Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHASE ONE > IMMS > Flashcards

IMMS Flashcards

1
Q

DNA structure

A

DNA double helix coils around nucleosomes, coils again into supercoils and then condenses further into chromosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Stain for chromosomes

A

Giemsa: G banding for complementary chromosome pair identification

Quinacrine: Q banding for individual light and dark bands on chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cell cycle

A

Interphase:
G1 growth phase
Synthesis phase
G2 growth phase

Mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

G0

A

Cells not in cell cycle (e.g. liver cells)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Cells that do not undergo mitosis

A

Myocyte cells in heart and neurones in the brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cells constantly in cell cycle

A

bone marrow cells

gut cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens during S-phase?

A

DNA replication and centrosome replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What occurs during prophase?

A

chromatin condenses into chromosomes and centrosomes nucleate microtubules which move to opposite poles of the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What occurs during prometaphase?

A

Nuclear membrane breaks down, microtubules invade nuclear space and chromatids attach to microtubules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What occurs during metaphase?

A

Chromosomes align along equatorial place (metaphase plate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What occurs during anaphase?

A

The sister chromatids separate, and chromatids are pulled to opposite poles of the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What occurs during telophase?

A

Nuclear membranes reform, chromosomes unfold into chromatin, and cytokinesis begins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What occurs during cyotkinesis?

A

2 identical daughter cells are produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Clinical relevance of mitosis (epithelium)

A

One of the indicators of precancerous lesions is mitotic figures at multiple levels in a microscope sample. No mitotic figures in areas where it shouldn’t be means that the tumour is benign. The number of mitotic figures helps grade the severity of the malignant tumours.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Mitosis + drugs

A

Chemotherapeutic agents such as taxol and vinca alkaloids (vinblastine, vincristine) work by preventing the formation of the mitotic spindle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is ispinesib?

A

Monoclonal antibody therapy targeting spindle poles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Colchicine-like drugs:

A

chemotherapeutic agents which arrest mitosis in anaphase and give rise to abnormal mitotic figures where the chromosomes form a circle.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Process of meiosis summary

A
  1. interphase
  2. prophase 1 (crossing over)
  3. metaphase 1
  4. anaphase 1
  5. telophase 1
  6. prophase 2
  7. metaphase 2
  8. anaphase 2
  9. telophase 2
  10. cytokinesis into 4 zygote cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Crossing over

A

Independent sorting of genes during prophase 1 of meiosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Production of sperm

A

Primordial germ cells undergo a lot of mitosis to produce spermatogonia (precursor stem cells).
Meiotic divisions commence at puberty.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Production of eggs

A

Primordial germ cells undergo 30 mitoses to produce oogonia, the primitive gametes of women. Oogonia enter prophase of meoisis 1 by 8th month of intrauterine life, at which point the process is suspended. Cells enter ovulation 10-50 years later.
Meiosis 2 is only completed if fertilisation occurs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Non-disjunction

A

Failure of chromosome pairs to separate in Meiosis I, or sister chromatids to separate properly in Meiosis II.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Monosomy

A

only one copy of chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Trisomy

A

extra copy of chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

3 causes of disease

A

genetic
multifactorial
environmental

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Classification of genetic disease

A 
Chromosomal 
Mendellian (autosomal dominant or recessive, X-Linked)
Non traditional (mitochondrial, imprinting, mosiacism)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Autosomal dominant inheritance definition, onset and example

A

Disease which manifests in the heterozygous state.
Adult onset.
Example: Huntingdon’s disease.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Autosomal recessive inheritance definition and example

A

Disease which manifests in homozygous recessive state i.e. no functioning copy of gene for the disease.
Example: sickle cell disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

X-linked recessive inheritance

A

caused by pathogenic variants in genes on the X chromosome.
Early onset in childhood.
Example: cystic fibrosis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Mitochondrial DNA

A

Mitochondria have their own ring shaped mitochondrial chromosome and mitochondrial genome which code for m. enzymes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Mitochondrial chromosome mutations

A

severe conditions such as epilepsy and brain conditions which can manifest from birth/early childhood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Imprinting

A

For some genes, only 1 out of the two alleles is active, the other is inactive. For particular genes, it is always the paternal or maternal allele which is inactivated. For example, growth genes inactivated by maternal allele keep fetus small to increase chance of survival.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Spinal bifidia

A

Multifactorial.
MTHFR gene function reduced; does not activate enough folic acid (needed for DNA synthesis and repair).
If the peri conceptual folic acid is reduced there is more likelihood child will get the congenital birth defect. An environmental reason for lack of folic acid is excessive alcohol consumption.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Familial Hypercholesterolaemia and Coronary Heart Disease

A

High levels of Low Density Lipoproteins are associated with increased risk of heart disease. Some people have a pathogenic variant in the gene for LDL receptors and have an increased genetic predisposition for coronary heart disease.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What doesn’t water interact with?

A

Non-polar substances
Lipids
Aromatic groups
Hydrophobic compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is a monosaccharide?

A

Chain of carbons, hydroxyl groups and one carbonyl (C=O) group.
An aldose monosaccharide has an aldehyde.
A ketose has a ketone.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Sugar derivatives

A

Aminosugars (containing an amino group; glucosamine)

Alcohol-sugars (sorbitol)

Phosphorylated (containing phosphate groups; glucose-6-phosphate)

Sulphated (containing sulphate groups; e.g. Heparin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Glycosidic bond

A

The hydroxyl group of a monosaccharide can react with an OH or NH group to form glycosides.

O-glycosidic bonds form disaccharides, oligosaccharides and polysaccharides.

N-glycosidic bonds are found in nucleotides and DNA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Disaccharides

A

Disaccharides contain 2 monosaccharides joined by a glycosidic bond.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Oligosaccharides

A

Oligosaccharides contain 3-12 monosaccharides. They are the products of digestion of polysaccharies, or part of complex proteins/lipids.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Polysaccharides

A

Formed by thousands of monosaccharides joined by glycosidic bonds.
Starch
Glycogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Lipids: Fatty Acids

A

Straight C chains with a methyl group and a carboxyl group at the end.

Melting point decreases with the degree of unsaturation. (number of C=C).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Phosphoacylglycerols

A

Derive from phosphatidic acid.

Formed from fatty acids esterified to glycerol and phosphorylated at C3.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Sphingolipids

A

Derive from ceramide (serine, plamitic aci and another fatty acid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Eicosanoids

A

Synthesised from 20 C atoms

Acids with 3,4,5 double bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Nucleotides

A

Nitrogenous base
Sugar
Phosphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Amino acids

A

Amino group
Carboxyl group
R side chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Charge of amino acid

A

Determined by all three components and changes with the pH of the environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Polarity of amino acid

A

Often determined by side chain (R).

