DNA Flashcards
Define DNA
Deoxyribonucleic Acid is a molecule composed of two polynucleotide chains that coil around each other to form a double helix carrying genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. DNA and ribonucleic acid are nucleic acids.
Define chromosome
A chromosome is a DNA molecule with part or all of the genetic material of an organism.
Define genes
A gene is a basic unit of heredity and a sequence of nucleotides in DNA or RNA that encodes the synthesis of a gene product, either RNA or protein
Define nucleotides
Nucleotides are organic molecules consisting of a nucleoside and a phosphate. They serve as monomeric units of the nucleic acid polymers deoxyribonucleic acid and ribonucleic acid, both of which are essential biomolecules within all life-forms on Earth.
Define Nucleosides
Nucleosides are glycosylamines that can be thought of as nucleotides without a phosphate group. A nucleoside consists simply of a nucleobase and a five-carbon sugar whereas a nucleotide is composed of a nucleobase, a five-carbon sugar, and one or more phosphate groups.
Define gametes
It’s a mature haploid male or female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
Define RNA
Ribonucleic acid is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid are nucleic acids.
Define chromatid
A chromatid is one half of a duplicated chromosome. Before replication, one chromosome is composed of one DNA molecule. In replication, the DNA molecule is copied, and the two molecules are known as chromatids.
Define phosphate group
A functional group characterized by a phosphorus atom bonded to four oxygen atoms (three single bonds and one double bond). One of these oxygen atoms must be bonded to another atom; if not, the structure is a phosphate ion.
Define Deoxyribose sugars
The sugar found in the side chains of DNA, differing from ribose in having a hydrogen atom instead of an OH group on one of its carbon atoms.
Define homozygous
When an individual has two alleles the same, such as the RR and rr combinations shown, then the individual is said to be homozygous for that allele.
Heterozygous
Individuals with the Rr meaning one dominant and one recessive of alleles are heterozygous.
Define dominant genes
It’s the phenomenon of one variant of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome.
Define recessive genes
A recessive gene is a gene whose effects are masked in the presence of a dominant gene.
Define haploid cell
Haploid cells contain only one set of Chromosomes (n).
