Test 4 Practice

Why did Mendel continue some of his experiments to the F2 or F3 generation?

The fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment most probably indicates which of the following?

In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygous tall plant, what is the probability that the offspring will be tall?

Which of the following describes the ability of a single gene to have multiple phenotypic effects?

Which of the following provides an example of epistasis?

Most genes have many more than two alleles. However, which of the following is also true?

A scientist discovers a DNA-based test for one allele of a particular gene. This and only this allele, if homozygous, produces an effect that results in death at or about the time of birth. Of the following, which is the best use of this discovery?

An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable biochemically in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient?

Labrador retrievers are black, brown, or yellow. In a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies.

These results indicate which of the following?

Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all.

The relationship between genes S and N is an example of

Gene S controls the sharpness of spines in a type of cactus. Cactuses with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cactuses have dull spines. At the same time, a second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn cactuses have no spines at all.

A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce

This disease is caused by the substitution of a single amino acid in the hemoglobin in red blood cells.

____________ are heterozygous individuals who carry the recessive allele, but are phenotypically normal.

Thomas Hunt Morgan's choice of Drosophila melanogaster has been proven to be useful even today. Which of the following has/have continued to make it a most useful species?

I. its four pairs of chromosomes
II. a very large number of visible as well as biochemically mutant phenotypes
III. easy and inexpensive maintenance
IV. short generation time and large number of offspring

A woman is found to have 47 chromosomes, including three X chromosomes. Which of the following describes her expected phenotype?

In cats, black fur color is caused by an X-linked allele; the other allele at this locus causes orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?

Cinnabar eyes is a sex-linked recessive characteristic in fruit flies. If a female having cinnabar eyes is crossed with a wild-type male, what percentage of the F1 males will have cinnabar eyes?

Calico cats are female because

What is the reason that linked genes are inherited together?

Recombination between linked genes comes about for what reason?

If nondisjunction occurs in meiosis II during gametogenesis, what will be the result at the completion of meiosis?

What is the source of the extra chromosome 21 in an individual with Down Syndrome?

A gene is considered to be non-Mendelian in its inheritance pattern if it seems to "violate" Mendel's laws. Which of the following would be considered Mendelian?

Suppose that a gene on human chromosome 18 can be imprinted in a given pattern in a female parent but not in a male parent. A couple in whom each maternal meiosis is followed by imprinting of this gene have children. What can we expect as a likely outcome?

In his transformation experiments, what did Griffith observe?

How do we describe transformation in bacteria?

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

Which of the following can be determined directly from X-ray diffraction photographs of crystallized DNA?

What is meant by the description "antiparallel" regarding the strands that make up DNA?

An Okazaki fragment has which of the following arrangements?

In E. coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation?

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork:
3' C C T A G G C (T) G C A A T C C 5'
An RNA primer is formed starting at the (T) of the template. Which of the following represents the primer sequence?

What is the function of DNA polymerase III?

The leading and the lagging strands differ in that

What is the function of topoisomerase?

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?

If a cell were unable to produce histone proteins, which of the following would be a likely effect?

Which of the following variations on translation would be most disadvantageous for a cell?

The nitrogenous base adenine is found in all members of which group?

Which of the following does not occur in prokaryotic eukaryotic gene expression, but does in eukaryotic gene expression?

A particular triplet of bases in the coding sequence of DNA is AAA. The anticodon on the tRNA that binds the mRNA codon is

Accuracy in the translation of mRNA into the primary structure of a polypeptide depends on specificity in the

When the ribosome reaches a stop codon on the mRNA, no corresponding tRNA enters the A site. If the translation reaction were to be experimentally stopped at this point, which of the following would you be able to isolate?

The central dogma is the concept that cells are governed by a cellular chain of command. What does the dogma state?

_______________ is the synthesis of RNA under the direction of DNA, which produces ___________________.

Codons must be read in the correct ___________________ in order for the specified polypeptide to be produced.

The DNA sequence where RNA polymerase attaches is called the ______________; in bacteria, the sequence signaling the end of transcription is called the _____________.

What are the three stages of transcription?

Noncoding regions are called intervening sequences, or ___________. The other regions are called _____________, because they are eventually expressed, usually translated into amino acid sequences.

The two ribosomal subunits (large and small) are made of proteins and ______.