Hydrophillicity (polarity) or hydrophobicity (non polarity).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Non polar amino acids

A 
Glycine
Alanine
Proline
Valine
Leucine
Isoleucine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Polar amino acids

A 
Methionine
Cysteine
Glutamine
Serine
Threonine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Negatively charged AA

A

Aspartate

Glutamate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Positively charged AA

A

Arginine
Lysine
Histidine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Peptide bond

A

Proteins are formed by amino acids linked by peptide bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Examples of protein structure-function relationship

A 
Immunoglobins
Fibrous protein: collagen
Enzymes
Channel and carrier proteins
Receptor proteins
Neurotransmitters
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Properties of peptide bonds

A

Very stable
Cleaved by proteolytic enzymes (proteases or peptidases)
Partial double bond

Flexibility around C atoms not involved in bond allowing multiple conformations. However there is usually one preferred native confirmation, determined mainly by the type of side chains and their sequence in the polypeptide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

Van der Waals forces

A

Weak attractive interactions between atoms due to fluctuating electrical charges. Only important when two macromolecular surfaces fit closely in shape.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Hydrogen bonds

A

Interactions between dipoles, involving a hydrogen and an oxygen/nitrogen. The partial negative charges on electronegative atoms such as O and N are bound to H, which then has a partial positive charge. These partial charges allow weak attractive interactions between amino acid side chains, main-chain oxygen and nitrogen and water.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Hydrophobic forces

A

Uncharged and non-polar side chains are poorly soluble in water and are repelled by water.
These hydrophobic side chains tend to form tightly packed cores in the interior of proteins, excluding water molecules. This attraction is the hydrophobic force.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Ionic bonds

A

Occur between fully or partially charged groups. Weakened in aqueous systems by shielding by water molecules and other ions in solution.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

Disulphide bonds

A

Covalent bonding between side chains of cysteine residues.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

Primary structure of proteins

A

Linear sequence of amino acids linked by peptide bonds. The primary structure determines its 3D conformation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Secondary structure - the alpha helix

A

Hydrogen bonds between each carbonyl group and the hydrogen attached to the nitrogen which is 4 amino acids along the chain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

Secondary structure - the beta-sheet

A

Formed by H bonds between linear regions of polypeptide chains.
Chains from two proteins, or the same protein.

Paralell or antiparallel chains, pleated or not.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

Tertiary structure

A

Overall 3D structure of protein.
Forces involved include electrostatic, hydrophobicity, H-bonds, and covalent bonds.

Can be affected by pH and temperature.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Quaternary stucture

A

3D structure of a protein composed of multiple subunits.

Same non-covalent interactions as tertiary structures.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Porphyrin Ring

A

(Haemoglobin)
At the core of a haemoglobin molecule is a porphyrin ring which holds an iron atom. An iron containing porphyrin is termed a ‘heme’. The iron atom is the site of oxygen binding.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

Factors influencing haemoglobin saturation

A

Temperature
[H+]
PCO2

An increase in these factors will modify the structure of haemoglobin and thus alter its affinity for oxygen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Factors influencing haemoglobin saturation

A

Temperature
[H+]
PCO2

An increase in these factors will modify the structure of haemoglobin and thus alter its affinity for oxygen. When these factors are increased Hb affinity for oxygen decreases and oxygen is unloaded more readily in the blood.
Decrease is vice-versa.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Immunoglobulins (Antibodies)

A

Antibodies are produced to bind antigens, typically toxins or proteins on the surface of microbial agents. These targets are consequently labelled for destruction by cells of the immune system or by lysis through the complement system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

Immunoglobulin structure

A

The immunoglobulin fold structure of antibodies comprises a supporting scaffold (framework regions) that serves to display highly variable loops of complementarity determining regions (CDRs).
The diverse nature of CDR regions enable a range of reversible bonding effects to act between antibody and antigen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Antigen recognition

A

The close proximity of the antibody CDR regions and the antigen surface allows the combination of relatively weak interactions to produce a strong binding surface. The CDR loops have a sequence of amino acids that “complement” the surace of the antigen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What is the name for the portion of the the antigen which is bound to an antibody?

A

epitope

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Which direction is RNA read in?

A

5’ => 3’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

3 characteristics of genetic code

A
  1. Degenerate (many amino acids specified by more than one codon)
  2. Universal (all organisms use same code)
  3. Non-overlapping (each nucleotide read only once)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

Factors turning off gene expression

A
  • activation of repressors
  • each step of RNA transcription or processing finds no longer actively produced transcription and processing proteins
  • complexes do not form anymore for lack of phosphorylation
  • enzymes no longer activated
  • RNA stability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

Prokaryotic DNA

A

No nuclear membrane
DNA arranged in a single chromosome
In E.Coli PDNA is circular

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Eukaryotic DNA

A

DNA in the nucleus bound to proteins (chromatin complex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

Eukaryotic DNA

A

DNA in the nucleus bound to proteins (chromatin complex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Antiparallel DNA strands

A

One strand goes 5’ to 3’ and the other strand is read 3’ to 5’.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What is heterochromatin?

A

DNA which has condensed and is out of action. The histones have changed and methylation renders DNA inactive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

Enzymes involved with DNA and their function

A

polymerase: reads 3’ to 5’ and prints 5’ to 3’
helicase: opens helix
ligase: joins DNA together
nuclease: digests elements
primase: synthesises primers
topoisomerase: unwinds helix and relieves supercoiling

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

Editing function of DNA polymerase

A

It detecs the incorrect insertion of a base and will excise it and repeat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

How is DNA damaged??

A

chemical damage
radiation damage
spontaneous insertion of incorrect bases during replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

What is benzopyrene?

A

Product of incomplete combustionof hydrocarbons. It is a DNA adduct, meaning it reacts with bases to form a bulky group that disrupts replication.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

Effect of ionising radiation

A

damage to bases

causes breaks in the phosphate backbone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

Effect of UV

A

Damages bases

In particular, causes the formation of thymine dimers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

What is the most popular type of genetic testing in the NHS?

A

Multi-gene panels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

What is the most effective genetic test?

A

Whole exome/genome sequencing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

Why does targeted mutation anaylsis not sequence the whole genome?

A

It is done with a known gene/mutation in mind

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

What is a suitable genetic test for cystic fibrosis and why?

A

Single gene sequencing because genetic diseases such as cystic fibrosis are caused by a single gene.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

What is a suitable genetic test for a child with a epilepsy?

