BIO

Albinism is a recessive trait. A man and woman both show normal pigmentation, but both have one parent who has albinism (without melanin pigmentation). What is the probability that their first child will have albinism?

1/4

If a cell at metaphase of mitosis contains 20 sister chromatids, how many chromosomes will be present in a G1 cell?

10

In a diploid cell with 5 chromosome pairs (2n = 10), how many sister chromatids will be found in a nucleus at prophase of mitosis?

20

A particular triplet of bases in the template strand of DNA is 5′-AGT-3′. What would be the corresponding codon for the mRNA that is transcribed?

3′-UCA-5′

What is the chromosome composition of a normal human female?

44 autosomes and 2 X chromosomes

What is the chromosome number found in humans cells if meiosis I is completed normally?

44 autosomes and 2 sex chromosomes

What is the chromosome composition of a normal human male?

44 autosomes, 1 X chromosome, and 1 Y chromosome

Achondroplasia is a form of dwarfism caused by a dominant allele. The homozygous dominant genotype causes death, so individuals who have this condition are all heterozygotes. If a person with achondroplasia mates with a person who does not have achondroplasia, what percentage of their children would be expected to have achondroplasia?

50%

Which cross will produce only heterozygous offspring?

AA x aa

The DNA codon GTA codes for an amino acid carried by a tRNA with the anticodon ________.

CAU

What happens during interphase?

Chromosome duplication occurs.

Chromatin consists of ________.

DNA and protein

Eukaryotic chromosomes are composed of which of the following macromolecules?

DNA and proteins

Which of the following facts did Hershey and Chase make use of in trying to determine whether DNA or protein is the genetic material?

DNA contains phosphorus, whereas protein does not.

What is the first level of control of eukaryotic gene transcription?

DNA packing and unpacking

In humans, the presence or absence of dimples is a trait controlled by a single gene. What is the genotype of an individual who is heterozygous for dimples?

Dd

In meiosis, how does prophase I differ from prophase II?

During prophase I there is one diploid cell; during prophase II there are two haploid cells.

Which of the following statements is true of a species that has a diploid number of 16?

Each diploid cell has eight homologous pairs of chromosomes.

Which of the following investigators was (were) responsible for the discovery that in DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine?

Erwin Chargaff

Which of the following events happens at the conclusion of meiosis I?

Homologous chromosomes of a pair are separated from each other.

Which of the following statements correctly describes the effect a nonsense mutation would have on a gene?

It introduces a premature stop codon into the mRNA.

A particular organism has 46 chromosomes in its karyotype. Which of the following statements is correct regarding this organism?

It produces gametes with 23 chromosomes.

Which of the following processes occurs during transcription?

RNA is synthesized

Which of the following enzymes is responsible for RNA synthesis?

RNA polymerase

Translation converts the information stored in ________ to ________.

RNA; a polypeptide

Which activity will help prevent cancer and increase survival?

Seek early detection of tumors.

Which event occurs during anaphase?

Sister chromatids become separate chromosomes.

________ is a stage of mitosis.

Telophase

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

The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

Which of the following statements describes the chromosomal makeup of each daughter cell after telophase and cytokinesis of meiosis I?

The cells are haploid, and the chromosomes are each composed of two sister chromatids.

If organisms reproduced sexually but without meiosis, what would result?

The chromosome number would double each generation.

What happens during prophase?

The mitotic spindle begins to form.

What is the key to the recognition of incomplete dominance?

The phenotype of the heterozygote falls between the phenotypes of the homozygotes.

A purebred plant that produces yellow seeds is crossed with a purebred plant that produces green seeds. The seeds of all of the offspring are yellow. Why?

The yellow allele is dominant to the green allele.

Which of the following types of mutation, resulting in an error in the mRNA just after the AUG start of translation, is likely to have the most serious effect on the polypeptide product?

a deletion of two nucleotides

Metaphase of mitosis is characterized by ________.

alignment of chromosomes on the equator (metaphase plate) of the cell

Metaphase is characterized by ________.

alignment of chromosomes on the equator of the cell

Peptide bonds form between ________.

amino acids

Chromosomes that do NOT determine the sex of an individual are called ________.

autosomes

A correct comparison between a benign and a malignant tumor is that ________.

benign tumors do not metastasize; malignant tumors do

An individual who is homozygous ________.

carries two copies of the same allele for a gene

Homologous chromosomes ________.

carry genes controlling the same inherited characteristics

The structure where sister chromatids are joined is called the ________.

centromere

During metaphase, ________.

chromosomes line up in the middle of the cell

An individual with the blood group genotype LMLN has the phenotype MN. What is the relationship between the LM and LN alleles?

codominance

Which characteristic seen in prophase I does NOT occur in prophase II?

crossing over occurs

During which of the following processes do sister chromatids separate from each other?

during both mitosis and meiosis II

After replication, ________.

each new DNA double helix consists of one old strand and one new strand

Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?

environmental factors such as soil pH affect the phenotype

The expressed (coding) regions of eukaryotic genes are called ________.

exons

An original section of DNA has the base sequence AGCGTTACCGT. A mutation in this DNA strand results in the base sequence AGGCGTTACCGT. What type of mutation does this change represent?

frameshift mutation

Mendel's law of segregation indicates that

gametes have one allele copy for each gene.

