Genetics Study guide Flashcards
What is heterozygous? Also known as
Heterozygous is two different alleles for a trait also known as a carrier
What is homozygous? Also known as?
Homozygous is 2 identical alleles for a trait, also known as true breeding.
What is a recessive trait
an unexpressed trait in the alleles. It is a trait that is not as common, for example, blue or green eyes.
What is a dominant trait?
a trait that is visibly expressed in the organism and are more likely to occur, for example, brown hair or brown eyes.
What are the phenotypes and genotypes of blood
Phenotype A; Genotype AA or AO
Phenotype: B; Genotype BB or BO
Phenotype AB Genotype AB Phenotype O Genotype OO
How many chromosomes are in a normal karyotype
46
What is the result of mitosis
two new genetically identical daughter cells (46 chromosomes)
Result of Meiosis
4 new different haploid cells being produced and it cuts the amount of chromosomes we have in half (from 46 to 23).
Where are sex-linked genes located?
sex chromosomes
Why do more men have sex linked disorders than women?
They only have one x chromosome while women have two so they can’t hide their recessive traits as well
Which parent determines the sex of an offspring
males; contributed y chromosome
What are the chromosomes for females and males
Females XX
Males XY
What is a polygenic trait?
multiple genes that determine a trait (eye color)
What is codominance
neither allele is recessive and the phenotypes of both alleles are expressed.
What is incomplete dominance
when individuals show a blended phenotype
What is independent assortment
Genes that segregate independently
What characteristics are caused by multiple alleles
Blood groups
what are autosomes
Any chromosomes that are not sex chromosomes
What is nondisjunction? How does this affect the offspring
failure of homologous chromosomes to separate properly during meiosis; results in incorrect number of chromosomes in offspring (ex: one extra chromosome = trisomy, another complete set of chromosomes = polyploidy)
Two phases of meiosis
The first phase is Prophase I, Metaphase I, Anaphase I, Telophase I and Cytokinesis.
The second phase is Prophase II, Metaphase II, Anaphase II, Telophase II and Cytokinesis.
what happens in prophase 1
homologous pairs cross over (can only occur in this phase) and chromosomes condense (spindle forms) and nuclear envelope fragments
what happens in metaphase 1
the homologous pairs align along the equator of the cell.
what happens in anaphase 1
homologs separate and move to opposite poles. The sister chromatids remain attached to their centromeres
What happens in telophase/cytokinesis
In Telophase I the nuclear envelope reassembles, the spindles disappear. In Cytokinesis the cells divide into
