Biology Test 2
Color-blindness is more common in males than in females because:
males only need to inherit the recessive material color blindness allele to be color blind.
In rabbits, coat color is governed by four alleles: C for dark gray, C^ch for chinchilla, C^h for himalayan, and c for white. This is an example of:
multiple alleles
The _________ is responsible for the separation of the chromosomes during the _______ of mitosis.
mitotic spindle; anaphase
_______ refers to multiple independent pairs of genes having similar and additive effects on the same characteristic.
Polygenic inheritance
To prevent disastrous consequences, the eukaryotic cell cycle is controlled by:
a series of cell cycle checkpoints.
An organism with the genotype of AaXx can produce gametes containing ______ if the two genes are unlinked.
either AX, Ax, aX, ax
Two Martians fall in love and marry. One Martian is homozygous for red eyes and the other is heterozygous. The recessive eye color is purple. What is the probability that they will have a child with purple eyes?
0
What are the possible genotypes for a monohybrid cross of Bb X Bb?
1 BB, 2 Bb and 1 bb
A brown-eyed couple heterozygous for eye color are planning on having two children. What is the probability that both children will have blue eyes, assuming brown eyes is dominant and blue eyes is recessive?
1/16
What is the probability of an aabb offspring when you cross AaBb X AaBb parents?
1/16
A brown-eyed couple already has a child with blue eyes. What is the probability that their next child will have blue eyes, assuming that the brown eye allele is dominant and the blue eye allele is recessive?
1/4
If a couple is planning on having two children, what is the probability that both will be male?
1/4
How many base pairs of DNA are wrapped around a single nucleosome?
146
An animal with a diploid number of 36 chromosomes will have ______ chromosomes in its gametes and ______ chromosomes in its somatic cells.
18; 36
A heterozygous fruit fly with normal wings and a gray body (VvBb) is crossed with homozygous flies with vestigial wings and black bodies (vvbb). If there are 800 F1 progeny, the expected phenotypes would be:
200 normal gray, 200 normal black, 200 vestigial gray, and 200 vestigial black
In a human cell at prophase I, there are ______ tetrads.
23
The height of pea plants from a cross between parent plants heterozygous for height, in which tall is dominant, would be:
3 tall, 1 short
A couple has already had three girls with cystic fibrosis, and are hoping to have a normal child for their fourth. What are the chances that the fourth child will be a normal male?
3/8
What is the mRNA codon sequence that must be first to start translation?
AUG
Which of the following represents the possible genotype(s) resulting from a cross between an individual homozygous for black hair (BB) and an individual homozygous for blonde hair (bb)?
Bb only
Which is the sequence for gene expression?
DNA-RNA-polypeptide
When we study the genotypes of four offspring of two individuals, those offspring are sometimes referred to as the _________.
F1 generation
A DNA tempate strand has a sequence of CGGATA. What would the transcribed mRNA sequence be?
GCCUAU
_______ organized on chromosomes carry the information that controls the functions of the cell.
Genes
Which is the shortest portion of a cell's life cycle?
M phase
During translation, which site within the ribosome holds the growing polypeptide chain?
P
Which characteristic is unique to prophase during meiosis rather than to mitosis?
Paired homologous chromosomes can exchange genetic material.
Chromosomes are duplicated during the _______ of the cell cycle.
S phase
_______ contain identical DNA sequences and are held together by _____ during mitosis.
Sister chromatids; cohesion proteins
A cell is dividing by binary fission. What can you conclude?
The cell is prokaryotic
When is a cell in metaphase?
The chromosomes are aligned at the midplane of the cell.
A heterozygous fruit fly with normal wings and a gray body (VvBb) is crossed with homozygous flies with vestigial wings and black bodies (vvbb). Out of 800 total F1 progeny, 296 are normal gray, 328 are vestigial black, 99 are normal black, and 77 are vestigial gray. What is the best explanation for this result?
The loci for wing length and body color are on the same chromosome
You buy two Nikko Blue hydrangeas, plant one in your yard and give the other to a friend, who also plants it in her yard. Your hydrangea produces bright blue flowers, but your friend's plant produces pink flowers. What is the likely cause for these two plants to show different colored flowers?
The soil's acidity is different in each person's yard.
What happens to the fragments of the broken down nuclear envelope during prometaphase?
They are sequestered for later use in the daughter cells.
What is the purpose of a cell-cycle checkpoint?
To ensure the events of one cell-cycle stage is completed before the next stage begins
Which genotype describes the mother of a color-blind female (X^eX^e) offspring?
X^EX^e or X^eX^e
What are the possible genotypes of a female child from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics?
X^HX^H or X^HX^h
During prophase I, each chiasma represents:
a site of crossing-over.