The process by which genotype becomes expressed as phenotype is ________.

gene expression

In sexual reproduction in humans ________.

haploid sperm fertilizes a haploid egg cell

A cell that completed the cell cycle without undergoing cytokinesis would ________.

have two nuclei

Which trait is polygenic in humans?

height

Mendel crossed purebred purple-flowered plants with purebred white-flowered plants, and all of the resulting offspring produced purple flowers. The offspring are all ________, and the allele for purple flowers is ________.

heterozygotes; dominant

During metaphase I, ________.

homologous chromosomes line up in the middle of the cell

Many human traits, such as our performance on intelligence tests or our susceptibility to heart disease, are ________.

influenced by both genes and the environment

The CORRECT sequence of events that occurs during transcription is ________.

initiation, elongation, termination

An individual who is heterozygous for cystic fibrosis ________.

is a carrier

To determine the phenotype of an individual who expresses a dominant trait, you would cross that individual with an individual who ________.

is homozygous recessive for that trait

What is the specific location of a gene on a chromosome?

locus

Which of the following molecular structures contain codons?

mRNA

Transcription is the ________.

manufacture of a strand of RNA complementary to a strand of DNA

Crossing over of chromosomes normally takes place during which of the following processes?

meiosis I only

The RNA that is translated into a polypeptide is ________ RNA.

messenger

A mating between a purebred purple-flowered pea plant and a purebred white-flowered pea plant would be called a ________.

monohybrid cross

An individual with (naturally) curly hair and an individual with (naturally) straight hair mate; all of their offspring have (naturally) wavy hair. What is the relationship between the alleles for hair texture?

ncomplete dominance

What name is given to a gene that causes cancer?

oncogene

What is the smallest number of nucleotides that must be added or subtracted to change the triplet grouping of the genetic message?

one

The best definition of a true breeding plant is one that ________.

passes on the next generation only those traits identical to the parent

What name is given to the collection of traits exhibited by an organism?

phenotype

Which of the following inheritance patterns describes the ability of a single allele to have multiple phenotypic effects?

pieiotropy

Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed, and have both cardiovascular and eye defects. Marfan syndrome is an example of ________.

pleiotropy

Inheritance of certain genes increases the risk of getting certain cancers; thus, it can be said that ________.

predisposition to these cancers is inherited

One difference between mitosis and meiosis is that mitosis ________.

produces cells genetically identical to the parent cell, but meiosis does not

The type of cell division that produces two genetically identical daughter cells is important for all of the following functions EXCEPT ________.

production of sperm and eggs

The region of DNA where RNA synthesis begins is the ________.

promoter

The CORRECT sequence of stages of mitosis is ________.

prophase, metaphase, anaphase, telophase

A mutation within a gene that will insert a premature stop codon in mRNA would ________.

result in a shortened polypeptide chain

What cellular structure facilitates the process of translation?

ribosomes

Homologous chromosomes ________.

separate at meiosis I

Which type of reproduction is most adaptive in a rapidly changing environment with many different parasitic diseases present?

sexual reproduction, because the diversity of genotypes increases the likelihood that there is one which can survive in a new environment

If a strand of DNA has the sequence GACTTA, transcription will result in a(n) ________.

single RNA strand with the sequence CUGAAU

A duplicated chromosome consists of two ________.

sister chromatids

Which of the following phenotypes is an example of polygenic inheritance?

skin pigmentation in humans

A human cell containing 22 autosomes and a Y chromosome is

sperm

Which of the following statements best defines a genome?

the complete set of an organism's genes and other DNA sequences

Genetic variation is accomplished by all but one of the following. Choose the EXCEPTION.

the events of meiosis II

During telophase, ________.

the events of prophase are reversed

How many nucleotides make up a codon?

three

The cells that result from the mitotic cell cycle can be described as ________.

two cells, each with the same amount of genetic material and the same genetic information

Upon completion of telophase I and cytokinesis in meiosis, there is(are) ________ cell(s).

two haploid