Deck 14: Dna and Genes

Question 1

The two strands of a DNA molecule are held together by _____ bonds between their base pairs.

A)hydrogen
B)amino acid
C)phosphate
D)protein

Answer 1

A

Question 2

When a cell divides, it

A)breaks down its DNA.
B)deletes old genetic information.
C)copies information from neighboring cells.
D)copies its own genetic information.

Answer 2

D

Question 3

The early hypothesis that protein was the genetic material was based in part on the

A)knowledge that chromosomes were composed of protein.
B)fact that proteins are small molecules and therefore easily copied.
C)fact that protein molecules are large and could carry a lot of information.
D)the idea that DNA molecules varied too much within cells of the same organism.

Answer 3

C

Question 4

Where in this diagram of the flow of genetic information of the cell would translation occur?

A)A
B)B
C)C
D)D

Question 5

The sequence of DNA differs among individuals within a species. This is the basis for

A)mutation.
B)protein structure.
C)base pairing.
D)variations in phenotypes.

Question 6

To start DNA replication, the bonds holding the strands together are broken, and the molecule begins to unwind. Which of the following statements best summarizes what happens next?

A)New strands are synthesized and paired with each other.
B)Each old strand acts as a template for a new strand.
C)Each old strand is broken down into nucleotides.
D)Transformation results in a new DNA molecule.

Question 7

The order of the base pairs in a DNA molecule

A)differs from species to species.
B)is identical in all organisms.
C)is identical in organisms of the same species.
D)differs from cell to cell in a given organism.

Question 8

What part of a nucleotide accounts for the genetic variation between individuals?

A)sugar
B)phosphate
C)base
D)polymerase

Question 9

Which of the following is not a base found in DNA?

A)thymine
B)adenine
C)guanine
D)uracil

Question 10

If one strand of DNA has the sequence CGATT, the sequence of the other strand of the same molecule will be

A)CGATT.
B)GCTUU.
C)TACGG.
D)GCTAA.

Question 11

Which of the following is true?

A)The two strands of a DNA molecule are held together by covalent bonds.
B)A single strand within a DNA molecule is held together by hydrogen bonds.
C)The bases on one strand of DNA are held to the bases on the other strand by hydrogen bonds.
D)Hydrogen bonding between complementary base pairs causes the DNA molecule to twist into a spiral.

Question 12

This figure shows a short sequence of DNA. During DNA replication, the piece of DNA depicted below will produce

A)one single-stranded molecule with the sequence CTAT.
B)two single-stranded molecules with the sequence GATA.
C)one single-stranded molecule with the sequence CTAT and a separate single-stranded molecule with the sequence GATA.
D)two double-stranded molecules that look just like the image above.

Question 13

DNA replication

A)involves the copying of only the parts of a chromosome that encode protein.
B)occurs during the S phase in the cell cycle.
C)is constantly occurring in all the cells in your body.
D)converts the double helix to two single helices.

Question 14

Once replication in a DNA molecule is complete, each new DNA molecule contains

A)one old strand and one new strand.
B)the paired old strands and the paired new strands.
C)new DNA polymerase.
D)a new sequence of nucleotides.

Question 15

Along one side of a DNA molecule, the nucleotides are connected to each other by

A)covalent bonds between phosphate groups and sugar molecules.
B)hydrogen bonds between adenine and guanine.
C)covalent bonds between bases and sugar molecules.
D)hydrogen bonds between adjacent sugar molecules.

Question 16

The hereditary genetic material present in all living cells is

A)carbohydrate.
B)protein.
C)DNA.
D)RNA.

Question 17

When examining the two complementary strands of nucleotides in one DNA molecule, you would expect to find that

A)the sum of Gs and Cs in one strand would be equal to the sum of the Gs and Cs in the other strand.
B)the sum of Ts and As in one strand would be equal to the sum of the Cs and Gs in the other strand.
C)the sum of Ts and As in one strand would be greater than the sum of the Ts and As in the other strand.
D)the sum of As and Cs in one strand would be less than the sum of the Ts and Gs in the other strand.

Question 18

What is not true of the five different cell types from the individual shown in the figure below?

A)They have the same DNA sequence.
B)They contain the same genes.
C)They express the same genes at the same time.
D)They have the same housekeeping genes.

Question 19

All cells in an organism contain a full copy of that organism's DNA. Your ears do not produce digestive enzymes because

A)stomach cells have extra DNA.
B)ear cells have nonfunctional DNA.
C)some DNA is deleted from cells where it is not needed.
D)different genes are expressed in different parts of an organism.

Question 20

Which of the following would not be a required biological property of genetic material?

A)It must be variable.
B)It must exist in paired copies.
C)It must be able to be copied accurately.
D)It must contain the information needed for life.

