Describe terms used in genetics and heredity and apply examples of types of inheritance Flashcards
Nucleus
Control centre of the cell that contains DNA
DNA shape/composition
3D double helix shape composed of sugar, phosphate and a AT/CG base
A, T, C, G
Adenine
Thymine
Cytosine
Guanine
How does Chromatin form and where do you find it?
Long threads of DNA wrap around histones that bind together and form Chromatin. Found within the Nuceleus
How are Chromosomes formed?
Chromatin tightly super coils up to form thick strands of Chromosomes
How are Duplicated Chromosomes formed? (2)
Chromosomes replicate (looking like an X) into 2 identical sister chromatids - each one ends in one of the 2 daughter cells that result from cell division.
Genes
Segments of DNA that controls hereditary characteristics
Genomes
A complete set of DNA in a cell
Haploid
Cells that contain one set of chromosomes (gametes)
Diploid
Cells that contain two sets of chromosomes (somatic/body cells)
How many chromosomes are there?
46, 23 pairs
Homologous Chromosome
Identical in size, shape and/or gene location
Homozygous
Two recessive alleles
Heterozygous
One dominant allele taking over a recessive allele
Allele
Gene pairs that are versions of a gene for a trait
Dominant Allele
Causes for the Dominant allele trait to be expressed through offspring
Recessive Allele
Taken over by Dominant allele and is not expressed through offspring unless both alleles are recessive
Genotype
The 2 alleles we express for each gene - genetic make up
Phenotype
How the gene is expressed through our physical characteristics
Karyotype
A test that evaluates the number and structure of a person’s chromosomes in order to detect abnormalities
22 Chromosome pairs are -
Autosomes
1 Chromosome pair is -
Sex chromosomes that determine sex of an organism
Normal Female Sex Chromosome
XX
Normal Male Sex Chromosome
XY
3 types of Dominant-Recessive inheritance
Simple D-R
Multiple Allele
Sex linked
Multiple Allele
More than 2 types of allele exist - ABO blood group
Sex Linked (5)
Female - XX
Male - XY
Genes for a recessive X-linked disorder are only located on the X chromosome (female).
There is no matching gene on the Y chromosome (male) to fight the expression of these disorders.
Therefore, recessive genes for these disorders can be expressed from the mother to the male offspring
Polygenic inheritance
When more than one gene determines the characteristic - e.g. skin: AABBCc
