Flashcards in Genetics Deck (41)
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1
Which bases have 2 carbon - nitrogen rings and are known as purines?
A and G
2
Which bases have a single carbon - nitrogen ring and are known as pyrimidines?
C and T
3
What are the base pairings?
A pairs with T
C pairs with G
4
Which bases have the strongest bond?
The bond between C and G is stronger than that of A and T
5
How many bases and genes are there in the human genome?
30,000 genes
3,000,000,000 bases
6
What are the stages of the cell cycle?
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
(these all make up mitosis)
Then;
G1, S, G2
7
Where are the checkpoints in the cell cycle?
G1 checkpoint towards the end of G1
G2 checkpoint at the end of G2
M check point during mitosis
8
What is mitosis and what is meiosis?
Mitosis is when one diploid parent cell forms two identical diploid daughter cells
Meiosis is when one diploid parent cell forms 4 haploid daughter cells
9
What is the difference between a mutation and a polymorphism?
A mutation is a gene that causes a genetic disorder
A polymorphism is any variation in the human genome that doesn't necessarily cause disease but can predispose to one
10
Are all mutations harmful?
NO - not necessarily if they don't affect the coding part of the DNA
11
Normal number of female and male chromosomes
Female 46 XX
Male 46XY
12
What is an acrocentric chromosome?
A chromosome in which the centromere is situated at or very near one end
13
What symbols are used for the long and short arm of a chromosome?
Short arm - p
Long arm - q
14
What is meant by a 'Robertsonian Translocation' ?
Two acrocentric chromosomes are stuck end-to-end.
15
What is meant by balanced and unbalanced chromosome changes?
Balanced - There is rearrangement of the chromosomes but all material is still present
Unbalanced- Rearrangement in which there is extra or missing material
16
Define the term 'ANEUPLOIDY'
Whole extra or missing chromosomes
17
Down's Syndrome
Trisomy 21
18
Edward's Syndrome
Trisomy 18 (death a few days post-birth)
19
Turner's Syndrome
45 X
Female
Mild learning difficulties
Appearance abnormalities
20
Klinefelter Syndrome
47 XXY
Male
Infertility
Lack of testosterone
Poor development of sexual features
21
Genetic tests
FISH (examines genes)
Microarray CGH (Detects missing/extra chromosomes)
PCR
NGS
22
What is meant by 'MOSAICISM' ?
A disease that affects part but not all of the body
23
List 5 types of mutations that can occur in DNA sequences and what term describes the normal/natural sequence
Wild Type (normal/natural)
Premature stop
Missense
Deletions
Insertions
Triplet Expansion
24
What does 'PENETRANCE' mean?
The likelihood of having a disease if you have a gene mutation
25
What are the differences between mendelian and multifactorial diseases?
Mendelian diseases are high penetrance with a high genetic contribution.
Multifactorial diseases are common but have low penetrance and are caused by both genes and the environment!
26
What is an SNP?
What is a CNV?
Single Nucleotide Polymorphism
Copy number variation
- Extra or missing stretches of DNA
27
What is meant by driver and passenger mutations?
Driver mutations drive carcinogenesis
Passenger mutations are incidental and occur because the tumour becomes unstable
28
What is meant by the 'Philadelphia Chromosome' and what does it cause
a 9 to 22 translocation
it drives leukaemia development
29
What is meant by 'imprinting'
Differences in gene expression depending on whether a gene is maternally or paternally inherited
30
