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).