BIOL 1000 Lecture Notes - Lecture 36: Punnett Square, Zygosity, Gamete

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erinchimpanzee657

13 May 2017

School

University of Manitoba

Department

Biological Sciences

Course

BIOL 1000

Professor

Kevin G.Scott

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Document Summary

Punnett square = diagram of the 4 possible combinations of alleles that could occur when 2 specific gametes combine . Homologous chromosomes bear the alleles for each character. Locus = a specific location of a gene along the chromosome . Homologous chromosomes have genes for the same characters located at the same positions along their lengths . 2 homologous chromosomes may have the same allele or different ones . Alleles of a gene reside at the same locus on homologous chromosomes. The law of independent assortment is revealed by tracking two characters at once. Mendel crossed homozygous plants having round yellow seeds (rryy) with plants having wrinkled green seeds (rryy) . Dna and rna are nucleic acids, consisting of long chains of nucleotides . Nucleotides = chemical unit that makes up dna and rna . Each type of dna nucleotide has a different nitrogenous base (a, g, c, t) .

Related Questions

QUESTION 1

Jim is blood type A, his brother John is type O and his sister Jane is type AB. What are the genotypes of their parents?

Which of the following is true for alleles that show incomplete dominance?

Heterozygotes have a genotype like the dominant allele.

Homozygotes have a genotype like the recessive allele.

Heterozygotes have a phenotype intermediate between the dominant and recessive alleles.

Homozygotes have the same phenotype as the heterozygotes.

QUESTION 3

Which principle of inheritance concluded that when games are formed in meiosis, the two alleles of each gene separate from one another, and each gamete receives only one allele?

independent assortment

Which term best describes a condition in which alleles at one locus can alter the expression of alleles at another locus?

polygenic inheritance

A single unit of genetic information located on a chromosome defines:

The physical expression (appearance or function) of an organism's genes defines:

genotype

a single characteristic

Palomino horses (golden color with a blond mane) are an incompletely dominant trait produced by the combination of the chestnut color allele and the cream color allele. If you wanted to produce as many palominos as possible, which mating strategy below would be the best choice?

Which term best describes the effect of a single gene on multiple aspects of the phenotype?

polygenic inheritance

QUESTION 9

Which term best describes the separate expression of both alleles for a single trait in the same cell?

polygenic inheritance

QUESTION 10

One form of a gene found on a single chromosome defines:

A chocolate lab (whose mother was a yellow lab) is mated with a black lab whose genotype is BbEe. What fraction of the offspring would be expected to be yellow labs?

What type of allele is always expressed regardless of whether the individual is homozygous or heterozygous for it?

Both the dominant and recessive alleles

Given the parents AABBGgHhrr Ã AabbGgHhRr, assume simple dominance and independent assortment. What proportion of the progeny will be expected to have the genotype AaBbggHHrr?

___________________ is defined as having two of the same type of allele for a particular trait.

The physical position of an allele on a single chromosome defines:

Which term best describes two or more genes affecting the phenotype in an additive fashion?

codominance

polygenic inheritance

2 Genetics -Match the terms with the most suitable description.
(Points : 16)

: An allele that can be expressed byan individual that is heterozygous.

: The genetic make-up of anindividual.

: The control of more than onephenotypic character by a single gene.

: The visible physical expression ofan individual's genetic make-up.

: An allele that can only beexpressed when an individual is homozygous.

: A trait controlled by more thanjust a single pair of alleles.

: A trait controlled by a genelocated on either the X or Y chromosomes.

: An individual carrying only oneallele of a recessively inherited disorder.

3. Evolution- Match the terms with the most suitable description.
(Points : 16)

Potential Matches:

1 : hybrid sterility

2 : habitat isolation

3 : hybrid inviability

4 : geographic isolation

5 : mechanical isolation

6 : gamete mortality

7 : temporal isolation

8 : behavioral isolation

Answer

: Because of a single mutation in adevelopmental gene, two closely related species of wasps have aslightly different anatomy of their sex organs making interbreedingimpossible.

: Two species of snakes aremorphologically very similar but breed during differentseasons.

: Males of two species of birds usedifferent mating dances to attract their mates.

: Due to a geographic barrier, asmall portion of a population remains isolated and its gene pooldiverges from that of the original population.

