Supplemental InstructionLeader: Taylor Thomas

BIOL/GEN 313Instructors: Myers & Vollbrecht

Iowa State UniversityDate: 2/21/16

Exam 2 Review

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  1. What is RNAi?
  1. What are the two types of RNA used in RNAi?
  1. What is the CRISPR/Cas9 system and why is it useful in biotechnology?
  1. Describe the four levels of protein structure, indicating how to distinguish between them.

Primary:

Secondary:

Tertiary:

Quaternary:

  1. Starting with the non-coding DNA strand, figure out the amino acid sequence. Draw the

amino acid sequence, noting the peptide bonds.

Noncoding DNA strand: 5’- A T G A C T G C A C A T G A G T C T T A A -3’

Coding DNA strand:

mRNA strand:

Amino acid sequence:

Polypeptide drawing:

How would a one base insertion/deletion affect the protein outcome?

What is an example of a specific substitution mutation that would not change the protein outcome?

  1. How many different codons are there? How many different amino acids are there? Why aren’t there an equal number of codons and amino acids?
  1. How many reading frames are there in double stranded DNA?
  1. If an mRNA codon is 5’- UCG- 3’, what is the anticodon sequence?
  1. What is an auxotrophic mutation?
  1. What is aminoacylation? What is the main enzyme used for this reaction?

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  1. How do you distinguish a chromosome vs. a chromatid vs. sister chromatids?
  1. What would you use to count the number of chromosomes? What would you use to count the number of DNA molecules?
  1. When in meiosis does crossing over occur?
  1. What does crossing over do?
  1. When does random chromosome segregation occur?
  1. What equation can you use to calculate the number of possible chromosome combinations in gametes using the haploid number?
  1. What is the function of cohesion and shugosin?
  1. Describe the steps of mitosis.
  1. How is mitosis different from meiosis?
  1. How is meiosis I different than meiosis II?
  1. When in meiosis does a cell go from diploid to haploid?

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  1. An organism with the genotype Tt is self-crossed. What are the probabilities of each possible genotypes of the F1?
  1. An organism with the genotype Tt is test-crossed. What are the probabilities of each possible genotypes of the F1?
  1. An unknown genotype, dominant phenotype individual is mated with a homozygous recessive individual. The F1 generation all expresses the dominant phenotype. What is the genotype of the unknown parent?
  1. What is the sum rule and when is it used?
  1. What is the product rule and when it is used?
  1. John has a recessive disease, but Sally does not have the disease. John and Sally have a child that has the recessive disease. Assuming the disease is controlled by one gene, what is the probability their next child will have the disease?
  1. A parent homozygous recessive for two genes and a parent homozygous dominant for two genes are mated. What is the probability of an offspring of the F2 generation expressing the recessive phenotypes of both genes? The F1 generation is crossed to itself to produce the F2 generation.
  1. Solve the following three questions using the genotypes of the two parents.

Parent 1: BbParent 2: Bb

What is the probability the first three offspring will be tt genotype?

What is the probability the first three offspring will express the dominant phenotype?

What is the probability the first five offspring will carry a recessive allele?

  1. Solve the following three questions using the genotypes of the two parents.

Parent 1: AaBbParent 2: Aabb

What is the probability an offspring will be aaBb?

What is the probability an offspring will express the dominant phenotype for both genes?

What is the probability an offspring will express the recessive phenotype for both genes?

  1. Solve the following three questions using the genotypes of the two parents.

Parent 1: AaBBCcParent 2: aabbCc

What is the probability an offspring will express the dominant phenotype for all three genes?

What is the probability the first two offspring will be heterozygous for all three genes?

What is the probability an offspring will express the recessive phenotype for all three genes?

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  1. Answer the following question using the information provided.

Parent genotypes

AaBb x aabb

Offspring genotypes

  • 25 of the offspring are AaBb
  • 48 of the offspring are aabb
  • 62 of the offspring are aaBb
  • 30 of the offspring are Aabb

Is there a difference between the observed data and the expected data? (use the chi square

test)

  1. A heterozygous plant and a homozygous recessive plant are mated. 165 of their offspring express the dominant phenotype, and 32 express the recessive phenotype. Is there a difference between the observed and expected data? (use the chi-square test)

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  1. What does hemizygous mean? Are human males or females hemizygous?
  1. How are the X and Y chromosomes still able to act as homologs?
  1. What is the typical inheritance pattern for X-linked recessive genes?
  1. White eyes in flies is a recessive X-linked gene. If a white eyed male is mated with a wild type female (carries no alleles for white eyes) what is the proportions of genotypes in the F1 generation? If a female and male from the F1 are crossed, what will be the proportion of genotypes in the F2 generation?
  1. Sally’s father has colorblindness, but Sally does not have colorblindness. Sally has children with a man who is colorblind. What are the chances her daughter will be colorblind? What are the chances her son will be colorblind?
  1. What is a Barr body?
  1. How is X inactivation in females related to calico cats?