Quiz 1 Flashcards
Phenotype
the observable train or set of traits that is created from your genetic makeup Ex: hair color, eye color, flower color, wrinkled seeds.
Genotype
an individual’s collection of genes, or can reference to two particular alleles that codes for a gene (AA, Aa, aa). Determines phenotype
Penetrance
the percentage of expression of a particular gene or set of genes. May be complete or incomplete.
4 base pairs of DNA
Adenine, Thymine, Cytosine, Guanine
Transcription
is the first step of gene expression, in which a particular segment of DNA is copied into RNA (mRNA) by the enzyme RNA polymerase. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language.
DNA transcribed into mRNA.
Translation
(mRNA)—produced by transcription from DNA—is decoded by a ribosome to produce a specific amino acid chain, or polypeptide. The polypeptide later folds into an active protein and performs its functions in the cell.
Chromosomal Structure
DNA is tightly wound around a histone to form nucleosomes that equal about 140 base pairs. Nucleosomes are linked to form chromatin that is further condensed into chromatin. 22 pairs and 1 pair of sex chromosomes.
Homozygous
both alleles are identical the individual is homozygous
Heterozygous
each allele is different
Allele
homologous copies of a gene…Human have two sets of each gene, once copy on each chromosome.
Locus
location of a particular gene on a chromosome
Germinal mutation
occurs during formation off an egg or sperm
somatic mutation
mutation occurs after conception
Chromosomal aberration
alteration in the number or the physical structure of a chromosome. Most pregnancies with these mutations end in spontaneous abortion.
Monosomy
only one chromosome of a pair is present
ex: Turner’s Syndrome
Trisomy
three chromosomes are present
Ex: Down’s Syndrome
Polysomy
one chromosome is present 4 or more times.
Causes of abnormal numbers of proteins
nondisjunction
Changes in phenotype
caused by deletions and insertions of a chromosomal region
Chromosomal abnormality associated with Down’s Syndrome
trisomy 21 - most common trisomy
3 physical features of a Down Syndrome child.
- decreased muscle tone.
- flat facial features
large, protruding tongue. - small nose
- Upward slant of eyes
- Abnormally shaped ears.
- Deep palmar crease
- hyperflexibility
- extra space between 1st and 2nd toes.
What are 3 medical complications associated with Downs Syndrome
- Cardiac defects
- intestinal malformations
- vision abnormalities
- hearing loss
- recurrent respiratory infections
- memory loss
- increased risk of Alzheimer’s at an early age.
Genotype of Kleinfelter
XXY
Effect of Kleinfelter Syndrome
usually sterile due to impaired spermatogenesis.
50% will develop breasts