Question 21

The difference between the different alleles of a gene is

A)their DNA base sequences.
B)the way they are copied when the cell divides.
C)the type of lipid they are composed of.
D)not heritable.

Question 22

In plants, transposons are often the cause of variegation (the formation of white stripes of cells on a green leaf). Which of the following explains why a transposon might have this effect?

A)The white cells are dead cells. When a transposon moves from one chromosome to another, it kills its host cell.
B)When a bacterium infects a plant cell, the plant cell begins producing bacterial proteins rather than plant proteins.
C)When a transposon "jumps" into the gene involved in the production of the green pigment in a plant, the gene no longer functions so the cells are all white.
D)When a transposon enters a cell, it inhibits the translation of all proteins.

Question 23

Most eukaryotic DNA is

A)single-stranded.
B)noncoding.
C)regulatory sequences.
D)prokaryotic.

Question 24

Which of the following will not generally cause mutations?

A)chemicals
B)radiation
C)mechanical forces
D)DNA replication

Question 25

DNA is often damaged or may be replicated incorrectly. Which of the following is not true?

A)Humans do not have DNA repair proteins.
B)A mutation in the gene for a DNA repair protein may make mutations in other genes more common.
C)Certain proteins can repair damaged DNA.
D)The vast majority of DNA damage is fixed.

Question 26

Mismatch errors are

A)almost always corrected by mutagens.
B)also called mutations.
C)almost always corrected by specialized proteins.
D)usually caused by mutated proteins.

Question 27

Is a species that lacks DNA repair mechanisms likely to have more or fewer variations between individuals than a species that possesses repair mechanisms?

A)Fewer, because there are fewer ways to change the DNA.
B)Fewer, because the repair mechanisms introduce more variation into the DNA sequence.
C)More, because more spontaneous mutations will go uncorrected.
D)More, because without a repair mechanism, the cell's tumor suppressor genes are inactivated.

Question 28

Which of the following must occur for a mismatch error to be repaired?

A)DNA repair proteins identify damaged DNA.
B)The sequence of nucleotides in the damaged DNA sequence guides the synthesis of the correct DNA sequence.
C)DNA-eating enzymes within the nucleus destroy entire strands of damaged DNA.
D)The damaged DNA undergoes DNA replication one more time.

Question 29

Noncoding DNA

A)codes for RNA but not proteins.
B)codes for introns and spacer DNA.
C)includes spacer DNA and transposons.
D)includes spacer DNA and introns.

Question 30

Which of the following does not correctly state a difference between prokaryotic and eukaryotic DNA organization?

A)Prokaryotic DNA groups genes with related functions together, whereas eukaryotic DNA does not.
B)Prokaryotic DNA has few noncoding regions, unlike eukaryotic DNA.
C)Eukaryotic DNA is usually arranged more simply than prokaryotic DNA.
D)Eukaryotic genomes contain more genes than prokaryotic genomes.

Question 31

Would you expect the presence of spacer DNA to increase or decrease the frequency of linkage between genes?

A)Decrease it, because the spacer DNA is removed from the genome before transcription.
B)Decrease it, because the spacer DNA increases the probability of crossing-over between genes.
C)Increase it, because the spacer DNA is tightly connected to the genes on both sides.
D)Increase it, because the spacer DNA encourages the insertion of transposons into the DNA.

Question 32

The significance of specific base pairing in DNA is that

A)it stabilizes the sugar molecule.
B)it provides a method for making exact copies of DNA.
C)it prevents errors in DNA replication.
D)protein copies can be made directly from the DNA.

Question 33

Damaged DNA may be repaired by a special class of

A)nucleotides.
B)proteins.
C)deoxyribose molecules.
D)phosphate bonds.

Question 34

The adenine bases in a DNA molecule are radioactively labeled. The DNA is then placed in a solution containing unlabeled nucleotides and the enzymes needed for DNA replication. The DNA molecule is allowed to replicate twice, forming four new DNA molecules. You would find the radioactively labeled adenine in

A)each of the eight strands.
B)two of the eight strands.
C)all but one strand.
D)six of the eight strands.

Question 35

The figure below illustrates DNA undergoing replication. The region indicated by the arrow in this image represents a

A)single base pair.
B)mismatch error.
C)mutation.
D)transformation.

Question 36

Bacterial cultures are sometimes exposed to ultraviolet (UV)light in order to generate organisms with new genetic traits. Why do microbiologists choose to use UV light for this purpose?

A)UV light makes all cells antibiotic resistant.
B)UV light has the ability to cause changes in DNA.
C)UV light is the usual source of energy for bacteria, thus giving them more energy for evolution.
D)none of the above

Question 37

Which of the following are removed from mRNA after transcription?