A

Chromosomal microarray analysis, which picks up microdeletions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

Sanger sequencing

A

Uses PCR to amplify regions of interest followed by sequencing of products. There is a single start point (primer).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

Benefits of Sanger sequencing

A

Useful for single gene testing

Very accurate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

Downsides of Sanger sequencing

A

slow

expensive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

Next-Generation sequencing

A

Rapid sequencing of targeted gene panels. Multi gene panels so whole genome can be sequenced.
Method = massively parallel sequencing.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

Benefits of NG sequencing

A

Fast

Can sequence a whole human genome in one day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

Downsides of NG sequencing

A

Huge amounts of raw data to interpret
expensive
Only moderately accurate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

Variants can either be …

A

Pathogenic variants, varients of unknown significance, normal variants

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

Types of mutation:

A

nonsense
frame shift
spice site
missense

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

What cell types are used in genetic testing?

A 
Blood (T-lymphocytes)
Skin/umbilical cord
Bone marrow
Solid tumour
Amniotic fluid/Chorionic villus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

Trisomy

A

Extra chromosome
Down’s Syndrome
Edward’s Syndrome
Patau Syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

Monosomy

A

Single chromosome

Turner syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

Polyploidy

A

Three copies of each chromosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

Sex Chromosome abnormalities

A

Klinefelter Syndrome
47, XXY in males
(slower development, reproductive issues, feminine body shape)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

Deletion of 15q

A

Prader Willi

Angelman Syndrome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

F.I.S.H

A

Fluorescence in situ hybridisation using DNA probes labelled with fluorophores. They are hybridized directly to the chromosome preparation or interphase nuclei.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

Nonsense mutation

A

If a mutation puts a STOP codon earlier than it needs to be, disrupting gene function. A nonsense mutation takes place when an out of frame deletion produces a stop codon either at the deletion site or further along.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

Splice-site variant

A

A SSV affects the accurate removal of an intron. Intron could be translated into protein (retained) which causes problems with protein structure and function. It can cause the presence or removal of an exon where it should not be.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

Mis-sense variant

A

single base substitution which changes the type of amino acid in the protein. This may or may not be pathogenic i.e. it may be a polymorphism of no function.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

Allelic heterogeneity

A

lots of different variants in one gene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

Dominant-negative variants

A

where the protein from the variant allele interferes with the protein from the normal allele.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
113
Q

Multifactorial inheritance definition

A

Disease due to a combination of genetic and environmental factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
114
Q

How do you identify that a condition has a genetic component?

A

By clinical observation: family studies, twin studies, adoption studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
115
Q

Family Studies

A

compare the incidence of a disease amongst the relatives of an affected individual with the general population.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
116
Q

In a multifactorial condition, the risk of the condition in relatives of an affected individual is —– than in the general population.

A

higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
117
Q

Twin studies

A

compare genetically identical (monozygotic) with genetically non-identical (dizygotic) twins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
118
Q

How to calculate the concordance rate in twin studies?

A

The percentage of twin pairs in the study that both have the condition.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
119
Q

How to calculate the concordance rate in twin studies?

A

The percentage of twin pairs in the study that both have the condition.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
120
Q

What effect would a genetic component have on concordance rate?

A

If the condition had a genetic component you would expect the concordance rate to be higher in monozygotic twins than dizygotic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
121
Q

Adoption studies

A

Adopted children of a biological parent with a multifactorial condition have a high risk of developing the disease.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
122
Q

What is the definition of hereditability?

A

The proportion of the etiology (cause) that can be ascribed to genetic factors as opposed to environmental factors.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
123
Q

How is hereditability expressed?

A

As a proportion of 1/as a percentage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
124
Q

Characteristics of multifactorial inheritance

A

The incidence of the condition is greatest amongst relatives of the most severely affected patients. The risk is greatest for the first degree relatives and decreases rapidly in more distant relatives. If there is more than one affected close relative then the risks for other relatives are increased.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
125
Q

Sex and multifactorial inheritance

A

If the condition is more common in one particular sex, then relatives of an affected individual of the less frequently affected sex will be at higher risk than relatives of an affected individual of the more frequently affected sex.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
126
Q

What is a neural tube defect?

A

Defective closure of the developing neural tube during the first month of embryonic life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
127
Q

What is the genetic component of neural tube defects?

A

About 10% of cases can be attributed to mutations in the MTHFR gene which leads to decreased plasma folate levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
128
Q

What is the environmental component of neural tube defects?

A

Environmental factors include poor socioeconomic status, multiparity and valproate. Periconceptional folate supplementation reduces recurrence risk to about 1%.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
129
Q

Environmental agents acting on embryogenesis

A 
Drugs and chemicals (thalidomide, alcohol)
Maternal infections (rubella) 
Physical agents (radiation)
Maternal illness (diabetes)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
130
Q

Definition of metabolism

A

Metabolism refers to the sum of the chemical reactions that take place within each cell of a living organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
131
Q

Dietary components are metabolised in cells through 4 main pathways

A

Biosynthetic
Fuel storage
Oxidative process
Waste disposal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
132
Q

Definition of anabolic metabolic process

A

Synthesis of larger molecules from smaller components

biosynthetic, fuel storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
133
Q

Definition of catabolic metabolic process

A

Break down of larger into smaller

oxidative

134
Q

What is a cofactor?

A

A cofactor is a non-protein chemical compound/metallic ion that is required for an enzyme’s activity as a catalyst (“helper molecules”)

135
Q

Adipose tissue

A

85% fat (mostly triglycerides)

Main function = storage of energy rich molecules

136
Q

Function of the liver

A

Gluconeogenesis (production of glucose for catabolic reactions)
Removal of toxins
Metabolism of xenobiotics to get them into a state ready for the disposal of toxins from the body, usually urine.

137
Q

The Cori Cycle brief description

A

In the Cori Cycle, lactate produced by the muscles is converted to glucose by the liver, and is fed back to the muscles.

138
Q

Why does the Cori cycle take place?

A

It is a metabolic route to get rid of lactate produced in the anaerobic breakdown of glucose.

139
Q

What happens to glucose generated in the Cori Cycle if the muscle activity stops

A

Glucose undergoes glycogenesis to replenish the glycogen stored in the muscles.

140
Q

Limitations of the Cori Cycle

A

Liver uses up 6 molecules of ATP to carry out gluconeogenesis but glycolysis only makes 2 mols of ATP.

141
Q

What is the name for the accumulation of excess lactic acid in the system?

A

Lactic acidosis

This brings down the pH of the blood, which can lead to tissue damage.

142
Q

3 main dietary energy sources

A

carbohydrates
lipids
proteins

143
Q

Storage of fat, carbohydrates and proteins?

A 
Fat = adipose tissue
Carb = glycogen in liver and muscles
Protein = muscle
144
Q

Which energy source has the most energy per gram

A

lipid

145
Q

BMR stands for:

A

basal metabolic rate

146
Q

What is the BMR?

A

A measure of the energy required to maintain non-exercise bodily functions (e.g. respiration, contraction of cardiac muscles).

