genetics lecture 3: mendelian genetics

What is the function of mRNA in the cell?
A. Forms the ribosome structure
B. Carries amino acids
C. Transports DNA into the cytoplasm
D. Serves as a template for protein synthesis

Serves as a template for protein synthesis

Which base is found in RNA but not in DNA?
A. Thymine
B. Uracil
C. Cytosine
D. Guanine

uracil

Which of the following occurs during transcription?
A. mRNA binds to tRNA
B. DNA is translated into amino acids
C. DNA is used to create a complementary RNA strand
D. Proteins are synthesized from RNA

DNA is used to create a complementary RNA strand

Where does translation occur in eukaryotic cells?
A. Nucleus
B. Ribosome
C. Nucleolus
D. Golgi apparatus

Ribosome

Which of the following codons initiates translation?
A. UAA
B. AUG
C. UGA
D. UAC

AUG

What characteristic of pea plants made them ideal for Mendel’s experiments?
A. Polyploid genome
B. Large chromosomes
C. True-breeding varieties with distinct traits
D. Fast mutation rate

True-breeding varieties with distinct traits

Which of the following best describes an allele?
A. A chromosome region controlling multiple traits
B. A version of a gene found at the same locus
C. A protein that regulates a gene
D. An RNA sequence that modifies DNA

A version of a gene found at the same locus

Which Mendelian law explains the 3:1 phenotypic ratio observed in F2 generation of monohybrid crosses?
A. Law of dominance
B. Law of linkage
C. Law of independent assortment
D. Law of segregation

Law of segregation

If two heterozygotes are crossed (Aa × Aa), what is the probability of a homozygous dominant offspring?
A. 1/4
B. 1/2
C. 3/4
D. 1

1/4

Which of the following describes a test cross?
A. Crossing two recessive individuals
B. Crossing a homozygous dominant with a heterozygote
C. Crossing an individual with unknown genotype with a homozygous recessive
D. Self-fertilization of a true-breeding plant

Crossing an individual with unknown genotype with a homozygous recessive

What is the phenotypic ratio in a monohybrid cross between heterozygotes?
A. 1:1
B. 2:1
C. 3:1
D. 9:3:3:1

3:1

The difference between genotype and phenotype is that:
A. Genotype is visible, phenotype is not
B. Phenotype refers to the genetic composition
C. Phenotype is the physical expression of the genotype
D. Genotype is always dominant

Phenotype is the physical expression of the genotype

What is the expected phenotypic ratio in the F2 generation of a dihybrid cross?
A. 9:3:3:1
B. 1:2:1
C. 3:1
D. 1:1:1:1

9:3:3:1

Which Mendelian law is demonstrated in a dihybrid cross?
A. Law of segregation
B. Law of dominance
C. Law of equal allocation
D. Law of independent assortment

Law of independent assortment

What gametes can be produced by an individual with the genotype RrYy?
A. RY and ry only
B. RY, Ry, rY, ry
C. R, r, Y, y
D. Only RY and rY

RY, Ry, rY, ry

If a plant with genotype RrYy is crossed with rryy, what is the expected phenotypic ratio of offspring?
A. 1:1:1:1
B. 9:3:3:1
C. 3:1
D. 1:2:1

1:1:1:1

In the product rule of probability, to find the probability of two independent traits occurring together, you:
A. Add their probabilities
B. Divide the probabilities
C. Multiply their probabilities
D. Subtract one from the other

Multiply their probabilities

What is the probability of a round green seed from a WwGg × wwgg test cross?
A. 1
B. 1/4
C. 1/2
D. 3/4

1/4

Which rule is used when calculating the probability of mutually exclusive outcomes?
A. Product Rule
B. Hardy-Weinberg Rule
C. Sum Rule
D. Law of Segregation

Sum Rule

If two traits are linked (close together on the same chromosome), they will:
A. Assort independently
B. Never be inherited together
C. Frequently appear in recombinant forms
D. Be inherited together more often than not

Be inherited together more often than not

In a trihybrid cross involving three independently assorting genes, how many possible gamete combinations can be produced?
A. 4
B. 8
C. 16
D. 32

8

When do we use a test cross?

Given that dominant trait defines the phenotype, we don’t know if the plant is homozygous or heterozygous for this trait

what ratio is produced when a dihybrid heterozygote is crossed with a double homozygous recessive?

1:1:1:1

what ratio is produced when a two dihybrid heterozygotes are crossed?

9:3:3:1H

How can we predict probabilities of genotype combinations?

the number of different gametes: 2ⁿ