Unit 2 Classical Genetics Exam Flashcards
Solve the following crosses:
a. Complete dominance mono hybrid cross
b. Incomplete Dominance
c. Codominance
d. Multiple alleles
e. Blood typing
f. Sex linked
Define Gamete
A gamete is a reproductive cell of an animal or plant.
Define Autosome
An autosome is one of the numbered chromosomes, as opposed to the sex chromosomes.
Define allele
Two alternate forms of a trait
Define genotype
the genetic makeup of an organism.
Define homozygous
having two identical alleles of a gene.
Define dominant
a dominant trait or gene or most important, powerful, or influential.
Define phenotype
The observable physical properties of an organism (what the genotype shows)
Define heterozygous
having two different alleles of a gene.
Define recessive
a recessive trait or gene or less important (not dominant)
which parent dictates the childs sex?
The sex of the child is determined by the father, as a sperm cells transmit either the Y or X chromosome.
Possible genotypes for blood types
Blood Type Genotype
Blood Type A Genotypes AA or AO
Blood Type B Genotypes BB or BO
Blood Type AB Genotype AB
Blood Type O Genotype OO
What is the difference between a gene and a chromosome?
Genes are segments of your DNA, Chromosomes carry DNA in cells.
What is the purpose of meiosis?
to create gametes for sexual production with half the genetic material of the parent cells.
How many chromosomes are at the beginning of meiosis?
46 chromosomes
How many chromosomes are at the end of meiosis?
23 chromosomes.
Understand how chromosomes divided through phase 1 and phase 2 of meiosis
There are two divisions in meiosis; the first division is meiosis I: the number of cells is doubled but the number of chromosomes is not. This results in 1/2 as many chromosomes per cell. The second division is meiosis II: this division is like mitosis; the number of chromosomes does not get reduced.
Define nondisjunction
The failure of the chromosomes to separate, which produces daughter cells with abnormal numbers of chromosomes.
Define crossing over
the exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring.
Describe the steps of meiosis
Interphase: The cell prepares for division by replicating its DNA, resulting in two identical sister chromatids held together by a centromere.
Prophase I: Chromosomes condense, homologous chromosomes pair up and exchange genetic material through crossing over, forming chiasmata. The nuclear envelope breaks down, and spindle fibers begin to form.
Metaphase I: Homologous chromosome pairs align at the cell’s equator, attached to spindle fibers at their centromeres.
Anaphase I: Homologous chromosomes separate and move toward opposite poles of the cell, pulled by spindle fibers.
Telophase I: Chromosomes arrive at opposite poles, and nuclear membranes may form around each set of chromosomes. The cell undergoes cytokinesis, resulting in two haploid daughter cells, each containing one set of chromosomes.
Prophase II: Chromosomes condense again, and the nuclear envelope breaks down if it reformed in telophase I. Spindle fibers begin to form.
Metaphase II: Chromosomes align at the cell’s equator, attached to spindle fibers at their centromeres.
Anaphase II: Sister chromatids separate and move toward opposite poles of the cell, pulled by spindle fibers.
Telophase II: Chromatids arrive at opposite poles, and nuclear envelopes form around each set of chromosomes. The cell undergoes cytokinesis again, resulting in four haploid daughter cells, each containing half the number of chromosomes as the original parent cell.
Understand how to read a pedigree
What is the purpose of a karyotype
To help identify genetic problems as the cause of a disorder or disease.
How many chromosomes do humans have?
46 chromosomes in total.
Understand how to read a karyotype