147
Q

What is the rate limiter of glycolysis

A

phosphofructokinase

148
Q

What is the rate limiter of glycolysis

A

phosphofructokinase

149
Q

Hydrolysis reaction of ATP

A

ATP -> ADP + Pi + H+

150
Q

Glycolysis step 1: glucose is converted to ..

A

glucose-6-phosphate

151
Q

Which enzyme converts glucose into glucose-6-phosphate?

A

hexokinase (phosphorylation of glucose by ATP)

glucokinase (liver)

152
Q

Glycolysis step 2: glucose-6-phosphate is converted to …

A

Fructose-6-phosphate

153
Q

Which enzyme converts glucose-6-phosphate into fructose-6-phosphate

A

phosphoglucose isomerase

154
Q

Glycolisis step 3: fructose-6-phosphate is converted to..

A

fructose-1,6-biphosphate

155
Q

Which enzyme converts fructose-6-phosphate into fructose-1,6-biphosphate

A

phosphofructokinase-1

156
Q

Glycolysis step 4: fructose-1,6-biphosphate is converted into …

A

Glyceraldehyde-3-phosphate

Dihydroxyacetone phosphate

157
Q

Which enzyme converts fructose-1,6-biphosphate into the two triose phosphates?

A

aldolase

158
Q

Glycolysis step 5: dihydroxyacetone phosphate is converted into …

A

Glyceraldehyde-3-phosphate

159
Q

Which enzyme converts dihydroxyacetone phosphate into glyceraldehyde-3-phosphate?

A

triose phosphate isomerase

160
Q

Glycolysis step 6: two glyceraldehyde-3-phosphate molecules are converted into …

A

two 1,3-biphosphoglycerate molecules

161
Q

Glycolysis step 6: two glyceraldehyde-3-phosphate molecules are converted into …

A

two 1,3-biphosphoglycerate molecules

162
Q

Which enzyme converts two glyceraldehyde-3-phosphate molecules into two 1,3-biphosphoglycerate molecules

A

glyceraldehyde-3-phopshate dehydrogenase

163
Q

Glycolysis step 7: two 1,3-biphosphoglycerate molecules are converted into …

A

two 3-phosphoglycerate molecules

164
Q

Which enzyme converts two 1,3-biphosphoglycerate molecules into two 3-phosphoglycerate molecules

A

phosphoglycerate kinase

165
Q

Glycolysis step 8: two 3-phosphoglycerate molecules are converted into …

A

two 2-phosphoglycerate molecules

166
Q

Which enzyme converts two 3-phosphoglycerate molecules into two 2-phosphoglycerate molecules?

A

phosphoglyceromutase

167
Q

Glycolysis step 9: two 2-phosphoglycerate molecules are converted into …

A

two phosphoenolpyruvate molecules

168
Q

Which enzyme converts two 2-phosphoglycerate molecules into two phosphoenolpyruvate molecules?

A

enolase

169
Q

Glycolysis step 10: two phosphoenolpyruvate molecules are converted into …

A

2 pyruvate molecules

170
Q

Which enzyme converts phosphoenolpyruvate into pyruvate?

A

pyruvate kinase

171
Q

Which glycolysis reactions require the conversion of ATP into ADP?

A

glucose –> glucose-6-p

fructose-6-p –> fructose-6-bip

172
Q

Which glycolysis reactions require the conversion of ADP into ATP?

A

1,3-biphosphoglycerate –> 3-phosphoglycerate

phosphoenolpyruvate –> pyruvate

173
Q

Which glycolysis reaction requires an oxidation reaction?

A

Glyceraldehyde-3-phosphate is oxidised by NAD+.

174
Q

Glycolysis symmary

A

Glucose + 2NAD+ + 2Pi + 2ADP –> 2 Pyruvate + 2NADH + 2H+ + 2ATP + 2H2O

175
Q

What is pyruvate converted to in anaerobic conditions?

A

Lactate

176
Q

Pyruvate -> Lactate reaction

A

glucose + 2ADP + 2Pi –> 2 lactate + 2ATP + 2H2O + 2H+

177
Q

Which tissues are reliant on anaerobic glycolysis?

A

Mature erythrocytes, lymphocutes, white blood cells, renal medulla, tissues of the eye, skeletal muscle, skin

178
Q

What are the various functions of glycolysis?

A

Glycolysis provides ATP, generates precursors for biosynthesis because the intermediates can be converted to ribose-5-phosphate (i.e. nucleotides) or amino acids like serine, glycine, cytesine.
Pyruvate is transaminated to alanine.
Pyruvate is a substrate for fatty acid synthesis.
Glycerol-3-P is backbone of triglycerides.

179
Q

Glycolysis when there is low [ATP]

A

When there is a low concentration of ATP and then the concentration is increased, the reaction will increase because ATP acts a substrate.

180
Q

Glycolysis when there is high [ATP]

A

When there is a high concentration of ATP, increasing ATP concentration will result in a decreased in reaction speed because the catalytic site of PFK-1 is saturated and ATP causes allosteric inhibition which is opposed by AMP.

181
Q

Citrate in regulating rate of glycolysis

A

Citrate is an allosteric inhibitor of PFK-1.

182
Q

What is the reaction for the conversion of pyruvate to acetyl-CoA

A

pyruvate + CoA + NAD+ —> acetyl-CoA + CO2 + NADH + H+

183
Q

What is malnutrition?

A

A state of nutrition with a deficiency, excess or imbalance of energy, protein or other nutrients, causing measurable adverse effects.
Adverse side effects are on tissue, body size, body function and clinical outcome.

184
Q

Re-feeding syndrome risks

A

Re-distribution of electrolytes (phosphate, potassium, magnesium etc) due to insulin causing irregular concentrations in blood stream.
Body switch back to carbohydrate use as the main fuel which requires phosphate and thiamine, that can be used pretty quickly.

185
Q

Essential fatty acids

A

(acids that the body cannot synthesize)
omega-3
omega-6

186
Q

Essential vitamins:

A

Vitamin C (ascorbic acid) which is useful for heat labile, collagen synthesis, iron absorption, antioxidant

Vitamin B12 useful for protein synthesis, DNA synthesis, folate regenration, folic acid synthesis, energy

Vitamin B1 / thiamine useful for energy production

Vitamin D increases calcium and phosphorous absorption, making teeth and bones stronger and healthier

187
Q

Overall Krebs reaction

A

acetyl-CoA + 3NAD+ + FAD + GDP + Pi + 2H2O –> 2CO2 + 3NADH + FADH2 + GTP + CoA + 3H+

188
Q

Reaction for conversion of pyruvate to acetyl-CoA

A

pyruvate + CoA + NAH+ –> Acetyl-CoA + CO2 + NADH + H+

189
Q

Enzyme action in conversion of pyruvate to acetyl-CoA

A

pyruvate dehydrogenase

pyruvate dehydrogenase multienzyme complex (3 enzymes + 5 co-factors) within the mitochondrial matrix

Inhibited by high concentrations of acetyl-Coa and NADH.

