Biology Exam Chapters 12-14

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 5 - AGATCCG - 3

3'-TCTAGGC-5'

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

64

The 3' end of eukaryotic pre-mRNA's are changed by

Adding 100-250 adenine nucleotides

_______ are alternative forms of a gene that govern the same feature, such as eyecolor, and occupy corresponding positions on homologous chromosomes

Alleles

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

BB and Bb

The wobble hypothesis states that:

Certain tRNA anticodons can pair with more than one codon sequence

chargaff determined that DNA from any source contains about the same amount of guanine as ______

Cytosine

Hydrogen bonds can form between guanine and ______, and between adenine and _______.

Cytosine and Thymine

A nonsense mutation is a base-pair substitution that results in the replacement of one amino acid with another

False

Dominant traits remove recessive traits when both are present in the same individual

False

Okazaki fragments are found in the leading strand of DNA

False

Shirt, Non-coding, guanine-rich DNA sequences found in the center of chromosomes are called telomeres

False

The Two strands of a DNA double helix are described as running parallel to each other

False

The nucleotide sequence in RNA to which RNA polymerase binds is called the promoter

False

The template DNA strand is described as being parallel to the complementary RNA strand

False

Dominant means that

One allele can mask the expression of another in a hybrid

RNA differs from DNA in all of the following except

RNA contains cytosine

Inpeas, Mendel found that tall plants and yellow peas are dominant. The phenotype for a pea plant with the genotype TtYy would be

Tall with yellow peas

Dominance is not consistent with blending inheritance

True

In one strand of a DNA molecule, adjacent nucleotides are joined by a phosphodiester linkage

True

Ribose differs from deoxyribose by having

an extra hydroxyl group

The process in which RNA is synthesized using a DNA template is called translation

False

A gene can now be defined as:

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

During protein synthesis, ribosomes

attach to the mRNA molecule and travel along its length

aminoacyl-tRNA synthetases _______ link _______ to their respective tRNA molecules

covalently; amino acids

Initiation of transcription requires

promoter sequence

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

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

only plants with pink roses

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

tRNA

The ends of eukaryotic chromosomes can be lengthened by:

telomerase

_______, The ends of eukaryotic chromosomes, shorten with every cell replication event.

telomeres

How is the 4-letter language of nucleic acids converted into the 20-word language of amino acids?

the 4 nucleic acid bases combine in 3-letter sequences that define different amino acids

Which of the following is a characteristic of uracil

the ability to bond with adenine

How is the chromosome of a bacterial cell replicated

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

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

two

Final product of DNA replication is

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

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

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

topoisomerases

RNA synthesis is also known as:

transcription

Using standard conventions for naming alleles, which of the following pairs is correct

tt- homozygous

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

ttyy

In essentially all organisms, the AUG codon codes for:

initiation of translation

replication fork

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

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

DNA helicase

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

either A or a

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 sequence of bases located upstream from a reference point occurs

Towards the 5 end of the mRNA sequence

If a couple is planning on having two children, what is the probability that both will be male?

1/4

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

Which of the following best describes semi conservative replication

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

The 5 end of each Okazaki fragments begins with

A Separate RNA primer

What are the possible phenotypes of the children if the mothers genotype is I^Ai for blood type and the father is I^Bi?

A, B, AB, O

Mendel's principle of segregation states that

Alleles separate from each other before forming gametes

Which of the following represents the possible genotypes resulting from a cross between an individual heterozygous (Bb) and one that is homozygous (bb)?

Bb and bb

Why is color blindness more common in males than in females

Because a male only needs to receive the recessive gene from his mother to be colorblind

Principle of independent assortment is not true for

linked genes

Cancerous cells differ from non-cancerous cells in that cancerous cells

Can maintain telomere length as they divide

Which of the following statements about DNA is false

DNA is only found in eukaryotic cells

Okazaki fragments are joined together by

DNA ligase

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

DNA polymerase

DNA pol III catalyzes the addition of successive nucleotides to the 5' end of a growing polynucleotide chain

False

DNA replication is described as being conservative

False

Examination of a phenotype can always determine the genotype of an organism

False

In eukaryotes, the initiator tRNA carries the amino acid leucine

False

Molecular chaperones assist in the folding of newly synthesized mRNAs

False

________ used x-ray diffraction to provide images of DNA

Franklin

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

Incomplete dominance

_______ refers to multiple independent pairs of genes having similar and additive effects on the same characteristics

Polygenic inheritance

Frameshift mutation's result from

The insertion or deletion of one or two base pairs

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

The large number of possible amino acid combinations

How are the chromosomes of a eukaryotic cell replicated?

The linear DNA molecules are replicated from multiple origins of replication bidirectionally

A transposon is a DNA sequence that "jumps" into the middle of a gene

True

Three nucleotides code for one amino acid

True

Uracil forms a complementary pair with ______ in RNA and _________ in DNA

adenine; adenine

two chains of DNA must run in ____ directions and must be ______ if they are to bond with each other

antiparaelle ; complementary

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

because DNA polymerase can only add nucleotides to the 3' end of a polynucleotide strand

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

Probability that two genes will be separated by crossing over is related to

distance between two genes on a chromosome

An organism with the genotype of AaXx can produce gametes containing ________ if the two genes are unlinked.

either AX, Ax, aX, ax

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

epistatic

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

sugar and phosphate

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

genetically pure lines

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

introns; only eukaryotic

In DNA replication, the lagging strand

is synthesized as a series of Okazaki fragments

Why is DNA able to store large amounts of information

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

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 physical location of a particular gene on a chromosome is called

locus

The codon is found in the

mRNA

Which of the following is made from DNA

mRNA, tRNA, rRNA

primase is the enzyme responsible for:

making short strands of RNA at the site of replication initiation

A mutation that replaces one amino acid in a protein with another is called a ________ mutation

missense

in replication, once the DNA strands have been separated, reformation of the double helix is prevented by:

single-strand binding proteins

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

specific nucleotide sequence of the DNA molecule

The sex of a human is determined by

the presence of a Y chromosome

All of the following characteristics of tRNA molecules are true except

they are considerably larger than rRNA molecules

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

translated into the protein that is found in humans

Introns in pre-mRNA are known to

undergo excision, whereby they are spliced out of the message