: Sperm from a male of one speciesdies in the reproductive tract of the female of a different speciesbefore fertilization can occur

: Mules are a cross between a donkeyand a horse; they are viable, healthy animals, but they cannotreproduce.

: A cross between two species ofsalamanders yields offspring, but they do not survive long enoughto reproduce

periwinkledeer332

1. Characters that show a continuous range of variation, such as height and eye color, usually are controlled:

a.	by a single gene with two alleles that are codominant.

b.	by many genes with an additive effect.

c.	by epistatic interactions between two genes.

d.	mainly by the environment, with only a small genetic component.

2. In humans, red-green colorblindness is inherited as a sex-linked recessive trait. In order for a woman to be red-green colorblind, which of the following statements must be true.

a.	Her mother must be red-green colorblind.

b.	All of her brothers must be red-green colorblind.

c.	Her father must be red-green colorblind.

d.	All of the above statements must be true if a woman is red-green colorblind.

3. The x-ray crystallography data collected by Rosalind Franklin suggested to Watson and Crick that the:

a.	structure of DNA is a double helix.

b.	two strands of the DNA molecule are joined by hydrogen bonds between the bases.

c.	four bases within DNA pair in a specific way.

d.	two strands of the DNA molecule are joined by covalent bonds between the bases.

4. In the genetic code, _________ one amino acid.

a.	one nucleotide specifies

b.	two nucleotides specify

c.	three nucleotides specify

d.	four nucleotides specify

5. During Meiosis I, a homologous pair of chromosomes may not separate, resulting in daughter cells that have extra chromosomes or are missing chromosomes. This can lead to genetic disorders, including Down Syndrome. This phenomenon is called:

a.	independent assortment.

b.	nondisjunction.

c.	segregation.

d.	crossing over.

6. You are a human geneticist studying the incidence of retinitis pigmentosa in the residents of Tristan de Cunha, a group of small islands in the middle of the southern Atlantic Ocean. The allele for retinitis pigmentosa, which causes a form of blindness, is inherited as an autosomal recessive. You have determined that the frequency of this allele (r) in the population is 0.4 (40%). Using the principles of the Hardy-Weinberg rule, you would estimate the frequency of individuals who are heterozygous for this allele (Rr) in the population to be:

a.	0.16 (16%)

b.	0.24 (24%)

c.	0.36 (36%)

d.	0.48 (48%)

7. Natural selection acts at the level of the:

a.	phenotype.

gene.

c.	population.

d.	nucleotide.

8. You are working with pea plants, trying to recreate the experiments that Mendel performed. You are doing a dihybrid cross with a plant that is heterozygous for both seed shape and seed color, with the genotype RrYy. Which allelic combinations would you expect to find in the gametes produced by this plant?

a.	This plant would produce only RY and ry gametes.

b.	This plant would produce only RrYy gametes.

c.	This plant would produce RY, Ry, rY, and ry gametes.

d.	You cannot determine which gametes this plant can produce without knowing the genotypes of its parents.

9. Biochemist Erwin Chargaff found that in DNA there is a special relationship between the four bases that we now call Chargaff's rule. His observation was that, in an organism's genome the:

a.	percentage of A nucleotides = the percentage of T nucleotides, and the percentage of C nucleotides = the percentage of G nucleotides.

b.	four bases all occur in an equal frequency (25%) within each organism.

c.	percentage of A nucleotides = the percentage of G nucleotides, and the percentage of C nucleotides = the percentage of T nucleotides.

d.	genetic material is composed of proteins, not DNA.

10. During DNA replication:

a.	each strand of the double helix acts as a template for the synthesis of a new strand.

b.	the enzyme DNA polymerase adds nucleotides to the strand being synthesized.

c.	the bases A,C,G and T are required.

d.	All of the above are true of DNA replication.

11. During translation, amino acids are joined by peptide bonds to make polypeptides. The formation of these peptide bonds is catalyzed by:

12. If an allele (R) at a gene with two alleles shows complete dominance, individuals with the genotypes ______ will have the same phenotype.

a.	RR and rr.

RR and Rr

Rr and rr

d.	Each of the three possible genotypes will have a different phenotype.

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BIOL 1000 Lecture Notes - Lecture 36: Punnett Square, Zygosity, Gamete

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