Define karyotype.
The number and appearance of chromosomes in the nucleus of a eukaryotic cell.
Define BMR.
The energy needed to stay at live rest. (24kcal/Kg/day)
Electrolyte homeostasis: What is the cause(s) of hypokalemia and what are its risks?
Causes: D+V, alkalosis, diuretics.
Risks: weakness and dysrhythmia.
Electrolyte homeostasis: What is the cause(s) of hyponatremia and what are its risks?
Causes: Excess water due to IV fluids, diuretics.
Risks: Over hydration - headache, confusion.
What enzyme catalyses the formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate?
Phosphoglyceratekinase.
Oxidative phosphorylation: What enzyme transports protons into the mitochondrial matrix?
ATP synthase.
What happens in the third week of embryonic life?
Gastrulation - formation of a tri-laminar embryonic disc.
What is the function of topoisomerase?
It unwinds the DNA double helix by relieving the supercoils.
Name 2 equations that form hydroxyl radicals.
- Fenton’s
2. Haber-Weiss
What part of the tri-laminar disc are somites formed from?
Paraxial plate mesoderm.
What is non-disjunction?
The failure of chromatids to separate.
For example; Down’s syndrome - trisomy 21. Turner’s syndrome - Monosomy of X chromosome.
What is the definition of osmosis?
Movement of H2O across a partially permeable membrane from an area of high water potential to an area of low water potential.
What enzyme, expressed normally in embryonic cells and abnormally in neoplastic cells, lengthens telomeres?
Telomerase.
Electrolyte homeostasis: what is the cause(s) of hypernatremia? And what are the risks?
Cause - water deficit (poor intake, diabetes insipidus etc).
Risks - Dehydration.
(High sodium = low H2O which dehydrates the brain).
Why can X linked genes not be passed from father to son?
Because the dad is XY and gives only the Y chromosome to his son and the X to his daughter.
A mutation in what gene results in HbS production?
HBB gene.
Gametogenesis: when is meiosis 2 complete in a female?
If fertilisation occurs.
What is the definition of oncotic pressure?
Oncotic pressure is a form of osmotic pressure exerted by proteins, notably albumin, that tends to pull fluid into its solution.
What is a non-sense mutation?
A single nucleotide change that produces a premature stop codon. This results in an incomplete/non-functional protein.
How do protein buffers work?
If the 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.
Name 3 ketone bodies
- acetoacetate
- acetone
- beta hydroxybutyrate
Name 2 allosteric activators of PFK-1.
- AMP.
2. Fructose-2,6-bisphosphate.
What does the blastocyst divide into?
Embryoblast (inner cell mass) and Trophoblast (outer cell mass).
Name 3 allosteric inhibitors of PFK-1.
- Acidosis.
- ATP.
- Citrate.
What are the functions of vesicles?
Transports and stores materials. These are membrane bound organelles.
What is serous effusion?
Excess H2O in a body cavity.
What is the function of smooth ER?
Lipid synthesis
Would an affected male of an x-linked recessive condition and an unaffected female have any affected children?
No affected children but all the daughters would be carriers.
What is the product of fatty acid beta oxidation?
Acetyl CoA.
What is an example of type 2 collagen?
Cartilage.
What will epiblasts in a 3-week embryo become?
Ectoderm.
What is Fenton’s equation?
Fe2+ + H2O2 -> Fe3+ + OH• + OH-
What is the function of chorionic villi?
Allows the transfer of nutrients from maternal blood to foetal blood.
How many days after fertilisation does implantation occur?
7-8 days.
When would ketogenesis occur?
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
Summarise autosomal dominant inheritance.
- Manifests in the heterozygous state.
- Male to Male transmission is seen.
- Both males and females are affected equally.
- The disease is present in several generations.
- There is a 50% chance of offspring having the disease.
What is oedema?
Excess H2O in the interstitial fluid.
Summarise autosomal recessive inheritance.
- Manifests in the homozygous state.
- The disease is often not seen in every generation.
- 25% chance of offspring having the disease.
- 50% chance of offspring being carriers.
- Healthy siblings have a 2/3 chance of being carriers.
What are steroid hormones synthesised from?
Cholesterol.
Define insensible losses.
Water loss that we are unaware of. It is comprised only of solvent and can not be measured.
What happens in the 4th week of embryonic life?
The flat tri-laminar disc folds into a cylindrical embryo.
What is the mechanism by which sickle cell RBC’s block capillaries?
They activate endothelial cells and cause inflammation, this results in blockage of the capillaries.
Would an X linked recessive condition be more common in males or females?
More common in males.
What is the definition of osmotic pressure?
The pressure that must be applied to a solution to prevent inward osmosis through a partially permeable membrane.
Electrolyte homeostasis: What is the cause(s) of hyperkalemia and what are its risks?
Causes: renal failure, acidosis, diuretic inhibitors.
Risks: Cardiac arrest.
