genetics & biotechnology Flashcards
(27 cards)
genetics
the branch of biology that studies the ways in which hereditary information is passed on from parents to offspring
Gregor Mendel
the father of genetics
trait
a trait or character is a feature of an organism
phenotype is used as synonym for trait
DNA
deoxyribonucleic acid, a self replicating material which is present in all living organisms as the main constituent of chromosomes. carrier of genetic information
gene
the basic physical and functional unit of heredity. Genes are made up of DNA
chromosomes
the small bodies in the nucleus of a cell that carry the chemical instructions for reproductions of the cell
threadlike structure of nucleic acid
alleles
one of the possible forms of a gene. most genes have two alleles (dominant and recessive)
dominant alleles
a variation of a gene that will produce a certain phenotype even in the presence of other alleles
recessive allele
only show their effect if the individual has two copies of the allele
karyotype
the number and visual appearance of the chromosomes in the cell nuclei
diploid 2n
containing two complete sets of chromosomes, one from each parent. Found in somatic cell of humans
haploid n
having a single set of unpaired chromosomes
found in gametes sex cells of humans
monosomy
missing one chromosome from a pair of chromosomes
trisomy
the presence of three copies of chromosomes rather than the normal two
phenotype
observable/ measurable characteristics of an organism
genotype
genetic constitution of an organism
Mendel’s laws of heredity
Inherited characteristics
Principle of dominance
law of segregation
Inherited characteristics
genes happen in pairs
during fertilization 2 genes come together to form a pair
principle of dominance
one gene masks the effect of another
law of segregation
genes separate (segregate) during the formation of sex cells. Organisms get one gene from each parent for a particular trait
monohybrid cross
involves the crossing of individuals and the examination of ONE(mono) character
dihybrid cross
a cross between two organisms that differ in two observed traits
ratio
9:3:3:1
sex linked traits
traits that are controlled by genes located on the sex chromosomes (usually the x chromosome)
incomplete dominance
lack of dominant gene. Both alleles contribute to phenotype of a heterozygote. Produces an offspring with traits unlike either parent
ex. snapdragons