IMMS Flashcards
1
Q
Water distribution: how much water is there in:
a) the ECF?
b) the ICF?
A
a) 14L
b) 28L
2
Q
Water distribution: how much water is there in the (ECF):
a) interstitial fluid
b) plasma
A
a) interstitial - 11L
b) plasma - 3L
3
Q
What is the predominant electrolyte(s) in the ICF?
A
K+
4
Q
What is the predominant electrolyte(s) in the ECF?
A
Na+, Cl-, HCO3-
5
Q
What is the definition of osmosis?
A
Movement of H2O across a partially permeable membrane from an area of high water potential to an area of low water potential.
6
Q
What is the definition of osmolarity?
A
The number of solute particles per L of fluid. (A high osmolarity has more solute particles per L).
OR:
Conc of a solution expressed as total number of solute particles per litre.
7
Q
What is the definition of oncotic pressure?
A
Oncotic pressure is a form of osmotic pressure exerted by proteins, notably albumin, that tends to pull fluid into its solution.
- water moves from interstitial fluid into plasma.
8
Q
What is the definition of osmotic pressure?
A
The pressure that must be applied to a solution by pure solvent to prevent inward osmosis through a partially permeable membrane.
9
Q
Electrolyte homeostasis: what is the cause(s) of hypernatremia? And what are the risks?
A
Cause -
Poor water intake/deficit (diabetes insipidus, osmotic diuresis) renal failure.
Sodium excess - mineralocorticoid (aldosterone excess)
Risks - Cerebral Intracellular Dehydration.
(High sodium = low H2O which dehydrates the brain)… as lower H2O concentration since H2O leaves intracellular to go extracellular as olute conc increases.
10
Q
Electrolyte homeostasis: What is the cause(s) of hyponatremia and what are its risks?
A
Causes: Excess water due to IV fluids, diuretics.
Sodium loss due to diuretics.
Risks: Cerebral intracellular over hydration - headache, confusion.
11
Q
Electrolyte homeostasis: What is the cause(s) of hyperkalemia and what are its risks?
A
Causes: renal failure, acidosis, diuretic/ACE inhibitors.
Risks: Cardiac arrest/myocardial infarction.
12
Q
Electrolyte homeostasis: What is the cause(s) of hypokalemia and what are its risks?
A
Causes: Diarrhoea+ Vomitting, alkalosis, diuretics.
Risks: weakness and arrhythmia.
13
Q
Electrolyte homeostasis: What is the cause(s) of hypercalcemia and what are its risks?
A
Causes: primary hyperparathyroidism, Vit D toxicity, malignancy/skeletal metastases.
Risks: renal stones and metastatic calcification.
14
Q
Electrolyte homeostasis: What is the cause(s) of hypocalcemia and what are its risks?
A
Causes: renal disease, Vit D deficiency, intestinal malabsorption, Parathyroidectomy.
Risks: tetany (spasms).
15
Q
What is the function of rough ER?
A
Site of protein synthesis
16
Q
What is the function of smooth ER?
A
Site of membrane lipid synthesis
17
Q
What is the function of the golgi apparatus?
A
Processes and modifies ER products.
18
Q
What is the cis face of the golgi apparatus?
A
The cis face is nearest the nucleus and receives ER vesicles.
Protein phosphorylation occurs here.
19
Q
What does the medial Golgi do?
A
It modifies products by adding sugars forming oligosaccharides by adding sugars to lipids and peptides.
20
Q
What does the trans face of the golgi do?
A
Proteolysis of peptides into active forms.
It sorts molecules into vesicles.
21
Q
What are the functions of vesicles?
A
Transports and stores materials. These are membrane bound organelles.
22
Q
What are desmosomes?
A
Attach cells via the intermediate filaments.
Physical joint between cells and connect the cytoskeletons
23
Q
List 4 functions of a plasma membrane.
A
- Physical boundary for the cell.
- Regulates the movement of substances.
- Has receptors for cell to cell signalling.
