genetics Flashcards
Genetics
is the study of heredity. Genetics involves studying how traits are passed from parents to offspring.
. Heredity
is the passing of traits from parents to offspring.
Traits
are the characteristics of an organism. Examples are eye color, freckles, height or dimples.
Chromosome
Chromosomes are thread-like structures in the nucleus of cells that carry genetic information. A chromosome consists of a long strand of DNA containing many genes.
DNA
- Deoxyribonucleic acid (DNA) is a molecule made up of nucleotides that contains genetic information for cell growth, division and function.
Gene -
A gene is a segment on a chromosome that determines a specific trait. Genes are the units of heredity.
allele
a different form or version of a gene - alleles usually occur in pairs.
. dominant
a gene variant that is expressed more strongly than other versions of the same gene - the dominant allele masks the effect of the recessive allele
recessive
a gene that is masked by a dominant gene, and is only expressed when two copies of the gene are present
genotype
- the genetic make up or code of an organism - Ex: BB, Bb, bb
phenotype
the observable traits or physical appearance of an organism - Ex: brown eyes or blue eyes
homozygous
If an organism has two of the same kind of gene for a trait, it is called pure or homozygous.
Example: Homozygous brown eyes (BB) ~ Homozygous blue eyes (bb)
heterozygous
An organism with two different alleles for a trait is called heterozygous or hybrid.
Example: A heterozygous tall plant (Tt) expresses the dominant allele (T or tall) and thus, is tall.