genetics definitions Flashcards
(37 cards)
DNA
paired double-stranded helical molecule capable of replicating and responsible for directing an organism’s inherited activities by directing the expression and composition/structure of cellular proteins
bases
the basic chemical building blocks of DNA that determine its sequence
Purine bases - Adenine (A) Guanine (G)
Pyrimidine bases - Thymine (T) Cytosine (C)
base pair
a single pair of complementary bases from opposite strands of the DNA double helix; A and T, G and C
gene
the basic hereditary unit, initially defined by phenotype (currently) defined by a DNA sequence that encodes either a protein or a non-coding RNA
non-coding regions
regions of the chromosome in-between genes which don’t code for proteins
chromosome
thread-like structure in the nucleus consisting mainly of a long DNA molecule comprising 50-300,000 base pairs which code for thousands of genes
Humans = 23 pairs of chromosomes containing a total of 20,000 genes
genome
an organism’s complete set of DNA
transcription
production of RNA from a DNA template initially in the form of a primary transcript
exon
blocks of a gene whose DNA sequence will ultimately determine amino acid sequence
introns
blocks of a gene which do not code for protein and which are removed during the processing of primary transcript to generate mRNA
translation
process in which protein is made using messenger RNA sequence as a template
mutation
change in DNA sequence
nonsynonymous mutation
mutation that ultimately results in a change in protein sequence
allele
one member of a number of different forms/variations of a gene
genotype
combination of alleles for a given gene within an individual
An individual’s genotype is defined by the 2 alleles present [chromosomes are paired]
SNP
DNA sequence variation when a single base differs at the same genetic location between different chromosomes
(either within an individual or between individuals of the same species) – most common type of genetic variation
haplotype
combination of SNPs present at different genetic locations that are transmitted together on the same chromatid
phenotype
observable characteristics (morphological, clinical; biochemical, or molecular) or disease
allele
one of the alternate versions of a gene present in a population
wild-type allele
normal functional version
mutant allele
rare genetic change often non-functional
variant allele
common genetic variation, may have minor differing properties for same function
locus/loci
where a gene maps
dominant trait
a characteristic that is seen in a heterozygote