A)introns
B)transposons
C)spacer DNA
D)exons

Question 38

Which of the following statements is not true of eukaryotic DNA?

A)It is located in each cell's cytoplasm.
B)It contains transposons.
C)It has more genes than prokaryotic DNA.
D)It contains many noncoding sequences.

Question 39

A rapidly dividing cell is exposed to a chemical that converts the bond that forms between adenine and thymine to a covalent bond. Which of the following is most likely to occur?

A)DNA replication would produce two molecules of DNA with mutations at every base that once held an A-T base pair.
B)DNA replication would not occur because the two nucleotide strands that make up the DNA molecule would not be able to separate.
C)DNA replication would occur more slowly because DNA repair proteins would have to fix the covalent bonds before replication could begin.
D)DNA replication would be faster because covalent bonds require less energy to break than hydrogen bonds.

Question 40

Replication of DNA cannot begin until

A)phosphate bonds between nucleotides are broken.
B)hydrogen bonds between complementary bases are broken.
C)covalent bonds between sugar molecules are broken.
D)hydrogen bonds between nucleotides in one strand are broken.

Question 41

Which is not a way that cells can control gene expression?

A)Tightly packed DNA is not expressed.
B)Cells break down DNA that codes for unexpressed proteins.
C)Cells regulate the breakdown of mRNA.
D)Cells can inhibit translation.

Question 42

Why do organisms have the ability to change gene expression?

A)Being able to change gene expression prevents an organism from wasting energy and resources on protein production.
B)The environment is constantly changing and an organism must be able to react to that change.
C)Changing gene expression ensures that exactly the right proteins are available when they are needed.
D)all of the above

Question 43

Which of the following can be described as housekeeper genes?

A)genes that code for processing arabinose in E. coli
B)genes that code for producing chemicals that transmit nerve signals
C)genes that code for making muscle proteins
D)genes that code for making rRNA

Question 44

Which of the following is directly involved in the regulation of transcription?

A)ribosomes
B)tRNA
C)DNA polymerase
D)repressor protein

Question 45

During interphase, the genes that are most tightly packed are not being expressed because

A)ribosomes are unable to bind to their promoters.
B)the proteins needed for transcription cannot reach them.
C)housekeeping genes are not produced.
D)repressor proteins cover their promoters.

Question 46

A cell has a repressor protein for the group of genes that makes substance A. If substance A is present in sufficient quantities,

A)the repressor protein will be bound to RNA polymerase.
B)the repressor protein will be bound to the promoter.
C)substance A will be bound to the operator.
D)a repressor protein-substance A complex will be bound to the operator.

Question 47

Why is regulating transcription the main way that cells control gene expression?

A)Because transcription is the last step in gene expression, stopping here ensures that the cell has a stockpile of proteins to prepare them from all unexpected environmental changes.
B)Because transcription involves interactions with DNA, preventing transcription reduces the changes of mutation in the cell's genome.
C)Because transcription is the first step in gene expression, stopping at transcription reduces the amount of energy and resources used by producing unnecessary gene products.
D)Because transcription is the shortest step in gene expression, preventing transcription has little effect on the rate of protein production.

Question 48

The most common way for cells to control gene expression is by controlling

A)translation.
B)transcription.
C)spacer DNA frequency.
D)mutation.

Question 49

How can a cell contain DNA molecules that are much longer than the cell?

A)The cell expands to fit the DNA inside.
B)DNA not used by that cell is deleted.
C)DNA is very narrow and tightly packed.
D)RNA copies allow DNA to dissolve.

Question 50

Housekeeping genes

A)prevent repressors from binding the promoter.
B)prevent operators from expressing genes.
C)are expressed by most of the cells in an organism
D)break down a cell's DNA.

Question 51

The table below shows which of these four genes are on or off in three different cell types.
Why is the expression of the rRNA gene so different from the expression of the other genes in the table?

A)rRNA is required for the proper functioning of all cells, but the products of the other genes are only essential to the function of one cell type.
B)rRNA is easier to produce than the products of the other genes.
C)The rRNA gene is found in the genomes of all three cell types, but the other genes are only found in the genomes of their specific cell type.
D)rRNA is needed at all stages of the cell cycle, but the products of the other genes are only needed during cell division.

Question 52

In the figure below, are the genes that encode the enzymes needed to make tryptophan on or off?

A)The genes are on because the genes involved in tryptophan production are housekeeping genes.
B)The genes are on because the complex of tryptophan and repressor protein allows RNA polymerase to bind to the promoter.
C)The genes are off because the complex of tryptophan and repressor protein prevents RNA polymerase from interacting with regulatory DNA.
D)The genes are off because when tryptophan is plentiful in the environment, RNA polymerase is not made.

