Neurogenetics Flashcards
what are the 4 bases of DNA
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
what are the two types of cell division? give a brief explanation.
mitosis - somatic cells (daughter cells identical to parent cells)
meiosis - gametes (daughter cells contain half the number of chromosomes)
what are transcription factors?
a protein that controls the rate of transcription from DNA to mRNA, by binding to a specific DNA sequence. they are activated during development or by intracellular signalling.
when was the DNA structure discovered?
1953
how does gene expression occur?
the DNA unravels, allowing a transcription factor to bind to the gene
what is translation?
the process of translating a DNA sequence from mRNA to a sequence of amino acids. a ribosome attaches to the mRNA and moves along it, reading each triplet codon (3 DNA bases) and using transfer RNA (tRNA) to put together an amino acid chain to make a protein.
describe Mendel’s Law
genes have two variants (alleles), different combinations of these alleles can be inherited. some genes are dominant and some are recessive.
what does homozygous mean?
that the two alleles inherited are identical
what does heterozygous mean?
that the two alleles inherited are not identical
what type of inheritance is Huntington’s disease?
dominant inheritance
describe dominant inheritance
that just one inherited allele can cause the disease
describe recessive inheritance
two of alleles must be inherited in order to cause the disease
for Huntington’s disease, which chromosome is affected?
chromosome 4, an excessive repeat of CAG bases
what type of inheritance is Phenylketonuria?
recessive
how is phenylketonuria caused?
a mutation in the PAH gene
what is monosomy?
a chromosomal abnormality which results in a single copy of a chromosome
what is trisomy?
a chromosomal abnormality which results in 3 copies of a chromosome, can result in down syndrome
what are x-linked conditions?
a genetic mutation on the x chromosome causes the phenotype to always be expressed in individuals who are homozygous for the gene mutation
what is an example of an x-linked condition?
Rett Syndrome, caused by a mutation in MeCP2, which turns off the expression of ‘unwanted’ genes during synapse formation
what is epigenetics?
the study of phenotype changes that do not alter the DNA sequence. the study of how genetics and the environment interact
what can affect the phenotype without altering the DNA sequence?
development (utero), aging, diet, drugs
what is transgenerational epigenetics?
epigenetic changes that can be passed down through generations
what are Genome Wide Association Studies?
used to associate genes with traits or illnesses
