BIOL 1107K Exam 4

Beadle and Tatum irradiated Neurospora and initially grew the mutual strains on complete medium. How were they able to determine what type of mutation each strain had?

By growing the mold on minimal media supplemented with different combinations of amino acids, vitamins, etc

Who first confirmed that the replication of DNA was semiconservative?

Meselson and Stahl

A polyribosome is:

a complex of many ribosomes and an mRNA

Initiation of transcription requires:

a promoter sequence

The portion of the molecule in box 3 of Figure 12-1 is:

a purine

Breeding a yellow dog with a brown dog produced puppies with both yellow and brown hairs intermixed. This is an example of:

codominance

if DNA replication rejoined 2 parental strands, it would be termed:

conservative

A gene that affects, prevents, or masks the expression of a gene at another locus is a(n) ____ gene.

epistatic

A replication fork:

is a Y shaped structure where both DNA strands are replicated simultaneously

The codon is found in the:

mRNA

The range of phenotypic possibilities that can develop from a certain dog genotype under different environmental conditions is called the:

norm of reaction

Retrovirused of RNA tumor viruses ___ to make DNA.

reverse transcriptase

The two molecules that alternate to form the backbone of a polynucleotide chain are:

sugar and phosphate

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

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

The process illustrated in Figure 13-3 is:

transcription

What are the predicted phenotypes of the male children from the union of a woman who is heterozygous for hemophilia and a man who has normal blood clotting characteristics?

1 hemophilia : 1 normal

Which of the following numbered events represents the correct sequence of events of prokaryotic translation initiation?

2 -> 3 -> 1

Which of the following numbered terms represents the correct order of sequences in a prokaryotic mRNA molecule as it was synthesized?

3 -> 2 -> 4 -> 1

One of the mRNA codons specifying the amino acid leucine is 5'-CUA-3'. Its corresponding anticodon is:

3' - GAU - 5'

Which of the following nucleotide sequences represents the complement to the DNA strand

3' - TCTAGGC - 5'

In a two-point test cross, 36 of the offspring were recombinant types. The remaining 64 offspring were parental types. How many map units separate the two loci?

36

The total number of different three-base combinations of the four nucleic acid bases is:

64

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

Which of the following best describes semiconservative replication?

A DNA molecule consists of one parental strand and one new strand

What are the possible phenotypes of the children if the mother has type A blood and the father has type AB blood?

A, B, AB

Which of the following represents the possible genotype(s) resulting from a cross between two individual homozygous (BB) and one heterozygous (Bb) individual?

BB and Bb

Which of the following represents the possible genotype(s) resulting from a cross between two individuals that are heterozygous (Bb)?

BB, Bb, and bb

Why does DNA synthesis only proceed in the 5' to 3' direction?

Because DNA polymerases can only add nucleotides to the 3' end of a polynucleotide strand

How is a single strand of DNA able to serve as a template for the synthesis of another strand?

Both the pairing of nucleotides and the breaking of hydrogen bonds.

Which of the following causes the unwinding of the DNA double helix?

DNA helicase

Okazaki fragments are joined together by:

DNA ligase

Which of the following adds new nucleotides to a growing DNA chain?

DNA polymerase

The bacteriophages used in Alfred Hershey's and Martha Chase's experiments showed that:

DNA was injected into bacteria

What conclusions did Beadle and Tatum reach with their studies of Neurospora?

Each mutant gene affected only one enzyme

___ used X-ray diffraction to provide images of DNA.

Franklin

Why is DNA able to store large amounts of information?

Its nucleotides can be arranged in a large number of possible sequences

The enzyme peptidyl transferase, which catalyzes the transfer of the polypeptide chain attached to the tRNA in the __________ site to the aminoacyl-tRNA in the __________ site, is thought to be a(n) __________ molecule and not a protein.

P; A; rRNA

RNA differs from DNA in all of the following except:

RNA contains cytosine

Refer to Figure 13-3. The component labeled B is:

RNA polymerase

How is the chromosome of a bacterial cell replicated?

