MCBG 16 Flashcards
If you preform a haemoglobin electrophoresis, two bands appear. Why are 2 bands seen after performing
haemoglobin electrophoresis?
In a normal person there are two types of Haemoglobin in blood. HbA2 and HbA1
Why has thalassemia not be naturally selected (died out) ?
Being Heterzygous gives protection against malaria
What are reticulocytes?
immature RBCs - released in early response to anaemia
What is Lassitude??
lack of energy due to anoxia
What is anoxia??
The absense of oxygen
osteopenia?
Loss in bone mass
What is the major protein found in bone?
Collagen
Why is glycine present at every 3rd position in the polypeptide chain? 1. Needed to make Hbonds 2. Small amino acid that fits inside the helix 3. Hydrophilic side chain to make interactions with other chains 4. All of the above
- Small amino acid that fits
inside the helix
What is the structure of Type I collagen? (chain type)
Two a1(I) and one a2(I) chains
In gel electrophoresis, if one band twice as intense as
the other. What does that ?mean
Twice as much protein
What does the blue tinge in the sclera signify?
Osteogenesis imperfecta. A condition which is caused by a lack of type I collagen
What is cytogenetics?
Study of inheritance in relation to the structure and function of chromosomes.
What are the two Prenatal Diagnosis methods?
Chorionic Villus Sampling
Amniocentesis
What is Aneuploidy?
Loss or gain of a whole chromosome.
What is down syndrome characterised as?
An extra chromosome 21
What is Edwards characterised as (chromosome wise)?
Edwards +18
What is Polyploidy?
Gain of a whole haploid SET of chromosomes
Whats the difference between polyploidy and anuerploidy?
Polyploidy - Gain of a whole haploid SET of chromosomes (+23 haploid chromosomes)
Loss or gain of a (single) whole chromosome.
Types of polyploidy?
Diploid (normal number)
Triploid/triploidy (three lots of 23)
Tetraploid
What causes Aneuploidy?
- Non-disjunction
What type of division causes mosacism?
Mitotic Chromosomes can be “left-behind” at cell division because of defects in spindle function or attachment to chromosomes
The lagging chromosome may be lost
entirely in mitosis or meiosis
.Whats Patau Syndrome?
Chromosome effect?
Effects (2)
Trisomy 13
Multiple congenital abnormalities
Polydactyly
Whats Turner syndrome?
Effects
45,X (female is missing an X)
Puffy feet,
redundant skin at back of neck
Whats the difference between mosaicism and chimerism?
Both are two different geneotypes within the same person. Mosaicism results from one person whereas Chimerism originates from different zygotes
Define chromosome translocation ?
Movement of Genetic Info from one chromosome to another
Define a balanced chromosome translocation ?
An even exchange of material with no genetic information extra or missing, and ideally full functionality
Define a unbalanced chromosome translocation ?
Unequal exchange of info
Get extra or missing genes
Why is it important to understand why translocation errors occurred in meiosis or mitosis?
MEIOSIS - problem with all of the mothers cells
MITOSIS - problem with just that cell line
Robertsonian Translocations
To acrocentric chromosomes fused together producing one big chromosome and one tiny tiny one. = 45 chromosomes
What does Acrocentric mean?
The p are is so small you cannot see it
Explain the steps in fish?
1) Get DNA probe (specific nucleotide sequence with labels or label attachments) and PCR it
2) De-nature DNA and add probe
3) MAGIC (aka hybridisation)
4) Wash unbound probe off
5) Visualise it using fluorescence microscopy
V.Important. Explain what tests FISH can be used for?
4
MORT
- Mircodeletion syndromes
- Identify chromosome of origin
3) Chromosome rearrangement/Translocation
4) Investigate telomeres
Name 4 different types of probes? (Think anatomy)
- Locus/gene specific probes
- Telomere probes
- Centromere probes
- Whole chromosome PAINTS
Whats the issue with using Locus specific probes on Microdeletion/duplication syndromes
Too small to see on G-banded chromosomes. (21,22, y)
Would you use a microarray for mutation detection
No
What are the two negatives of Microarrays? (hint in terms of chromosomes)
1) Can’t detect balanced rearrangements
2) Not used for mutation detection
Whats 45,X
effects?
Turners syndrome
Excess skin on back neck
swollen feet/hands at birth
Short statue
Whats XXX
effects?
Tiple X syndrome
Low IQ
Can have normal offspring
Whats XXY
effects?
Klinefelter Syndrome More than one X for a male Sterile Weak muscle Greater height Small genitals Breasts Symptoms increase with more Xs
Whats XX Male
effects?
XX Male syndrome
Sry gene translocated on X chromosome
