Bio 101 10-12

A DNA molecule usually is made up of how many strands? Question options: 1 2 3 6 12

2

Codons consist of how many nucleotides? Question options: 2 3 5 6 12

3

In terms of their base component, how many different kinds of RNA nucleotides are there? Question options: 3 4 5 6 12

4

Muscular dystrophy is a group of inherited disorders that lead to increasing muscle cell loss and thus muscle weakness over time. There are many different types of muscular dystrophy. Symptoms can vary, although all involve muscle weakness. Duchenne muscular dystrophy (DMD) is a recessive X-linked form that leads to muscle degeneration and death usually by age 25. Symptoms begin before age 5 and include low endurance and difficulties standing. As the condition progresses, muscle tissue is replaced with adipose and other types of connective tissue. Abnormal bone development and some neurobehavioral and learning disabilities may also occur. DMD occurs as a result of a mutation in a single gene on the X chromosome. This gene codes for a particular protein, dystrophin, which plays a major role in the structure of muscle cells. The protein formed by the mutated gene is nonfunctional, and the absence of a functional protein eventually leads to cell death. A woman who is a carrier for DMD marries a man who does not have the disease. What is the probability that they will have a boy with DMD? Question options: 0 percent 25 percent 50 percent 100 percent

50 percent

Sickle-cell anemia is an inherited chronic blood disease caused by an autosomal recessive allele. Suppose a man who is homozygous recessive for the sickle-cell gene fathers a child by a woman who is a carrier for sickle-cell. What are the chances their children will exhibit the disease? (Note: A Punnett square may be useful.) Question options: 0 percent 2 percent 50 percent 75 percent 100 percent

50 percent

U forms a complementary pair with ____________ in RNA and _____________ in DNA. Question options: A; A A; T T; T U; A A; U

A; A

Frameshift mutations may involve: Substitution of nucleotides Substitution of codons Substitutions of amino acids Addition or deletion of bases

Addition or deletion of bases

In a mutation, Question options: the new codon may specify a different amino acid, but may not destroy the function of the new protein produced. the new codon may specify the same amino acid as the old codon. the new codon and resulting amino acid may destroy the function of the protein specified. All of these may be true.

All of these may be true.

Which of the following is true? the bases a and T are connected by 3 hydrogen bonds RNA splicing happens in the cytoplasm An amino acid might be coded for by multiple codons tRNA acts as an enzyme, bonding amino acids together in the ribosome

An amino acid might be coded for by multiple codons

Which of the following events does not occur during the process of translation? Question options: The information in mRNA is used to guide the assembly of amino acids into proteins. C in DNA pairs with G in RNA, and T in DNA pairs with A in RNA. Start and stop codons present in the mRNA molecule help control the process. Amino acids are attached to the end of the new protein molecule under construction. The ribosome interacts with mRNA in the cytoplasm.

C in DNA pairs with G in RNA, and T in DNA pairs with A in RNA.

Use the figure below to answer the corresponding questions. nar001-1.jpg The transcript in Figure 12-02 is labeled: Question options: D. C. G. H. A.

D

A codon can specify up to three different amino acids. Question options: False True

False

All humans are capable of producing gametes containing different sex chromosomes. Question options: True False

False

Each time transcription occurs, the entire genome of a cell is copied. Question options: False True

False

From the very start, lipids were thought to be a good candidate for the hereditary material because geneticists believed it was a complex molecule. Question options: True False

False

Recessive genetic disorders are quickly eliminated from human populations because people who have them die before they can reproduce. Question options: False True

False

The cells of organisms can control when, where, and how much of each gene product is made. Question options: True False

False

The stop codon signals RNA polymerase to stop making an mRNA transcript. Question options: True False

False

If a strand of DNA has the sequence CGTAA, the RNA made from this molecule will have the sequence Question options: CGTAA. GCUTT. TAGCC. GCAUU.

GCAUU.

Which of the following is true of rRNA? Question options: It is made up of base pairs. It carries amino acids. It is not translated. It helps transcribe DNA.

It is not translated.

Which of the following ideas or events related to the chromosomal theory of inheritance is false? Question options: Mendel was the first to discover that chromosomes contain genes. Chromosomes are made of a single molecule of DNA and many proteins. Genes are located in specific places on the chromosome, called "loci." Homologous chromosomes separate into different gametes during meiosis.

Mendel was the first to discover that chromosomes contain genes.

Is a species that lacks DNA repair mechanisms likely to have more or fewer variations between individuals than a species that possesses repair mechanisms? Question options: Fewer, because there are fewer ways to change the DNA. Fewer, because the repair mechanisms introduce more variation into the DNA sequence. More, because more mutations will go uncorrected. More, because without a repair mechanism, the cell's tumor suppressor genes are inactivated.

More, because more mutations will go uncorrected.

Which of the following statements would be true if the linkage between two traits were complete? Question options: Only the parental combinations of phenotypes could appear in the progeny. The rules of independent assortment would hold true. Combinations of phenotypes different from those seen in the parents would be produced. The exchange of genetic material between chromosomes would be frequent.

