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