bio exam 4

DNA possesses many negative charges because of the presence of _________, which also help form the backbone of each DNA strand phosphate groups deoxiribose sugars nitrogenous base hydrogen bonds

A

How many genetically unique types of gametes could be produced by an individual with the genotype RrYY? Hint 1. Assume that the alleles assort independently of each other during gamete formation. ANSWER: Two One Three Eight

A

Regions of the RNA transcript that contain non-coding bases are called _____. These regions are not present in the mRNA that leaves the nucleus. introns splicing spliceosomes exons ribosomes

A

Spliceosomes are composed of _____. ANSWER: snRNPs and other proteins polymerases and ligases introns and exons the RNA transcript and protein snRNPs and snurps

A

DNA does not store the information to synthesize which of the following? ANSWER: Organelles Messenger RNA DNA Proteins

A

The action of helicase creates _____. ANSWER: replication forks and replication bubbles primers and DNA fragments DNA fragments and replication bubbles DNA fragments and replication forks primers and replication bubbles

A

Translation occurs in the _____. ANSWER: cytoplasm lysosome nucleus Golgi apparatus nucleoplasm

A

What name is given to the process in which pre-mRNA is edited into mRNA? ANSWER: RNA processing gene expression polypeptide formation transcription translation

A

Which of the following parental genotypes would yield a 1:1:1:1 phenotypic ratio in the offspring? Hint 1. Use a Punnett square to diagram the genotypic and phenotypic ratios that would result from the crosses. ANSWER: AaBb, aabb aaBb, aabb AaBb, AaBb aaBb, AaBb

A

According to Mendel's law of segregation, a gamete ANSWER: always receives both of the parent's alleles for each gene. always receives only one of the parent's alleles for each gene. may receive either one or two of the parent's alleles for each gene.

B

After DNA replication is completed, _____. ANSWER: there are four double helices each new DNA double helix consists of one old DNA strand and one new DNA strand each of the four DNA strands consists of some old strand parts and some new strand parts one DNA double helix consists of two old strands and one DNA double helix consists of two new strands each new DNA double helix consists of two new strands

B

DNA contains ________, which distinguish DNA from RNA and help form the backbone of each DNA strand. phosphate groups deoxiribose sugars nitrogenous base hydrogen bonds

B

Double-stranded viral DNA is incorporated into a host cell as a _____. ANSWER: promoter provirus transposon lac homeoboxes

B

During RNA processing a(n) _____ is added to the 3' end of the RNA. ANSWER: 3' untranslated region a long string of adenine nucleotides 5' untranslated region coding segment modified guanine nucleotide

B

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand. ANSWER: cytosine ... thymine thymine ... cytosine uracil ... cytosine cytosine ... uracil guanine ... adenine

B

In a process called _____, non-coding regions of the RNA transcript are removed. introns splicing spliceosomes exons ribosomes

B

The RNA segments joined to one another by spliceosomes are _____. ANSWER: caps exons snRNPs tails introns

B

The direction of synthesis of an RNA transcript is _____. ANSWER: 1' —> 5' 5' —> 3' 1' —> 3' 3' —> 5' 2' —> 4'

B

The first step in the replication of DNA is catalyzed by _____. ANSWER: DNA polymerase helicase ligase single-strand binding protein primase

B

The genetic material of HIV consists of _____. ANSWER: single-stranded DNA single-stranded RNA double-stranded DNA double-stranded RNA none of the above

B

The synthesis of a new strand begins with the synthesis of a(n) _____. ANSWER: short pieces of DNA RNA primer complementary to a preexisting DNA strand poly(A) tail Okazaki fragment single-strand binding protein

B

What happens to RNA polymerase II after it has completed transcription of a gene? ANSWER: It joins with another RNA polymerase to carry out transcription. It is free to bind to another promoter and begin transcription. It begins transcribing the next gene on the chromosome. It is degraded.

B

Which of the following statements best describes the promoter of a protein-coding gene? Hint 1. Transcription of a gene is initiated by its promoter. ANSWER: The promoter is a site at which only RNA polymerase will bind. The promoter is a nontranscribed region of a gene. The promoter is part of the RNA molecule itself. The promoter is a site found on RNA polymerase.