Only the parental combinations of phenotypes could appear in the progeny.

A short sequence of bases on one strand of DNA is AGTCTACCGATAGT. If this sequence serves as a template for the formation of a new strand of DNA, what will be the complementary DNA sequence? Question options: AGTCTACCGATAGT TCAGATGGCTATCA TGATAGCCATCTGA UCAGAUGGCUAUCA THISISNOTCORRECT

TCAGATGGCTATCA

A person is genetically XX and develops as a male. How can this be explained? Question options: In humans, males are XX. A mistake of genetic analysis must have taken place, because XX cannot develop into a male. The SRY gene is also present in this individual. The X chromosomes have nothing to do with sex determination in humans. none of the above

The SRY gene is also present in this individual.

A mutation occurs in the promoter of a protein-encoding gene. How might this mutation affect the production of the protein encoded by the gene? Question options: The mRNA made from this gene would exhibit the same mutation and, therefore, would not fold or function properly. The protein made from the promoter would have a different amino acid sequence and, therefore, would not function properly. The promoter might not be recognized by RNA polymerase, so the enzyme would be unable to attach to the promoter and start transcription. The start codon would be missing from the mRNA made from this gene, so the mRNA could not be translated.

The promoter might not be recognized by RNA polymerase, so the enzyme would be unable to attach to the promoter and start transcription.

If a recessive allele causes a fatal disease that kills the affected individual before he or she can reproduce, why doesn't that allele quickly become extinct in the population? Question options: Alleles are never lost from a population. The homozygous dominant individuals protect the recessive allele in their genomes. The recessive allele is carried in the genome of heterozygotes, who do not suffer from the disease. The homozygous recessive individuals give their alleles to other individuals before they die from the disease.

The recessive allele is carried in the genome of heterozygotes, who do not suffer from the disease.

Which of the following statements is a basic summary of one of Mendel's laws? All beneficial human genetic traits are dominant, and harmful traits are recessive The pattern of inherited characteristics of organisms is not predictable The separation of alleles for one gene does not affect the separation of alleles for other genes Pleiotropy results in several phenotypes controlled by one gene

The separation of alleles for one gene does not affect the separation of alleles for other genes

Which base in a codon is called the wobble position? First Second Third Fourth Fifth

Third

The first amino acid in most proteins is methionine. Question options: True False

True

The position of the start codon is important because every molecule of mRNA can be read by a ribosome in several different ways. Question options: True False

True

Which of the following genotypes represents a human female? Question options: XY XX YY Zz

XX

Down syndrome in humans is an example of Question options: normal genetic recombination. a change in the overall number of chromosomes. an X-linked recessive disorder. a single-gene autosomal mutation. a change in the structure of one of the sex chromosomes.

a change in the overall number of chromosomes.

Which substance is found in RNA but not in DNA? Question options: t a different kind of sugar (ribose) g c a

a different kind of sugar (ribose)

Which of the following genetic changes would not be heritable? Question options: a mutation in a skin cell the loss of a chromosome in a sperm cell the addition of a chromosome in an egg cell a mutation in a gene in a gamete

a mutation in a skin cell

During translocation, Question options: pieces of DNA are exchanged between the non-sister chromatids of a homologous pair. a segment of DNA is broken off of a chromosome and reattached to the same chromosome, but backward in orientation. segments of DNA involved in crossing-over undergo somatic mutations. a segment of DNA breaks off one chromosome and is attached to a nonhomologous chromosome.

a segment of DNA breaks off one chromosome and is attached to a nonhomologous chromosome.

When a molecule of DNA replicates without error, each of the resulting molecules contains Question options: the same amount of A as T. the same amount of G as C. the same sequence of bases as did the original molecule. all of the above

all of the above

Which of the following would you expect to find in a sample of DNA from one of your liver cells? Question options: terminator sequences promoter sequences DNA that includes directions for the eventual production of proteins DNA that codes for RNA all of the above

all of the above

Mendel's law of segregation states that: Question options: alleles from one parent mask the expression of alleles from the other parent. alleles separate from each other before forming gametes. hybrids will express a phenotype intermediate between the two parental phenotypes. true-breeding parents produce offspring of the same phenotype. different loci separate from each other.

alleles separate from each other before forming gametes.

Each set of three bases in an mRNA molecule codes for one of 20 specific Question options: rRNA molecules. nucleotides. amino acids. proteins.

amino acids

Introns in mRNA: Question options: code for specific protein domains. are removed out of the message. move within the mRNA, thereby giving rise to new exon combinations. protect pre mRNA from enzyme degradation. code for important amino acid sequences.

are removed out of the message.

During protein production, ribosomes: Question options: attach to the mRNA molecule and travel along its length. attach to the DNA molecule and travel along its length to produce an mRNA molecule. translate mRNA into tRNA. transcribe mRNA to tRNA. translate mRNA into DNA.

attach to the mRNA molecule and travel along its length.