Question 53

Proteins found in the blood respond to blood vessel damage by clumping together forming a clot that physically blocks the hole in the vessel and prevents further blood loss. If clotting proteins were active all the time, they would create clots throughout your circulatory system. Which of the following would be the most efficient way for the body to regulate the expression of the proteins involved in clotting?

A)Produce and store the clotting protein in an inactive form. When the protein is needed, use another protein to activate the clotting protein.
B)Use a repressor protein to keep clotting genes turned off until they are needed.
C)Tightly package the genes for clotting proteins so that RNA polymerase cannot access them unless they are needed.
D)Constantly make the clotting proteins, but then break them down instantly after translation if they are not needed.

Question 54

The enzymes involved in ATP synthesis in the mitochondria are likely to be encoded by _____ genes.

A)regulatory
B)DNA repair
C)housekeeping
D)transposon

Question 55

In condensed chromosomes, histone proteins

A)lie between introns in the DNA molecule.
B)contain most of the spacer genes in a cell.
C)have DNA wrapped around them.
D)are sites where active transcription takes place.

Question 56

One level of DNA packing involves the DNA being wound around

A)histone proteins.
B)an RNA molecule.
C)cytoplasmic organelles.
D)translation enzymes.

Question 57

The figure below illustrates two levels of DNA packing in a eukaryotic cell. Conformation B is an enlargement of the area in Conformation A, indicated by the start of the arrow. In which conformation is transcription most likely to occur?

A)Conformation A, because the tight coiling brings regulatory DNA sequences closer together.
B)Conformation A, because tight coiling only occurs during cell division, which is when transcription occurs.
C)Conformation B, because RNA polymerase can only access regulatory DNA when chromosomes are not condensed.
D)Conformation B, because in this conformation, the DNA is completely separated from histones that bind to regulatory DNA sequences preventing transcription.

Question 58

An operator is a sequence of DNA whose function it is to

A)bind to the chromosome to prevent replication.
B)bind to the chromosome to prevent gene expression.
C)control the transcription of a gene or group of genes.
D)control the translation of a gene or group of genes.

Question 59

The protein product of the Sonic Hedgehog gene plays a role in

A)determining how fast the cell cycle occurs during early development.
B)the production of the hormone estrogen.
C)the breakdown of phthalates absorbed from the environment.
D)allowing different cell types to specialize in performing specific functions.

Question 60

Which of the following is not true? Organisms turn genes on and off

A)depending on the function of the cell.
B)in response to environmental changes.
C)to cause certain developmental changes.
D)to switch from prokaryotic to eukaryotic status.

Question 61

A(n)____________________ error occurs when the wrong base is inserted during DNA replication.

Question 62

People with xeroderma pigmentosum frequently exhibit skin cancer. The disease is a result of a mutation in a gene that produces a ____________________ protein. Without this protein, cells cannot fix changes in their DNA sequence caused by exposure to ultraviolet (UV)light.

Question 63

Exposure to ____________________ light can cause sunburn and massive DNA damage to skin cells.

Question 64

The "rungs" in the DNA "ladder" consist of ____________________ pairs.

Question 65

When compared, the nucleotide sequences of different individuals are____________________.

Question 66

Gene ____________________ is the synthesis of a gene's protein or RNA product.

Question 67

DNA ____________________ results in the copying of a DNA molecule.

Question 68

DNA consists of two twisted strands of ____________________.

Question 69

A(n)____________________ is a DNA sequence that is capable of moving from one position to another.

Question 70

The backbone of a DNA molecule is made up of sugars and ____________________.

Question 71

____________________ DNA consists of stretches of nucleotides that separate genes.

Question 72

The amount of DNA in a prokaryotic cell is ____________________ than the amount of DNA in a eukaryotic cell.

Question 73

The process labeled with the letter D in this diagram of the process of gene flow in a cell requires ____________________ to convert genetic information into a phenotype.

Question 74

The ____________________ of eukaryotes vary greatly in size from 12 million base pairs in some to more than a trillion base pairs in others.

Question 75

The genome of a prokaryote rarely contains ____________________ DNA sequences that do not undergo transcription.

Question 76

A permanent change in the DNA base sequence due to an uncorrected mismatch error is called a ____________________.

Question 77

A change in an organism's environment generally results in a change in ____________________, leading to the production of different types of proteins.

Question 78

DNA is ____________________ [more or less] tightly packaged during interphase when most gene expression occurs.

Question 79

During DNA replication, the enzyme ____________________ builds a new strand of DNA while using the old strand of DNA as a template.

Question 80

DNA is tightly packed around protein spools known as ____________________.