Cytokinesis in animal cells involves contraction of a ring of ______ microfilaments.
actin plus myosin
Different forms of the same genes are called __________.
alleles
Mendel's principle of segregation states that:
alleles separate from each other before forming gametes
Duplicated centrioles move to opposite poles of a dividing ______ cell during the _______ of the cell cycle.
animal; prophase
A new human epithelial cell is an exact copy of its parent cell due to ________.
asexual reproduction
Binary fission is used to replicate what kind of cells?
bacteria
In humans, assume that the allele for brown eyes is dominant and the allele for blue eyes is recessive. If two brown-eyed individuals have a child with blue eyes, that means:
both parents are heterozygous for eye color
Cytokinesis in plant cells occurs via the formation of a(n):
cell plate
During cytokinesis, plant cells will form a ________ to divide the newly replicated cells.
cell plate
During prophase, _____ is(are) compacted into visible chromosomes.
chromatin
Eukaryotic chromosomes are composed of:
chromatin
Breeding a yellow dog with a brown dog produced puppies with both yellow and brown hairs intermixed. This is an example of:
codominance
Which event occurs in prophase II?
condensation of the chromatin into chromosomes
The offspring of two heterozygous gray-bodied, normal-winged flies should be 50% gray-bodied/normal wings (BbRr) and 50% black-bodied/vestigial wings (bbrr) because these alleles are linked. Suppose a small number, say 15%, of the offspring are instead black-bodied with normal wings. This is most likely the result of:
crossing-over
To control the cell cycle:
cyclins fluctuate during the cell cycle.
Plant hormones known as _______ stimulate mitosis.
cytokinins
In what part of a eukaryotic cell is a mature mRNA deposited after it is transcribed?
cytosol
The microtubules of the mitotic spindle shorten, thus pulling apart the chromosomes by way of __________.
depolymerization
A heterozygous fruit fly with normal wings and a gray body (VvBb) is crossed with homozygous flies with vestigial wings and black bodies (vvbb). This type of cross is known as a:
dihybrid cross
When a black Labrador Retriever is cross with a chocolate Labrador Retriever, one of the puppies is a yellow Labrador Retriever. This recessive form of offspring is an example of _________.
epistasis
A gene that affects, prevents, or masks the expression of a gene at another locus is a(n) _______ gene.
epistatic
Nucleosomes are best described as:
eukaryotic DNA associated with histone proteins
What is the end result of meiosis II in animal cells?
four gametes
Insertion of a nucleotide base pair in a DNA sequence results in what kind of mutation?
frameshift mutation
A cell in the G2 phase:
has twice the amount of DNA present in a telophase nucleus.
As a cell prepares itself for division, DNA first wraps around what kind of protein to form nucleosomes?
histone
The chromosome theory of inheritance, developed by Sutton and Boveri, provided an explanation for Mendel's principle of segregation by proposing that:
homologous chromosomes segregate during meiosis
DNA nucleotides and RNA polymerase bind to the promoter region of DNA during which stage of transcription?
initiation
Centrioloes are replicated during the synthesis phase of _________.
interphase
The cell cycle of a typical somatic cell consists of the ______ and M phases.
interphase
What part of an mRNA transcript is removed by the process of splicing?
introns
Why did Beadle and Tatum choose Neurospora as their experimental organism to test the one-gene, one-enzyme hypothesis?
it exhibits recessive mutations
Microtubules are able to attach with what region of a chromosome?
kinetochore
Genes that are inherited together imply that they are __________.
linked
At what mitotic phase do chromosomes line up along a cell's equatorial plane?
metaphase
While Mendel did not know how cell division occurred, his principles of independent assortment can be applied to which stage of meiosis?
metaphase I
What type of molecule can cause RNA interference?
miRNA
Gametophyte plants produce gametes using:
mitosis
In a prometaphase cell, the:
nucleolus disappears
In what part of a eukaryotic cell does transcription take place?
nucleus
If an allele is dominant, then:
one allele can mask the expression of a recessive allele in a hybrid
At the completion of oogenesis, ______ are produced.
one egg cell and three polar bodies
Crick proposed the wobble hypothesis, which suggests that some tRNA molecules can
pair with up to three separate codons
Mating a true-breeding pink rose plant with a true-breeding pink rose plant will produce:
plants with only pink roses
What is evident in the gene in a human disorder like cystic fibrosis?
pleiotropy
The function of a nucleosomes is to:
prevent DNA strands from tangling
Which of Mendel's principles describe how alleles are distributed among the gametes during meiosis?
principles of independent assortment
What must RNA polymerase identify before it can unwind the DNA and initiate transcription?
promoter
Mendel's principle of independent assortment is explained by which metaphase I event?
random orientation of homologous chromosomes on the metaphase plate
What Mendel referred to as a masked factor, we now call a(n) ________ trait.
recessive
The purpose of meiosis is to ________.
reduce a diploid to form haploid nuclei
What must tRNAs bind to during translation?
ribosome
In unwound chromatin, nucleosomes are organized into large coiled loops held together by:
scaffolding proteins
The sex of most mammals, birds, and insects is determined by:
sex chromosomes
What gamete carries the Y chromosome in mammals?
sperm
In peas, Mendel found that tall plants and yellow peas are dominant. The phenotype for a pea plant with the genotype TTyy would be:
tall with green peas
What method did Mendel use to verify his hypothesis that there is 1:1 segregation of the alleles of a heterozygous parent?
test cross
All calico cats are female because:
the calico phenotype is caused by random X chromosome inactivation
Homologous chromosomes can be identified and/or characterized by:
their similar and characteristic staining patterns
Which of the following is produced by meiosis?
zygotes
Which enzyme is responsible for copying DNA into an RNA transcript?
RNA polymerase
Neurospora is an ideal organism to study the effects of genetic mutations because of several reasons. What is one of these?
Neurospora mutant strains that cannot make a particular amino acid can still grow if that amino acid is added to the growth medium
Garrod first proposed that:
metabolic defects were due to the lack of an enzyme
When you crossed a red flower with a white flower, you produced pink flowers. Now take one of the pink flowers and cross it with another red flower. What are the genotypes of the new offspring?
two red flowers and two pink flowers