What cells does the epiblast give rise to?
Amnioblasts that line the amniotic cavity.
What happens in anaphase?
The chromosomes are pulled apart and the sister chromatids are pulled towards the nuclear poles.
What happens to the PaCO2 levels in respiratory acidosis?
PaCO2 increases leading to an increase in H+ ions and so pH decreases.
CO2 production is greater than CO2 elimination
Which phase of mitosis is this: The chromosomes are moving towards opposite poles of the cell and there are no nuclear membranes.
Anaphase.
Define phenotype.
The appearance of an individual due to the environment and genetics.
Name 4 ways in which ATP can be produced?
- Krebs cycle.
- Glycolysis.
- Oxidative phosphorylation.
- Substrate level phosphorylation.
What are the 4 bases in RNA?
Adenine, Cytosine, Guanine, Uracil.
Water distribution: how much water is there in:
a) the ECF?
b) the ICF?
a) 14L
b) 28L
Is the mitochondrial membrane permeable or impermeable to ions?
Impermeable.
What are tight junctions?
Binds cells together to prevent leakage of molecules in between them.
What do fatty acids produce.
Where is this product used?
Acetyl CoA
Used in the Krebs cycle
How is genetic diversity introduced in meiosis?
- Metaphase 1 = random assortment.
- Prophase 1 = crossover.
List 3 causes of metabolic acidosis?
Renal failure, loss of HCO3-, excess H+ production.
What is the product of transcription?
mRNA
Gametogenesis: when is meiosis 1 complete in a female?
At ovulation.
If a patient has diabetes insipidus and is not producing any ADH what is her blood and urine osmolality after 3 hours of water deprivation going to look like?
Blood osmolality would be high.
Urine osmolality would be low - very dilute urine.
Name the 4 types of oedema.
- Lymphatic.
- Venous.
- Hypoalbuminaemic.
- Inflammatory.
Where does oxidative phosphorylation occur?
In the mitochondrial matrix.
In what direction does DNA polymerase read?
3’ to 5’ (but replication occurs in the 5’ to 3’ direction).
What transports H+ out of the mitochondrial matrix?
Cytochrome-C oxidase complex.
Name 2 electron accepting coenzymes.
- NAD.
2. FAD.
What happens in prometaphase?
Spindles form. Nuclear membrane completely breaks down.
Where in a cell does the Krebs cycle take place?
The matrix of the mitochondria
What does the trophoblast divide into?
Cytotrophoblast (inner) and Syncytiotrophoblast (outer).
Define allele.
An alternative form of a gene at a specific locus.
Electrolyte homeostasis: What is the cause(s) of hypercalcemia and what are its risks?
Causes: hyperparathyroidism, Vit D toxicity, malignancy.
Risks: renal stones and metastatic calcification.
Approximately how many ATP molecules are produced from oxidation of FADH2?
1.5.
A gene sequence is coded in …
Single strand DNA.
What is a triglyceride?
A glycerol backbone with 3 fatty acids.
What is the role of ATP synthase in oxidative phosphorylation?
It transports H+ into the mitochondrial matrix.
What molecules make up ATP?
1 adenine, 1 ribose, 3 phosphate
Name 3 ways in which we intake fluids.
- Drink.
- Food.
- IV Fluids.
Define genotype.
The genetic constitution of an individual.
List 3 features of the genetic code.
- Non-overlapping
- Universal
- Degenerate
What happens in telophase?
The nuclear membrane reforms and the chromosomes unravel to form chromatin. The spindle fibres disappear.
What is meiosis used for?
The production of gametes.
Give 3 examples of endocytosis.
- Phagocytosis.
- Pinocytosis.
- Receptor mediated.
What are the 3 layers of the walls of arteries and veins called?
Intima, Media, Adventitia
Give 2 reasons why cancers are more commonly in the elderly.
- The elderly are more likely to have accumulated mutations.
- Their immune system is weaker and so they’re more vulnerable.
Name 2 places DNA can be found.
- Nucleus of a cell.
2. Mitochondria (purely maternal DNA).
What does the ectoderm form?
CNS, PNS, skin, posterior pituitary and sweat glands.
What is gonadal mosaicism?
When there are 2 different populations of cells in the gonads. One population is normal and the other is mutated. All gametes from the mutated line are effected.
How much energy is stored as glycogen? And where is it stored?
350g
- 200g in the liver
- 150g in muscle
Where does ketogenesis usually occur?
In the liver
What is the Haber Weiss equation?
O2- + H2O2 -> O2 + OH• + OH-
What enzyme of glycolysis is inhibited in acidosis?
Phosphofructosekinase-1 (PFK-1 is pH dependent).
How much energy is stored as protein?
6kg
Name 3 exogenous sources of ROS?
Smoking, UV radiation, drugs
Name 3 biological buffers.
- Protein
- Haemoglobin
- Bicarbonate
What is a transcriptome?