What type allele for a lethal disorder is expected to be the most common in a population? autosomal recessive autosomal dominat sex-linked recessive sex-linked dominant

autosomal recessive

The information in a gene is encoded by the Question options: introns of eukaryotic cells. amino acids that make up the genes. base sequences of the gene. rRNA that transfers amino acids to ribosomes.

base sequences of the gene.

The order of the bases in DNA determines the order of the Question options: amino acids in DNA. bases in a protein. amino acids in mRNA. bases in mRNA.

bases in mRNA.

The process of gene transcription begins with the Question options: binding of RNA polymerase to a region of DNA called the "promoter." removal of introns from the newly formed mRNA. joining of rRNA with various ribosomal proteins. attachment of an mRNA molecule to the ribosome. insertion of new DNA bases into the gene.

binding of RNA polymerase to a region of DNA called the "promoter."

tRNA differs from other types of RNA because it Question options: transfers genetic instructions from cell nucleus to cytoplasm. specifies the amino acid sequence of a particular protein. carries an amino acid at one end. contains codons. none of these

carries an amino acid at one end.

evolution is defined as the formation of new species true false

false

The chromosome theory of inheritance states that Question options: chromosomes are made of DNA. genes are located on chromosomes. genes are inherited. patterns of inheritance are based on probability.

genes are located on chromosomes.

Which of the following does NOT increase the genetic variation in a population? segregation of alleles independent assortment crossing-over genetic linkage random fertilization of gametes

genetic linkage

Which of the following are removed from mRNA after transcription? Question options: introns transposons spacer DNA exons

introns

During RNA splicing, Question options: introns are removed from RNA and the remaining exons are glued together to form a mature mRNA. a tRNA molecule is cut up into many small pieces and each piece forms a single tRNA. exons are removed from RNA and the remaining introns are fused to form a single mRNA. RNA is used to remove mutations from essential genes.

introns are removed from RNA and the remaining exons are glued together to form a mature mRNA.

A potential danger of a mutation to an organism is that Question options: it can affect codons within the spacer DNA. all mutations are fatal. it can cause a change in the function of a gene's protein product. it can increase the length of the introns of that organism's genome.

it can cause a change in the function of a gene's protein product.

Protein coding genes specify the production of _____ as their immediate product. Question options: rRNA tRNA DNA mRNA

mRNA

Use the chart below to determine the chain of amino acids that would be produced by the sequence of this very short, complete gene: UAUUAUGCCUGAGUGAAUUGCUA. mc151-1.jpg Question options: tyrosine-tyrosine-alanine tyrosine-tyrosine-alanine-stop-valine-asparagine-cysteine methionine-proline-glutamate methionine-proline-glutamate-isoleucine-alanine

methionine-proline-glutamate

Nucleic acids contain Question options: sulfur. phosphate. potassium. iron. manganese.

phosphate.

In bacteria, the antibiotic tetracycline blocks the site where tRNA molecules enter the ribosome. The most likely reason that bacteria die from treatment with tetracycline is because the antibiotic Question options: inhibits the cell from producing the mRNA. causes the tRNA molecules to randomly arrange into proteins that do not function. causes tRNA rather than mRNA to be made into proteins. prevents the bacteria from assembling proteins.

prevents the bacteria from assembling proteins.

Without the ________ site on a molecule of DNA, ________ cannot bind to the DNA to begin the process of ________. Question options: active; introns; tRNA translation promoter; RNA polymerase; transcription promoter; rRNA; ribosome activation attachment; ribosomal proteins; frameshift mutation start codon; amino acids; translation

promoter; RNA polymerase; transcription

Most inherited human disorders are the result of Question options: recessive mutations of genes located on autosomes. recessive mutations of genes located on the X chromosome. recessive mutations of genes located on the Y chromosome. simultaneous mutations of the same gene on homologous chromosomes.

recessive mutations of genes located on autosomes.

Which of the following carries amino acids to ribosomes, where amino acids are linked into the primary structure of a protein? Question options: mRNA tRNA hnRNA rRNA all of these

tRNA

In all organisms, the AUG codon codes for: Question options: the initiation of translation. the termination of transcription. the termination of chain elongation. the amino acid valine. a termination tRNA molecule.

the initiation of translation.

It is possible for a mutation to occur and yet not alter the end product of translation if Question options: the RNA polymerase skips over the mutated area. the new codon codes for the same amino acid. a deletion mutation removes the entire codon. the mutation affects the active site of the protein product.

the new codon codes for the same amino acid.

The sex of a human is usually determined by: Question options: the number of chromosomes. the number of autosomes. the presence of only one X chromosome. the number of sex chromosomes. the presence of the Y chromosome.

the presence of the Y chromosome.

On chromosomes, a pair of linked genes will be found only on Question options: autosomes. sex chromosomes. the same chromosome. opposite ends of the same chromosome. none of the above

the same chromosome.