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A bacterial chromosome consists of:
a circular DNA molecule many times larger than the cell.
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Nucleosomes are best described as:
eukaryotic DNA associated with histone proteins.
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What is the function of nucleosomes?
To prevent DNA strands from tangling.
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The cell cycle of a typical somatic cell consists of ____________ and M phase.
interphase
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The M phase of the cell cycle involves two main processes:
mitosis and cytokinesis.
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Chromosomes are duplicated during of the cell cycle.
S phase
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Which of the following represents the sequence of events during mitosis?
prophase � metaphase � anaphase � telophase
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During prophase, ____________ is/are compacted into visible chromosomes.
chromatin
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The mitotic spindle is made of:
microtubules.
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A cell is in metaphase if:
the chromosomes are aligned at the midplane of the cell.
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Duplicated centrioles move to opposite poles of a dividing ____________ cell during ____________ of the cell cycle.
plant; anaphase
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The chromosome makeup of an individual organism is called a:
centriole.
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Cytokinesis in animal cells involves contraction of a ring of ____________ microfilaments.
cyclin plus actin
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Cytokinesis in plant cell mitosis occurs initially by the formation of a(n):
cell plate.
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If meiosis did not occur in sexually reproducing organisms, then:
chromosome number would double in each generation.
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A maternal homologue and a paternal homologue synapse to form:
a tetrad.
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A zygote typically contains the ________________ complement of chromosomes.
polyploid
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During prophase I, each chiasma represents:
a site of crossing-over.
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The sources of genetic variation during meiosis are:
crossing-over and random pairing of tetrads.
-
Sporophyte plants produce spores using:
meiosis.
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The physical appearance of an organism for a given trait is termed:
phenotype.
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____________ are alternative forms of a gene that govern the same feature, such as eye color, and occupy corresponding positions on homologous chromosomes.
Loci
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Mendel�s principle of segregation states that:
alleles separate from each other before forming gametes.
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A pear plant with the genotype Aa can produce gametes containing:
either A or a.
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The physical location of a particular gene on a chromosome is called:
a locus.
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Which of the following represents the possible genotype(s) resulting from a cross between two individuals that are heterozygous (Bb)?
BB, Bb, and bb
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The heights of pea plants from a cross between parent plants heterozygous for height, in which tall is dominant, would be:
2 short : 2 tall.
-
What is the probability that two lizards that are heterozygous for stripes on their tails (Ss) will produce an offspring that is homozygous for no stripes (ss)?
1/4
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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
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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 are the chances that the alien couple will have a child with red eyes?
1
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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. If a small number, say 15%, of the offspring are instead black-bodied with normal wings, this is most likely the result of:
crossing-over.
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The probability that two genes will be separated by crossing-over is related to:
the distance between the two genes on the chromosome.
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A lizard with a striped tail is crossed with one having a spotted head, producing normal looking (no stripes or spots) lizard progeny. What progeny would be expected to be produced by mating these progeny with each other, if the genes conferring stripes and spots were on different chromosomes?
9 normal : 3 striped : 3 spotted : 1 striped and spotted
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The sex of most mammals, birds, and insects is determined by:
sex chromosomes.
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Why is color-blindness more common in males than in females?
All of these.
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A Barr body in a mammalian female cell represents:
an inactivated X chromosome.
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What are the possible phenotypes of the children if the mother has Type A blood and the father has type AB blood?
A, AB
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A particular gene that controls seed coat color in peas also determines the susceptibility of these peas to a particular disease. This situation is referred to as:
pleiotropy.
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Breeding a yellow dog with a brown dog produced puppies with both yellow and brown hairs intermixed. This is an example of:
codominance.
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A gene that affects, prevents, or masks the expression of a gene atanother locus is a(n) ______ gene.
epistatic
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The two molecules that alternate to form the backbone of a polynucleotide chain are:
sugar and phosphate.
-
______________________ determined the structure of the molecule DNA.
Watson and Crick
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The information carried by DNA is incorporated in a code specified by the:
specific nucleotide sequence of the DNA molecule.
-
Hydrogen bonds can form between guanine and ____________, and between adenine and ____________.
cytosine; thymine
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Which of the following nucleotide sequences represents the complement to the DNA strand 5� � AGATCCG- 3�?
3� � TCTAGGC- 5�
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Which of the following best describes semiconservative replication?
A DNA molecule consists of one parental strand and one new strand.
-
When a DNA molecule containing a wrong base at one location in one strand is replicated:
the mutation is copied into one of the two daughter molecules.
-
Which of the following cause the unwinding of the DNA double helix?
DNA helicase
-
A replication fork:
is a Y-shaped structure where both DNA strands are replicated simultaneously.
-
In replication, once the DNA strands have been separated, reformation of the double helix is prevented by:
single-strand binding proteins.
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