B

Which of the following statements most accurately describes the process of independent assortment? ANSWER: Alleles found on separate chromosomes segregate based upon their origin. Alleles of different genes segregate from one another in a random manner. Genes located on the same chromosome assort as an independent unit. Dominant alleles segregate with recessive alleles.

B

Which of these correctly illustrates the pairing of DNA and RNA nucleotides? ANSWER: GTTACG CAATCG GTTACG CAAUGC GTTACG GTTACG GTTACG ACCGTA GTTACG UAACAU

B

Which of these is a difference between a DNA and an RNA molecule? ANSWER: DNA contains uracil, whereas RNA contains thymine. DNA is usually double-stranded, whereas RNA is usually single-stranded. DNA contains five-carbon sugars, whereas RNA contains six-carbon sugars. DNA contains nitrogenous bases, whereas RNA contains phosphate groups. DNA is a polymer composed of nucleotides, whereas RNA is a polymer composed of nucleic acids.

B

Which of these nitrogenous bases is found in DNA but not in RNA? ANSWER: adenine thymine cytosine guanine uracil

B

Which statement correctly explains how to determine the frequencies of the F2 progeny? ANSWER: The progeny frequencies are determined by the addition rule (adding the gamete frequencies together). The progeny frequencies are determined by the multiplication rule (multiplying the gamete frequencies together). The progeny frequencies cannot be predicted from gamete frequencies.

B

What determines which base is to be added to an RNA strand during transcription? ANSWER: The previous base Base pairing between the two DNA strands The order of the chemical groups in the backbone of the RNA molecule Base pairing between the DNA template strand and the RNA nucleotides

D

Which two statements correctly describe the template and/or coding strands? ANSWER: The four types of bases that are used in the coding strand are different from the types that are used in the template strand. During transcription, the DNA bases on the template strand are paired with their complementary RNA bases to form the RNA transcript. The template and coding strands are always antiparallel; that is, if one strand has its 3' end on the left and its 5' end on the right, the other strand has the opposite orientation. As the RNA polymerase moves along the DNA, the DNA bases on the coding strand are copied, producing the identical sequence of bases in the RNA transcript.

B,C

According to Mendel's law of segregation, ANSWER: dominant alleles segregate into gametes more frequently than recessive alleles. allele frequencies (i.e., proportions) in gametes cannot be predicted in advance. alleles segregate into gametes with equal frequency.

C

Adenine and thymine are examples of _______, which pair with each other in the double helix. phosphate groups deoxiribose sugars nitrogenous base hydrogen bonds

C

An old DNA strand is used as a _____ for the assembly of a new DNA strand. ANSWER: primer source of nucleotides template complement model

C

Does RNA polymerase move in a set direction along a strand of DNA during transcription? ANSWER: No; the RNA polymerase can move in either direction along the DNA strand because the same sequence of bases in the RNA will be produced regardless of direction. Yes, the RNA polymerase moves in a direction that reads the bases of the DNA sequence from the 5' end toward the 3' end. Yes, the RNA polymerase moves in a direction that reads the bases of the DNA sequence from the 3' end toward the 5' end.

C

How do cells acquire homologous chromosome pairs that carry the alleles that are independently assorted? ANSWER: Mitosis Meiosis Fusion of gametes DNA replication

C

Molecular complexes called _______ carry out RNA splicing in the nucleus. introns splicing spliceosomes exons ribosomes

C

What is the process called that converts the genetic information stored in DNA to an RNA copy? ANSWER: Translocation Replication Transcription Translation

C

When constructing a Punnett square, the symbols on the outside of the boxes represent _______, while those inside the boxes represent _______. ANSWER: gametes, parents progeny, gametes gametes, progeny parents, gametes

C

In bacteria, DNA polymerase III is the enzyme that adds new nucleotides to a primer or growing strand of DNA. Which of the following statements correctly describes the formation of the bond between a new nucleotide and the primer? ANSWER: The newly added nucleotide forms a bond with the phosphate group on the 3' end of the primer. The newly added nucleotide forms a bond with the phosphate group on the 5' end of the primer. The newly added nucleotide forms a bond with the hydroxyl (-OH) group on the 5' end of the primer. The newly added nucleotide forms a bond with the hydroxyl (-OH) group on the 3' end of the primer.