- Attaches the cell to the external environment.
24
Q
Name 4 molecules you’d find in a plasma membrane.
A
- Cholesterol
- Glycoproteins
- Glycolipids
- Integral proteins
25
Define genotype.
The genetic constitution of an individual.
26
Define phenotype.
The appearance of an individual due to the environment and genetics.
27
Water distribution: How much water is there in the ICF?
28L
28
What is an example of type 1 collagen?
Bone, skin and teeth.
29
What is an example of type 2 collagen?
Cartilage.
30
What is an example of type 3 collagen?
Arteries, liver, kidneys, spleen, uterus
31
What is an example of type 4 collagen?
Basement membranes
32
What is an example of type 5 collagen?
Placenta
33
Define allele.
An alternative form of a gene at a specific locus.
34
Give an example of an autosomal dominant condition.
Huntingtons disease.
35
Give an example of an autosomal recessive condition.
Cystic fibrosis.
36
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.
37
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.
38
Give an example of an X linked recessive condition.
Duchenne muscular dystrophy
39
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).
40
What is a non-sense mutation?
A single nucleotide change that produces a premature stop codon. This results in an incomplete/non-functional protein.
41
What are the products of glycolysis?
2 ATP, 2 NADH, 2 Pyruvate
42
What is the rate limiting enzyme in glycolysis?
Phosphofructokinase-1
43
Where in a cell does glycolysis take place?
Cytoplasm
44
Where in a cell does the Krebs cycle take place?
The matrix of the mitochondria
45
Define metabolism.
Chemical reactions that occur in a living organism.
46
Define BMR.
The energy needed to stay at live rest. (24kcal/Kg/day)
47
How much energy do carbohydrates provide?
4kcal/g
48
How much energy do proteins provide?
4kcal/g
49
How much energy do lipids provide?
9kcal/g
50
How much energy does alcohol provide?
7kcal/g
51
How much energy is stored as triglycerides?
15kg
52
How much energy is stored as glycogen? And where is it stored?
350g
- 200g in the liver
- 150g in muscle
53
How much energy is stored as protein?
6kg
54
What factors increase BMR?
Being overweight, pregnancy, low temperature, exercise, hyperthyroidism
55
What factors decrease BMR?
Increasing age, being female, starvation, hypothyroidism
56
What are reactive oxygen species?
Reactive molecules and free radicals derived from O2
57
Name 3 exogenous sources of ROS?
Smoking, UV radiation, drugs
58
Name an endogenous source of ROS?
Produced as a by product of O2 metabolism
59
Name 3 ketone bodies
- acetoacetate
- acetone
- beta hydroxybutyrate
60
Where does ketogenesis usually occur?
In the liver
61
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
62
What molecules make up ATP?
1 adenine, 1 ribose, 3 phosphate
63
Define buffer.
A solution that resists changes in pH when small amounts of acid/base are added.
64
Name 3 biological buffers.
1. Protein
2. Haemoglobin
3. Bicarbonate
65
What is the equation to demonstrate the mechanism of a bicarbonate buffer?
H2O + CO2 -> H2CO3 -> HCO3- + H+
| Arrows are reversible
66
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.
67
What can cause respiratory acidosis?
Inadequate ventilation due to airway obstruction (COPD, asthma).
68
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
69
What can cause respiratory alkalosis?
Hyperventilation in response to hypoxia.
| CO2 elimination exceeds O2 reabsorption.
70
List 3 causes of metabolic acidosis?
Renal failure, loss of HCO3-, excess H+ production.
71
List 2 causes of metabolic alkalosis.
Vomiting (loss of H+), increased reabsorption of HCO3-.
72
What do fatty acids produce.
| Where is this product used?
Acetyl CoA
| Used in the Krebs cycle
73
Name 4 ways in which ATP can be produced?
- Krebs cycle.
- Glycolysis.
- Oxidative phosphorylation.
- Substrate level phosphorylation.
74
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.