The circular DNA molecule is replicated from one origin of replication bidirectionally

All of the following characteristics of tRNA molecules are true except:

They are considerably larger than rRNA molecules

The final product of DNA replication is:

Two DNA molecules, each of which contains one new and one old DNA strand

___ determined the structure of the molecule DNA.

Watson and Crick

A gene can now be defined as:

a DNA sequence that carries information to produce a specific RNA or protein product

Beadle and Tatum began their studies with wild-type Neurospora, which is:

a normal phenotype that will grow on minimal medium

The portion of the molecule in box 5 of Figure 12-1 is:

a phosphate

Refer to Figure 12-2. The correct designation for the DNA strand labeled C is:

a strand serving as a template

Mating an individual expressing a dominant phenotype, but whose genotype is unknown, with an individual expressing the corresponding recessive phenotype is an example of:

a test cross

The 3' end of eukaryotic pre-mRNAs are changed by:

adding 100-250 adenine nucleotides

Mendel's principle of segregation states that:

alleles separate from each other before forming gametes

A Barr body in a mammalian female cell represents:

an inactivated X chromosome

Cancerous cells differ from noncancerous cells in that cancerous cells:

can maintain telomere length as they divide

Meselson and Stahl separated DNA from different generations using:

density gradient centrifugation

A pear plant with the genotype Aa can produce gametes containing:

either A or a

Binding of the appropriate aminoacyl-tRNA to the A site requires:

energy supplied by GTP

Mendel verified true-breeding pea plants for certain traits before undertaking his experiments. The term "true-breeding" refers to:

genetically pure lines

When certain medium height hybrid plants were crossed, they produced offspring that were dwarf, medium, and tall in a ratio of 1:2:1. This is an example of:

incomplete dominance

Interrupted coding sequences include long sequences of bases that do not code for amino acids. These noncoding sequences, called __________, are found in __________ cells.

introns; only eukaryotic

In DNA replication, the lagging strand:

is synthesized as a series of Okazaki fragments

The DNA strand that is replicated smoothly and continuously is called the:

leading strand

Genes that tend to be inherited together are said to be:

linked

The principle of independent assortment is not true for:

linked genes

Primase is the enzyme responsible for:

making short strands of RNA at the site of replication initiation

Substitution of one base pair for another can result in a ____ mutation that results in the conversion of an amino acid specifying codon to a termination codon.

nonsense

The term "dominant" means that:

one allele can mask the expression of another in a hybrid

Mating a true-breeding pink rose plant with a true-breeding pink rose plant will produce:

only plants with pink roses

The physical appearance of an organism for a given trait is termed:

phenotype

The sex of most mammals, birds, and insects is determined by:

sex chromosomes

The information carried by DNA is incorporated in a code specified by the:

specific nucleotide sequence of the DNA molecule

Which of the following serves as an "adapter" in protein synthesis and bridges the gap between mRNA and proteins?

tRNA

When cultured normal human cells were infected with a virus that carried the genes that coded for a subunit of telomerase:

the cells underwent more cell divisions than normal

In essentially all organisms, the AUG codon codes for:

the initiation of translation

The main reason scientists thought that proteins, rather than DNA, were the carriers of genetic material in the cell was:

the large number of possible amino acid combinations

The sex of a human is determined by

the presence or absence of a Y chromosome

Enzymes called ____ form breaks in the DNA molecules to prevent the formation of knots in the DNA helix during replication.

topoisomerases

What prevents knot formation in replicating DNA?

topoisomerases

If a human gene mRNA were placed into a cell of yeast, it would be:

translated into the protein that is found in humans

The genotype for a pea plant that is homozygous recessive for both height and pea color would be:

ttyy

A diploid individual has a maximum of ___ different alleles for a particular locus.

two

Calico cats are never male because:

two different X chromosomes are needed for the expression of the calico phenotype

A _____ is best used to demonstrate the linkage of two genes.

two-point test cross

Introns in pre-mRNA are known to:

undergo excision, whereby they are spliced out of the message