Inactivated by phosphorylation
Activated by phosphate removal

190
Q

1: acetyl-CoA –> …

A

citrate

191
Q

1: acetyl-CoA –> citrate enzyme

A

citrate synthase

192
Q

1: acetyl-CoA –> citrate cofactors and products

A

cofactors: +h2O

products = CoA

193
Q

2:citrate –> …

A

isocitrate

194
Q

2:citrate –> isocitrate enzyme

A

aconitase

195
Q

3: isocitrase -> …

A

alpha-ketoglutarate

196
Q

3: isocitrase –> alpha-ketoglutarate enzyme

A

isocitrate dehydrogenase

197
Q

3: isocitrase –> alpha-ketoglutarate products

A

products = NADH + H+

and CO2

198
Q

4: alpha-ketoglutarate –> ..

A

succinyl-CoA

199
Q

4: alpha-ketoglutarate –> succinyl-CoA enzyme

A

alpha-k… dehydrogenase

200
Q

4: alpha-ketoglutarate –> succinyl-CoA c+p

A

cofactors: CoA
products = NADH + H+
and CO2

201
Q

5: succinyl-CoA –> …

A

succinate

202
Q

5: succinyl-CoA –> succinate enzyme

A

succinyl-CoA thiokinase

203
Q

5: succinyl-CoA –> succinate CF+P

A

CF: Pi (GDP –> GTP)

P = CoA

204
Q

6: succinate –> …

A

fumarate

205
Q

6: succinate –> fumarate enzyme

A

succinate dehydrogenase

206
Q

6: succinate –> fumarate CF + P

A

P = FADH2

207
Q

7: fumarate –> …

A

malate

208
Q

7; fumarate –> malate enzyme

A

fumarase

209
Q

7: fumarate –> malate CF

A

H2O

210
Q

7: malate –> …

A

oxaloacetate

211
Q

7: malate –> oxaloacetate enzyme

A

malate dehydrogenase

212
Q

7: malate –> oxaloacetate P

A

P = NADH + H+

213
Q

Citrate synthase regulation

A

ATP and NADH allosterically inhibit citrate synthase by reducing the affinity of citrate synthase for its substrates. This reduces the rate of reaction of Krebs.

Succinyl CoA competetively inhibits citrate synthase (competetive feedback of Krebs’ Cycle).

Oxidative phosphorylation causes a decrease in the NADH: NAD+ ratio. This increases conversion of malate to oxaloacetate which is a substrate for citrate synthase.

Increased [citrate] inhibits citrate synthase, reduces speed of cycle

214
Q

Isocitrate Dehydrogenase Regulation

A

Isocitrate DH activation decreases [citrate] which increases the citrate synthase reaction rate.

ICDH is made up of subunits. Isocitrate binds IDCH subunit leading to a conformational change in other IDCH subunits to active form.

ICDH is inactivated by phosphorylation when concentrations of pyruvate are low.

ADP is an ICDH allosteric activator and binds to it when all ICDH subunits are in active form.

ICDH inhibited by high [ATP] and [NADH].

215
Q

Α-ketoglutarate DH Regulation:

A

Inhibited by its products NADH and succinyl-CoA as well as GTP, ATP, and reactive oxygen species.

Activated by Ca2+ which may be useful in generating ATP during intense muscle exercise due to increased calcium flux.

216
Q

Fatty acid components/structure

A

Hydrophillic carboxylate acid head group with hydrophobic aliphatic tail.

Saturated C-C or unsaturated C=C

217
Q

Lipid absorption and transport

A

Fatty acids are not soluble.
The gall blader secretes bile salts which emulsify fatsinto micelles (phospholipids encapsulating the oils) within the small intestine. Intestinal lipases hydrolyse triglycerols. Fatty acids and other products are taken up by the intestinal mucosa and converted into triglycerols. The triglycerols are in corporated, with cholesterol and apoproteins, into chylomicrons. Chylomicrons move through the lympathic system and blood stream to tissues. Lipoprotein lipase, activated by apoC-II in the capillaries, releases fatty acids and glycerol. FA enter cells and are oxidised as fuels or re-esterified for storage.

218
Q

Fatty Acid activation

A

Fatty acid => Acyl Adenylate => Acyl-Coa (using acyl-CoA synthase)

219
Q

Movement of fatty acids into mitochondria

A

If Acyl-Coa has less than 12 carbons can diffuse through mitochondrial membrane.
More dietary fatty acids have more than 14 carbons so are taken through the mitochondrial membrane using the carnitine shuttle.
Fatty acids must be activated in the cytoplasms before they can be oxidised in the mitochondria.

220
Q

Utilisation of Acetyl-CoA

A
  • Krebs Cycle (normal conditions)

- converted into ketones (ketogenesis)

221
Q

Ketogenesis overview

A

During high rates of FA oxidation, primarily in the liver, large amounts of acetyl-CoA are generated. These exceed the capacity of Krebs and one result is ketogenesis.

Ketone bodies (acetone, acetoacetate and beta-hydroxybutyrate) are synthesised in the mitochondrial matrix from acetyl-CoA generated from beta-oxidation of fatty acids.

222
Q

Ketogenesis process

A

two Acetyl CoA ’s are converted by the enzyme thiolase (used in b-oxidation), back to Acetoacetyl CoA. Under the action of two further enzymes the Acetoacetyl CoA can be converted to Acetoacetate, acetoacetate can then enter the blood or it can be converted to b-hydroxybutyrate under the action of another enzyme, which can then enter the blood. When the level of glycogen in the liver is high the production of b-hydroxybutyrate increases. Another fate of the acetoacetate is that it can spontaneously be converted to acetone. Since acetone is volatile it is rapidly expired by the lungs

223
Q

Utilisation of acetoacetate and beta-hydroxybutyrate

A

Acetoacetate & b-hydroxybutyrate can both be oxidised as fuels in most tissues, including skeletal muscle (see diagram).
Cells transport the acetoacetate and b-hydroxybutyrate from the blood into the cytosol then into the mitochondrial matrix. Here b-hydroxybutyrate is oxidised back to acetoacetate.
Acetoacetate can then be activated to Acetoacetyl CoA which can then be cleaved into two molecules of Acetyl CoA by the thiolase enzyme (same enzyme involved in b-oxidation).
Then the Acetyl CoA can be used in the Kreb’s cycle to produce ATP

224
Q

Why does the liver not have the enzyme succinyl CoA: acetoacetate CoA in sufficient concentrations?

