Biology Quiz #3 - Chapters 8, 9, &10

What is the probability that the parents heterozygous for a trait will have a homozygous offspring?

50%

p53 mutations lead to cancer because

DNA damage is not repaired, mutated cells are allowed to grow, and multiple mutations in the cell's regulatory proteins occur

Which of the following is true of interphase?

DNA replication occurs in this phase

______ is the cellular process of deciding which genes a cell will express when mature.

Determination

(T/F) Mendelian principles apply when genes are found close to each other on the same chromosomes.

False

(T/F) Phenotype is the combination of alleles that an organism has, whereas genotype is its appearance.

False

(T/F) The sex of an organisms is determined by the number of chromosomes it possesses.

False

What is the key difference between mitosis and meiosis?

Mitosis produces cells genetically identical to the parent, whereas meiosis produces cells with half the genetic information as the parent

______ occur when there are more than 2 alleles in heterozygous organisms.

Multiple alleles

Which best describes the sequence of events followed by the human immunodeficiency virus in its replication?

RNA - DNA - RNA

(T/F) Mutagens can be carcinogens.

True

(T/F) Segregation happens during meiosis.

True

A deletion of a single base in the protein-coding sequence of a gene will likely create

a frameshift

The difference between ribose and deoxyribose is

an oxygen atom

Using the amino acid-nucleic acid dictionary, which amino acid would be coded for by the mRNA codon GAC?

asparatic acid

The function of tRNA is to

carry an amino acid to a working ribosome

Haploid cells

carry one copy of the genetic information

In the ABO system, A and B show ______ when they are together in an individual, but both alleles are dominant over the O allele.

codominance

Chemical changes of chromatin (DNA and histones) that do not alter the nucleotide sequence are called ________ changes.

epigenetic

Double-factor crosses

follow the alleles for 2 genes

Transcription copies genetic information

from DNA to RNA

Which of the following types of information do cells use to determine if they will divide?

genetic health, their current location, and the need for more cells

A homozygous organism

has the same alleles at a locus, has the same alleles at a gene, and produces gametes that all carry the same allele.

Homologous chromosomes

have the same genes in the same places

The nitrogenous bases in DNA

hold the two DNA strands together and are part of the genetic blueprint

A nondisjunction event occurs when

homologous chromosomes did not separate correctly

Which of the following pairs would be incorrect according to the base-paring rules?

in RNA: UT

Reduction divison occurs

in meiosis I

When a heterozygote appears to be a "blend" of the two parental phenotypes, the trait is considered to be exhibiting _____.

incomplete dominance

Enhancers (do what?)

increase the transcription of specific genes

Genetic diversity in the gametes of an individual is generated through

independent assortment and crossing-over

RNA polymerase starts synthesizing mRNA in eukaryotic cells because

it finds a promoter sequence, transcription factors interact with RNA polymerase, the gene is in a region of loosely packed chromatin

The place where a gene is located on a chromosome is known as its ______.

locus

Chromosomes are most likely to appear to be lining up near the middle of the cell during which phase of mitosis?

metaphase

These features characterize which kind of cell devision? (a) Homologous chromosomes do not cross-over. (b) Centromeres divide in anaphase.

mitosis

Genetic information is stored in what type of chemical?

nucleic acids

The gonads in females are known as ________.

ovaries

The term ______ describes the multiple effects a gene has on a phenotype.

pleiotropy

Under normal conditions, tranlsation

reads in sets of three nucleotides called codons

Dominant alleles mask ______ alleles in heterozugous organisms.

recessive

Genes that are found only on the X chromosome in humans most consistently illustrate

sex-linkage

Which is an example of missense mutation?

sickle-cell anemia

The process that removes introns and joins exons from mRNA is called

splicing

Trisomy means

that three copies of a chromosome are present

If the two subunits of a ribosome do not come together with an mRNA molecule, which will not occur?

translation