1: Introduction to the human genome Flashcards
Genes and the ___ combine to create disease.
environment
Strands of DNA pair up in a (parallel / antiparallel) fashion.
antiparallel
DNA is read…
a) 3’ to 5’
b) 5’ to 3’
b) 5’ to 3’
What is the sugar backbone of DNA called?
2-deoxyribose
What is the sugar backbone of RNA called?
Ribose sugar
What are the four bases of DNA?
ACGT
What are the four bases of RNA?
ACGU
The information in DNA is found in the ___ of base pairs.
sequence
What are the base pairs of DNA?
A ⇔ T
C ⇔ G
What are DNA strands wound into?
Which protein is involved?
Chromosomes
Histone
How many bases are found in the human genome?
3 billion
How many genes are found in the human genome?
30,000
In which phase of the cell cycle does DNA replication occur?
S phase
What occurs during the S phase of the cell cycle?
DNA replication
___ mechanisms fix DNA damage which may occur during the S phase.
Repair
Defects in DNA repair mechanisms can lead to ___.
disease
What is cell division otherwise known as?
Mitosis
What occurs during mitosis in terms of cell number?
Are the daughter cell(s) haploid or diploid?
One diploid parent cell divides into two genetically identical diploid daughter cells
What occurs during meiosis in terms of cell number and ploidy number?
1 diploid parent cell becomes 4 haploid daughter cells
Which process introduces variation during meiosis by swapping genes between chromosomes?
Crossing over
Meiosis is the process behind ___ formation.
gamete
In terms of strand number, what is the difference between DNA and RNA?
DNA is double stranded
RNA is single stranded
DNA is ___ into pre-mRNA.
Pre-mRNA is ___ into mRNA.
mRNA is ___ into protein.
transcribed
spliced
translated
DNA is transcribed into ___.
pre-mRNA
Pre-mRNA is spliced into ___.
mRNA
mRNA is translated into ___.
protein
How many bases correspond to one amino acid (or a stop)?
3
Every copy of the human genome is ___.
different
What is a polymorphism?
Any variation in the human genome which appears in > 1% of the population.
What are the two components of a karyotype (e.g 46 XX)?
46 - the total number of chromosomes
XX - the sex chromosome complement
(Balanced / unbalanced) chromosome rearrangements are liable to cause disease.
Unbalanced
What is aneuploidy?
Having a whole extra or missing chromosome
What is a Robertsonian translocation?
When two acrocentric chromosomes become stuck end to end.
What is the more genetic name for Down Syndrome?
Trisomy 21
A Robertsonian translocation is likely to cause ___ - the cause of genetic disorders such as Down Syndrome.
trisomy
Why is X chromosome aneuploidy (having one missing or one extra chromosome) better tolerated?
Random X inactivation
What genetic disorder has the karyotype 45 X?
Turner syndrome
What genetic disorder has the karyotype 47 XXY?
Klinefelter syndrome
Other than Robertsonian, name a type of translocation.
Reciprocal translocation
Most reciprocal translocations tend to be (balanced / unbalanced);
balanced
What does FISH stand for?
Fluoresence in situ Hybridisation
FISH allows you to detect individual ___ in genes using fluorescent probes.
mutations
Which genetic test can be used to examine a whole genome?
Microarray CGH
What are some consequences of unbalanced translocations in developing foetuses?
Malformations
Miscarriage
Different cells have different genetic make-ups and will proliferate in a patchy nature - what is this phenomenon called?
Mosaicism
Somatic mosaicism for a chromosome abnormality is a genetic change which can contribute towards ___.
cancer
Amplification of the HER2 gene is associated with which disease?
How can it be treated?
Breast cancer
HER2+ breast cancer can be treated using HERCEPTIN (trastuzumab), a monoclonal antibody which targets it specifically
An abnormality in chromosome 22 (Philadelphia chromosome) can cause which disease?
How can it be treated?
Acute myeloid leukaemia
AML can be treated using IMATINIB, a monoclonal antibody which targets cells which express BCR-ABL, the protein produced as a result of a Philadelphia chromosome translocation