A

This enzyme is used to convert acetoacetate to acetoacetyl CoA.
As a result of the liver not having this enzyme, it CANNOT utilise ketone bodies as fuel. This ensures that extrahepatic tissues have access to ketone bodies as a fuel source during starvation.

225
Q

Regulation of Ketogenesis (glycerol-3-phosphate conc.)

A

A high [glycerol-3-phosphate] results in triglyceride production, whilst a low level results in increased ketone body production.

226
Q

Regulation of Ketogenesis (ATP demand and ATP levels)

A

High demand for ATP means that most acetyl-CoA will be further oxidised in TCA cycle.
High ATP levels means that more ketones are produced.

227
Q

Regulation of ketogenesis (glucagon and insulin levels)

A

Fat oxidation is dependent on theamount of glucagon (activation) and insulin (inhibition) present.

Insulin is produced when there is too much glucose in the blood, removes glucose and stores it in the liver.

Glucagon is produced when there is not enough glucose in the blood. It is converted to glucose.

228
Q

Clinical significance of ketogenesis

A

Under normal feeding and normal physiological state, ketone body production occurs at a relatively slow rate.
Carbohydrate shortages cause the liver to increase ketone body production from acetyl CoA.
In the early stages of starvation, the last remnants of fat are oxidised, the heart and skeletal muscle will consume primarily ketone bodies in order to PRESERVE GLUCOSE FOR USE BY THE BRAIN - when glucose in the brain decreases then the brain CAN use ketone bodies for energy

229
Q

Ketoacidosis (clinical)

A

Occurs in insulin-dependent diabetics when dose is inadequate or because of increased insulin requirement (infection, trauma, acute illness).
Is often the presenting feature in newly diagnosed type 1 diabetics.
Occurs in chronic alcohol abuse or starvation.
Patients present with hyperventilation and vomiting.

230
Q

Diabetic Ketoacidosis overview of the three routes

A

Insulin deficiency leading to either hyperglycaemia or increased production of acetoacetate and beta-hydroxybutyrate.

ID&raquo_space; inhibition of glycolysis and stimulation of gluconeogenesis&raquo_space; hyperglycaemia.

ID&raquo_space; glycogen breakdown and inhibition of glycogen synthesis&raquo_space; hyperglycaemia

ID&raquo_space; increasing lipolysis (increased free fatty acids)&raquo_space; increased production of acetoacetate and beta-hydroxybutyrate

231
Q

Alcoholic Ketoacidosis

A

High blood ethanol concentration and depleted protein and carbohydrate stores lead to impaired gluconeogenesis and decreased insulin and increased glucagon production. As a result there is increased lipolysis (increased free FAs). This leads to increased ketone production.

232
Q

Consequences of Ketoacidosis

A

Ketones are relatively strong acids (pH/pKa ~ 3.5). Therefore excessive ketone levels lower the blood pH. This impairs the ability of haemoglobin to bind to oxygen.

233
Q

Ketoacidosis treatment

A

Sliding scale of insulin
IV fluid Hydration (10%dextrose, 0.9% saline)
Monitor fluid balance closely
40 mmol potassium
Pabrinex (injection containing vitamin C, B1, B2, B3, B6)

234
Q

What are some impermeable substances which require transport proteins and energy to pass through membrane?

A

Large uncharged polar molecules
Ions
Charged polar molecules such as glucose

235
Q

Features of membrane channels

A 
Narrow aqueous pores from intracellular to extraceullular
Selective for size and charge 
Passive
May be voltage or ligand gated
Usually ions or water (aquaporins)
236
Q

Features of carriers in membrane

A

Specific binding site
Carrier undergoes a conformational change
Active or passive

237
Q

3 types of carrier protein

A

Uniport (single substance/simple diffusion)
Symport (two substances in the same direction)
Antiport (two substances in the opposite direction)

238
Q

Driving forces behind movement across membranes

A

Chemical
Electrical
Electrochemical
Based on gradient

239
Q

Chemical driving force

A

Based on concentration gradient

240
Q

Electrical/membrane potential driving force

A

Based on the distribution of charges across the membrane

241
Q

Electrical/membrane potential driving force

A

Based on the distribution of charges across the membrane.
Only charged substances such as sodium and potassium ions are involved.
Force depends on:
-size of membrane potential
- charge of the ion

242
Q

Electrochemical driving force

A

Combines the chemical and electrical forces. Net distribution is equal to the sum of chemical and electrical forces.
Only charged substances

243
Q

When passive diffusion goes wrong:

A

GLUT1 is a carrier protein present in many cells, including in the brain, where it transports glucose across the blood-brain barrier via facilitated diffusion. GLUT1 Deficiency syndrome is a very rare disorder where there is a mutation in the gene that encodes GLUT1. Less functional GLUT1 reduces the amount of glucose available to brain cells. Symptoms include seizures, microephaly, developmental delay.

244
Q

Sodium-potassium pump in resting state

A

Open on the internal side of the cell

Has an affinity for sodium ions.

245
Q

When active transport goes wrong

A

ATP7B protein is a Cu2+-ATPase present in the liver that transports copper into bile. Wilson’s Disease is a rare disorder where mutations occur in ATP7B gene resulting in deposition of copper in the liver and other tissues such as the brain and eyes. Symptoms include liver disease, tremor, Kayser-Fleischer rings (dark ring pigmentation around iris of eye).

246
Q

Co-transport/Secondary active transport

A

One ion goes against gradient coupled to a different ion (Na+ or H+) which moves down its gradient. This method uses energy from the generation of the ions electrochemical gradient by primary active transport. When the sodium ions and glucose bind to the co-transport protein, only then will a conformational change occur releasing the products.

247
Q

Example of co-transport

A

Intestinal lumen/renal tubules co-transport of sodium and glucose.
Glucose moves from low to high concentration. Na+/K+-ATPase generates a sodium gradient to enable co-transport for glucose by allowing sodium to diffuse across membrane.

248
Q

What is cellular signalling?

A

Communication between cells takes place via signalling molecules such as hormones, neurotransmitters and growth factors.

249
Q

What do signalling molecules bind to? Give two examples.

A

Steroid hormones bind to intracellular receptors.

Peptide hormones bind to cell-surface receptors.

250
Q

What are some secondary messengers?

A

cAMP
IP3
DAG
Calcium ions

251
Q

What is a ligand-gated ion channel?

A

The binding of a ligand either opens or closes the channel

252
Q

What is a G protein-coupled receptor

A

When an external signaling molecule binds to a GPCR, it causes a conformational change in the GPCR. This change then triggers the interaction between the GPCR and a nearby G protein.