75
What type of cells are produced in mitosis?
2 diploid daughter cells which are genetically identical to the parent cells.
76
What is mitosis used for?
Growth and repair.
77
What are the 4 phases of the cell cycle?
G1, S, G2 and M
78
What phases of the cell cycle make up interphase?
G1, S and G2
79
What happens in prophase?
Chromatin condenses into chromosomes. Nuclear membrane begins to break down.
80
What happens in prometaphase?
Spindles form. Nuclear membrane completely breaks down.
81
What happens in metaphase?
The chromosomes line up along the midline of the cell. The spindles attach to the centromeres.
82
What happens in anaphase?
The chromosomes are pulled apart and the sister chromatids are pulled towards the nuclear poles.
83
What happens in telophase?
The nuclear membrane reforms and the chromosomes unravel to form chromatin. The spindle fibres disappear.
84
What happens in cytokinesis?
The cytoplasm divides producing 2 genetically identical daughter cells.
85
What type of cells are produced in meiosis?
4 haploid daughter cells that are genetically different to the parent cell.
86
What is meiosis used for?
The production of gametes.
87
How is genetic diversity introduced in meiosis?
- Metaphase 1 = random assortment.
| - Prophase 1 = crossover.
88
Name 3 molecules that make a nucleotide.
1. Pentose sugar.
2. Phosphate.
3. Nitrogenous base.
89
What is splicing?
The removal of exons from pre-mRNA
90
List 3 features of the genetic code.
1. Non-overlapping
2. Universal
3. Degenerate
91
What condition is trisomy 21?
Down's syndrome
92
Define lyonisation.
One of the female X chromosomes becomes inactivated early in embryogenesis.
93
What is a triglyceride?
A glycerol backbone with 3 fatty acids.
94
What 2 carbohydrates form sucrose?
Glucose and fructose
95
What 2 carbohydrates form maltose?
Glucose and Glucose
96
What 2 carbohydrates form lactose?
Glucose and galactose
97
What is the respiratory burst?
WBC's using ROS in phagocytosis to damage the membrane of invading cells.
98
Name 2 equations that form hydroxyl radicals.
1. Fenton's
| 2. Haber-Weiss
99
What is Fenton's equation?
Fe2+ + H2O2 -> Fe3+ + OH• + OH-
100
What is the Haber Weiss equation?
O2- + H2O2 -> O2 + OH• + OH-
101
Give 3 examples of endocytosis.
1. Phagocytosis.
2. Pinocytosis.
3. Receptor mediated.
102
Name 3 mechanisms by which a molecule can move across a plasma membrane.
1. Diffusion - movement down a concentration gradient.
2. Facilitated diffusion.
3. Active transport - uses ATP, against concentration gradient.
103
Name 3 types of cell receptors.
1. Ion channel receptors.
2. G-protein coupled receptors.
3. Enzyme linked receptors.
104
Name 3 ways in which we intake fluids.
1. Drink.
2. Food.
3. IV Fluids.
105
Define insensible losses.
Water loss that we are unaware of. It is comprised only of solvent and can not be measured.
106
Name 3 hormones involved in water homeostasis.
1. Aldosterone.
2. ADH - antidiuretic hormone.
3. ANP - atrial natriuretic peptide.
107
What is oedema?
Excess H2O in the interstitial fluid.
108
Name the 4 types of oedema.
1. Lymphatic.
2. Venous.
3. Hypoalbuminaemic.
4. Inflammatory.
109
What is serous effusion?
Excess H2O in a body cavity.
110
Name 2 places DNA can be found.
1. Nucleus of a cell.
| 2. Mitochondria (purely maternal DNA).
111
What is the function of topoisomerase?
It unwinds the DNA double helix by relieving the supercoils.
112
In what direction does DNA polymerase read?
3' to 5' (but replication occurs in the 5' to 3' direction).
113
What is the product of transcription?
mRNA
114
Where does translation occur?
At a ribosome.
