Chapter 9: Genetics Flashcards
DNA:
- Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living things.
Chromosome:
- A thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
Chromatin:
A complex of proteins and DNA in eukaryotic chromosomes
Centromere:
The waist like constriction in a chromosome required for the movement of chromosomes during cell division
Karyotype:
A display of the number and appearance of the chromosomes on an organism or cell observed at metaphase
Gene:
A unit of heredity that transmits information from one generation to the next, a segment of dna that codes for a polypeptide
Genetics:
The study of the mechanisms and patterns of inheritance through the transmission of coded chemical instructions from one generation to the next
Allele
One of different versions of the same gene (at the same locus) determined by small differences in the DNA sequence of the gene
Geneome
All the genetic material contained in an organism, or a cell, includes the chromosomes within the nucleus and the DNA in mitochondria and chloroplasts
Heredity
The study of inheritance the genetics transmission of characteristics from one generation to another
Somatic Cells
A normal body cell, as compared with a germ-line cell from which a gamete (ie. sperm or ovum) is derived
Homologous chromosomes
A pair of chromosomes that have the same size,shape and genes at the same locations
Independent assortment
When alleles of gene pairs redistribute independently into different combinations in gametes during meiosis.
Autosome
A chromosome that is the same in both males and females of a species, autosomes do not include sex chromosomes
Hetero-some
Non-identical chromosomes that pair up at meiosis (eg the X and Y chromosomes in human males)
Locus
The position of a gene occupies in a chromosome
Sex linked
Refers to the inheritance pattern shown by a gene located on a sex chromosome
Mitchocondrial DNA
DNA contained in mitochondria (small circular chromosome)
Sex chromosomes
The pair of chromosomes that determines the sex of an individual
DNA sequence
The order if nucleotide bases within a DNA molecule
Complementary bases
The nucleotide bases that pair on the opposite strands of DNA: A pairs with T and C pairs with G
Nucleotides
The basic building block of nucleic acids (DNA and RNA), which are linked together by phosphodiester bonds; each nucleotide is made up of a five carbon sugar, a phosphate group and a nitrogenous base
Nucleotide base pairs
Two complementary nucleotide bases that are joined together by hydrogen bonding in a DNA double strand
Double helix
The spiral shape of a DNA molecule
Nitrogenous base
A structural component of nucleotides, DNA has adenine (A), cytosine (C), guanine (G) and thymine (T), in RNA thymine is replaced with uracil (U).
Hydrogen bonds
A weak molecular chemical bond
Polyploidy
When a cell or organism has a genome compromising three or more copies of each chromosomes, represented by 3n, 4n, 5n, 6n etc. (more than two paired homologous pairs)
Monoploidy
An individual that contains one half the normal number of chromosomes is a monoploid and exhibits monoploidy. Monoploids are very rare in nature because recessive lethal mutations become unmasked, and thus they die before they are detected.
Aneuploidy
Aneuploidy is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46.
Trisomy 21 (Down syndrome)
The condition in which is caused by an extra copy of chromosome number 21.
Klinefelter’s syndrome (XXY syndrome)
A genetic condition in which a male is born with an extra copy of the X chromosome
