Midterm II Study Questions

What is Mendel’s First Law?

The law of segregation: at any given genetic locus, each gamete randomly recieves one of the two alleles carried by the parent.

That is, the two alleles at a genetic locus within an individual segregate from one another during the proces of gamete formation.

What law is this?

Gregor Mendel’s First Law: The Law of segregation

What is Mendel’s second law?

Law of independent assortment: each pair of alleles segregates independently of the alleles at other loci. This is most likely to be true when genetic loci occur on different chromosomes.

What is independent assortment

The biological principle that the alleles for different traits are sorted into gametes independently of one another.

An unfertilized egg contains 39 chromsomes.

N=what?

2N=What?

Cells taken from a chicken feather have ___ chromsomes

N=39

2N=78

Chicken feather cells have 78 chromosomes.

Plant pollen is analogous to animal ___.

Sperm

List the genotypes of all the different gametes that could be formed by an individual wirth the genotype RrSsTt.

Rst, RsT, RSt, RST; rst, rsT, rSt, rST

If an adult male has the genotype AABcc, list all the possible haploid genotypes which could be produced by this male in his sperm.

ABc, Abc

How many different possible eggs could a female with the genotype RRssTt produce?

Two: RsT and Rst

If a female has the genotype AABbC, what is the probability that any one of her gametes will have the genotype ABC?

1/4

What is recombination

The process where pieces of DNA are broken and combined to produce new combinations of alleles. Creates genetic diersity by mixing traits from both parent during meiosis

What is meiosis

A specialized type of cell division that creates sex cells

What is mitosis

Produces identical cells for differentation

If an organism practiced self fertilization, could recombination occur? If an organism practiced self-fertilization, would all ther offspring be genetically identical? Why/why not?

Not really. This is because chromsomes still sort independently of one another.

What would be the only time one could expect offspring to be identical to their paent in a self-fertilizing organism?

IOf the parent were homozygous at every genetic locus.

When a gene has several different versions that create slightly different gene products, each version of the gene is called an___.

Allele

How would it be possible for a cross between two plants, one with red flowers and one with white flowers, to produce all pink flowered offspring, when a cross between two pink flowered plants produce pink, white, and red flowered offspring.

The pink flowered plants are heterozygotes with a color intermediate between that of their red and white parebnts.

The allele responsible for the peculiar markings of Siamese cats is also responsible for crossed-eyes that occur in many members of this breed.This example best illustrates which of the following general principles.

Pleiotropy

A single locus has 12 alleles within a population. At most, how many different alleles for this locus should be found in a single, diploid individual?