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