115
Briefly describe translation.
A tRNA with a complementary anticodon to the codon on mRNA binds. Peptide bonds from between amino acids = polypeptide chain.
116
What are the 4 bases in RNA?
Adenine, Cytosine, Guanine, Uracil.
117
What is non-disjunction?
The failure of chromatids to separate.
| For example; Down's syndrome - trisomy 21. Turner's syndrome - Monosomy of X chromosome.
118
What enzyme of glycolysis is inhibited in acidosis?
Phosphofructosekinase-1 (PFK-1 is pH dependent).
119
Which phase of mitosis is this: The chromosomes are moving towards opposite poles of the cell and there are no nuclear membranes.
Anaphase.
120
What enzyme catalyses the formation of 3-phosphoglycerate from 1,3-bisphosphoglycerate?
Phosphoglyceratekinase.
121
What enzyme catalyses the formation of glyceraldehyde-3-phosphate from dihydroxyacetone phosphate?
Triose phosphate isomerase.
122
Oxidative phosphorylation: What enzyme transports protons into the mitochondrial matrix?
ATP synthase.
123
Is the mitochondrial membrane permeable or impermeable to ions?
Impermeable.
124
What are steroid hormones synthesised from?
Cholesterol.
125
What will epiblasts in a 3-week embryo become?
Ectoderm.
126
How many days after fertilisation does implantation occur?
7-8 days.
127
How long is pregnancy?
40 weeks.
128
What does the blastocyst divide into?
Embryoblast (inner cell mass) and Trophoblast (outer cell mass).
129
What does the embryoblast divide into?
Epiblast and Hypoblast = bi-laminar disc.
130
What does the trophoblast divide into?
Cytotrophoblast (inner) and Syncytiotrophoblast (outer).
131
How is the primary utero-placental circulation established?
Lacunae form in the syncytiotropohoblast and maternal blood enters.
132
What happens in the third week of embryonic life?
Gastrulation - formation of a tri-laminar embryonic disc.
133
What is the function of chorionic villi?
Allows the transfer of nutrients from maternal blood to foetal blood.
134
What part of the tri-laminar disc are somites formed from?
Paraxial plate mesoderm.
135
What part of the tri-laminar disc is the circulatory system formed from?
Lateral plate mesoderm.
136
What does the ectoderm form?
CNS, PNS, skin, posterior pituitary and sweat glands.
137
What does the endoderm form?
Respiratory tract, GI tract, urinary tract, auditory tube, liver, pancreas, thyroid and parathyroid glands.
138
What happens in the 4th week of embryonic life?
The flat tri-laminar disc folds into a cylindrical embryo.
139
What are the 3 layers of the walls of arteries and veins called?
Intima, Media, Adventitia
140
What causes trisomy 21?
Failure of the chromatids to separate; non-dysjunction.
141
Name 2 electron accepting coenzymes.
1. NAD.
| 2. FAD.
142
Approximately how many ATP molecules are produced from oxidation of NADH?
2.5.
143
Approximately how many ATP molecules are produced from oxidation of FADH2?
1.5.
144
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.
145
What is the normal pH range of the human body?
7.35-7.45
146
What is the importance of acylcarnitine?
It is required to transport fatty acids into the mitochondria for beta oxidation.
147
What is the product of fatty acid beta oxidation?
Acetyl CoA.
148
Where does the acetyl CoA from beta oxidation go?
To the krebs cycle.
149
What are removed in splicing of pre-mRNA?
Introns.
150
What is gametogenesis?
Precursor cells undergo cell division and differentiation to form haploid gametes.
151
Gametogenesis: when do meiotic divisions occur in a male?
At puberty.
152
Gametogenesis: when is meiosis 1 complete in a female?
At ovulation.
153
Gametogenesis: when is meiosis 2 complete in a female?
If fertilisation occurs.
154
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.
155
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.
156
Can males ever be carriers of X linked conditions?
No. They are either affected or they do not carry the gene.
157
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.
