Chapter 4: Genetics Flashcards
What are eukaryotes made of?
DNA and proteins
Gene
a heritable factor that controls a specific characteristic
Allele
one specific form of a gene, differing from other alleles by one or a few bases only and occupying the same gene locus as other alleles of the gene
Genome
The whole of the genetic information of an organsom
genemutation
a change to the base sequence of a gene
What is meiosis for a kind of division?
Meiosis is a reduction division of a diploid (2n) nucleus to form a haploid (n) nucleus
Homologous chromosomes
they have the same genes as each other, in the same sequence, but not necessarily the same alleles of those genes
What is chrossing over
crossing over is the exchange of genetic material between non-sister chromatids
Stages of Meiosis
prophase, metaphase, anaphase, telophase
What is non-disjunction?
This occurs when the chromosomes do not separate properly during meiosis. This leads that the production of gametes have either to many or to few chromosomes. Zygotes that have to few chromosomes usually die, but the ones with too many survive. E.g. Down syndrom
Karyotyping
chromosomes are arranged in pairs according to their size and structure
How is karyotyping performed?
Itis performed using cells collected by chorionic villus sampling or amniocentesis, for pre-natal diagnosis of chromosome abnormalities
Phenotype
the characteristics of an organism
Dominant allele
an allele that has the same effect on the phenotype wether it is present in homozygous or heterozygous state
Recessive allele
an allele that only has an effect on the phenotype when it is present in a homozygous state
Locus
the particular position on a homologous chromosome of a gene
Homozygous
having 2 identical alleles of a gene
Heterozygous
having 2 different alleles of a gene
Carrier
an individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this allele
Test cross
testing a suspected homozygous and crossing it with a known homozygouse recessive
Sex linkage
the assiciation of a characteristic with gender, because the gene controlling the characteristics is located on a sex chromosome
What happens with the DNA in gel electrophoresis
fragments of DNA move in an electric field and are seperated according to their size (this method is used in DNA profiling)
What happens with the amino acid sequence when genes are transfered between species
the amino acid sequence of polypeptides translated from them is unchanged because the genetic code is universal
Clone
a group of genetically identical organsim or a group of cells derived from a single parent cell