All the messenger RNA molecules in a cell.
What factors decrease BMR?
Increasing age, being female, starvation, hypothyroidism
What happens in cytokinesis?
The cytoplasm divides producing 2 genetically identical daughter cells.
Name an endogenous source of ROS?
Produced as a by product of O2 metabolism
What does the medial Golgi do?
It modifies products by adding sugars forming oligosaccharides
Define metabolism.
Chemical reactions that occur in a living organism.
Give an example of an X linked recessive condition.
Duchenne muscular dystrophy
What type of cells are produced in meiosis?
4 haploid daughter cells that are genetically different to the parent cell.
What is the rate limiting enzyme in glycolysis?
Phosphofructokinase-1
Name 3 molecules that make a nucleotide.
- Pentose sugar.
- Phosphate.
- Nitrogenous base.
Water distribution: how much water is there in the (ECF):
a) interstitial fluid
b) plasma
a) interstitial - 11L
b) plasma - 3L
What part of the tri-laminar disc is the circulatory system formed from?
Lateral plate mesoderm.
What layer of the tri-laminar disc does the epiblast form?
Ectoderm.
What is a single nucleotide polymorphism?
A single nucleotide substitution in DNA resulting in variation amongst a population.
What is an example of type 5 collagen?
Placenta
Define buffer.
A solution that resists changes in pH when small amounts of acid/base are added.
What is an example of type 1 collagen?
Bone, skin and teeth.
What cells does the hypoblast give rise to?
Cells that line the blastocyst cavity.
What is a mis-sense mutation?
A single nucleotide change results in a codon coding for a different amino acid. This can result in a non functional protein or can have no effect (degenerative nature of the genetic code).
How much energy do carbohydrates provide?
4kcal/g
What is the function of rough ER?
Protein synthesis
Where does translation occur?
At a ribosome.
What type of inheritance pattern is seen with sickle cell disease?
Autosomal recessive.
Where does the acetyl CoA from beta oxidation go?
To the krebs cycle.
Define penetrance.
The proportion of people with a gene who show the expected phenotype.
What causes trisomy 21?
Failure of the chromatids to separate; non-dysjunction.
What does the endoderm form?
Respiratory tract, GI tract, urinary tract, auditory tube, liver, pancreas, thyroid and parathyroid glands.
What type of bond is a peptide bond?
A covalent bond.
What enzyme catalyses the formation of glyceraldehyde-3-phosphate from dihydroxyacetone phosphate?
Triose phosphate isomerase.
What 2 carbohydrates form sucrose?
Glucose and fructose
Briefly describe translation.
A tRNA with a complementary anticodon to the codon on mRNA binds. Peptide bonds from between amino acids = polypeptide chain.
What is the importance of acylcarnitine?
It is required to transport fatty acids into the mitochondria for beta oxidation.
Approximately how many ATP molecules are produced from oxidation of NADH?
2.5.
Give an example of an autosomal recessive condition.
Cystic fibrosis.
Gametogenesis: when do meiotic divisions occur in a male?
At puberty.
What phases of the cell cycle make up interphase?
G1, S and G2
Which protein structure is created by covalent bonds?
Primary structure (peptide bonds between amino acids are covalent).
Where in a cell does glycolysis take place?
Cytoplasm
Can males ever be carriers of X linked conditions?
No. They are either affected or they do not carry the gene.
Define variable expression.
Variation in clinical features of a genetic disorder between individuals with the same gene alteration.
What is the equation to demonstrate the mechanism of a bicarbonate buffer?
H2O + CO2 -> H2CO3 -> HCO3- + H+
Arrows are reversible
What are Mendel’s 3 laws?
- Law of dominance.
- Law of independent assortment.
- Law of segregation.
What is gametogenesis?
Precursor cells undergo cell division and differentiation to form haploid gametes.
Electrolyte homeostasis: What is the cause(s) of hypocalcemia and what are its risks?
Causes: renal disease, Vit D deficiency, intestinal malabsorption.
Risks: tetany (spasms).
List 4 functions of a plasma membrane.
- Physical boundary for the cell.
- Regulates the movement of substances.
- Has receptors for cell to cell signalling.
- Attaches the cell to the external environment.
How much energy does alcohol provide?
7kcal/g
What is it called when a child shows a phenotype for a disease younger than their father/mother does? e.g. in huntington’s disease.
Anticipation.
Give 4 functions of tight junctions.
- Holds cells together.
- Generates a concentration gradient across the epithelium.
- Allows the passage of water and glucose.
- Prevents the passage of large molecules.
What does the embryoblast divide into?
Epiblast and Hypoblast = bi-laminar disc.
What are reactive oxygen species?
Reactive molecules and free radicals derived from O2
How is the primary utero-placental circulation established?
Lacunae form in the syncytiotropohoblast and maternal blood enters.
What is splicing?
The removal of introns from pre-mRNA