158
Would an X linked recessive condition be more common in males or females?
More common in males.
159
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.
160
What is multifactorial disease?
A disease due to genetic and environmental factors e.g. diabetes or schizophrenia.
161
Define karyotype.
The number and appearance of chromosomes in the nucleus of a eukaryotic cell.
162
Define penetrance.
The proportion of people with a gene who show the expected phenotype.
163
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.
164
Define variable expression.
Variation in clinical features of a genetic disorder between individuals with the same gene alteration.
165
Name 2 allosteric activators of PFK-1.
1. AMP.
| 2. Fructose-2,6-bisphosphate.
166
Name 3 allosteric inhibitors of PFK-1.
1. Acidosis.
2. ATP.
3. Citrate.
167
Lipids have hydrophobic and hydrophillic parts. What is this called?
Amphipathic.
168
What layer of the tri-laminar disc does the epiblast form?
Ectoderm.
169
What cells does the epiblast give rise to?
Amnioblasts that line the amniotic cavity.
170
What cells does the hypoblast give rise to?
Cells that line the blastocyst cavity.
171
What is the chorion composed of?
The extra-embryonic mesoderm and the 2 layers of trophoblast.
172
What is the role of ATP synthase in oxidative phosphorylation?
It transports H+ into the mitochondrial matrix.
173
What is the role of cytochrome-C oxidase complex in oxidative phosphorylation?
It transports H+ out of the mitochondrial matrix.
174
What generates the energy needed to phosphorylate ADP -> ATP?
The movement of H+ in and out of the mitochondrial matrix.
175
Where does oxidative phosphorylation occur?
In the mitochondrial matrix.
176
What transports H+ out of the mitochondrial matrix?
Cytochrome-C oxidase complex.
177
A gene sequence is coded in ...
Single strand DNA.
178
A promoter sequence is coded in ...
Single strand DNA.
179
What is a promoter sequence?
The promoter region controls when and where the RNA polymerase will attach to DNA so transcription can commence.
180
What is a transcriptome?
All the messenger RNA molecules in a cell.
181
Which protein structure is created by covalent bonds?
Primary structure (peptide bonds between amino acids are covalent).
182
What type of bond is a peptide bond?
A covalent bond.
183
What is a single nucleotide polymorphism?
A single nucleotide substitution in DNA resulting in variation amongst a population.
184
What type of inheritance pattern is seen with sickle cell disease?
Autosomal recessive.
185
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.
186
What are the sub-units of haemoglobin?
2 alpha and 2 beta subunits.
187
A mutation in what gene results in HbS production?
HBB gene.
188
How do HbS sub-units cause sickling?
They bind to the cytoskeleton which causes sickling.
189
What is the affect on HbS in hypoxia?
The HbS sub-units polymerise.
190
What is the affect on insensible losses if temperature increases by 1 degree?
Insensible losses will increase by 10%.
191
Why is sodium doubled in the plasma osmolality equation?
To account for negatively charged ions.
192
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.
193
What are Mendel's 3 laws?
1. Law of dominance.
2. Law of independent assortment.
3. Law of segregation.
194
How many hydrogen bonds form between adenine and thymine?
2.
195
How many hydrogen bonds form between cytosine and guanine?
3.
196
How many genes are there in the human genome?
20,000.
197
What enzyme, expressed normally in embryonic cells and abnormally in neoplastic cells, lengthens telomeres?
Telomerase.
198
Give 2 reasons why cancers are more commonly in the elderly.
1. The elderly are more likely to have accumulated mutations.
2. Their immune system is weaker and so they're more vulnerable.
199
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.
200
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.
201
Give 4 functions of tight junctions.
1. Holds cells together.
2. Generates a concentration gradient across the epithelium.
3. Allows the passage of water and glucose.
4. Prevents the passage of large molecules.
202
What enzyme does high insulin levels stimulate?
PFK-1 due to increasing fructose-2,6-bisphosphate levels.
203
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.