253
Q

Enzyme linked receptor

A

Ligand activates and releases enzyme

254
Q

Intraceullar receptor

A

Ligand moves through bilayer and binds to inside receptor

255
Q

Cholera

A

Vibrio cholerae bacteria produce the cholera toxin. This crosses the cell membrane and modifies a subunit of the G-protein with increase adenylate cyclase activity. This results in increased cAMP levels. This stimulates several transporters in the cell membrane of intestinal cells. Resulting in massive secretion of ions and water into the gut. This leads to severe diarrhoea and dehydration that can be fatal.

256
Q

Endocytosis

A

Transports molecules into cells through:

  • phagocytosis
  • pinocytosis
  • receptor-mediated endocytosis
257
Q

Exocytosis

A

transports molecules out of cell through:

  • constitutive secretion receptors on vesicle
  • regulated secretion needing an external signal
258
Q

Cystic fibrosis

A

Hereditory disorder
Mutation in CFTR protein meaning chloride channel cannot be released. Found in many tissues such as pancreas, lungs, skin. Abnormal function results in sticky, viscous mucus where bacteria can spread.

259
Q

Drugs targeting membrane transporters

A

Cardiac glycosides
Proton pump inhibitors
Loop diuretics
Thiazide diuretics

260
Q

Major communication systems and their signals

A

Endocrine (hormones) nervous (electrical) and immune (ions).

261
Q

Autocrine definition

A

cells talking to themselves

262
Q

Paracrine

A

cells talking to neighbouring cells a short distance away
signal diffuses across the gap between cells
Inactivated locally, so doesn’t enter the blood stream - to prevent too much signal build up e.g. acetylcholine at neuromuscular junctions

263
Q

Endocrine

A

cells talking to other cells elsewhere in the body using hormones travelling through blood stream

264
Q

Endocrine organs

A 
Hypothalamus
Pituitary 
Thyroid
Parathyroid
Thymus
Adrenals 
Pancreas 
Ovaries
Testes
265
Q

General system of endocrine activity

A
  1. Hypothalamus releases 6 main hormones into blood stream.
  2. Anterior pituitary gland stimulates 6 main hormones (Some send directlyto target tissue)
  3. Sends to various endocrine glands.
  4. Sends hormone to target tissue
266
Q

Hormone

A

Molecule that acts as a chemical messenger
Classified according to structure
- peptide hormonne - AA derivatives
- steroid

267
Q

Peptide hormones

A

Peptide and AA hormones produce a quick reaction in the body e.g insulin, growth hormone. Peptide hormones are made up of amino acids and vary in size, depending on the number of amino acids. Some have carbohydrate side chains. They are hydrophillic.

268
Q

TSH

A

hormone premade and stored in pituitary cell ready to be released when needed. It dissolves into blood since its a protein and can dissolve in water. It acts on receptors on cell membrane and chemical reaction produces a quick response in thyroid cell.

269
Q

AA hormones

A

synthesised from tyrosine

270
Q

Steroid hormone response speed

A

slow

271
Q

What are steroid hormones made from?

A

cholesterol

272
Q

Steroid hormones + enzymes

A

Different enzymes modify molecule to produce a variety of hormones

273
Q

Solubility of steroid hormones

A

Can dissolve in lipids

Can’t dissolve in water

274
Q

Examples of steroid hormones

A

Testosterone
estrogen
cortison

275
Q

Extracellular fluid components

A 
Sodium ions 
Chloride ions
Bicarbonate ions
Glucose
Urea
Protein colloid
276
Q

ICF components which ion is dominant

A

Potassium

277
Q

Plasma osmolality

A

total number of particules dissolves in a solution

278
Q

What is plasma osmolality determined by

A

[Na+ and associated anions]

279
Q

When can plasma osmolality increase?

A

Diabetes
Kidney failure
Alcohol

280
Q

Normal plasma osmolality

A

275-295mmol/kg

281
Q

Antidiuretic hormone effect

A

Opens aquaporins in collecting duct within nephron. Kidney creates a large gradient of osmolality. In the medulla the ICF and ECF are not equal, producing a gradient. Water channels are opened up in the collecting duct. This produces a small volume of concentrated urine.

282
Q

Where is renin enzyme produced?

A

kidneys

283
Q

1) Kidneys detect decrease in ECF volume and …

A

less blood is delivered to kidney causing a pressure decrease. Renin is released.

284
Q

2) Once renin is released, what is its effect

A

Angiotensinogen => angiotensinogen I

285
Q

3) What happens to angiotensin I?

A

Converted in lungs by ACE into angiotensinogen II

286
Q

What is the function of angiotensinogen II?

A

Angiotensinogen II helps restore blood pressure. A2 causes vasoconstriction and an increased production of aldosterone produced in the adrenal gland allowing for more absorption of sodium/water and excretion of potassium ions. Stimulates ADH from pituitary gland to reabsorb water and restore ECF.

287
Q

Water depletion causes

A 
Reduced intake
Sweating
Vomiting
Diarrhoea
Diruesis/diuretics
288
Q

Consequences of water excess

A

Hyponatraemia (low sodium ion concentration)
Cerebral overhydration (headache, confusion, convulsions)
ECF volume expansion (heart and kidney failure, cirrhosis w/ascites)
Loss of intravascular fluid
Low effective circulating volume stimulates RAAS and ADH
Renal sodium retention and water retention
Oedema

289
Q

Oedema

A

Excess accumulation of fluid in interstitial space.
There is disruption of the filtration and osmotic forces of circulating forces. Obstruction of venous blood and lymphatic return.
Inflammation; increased capillary permability.
Loss of plasma protein.

290
Q

Serous effusion

A

Excess water in body cavity

291
Q

Formation of ISF - capillary bed

A

High hydrostatic pressure at arteriole end of capillary and low at venule end. The fluid gets pushes out into interstitial space. Oncotic pressure acts as a balancing force and proteins cause reabsorption of water at venule end. The small amount that isnt reabsorbed is taken by lymphatics.

292
Q

Hydrostatic pressure

A

Pressure difference between plasma and ISF. Water moves from plasma => ISF.

293
Q

Oncotic pressure

A

pressure caused by the difference in protein concentration between plasma and ISF. Water moves from ISF to plasma.

294
Q

Pathogenesis

A

Increased fluid leakage into ISS/impaired reabsorption of fluid. Caused by oedema and serous effusion.

295
Q

Inflammatory oedema

A

Causes gaps between endothelium. More water leaves capillary into ISS. Albumin leaves.

296
Q

Venous oedema

A

blockage at venous end, water can’t leave to heart causing backwards pressure effect, not enough water reabsorption, overwhelming lymphatics.

297
Q

Lymphatic oedema

A

blockage in lymphatic and water cant enter lymph

298
Q

Hypalbuminaemia oedema

A

Less albumin => less water reabsorption

299
Q

How much fluid is contained in normal pleural space

A

~10ml

300
Q

What is a pleural effusion

A

A pleural effusion results from the disruption of the balance between hydrostatic+oncotic forces in the visceral + parietal pleural vessels and lymphatic drainage. In pleural effusion, different fluids can enter the pleural cavity.

