Genetics Flashcards
How are chromosomal abnormalities caused during meiosis?
- Misaligned pairing during chromosomal recombination
- Non-disjunction during meiosis- a cause of numerical abnormalities (aneuploidy)
Define deletion with regards to genetics
A loss of a segment of a chromosome
Define duplication with regards to genetics
A part of the chromosome is duplicated
Define translocation with regards to genetics
A segment of a chromosome breaks off and attaches to another chromosome
Define inversion with regards to genetics
Two-break rearrangement in a chromosome in which a segment is reversed
State the central dogma of genetics
DNA is transcribed into mRNA, which is translated into an amino acid chain, which is folded into a protein
How is pre-mRNA edited before it leaves the nucleus?
It gets spliced. Introns are removed and exons are rearranged, depending on which proteins are needed.
Which direction is DNA coded in?
5’ –> 3’
Describe some of the post-translational modifications proteins undergo
Phosphorylation- the addition of a phosphate group
Acetylation- the addition of an acetyl group
Methylation- the addition of a methyl group
Palmitoylation- the addition of a fatty acid
Glycosylation- the addition of glycans (sugar chains)
Polyubiquitination on Lys- targets proteins for degradation
Why are post-translational modifications required?
- regulating the folding of proteins
- targeting of proteins to specific subcellular compartments
- help with protein’s interaction with ligands or other proteins
Define the term ‘transcriptome’
The whole population of mRNA and non-coding RNAs in a cell, tissue or organ at one time
Define the term ‘proteome’
Population of proteins in a cell, tissue or organ at one time
Why is genetic stability important?
It maintains organisms and species by:
• Ensuring accurate DNA replication
• Providing a mechanism to repair accidental DNA damages
Define the term ‘homozygote’
An organism in which the two alleles of a given gene are the same
Define the term ‘heterozygote’
An organism in which the two alleles of a given gene are the different
Define the term ‘locus’
The position of a gene on the chromosome
Define the term ‘allele’
One of the two homologous genes on the same locus
What letters are give to the arms of chromosomes, separated by the centromere?
P (short arm) and q (long arm)
In a heterozygous pair of alleles, what phenotype will be shown?
The dominant allele will have more influence over the phenotype displayed. In other words, one allele (the dominant one) may “mask” the other allele
What does autosomal dominant inheritance mean?
When a single affected allele is sufficient to cause the phenotype (heterozygote). There’s no generational skip
What does autosomal recessive inheritance mean?
When you need both affected alleles to cause the phenotype. Only recessive homozygote (aa) is affected
Give the most likely genes of the parents for autosomal recessive inheritance
Father: Aa
Mother: Aa
What causes variation in genetic information?
DNA mutation, which gets passed on to offspring if the mutation is in the gametes
Why don’t mutations matter much for most of the genome?
Only 25-33% of the whole genome encodes for genes