D

RNA processing converts the RNA transcript into _____. ANSWER: a protein DNA a eukaryotic cell mRNA a polypeptide

D

The complementary DNA strands of a double helix are held together by _______ between their nitrogenous bases. phosphate groups deoxiribose sugars nitrogenous base hydrogen bonds

D

The completed mRNA contains the gene's _____ joined together in the correct order. introns splicing spliceosomes exons ribosomes

D

Transcription begins at a promoter. What is a promoter? ANSWER: Part of the RNA molecule itself The same as a start codon A site found on the RNA polymerase A site in DNA that recruits the RNA Polymerase

D

Two mice are heterozygous for albinism (Aa) . The dominant allele (A) codes for normal pigmentation, and the recessive allele (a) codes for no pigmentation. What percentage of their offspring would have an albino phenotype? ANSWER: 100 50 75 25

D

What is the difference between heterozygous and homozygous individuals? ANSWER: Homozygotes have one chromosome while heterozygotes have two similar chromosomes. The homozygote will express the dominant trait and the heterozygote will express the recessive trait. Heterozygotes carry two copies of a gene while homozygotes only carry one. All of the gametes from a homozygote carry the same version of the gene while those of a heterozygote will differ.

D

What is the source of a viral envelope? ANSWER: host cell DNA prophages provirus host cell membrane viral glycoproteins

D

What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA? ANSWER: RNA processing gene expression polypeptide formation transcription translation

D

What process is responsible for the independent assortment of alleles? ANSWER: DNA replication. Cytokinesis. Mitosis Meiosis.

D

Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand? Hint 1. The relationship between the RNA strand and the DNA template strand is similar to that of the two strands of a DNA double helix. ANSWER: Covalently bound Permanently base-paired Identical Complementary

D

_____ bind(s) to DNA enhancer regions. ANSWER: RNA polymerase Promoters Introns Activators Exons

D

During RNA processing a(n) _____ is added to the 5' end of the RNA. ANSWER: 3' untranslated region a long string of adenine nucleotides 5' untranslated region coding segment modified guanine nucleotide

E

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand. ANSWER: uracil ... cytosine cytosine ... uracil cytosine ... thymine guanine ... adenine thymine ... cytosine

E

In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon. ANSWER: 2' ... 1' 1' ... 2' 2' ... 3' 1' ... 3' 1' ... 5'

E

Nucleic acids are assembled in the _____ direction. ANSWER: 4' to 5' 5' to 1' 1' to 5' 2' to 3' 5' to 3'

E

Polypeptides are assembled from _____. ANSWER: hexoses glycerol nucleotides proteins amino acids

E

Viral DNA makes mRNA by the process of _____. ANSWER: replication infection translation lysis transcription

E

What is the function of reverse transcriptase? ANSWER: It catalyzes the formation of a polypeptide from an RNA template. It catalyzes the formation of DNA from a polypeptide template. It catalyzes the formation of RNA from a polypeptide template. It catalyzes the formation of RNA from a DNA template. It catalyzes the formation of DNA from an RNA template.

E

What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein? ANSWER: RNA processing gene expression polypeptide formation transcription translation

E

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments? ANSWER: it is more efficient than assembling complete new strands the replication forks block the formation of longer strands DNA polymerase can assemble DNA only in the 3' to 5' direction only short DNA sequences can extend off the RNA primers DNA polymerase can assemble DNA only in the 5' to 3' direction

E

True or false? In diploid organisms, a dominant phenotype will only be expressed if the individual is homozygous dominant for that trait. Hint 1. Review the relationship between genotypes and phenotypes and the relationship between dominant and recessive traits. ANSWER: True False

FALSE

True or false? The principle of independent assortment is best illustrated by events that take place during metaphase II, during which sister chromatids segregate independently of each other. ANSWER: True False

FALSE

True or false? The same phenotype can be produced by more than one genotype. ANSWER: True False

TRUE