Genetics Final

Color blindness is more common in males than in females. What is the reason for this?

Color blindness is more common in males than in females. What is the reason for this?

The gene responsible for causing color-blindness is located on the X chromosome

What is the name of the gene located on the Y chromosome that promotes development of male internal and external sex organs?

SRY

Which of the following are advantages of genetic recombination?

Recombination promotes genetic diversity

Recombination helps chromosomes separate during cell division

Recombination reduces the likelihood of offspring developing trisomy 21 (Down syndrome)

DNA consists of four nitrogenous bases. According to the principle of complementary base pairing, which bases pair together in a DNA molecule?

T pairs with A, and C pairs with G

Which of the following statements about RNA is correct?

RNA is usually single-stranded

Which of the following models states that, after one round of replication every new DNA double helix is a hybrid consisting of one strand of old DNA bound to one strand of newly synthesized DNA?

Semi-conservatice model

Which of the following pieces of DNA replication machinery adds new bases to a growing DNA strand?

Polymerase

Which of the following pieces of DNA replication machinery unwinds DNA so new bases can be added?

Helicase

What is a method that researchers can use to generate novel (new) mutations in research animals?

Expose research animals to X-rays to generate thymine dimers

Why are mutations more common in sperm cells than in egg cells?

Mature sperm are constantly produced after onset of puberty

Which of the following types of RNA carry amino acids to the growing polypeptide chain during translation?

Transfer RNA (tRNA)

What is a function of the promoter sequence of DNA?

Promoter sequences attract RNA polymerase to the gene being transcribed

Which of the following characteristics is unique to DNA replication in eukaryotes (and not prokaryotes)?

Eukaryotes have an enhancer region to help promote transcription

Which of the following components of DNA are NOT present in a mature mRNA molecule?

Introns

Which of the following components are typically found in a plasmid?

Origin of replication

Gene for antibiotic resistance

DNA inserted at restriction sites

There are multiple types of genetic variants present in organisms. Variants can be classified by their size. Which genetic variant describes a change in 1 base pair of DNA?

Single nucleotide polymorphisms (SNPs)

What happens during the annealing stage of a polymerase chain reaction?

Primers adhere to DNA via complementary base pairing

Gel electrophoresis

Separates DNA fragments based on molecular weight

DNA microarray

Determines which SNPs of a gene are present in a sample

Sanger sequencing

Utilizes labeled DNA bases to determine order of DNA bases

Ames test

Used to test if a substance is a potential carcinogen

Polymerase chain reaction

Amplifies a specific DNA fragment for other procedures

Which of the following are reasons why the pea plant was a good model of Mendel’s studies?

The plants are easy to self-fertilize

Large numbers of offspring are produced

The plants exhibit many discrete traits

One of the traits Mendel studied was petal color of the pea plant. Mendel found that roughly 3 out of every 4 plants had purple flowers. The remaining plants had white petals. What can be concluded from this finding?

Purple petal color is dominant to white petal color in pea plants.

Which term describes offspring that have different phenotypic combinations than their parents?

Recombinant

An individual with type B blood has children with an individual who has type B blood. Assume both parents are heterozygous for this trait. What is the probability of having a child with type A blood?

0%

An individual with type B blood has children with an individual who has type B blood. Assume both parents are heterozygous for this trait. What is the probability that their child will have at least one A allele in their genotype?

0%

Individuals with type AB blood carry one allele for type A blood and one allele for type B blood. What is the relationship between the A and B alleles in this context?

The A and B alleles are codominant

Snapdragon flower petals come in three different colors: red, white, and pink. When red and white true breeding plants are crossed, F2 offspring have a phenotypic ratio of 1 red: 2 pink: 1 white. What do these results suggest?

This could be an example of incomplete dominance

Coat color in labrador retrievers is determined by two genes. One gene is responsible for producing pigment, while a second gene is responsible for depositing the pigment in the fur. What concept is this an example of?

Epistasis

Which of the following events occur during prophase of mitosis?

chromosomes condense and become visible

Which of the following statements regarding meiosis is correct?

crossing over occurs in meiosis to increase genetic diversity

Meiosis occurs in germ cell lines (i.e. sperm and egg)

During which phase of the cell cycle does DNA duplication occur?

S phase

Which of the following can be inferred from looking at a karyotype?

the likelihood of being infected with malaria

An individual has the genotype AaBBcc. Which of the following gametes can be produced by this individual?

aBc

You flip a quarter four times. What is the probability of getting head all four times?

1/16

What does a pair of homologous chromosomes look like?

Full chromosome (looks like an “X” with centromeres in middle)

What does a chromatid look like?

Picture an “X” chromosome split vertically down the middle. It’s one half of the chromosome

In which part of the cell does eukaryotic transcription occur?

Nucleus

What function does the sigma (o) factor serve during transcription initiation?

Attracts RNA polymerase to the transcription site

The lacl gene of the lac operon acts in trans to regulate gene expression. What does it mean?

The protein coded by lacl can diffuse through the cytoplasm to regulate transcription

Which of the following components are present in a mature mRNA transcript?

Exons

5’ cap

Which of the following regulatory components is capable of promoting transcription from distant initiation points in the genome?

enhancer

Which of the following are ways in which a cell can up regulate gene expression in one tissue while inhibiting expression of the same gene in another tissue?

Produce tissue-specific proteins that dock to enhancer regions of the target gene

Produce different patterns of histone acetylation at the promoter region of the gene

Regulate gene expression via hormone production

Which of the following terms is used to describe DNA that has been “silenced”, and thus cannot be accessed by transcription machinery?

Heterochromatin

How can CpG methylation contribute to a broad range of phenotypes for a given trait?

Not all methylation sites must be occupied, leading to variable DNA access

Which of the following terms is used to describe an organism whose genome has been altered but the introduction of one or more foreign DNA sequences from another species.

Transgenic organism

One of the tools used to produce genetically modified organisms are plasmid vectors that contain p-elements. What are p-elements?

Recognition sites for the transposase enzyme

Once a double stranded break is induced in a DNA strand, Which of the following can occur?

A DNA template is used to repair the break, ensuring that no bases are lost

Which of the following is NOT a characteristic of cancer cells?

Possessing the ability to regulate the frequency of cell division

Which of the following terms is used to describe the ability for a cell to break through membrane barriers and travel through the bloodstream?

metastasis

Why does the risk of developing cancer tend to increase with age?

The more times a cell divides, the more likely that a delirious mutation will arise