inheritance Flashcards
what is inheritance?
transmitting genetic information from one generation to the next
what is a genotype?
the genetic constitution of an organism
what is a phenotype?
the expression of an organisms genetic constitution/ genotype, combined with its interaction with the enviornment
what is an allele?
different versions of the same gene
what is meant by dominant allele?
an allele whose characteristic will always appear in the phenotype, whether one or two are presented
what is a recessive allele?
an allele whose characteristic only appears in the phenotype if two are present
what is meant by homozygous and heterozygous?
homozygous - when an organism has two copies of the same allele ( two recessive or two dominant)
heterozygous - when an organism has two different versions of the same gene (one dominant and one recessive)
define monohybrid inheritance
where one phenotypic characteristic is controlled by a single gene
define dihybrid inheritance
where two phenotypic characteristics are determined by two different genes present on two different chromosomes at the same time
what is sex linkage?
where an allele is located on one of the sex chromosomes meaning its expression depends on the sex of the individual
what is a gene?
a section of DNA that codes for a specific protein
how is sex determined by genes?
one of the 23 pairs of chromosomes determines sex
the pair can either be XX for a female or XY for a male
what is a haploid nucleus?
what is a diploid nucleus?
a nucleus with one set of chromosomes
a nucleus with two sets of chromosomes where there is a pair of each type of chromosome - 23 pairs
what is mitosis?
what are the 4 stages
a type of nuclear division that produces two genetically identical daughter cells
- growth
- replacing worn out cells
- repairing tissues
- asexual reproduction
what are stem cells
cells that don’t lose the ability to differentiate so can differentiate into many different types of cells
what is meiosis?
a type of reduction division which halves the chromosomes number
producing 4 genetically different daughter cells
it produces sex cells / gametes
what is a genotype?
the genes present for a trait
what is a phenotype?
the visible characteristic