301
Q

What is transudate?

A

Fluid pushed through the capillary due to high pressure within the capillary. It has low protein content.

302
Q

What is exudate?

A

Fluid that leaks around the cells of the capillaries caused by inflammation and increases the permeability of pleural capillaries to proteins. It has a high protein content.

303
Q

Why is pleural fluid protein measured?

A

To differentiate between exudative and transudative effusions

304
Q

Conditions associated with transudative/exudative effusions respectively?

A

Transudative: left ventricular failure, cirrhosis, hypalbuminaemia, peritoneal dialysis

Exudative: malignancy, pneumonia

305
Q

Normal range of plasma sodium concentration

A

135-145mmol/L

Concentration is a ratio, not a measure of total body content

306
Q

What is changes in plasma sodium concentration usually a result of

A

Gain/loss of water rather than gain/loss of sodium

307
Q

Clinical effects of disorders of plasma sodium

A

On the brain due to constrained volume in the skull

308
Q

Causes of hypernatremia (high Na+)

A

Water defecit

  • poor intake
  • osmotic diuretics
  • diabetes inspidus

Na+ excess

  • Minteralcorticoid (aldosterone) excess
  • salt poisoning
309
Q

hypernatremia effects

A

Cerebral intercellular dehydration (tremors, irritability and confusion)

310
Q

Causes of hyponatremia (low Na+)

A

Artefactual

Na+ loss

  • Diuretics
  • Addison’s disease

Excess water

  • IV fluids (iatrogenic)
  • SIADH (excess ADH production)

Excess water and Na+
- oedema (congestive cardiac failure, liver disease)

311
Q

hyponatremia effects

A

Cerebral intracellular overhydration (headache, confusion, convulsions)

312
Q

Fertilisation and early cell division

A

Sperm + egg => morula => blastocyst (Day 7)

313
Q

What does ectoderm end up becoming

A 
Epidermis of skin, hair, nails
Mammary sweat and sebaceous glands
Central Nervous System 
Peripheral nervous system 
Pituitary gland
Enamel of teeth 
Lens of the eye/parts of inner ear
Sensory epithelium of nose, ear and eye
314
Q

What does endoderm end up becoming

A

Epithelial lining of GI tract, respiratory tract and urinary bladder
Parenchyma of the thyroid gland, parathyroid gland, and pancreas
Epithelial lining of the tympanic cavity and auditory tube
Plays a part in the development of the notochord

315
Q

What does mesoderm end up becoming

A 
Musculoskeletal system 
Deep layers of the skin
Abdominal and chest walls and lining
Walls of the bowel 
Urogenital system
316
Q

How is mesoderm formed?

A

As ectoderm grows a folding occurs along the caudal midline (primitive streak). Cells from the base of the primitive streak break off and migrate to lie between the layers of the ectoderm and endoderm, forming the mesoderm. On day 17 the mesoderm separates the whole of the ectoderm from the endoderm except for 2 small areas, one at each end of the trilaminar disc.

317
Q

Formation of notochord

A

A tube develops from the end of the primitive stream and extends towards the cranial end. The tube fuses with the endoderm to become a groove in the endoderm layer. The plate folds to become a tube again - the notochord. This plays a central role in further developments in the midline.

318
Q

Ectoderm - formation of CNS

A

Neuroectodermal tissues differentiate from the ectoderm and thicken into the neural plate. The neural plate border separates the ectoderm from the neural plate. The neural plate bends to form a u shape (dorsally) with the two ends eventually joining at the neural plate borders, which are nowreferredto as the neural cret. The closure of the neural tube disconnects the neural crest from the epidermis. Neural crest cells differentiate to form most of the peripheral nervous system. The notochord degenerates and only persists the nucleus pulposus of the inervertebral discs. Other mesoderm cells differentiate into the somites, the precursos of the axial skeleto nand skeletal muscle.

319
Q

Day 22-23

A

Somites become the myotomes, the endoderm overlying them are the dermatomes.

320
Q

Day 22-23 embryology

Failures of fusion

A

If fusion does not extend all the way to the CAUDAL end of the embryo, the child is born with spina bifida.

If fusion does not extend all the way to the CRANIAL end of the embryo, the child is born without the cerebral cortex - ANENCEPHALY.

321
Q

Mesoderm splits into… (brief overview)

A
  • Paraxial mesoderm
  • Intermediate mesoderm
  • Lateral mesoderm
322
Q

Paraxial mesoderm

A 
Along the neural tube. 
Somites form the: 
- myotome (muscle tissue) 
- sclerotome (cartilage and bone) 
- dermatome (Dermis of the skin N.B not superficial layer)
323
Q

What is each somite supplied by?

A

A single spinal nerve

324
Q

Intermediate mesoderm

A

More lateral

Forms the urogenital system
- the kidneys, the gonads, and their reproductive duct systems

325
Q

Lateral mesoderm

A

extending to the edge of the embro

Somatic parietal layer mesoderm: the outer layer covers the inside of the chest and abdominal walls

Splanchic visceral layer mesoderm: the inside layer covers the organs in the thorax and abdomen

326
Q

Where does lateral folding start?

A

The developing trilaminar disc. Cuts across embro in an axial slice.

327
Q

What happens to yolk sac?

A

Portion of the yolk sac lined with endoderm is incorporated into the embryo to form the primitive gut; the remaining part of the yolk sac and allontois remain outside, connected through the umbilicus. Folding of the yolk sac lead to formation of body cavities.

328
Q

Where does cephalo-caudal folding take place?

A

Starting with bilaminar disc.

Cuts across length of embro in saggital slice.

329
Q

What does the cranial area of the embryo contain??

A

The buccopharyngeal (oropharyngeal) membrane, the cardiogenic area (heart) and the septum transversum.

330
Q

Cranial flexion

A

Cranial flexion brings the buccopharyngeal membrane, cardiogenic area and septum transversum ventrally, forming the surface of the future face, neck and chest. It brings the heart into its thoracic position and septum transversum to the diaphragm.

331
Q

Caudal flexion

A

Caudal flexion brings the cloacal membrane onto the ventral surface of the embryo.

332
Q

Summary of first 8 weeks of embryology

A

1st week: fertilization, formation of the morula and blastocyst
2nd week: implantation of the blastocyst and formation of bilaminar embryonic disc and early placenta
3rd weel: differentiation of cell layers to form the trilaminar embryonic disc
4th week: folding of the embryo and continuing development of the 3 germ layers
5th - end of 8th week: development of all organs
By the end of 8th week: the embryo looks like an adult and is called the foetus; growth becomes the predominant feature

PHASE ONE (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions