High School Academy Honors Biology - Unit 8 - DNA - Part 2
Which event would most likely cause a change in a genetic sequence in an organism? a. eating certain foods high in saturated fats b. strenuous physical activity c. exposure to radiation d. a sudden exposure to cooler temperatures
c. exposure to radiation
Rosalind Franklin's X-ray diffraction photographs of DNA were critical to understanding which of the following aspects of DNA structure? a. DNA is made up of two strands, and they are antiparallel. b. DNA is made up of nitrogenous bases, 5-carbon sugars, and phosphate. c. DNA has a helical structure and is antiparallel. d. DNA has a helical structure and the nitrogenous bases are stacked near the center.
d. DNA has a helical structure and the nitrogenous bases are stacked near the center.
The sequence of DNA below is part of a gene. How many amino acids are coded for by this segment? 5' ATCAGCGCTGGC 3' A. 4 B. 8 C. 12 D. 20
A. 4
During translation, what does the tRNA deliver to the ribosomes? A. amino acids B. DNA C. mRNA D. proteins
A. amino acids
At what point in the cell cycle does DNA replication occur and why? A. before a cell divides, to provide each of the two resulting cells with a complete set of DNA instructions B. before a cell divides, to ensure that the DNA will fit into the resulting cells C. during cell division, to ensure that the DNA will fit into the resulting cells D. after a cell divides, to provide each of the two resulting cells with a complete set of DNA instructions
A. before a cell divides, to provide each of the two resulting cells with a complete set of DNA instructions
What are the subunits of DNA and their function? A. nucleotides that store information B. monosaccharides that provide quick energy for the cell C. lipids that store energy and provide insulation D. proteins that provide the building blocks for the structural components of organisms
A. nucleotides that store information
Which factor most affects the order of amino acids in a protein? A. the DNA located in the nucleus of the cell B. the cell in which the protein is located C. the amount of ATP available for the cell's use D. the area in a cell where proteins are produced
A. the DNA located in the nucleus of the cell
A section of DNA has these bases: TAG CAG TAC Which mRNA sequence is produced from this DNA section? A. ATC GTC ATG B. AUC GUC AUG C. AUG CUG AUC D. UTC GTC UTG
B. AUC GUC AUG
How would overexposure to X-rays affect most animal cells? A. It would increase cell specialization in organs. B. It would change the sequence of DNA nucleotides in affected cells. C. It would produce new nucleotides for DNA molecules. D. It would cause an increase in red blood cell production
B. It would change the sequence of DNA nucleotides in affected cells.
A strand of DNA has these bases: AGC CAT GTA TAC What is the complementary DNA strand? A. ACG GAT CTA TAG B. TCG GTA CAT ATG C. TGC CTA GAT ATC D. UCG CUA CAU AUG
B. TCG GTA CAT ATG
A scientist puts nucleotide chains of UUUUUU in a test tube under conditions allowing protein synthesis. Soon the test tube is full of polypeptide chains composed only one the amino acid phenylalanine. What does this experiment indicate? A. The amino acid phenylalanine is composed of uracil. B. UUU codes for the amino acid phenylalanine. C. Protein synthesis malfunctions in test tubes. D. Most proteins contain only one type of amino acid.
B. UUU codes for the amino acid phenylalanine.
Which would most likely produce a mutation that is passed on to offspring? A. radiation changing the DNA sequence in skin cells B. a gamete with an extra chromosome forming C. tobacco smoke altering the genes in lung cells D. exposure to chemicals altering nerve cell function
B. a gamete with an extra chromosome forming
Two people believe they are related. Which would be the best technique to determine if they are related? A. testing blood types B. comparing DNA C. examining karyotypes D. testing for genetic disorders
B. comparing DNA
Four different segments of a DNA molecule are represented below. There is an error in the DNA in which molecule? A. segment 1 only B. segment 3 only C. segment 2 and 3 D. segment 2 and 4
B. segment 3 only
Which of the following would most likely cause a mutation? A. the placement of ribosomes on the endoplasmic reticulum B. the insertion of a nucleotide into DNA C. the movement of transfer RNA out of the nucleus D. the release of messenger RNA from DNA
B. the insertion of a nucleotide into DNA
What is the difference between the DNA of a dog and the DNA of a fly? A. the type of sugar building blocks B. the sequence of nucleotides C. the strength of hydrogen bonds D. the strength of covalent bonds
B. the sequence of nucleotides
Which choice describes DNA after replication has taken place? A. one molecule with two original strands and one molecule with two new strands B. two molecules, each with one original and one new strand C. two molecules, each with two new strands D. two molecules, each with two old strands
B. two molecules, each with one original and one new strand
Which best summarizes the role of DNA in the production of proteins? A. DNA moves to the cytoplasm to build proteins. B. DNA transports amino acids to the ribosomes to make proteins. C. DNA contains the instructions used to make proteins. D. DNA breaks hydrogen bonds between amino acids.
C. DNA contains the instructions used to make proteins.
During transcription the DNA base sequence is transcribed into a complimentary mRNA sequence. A codon table like the one shown below lists the amino acids coded for by particular triads of mRNA bases. A segment of DNA has undergone a mutation in which one nucleotide has been changed. The original sequence was ACG and the new sequence is ACA. Use the codon table to determine whether or not this mutation will cause a change in the phenotype of the organism. A. yes, the phenotype of the organism would change because a new amino acid will be coded for. B. yes, the phenotype of the organism would change because any change in the DNA sequence will cause a change in phenotype. C. Even though the DNA sequence changed, the sequence still codes for the same amino acid, so no change in phenotype will occur. D. It is impossible to determine if a change in phenotype will occur using only the DNA sequence.
C. Even though the DNA sequence changed, the sequence still codes for the same amino acid, so no change in phenotype will occur.
Genes for medically important proteins can be cloned and inserted into bacteria, as shown in the diagram below. Why can bacteria recognize a human gene and then produce a human protein? A. DNA replication in bacteria and humans is the same. B. Bacterial cells contain the same organelles as human cells. C. The basic components of DNA are the same in humans and bacteria. D. Bacterial cells and human cells contain the same kind of chromosomes.
C. The basic components of DNA are the same in humans and bacteria.
A segment of DNA has this sequence: ATA GCA CAT GTA What is the mRNA sequence transcribed from this segment? A. TAT CGT GTA CAT B. TAT GCT CTA GAT C. UAU CGU GUA CAU D. UAU GCU CUA CAU
C. UAU CGU GUA CAU
Which of the following carries amino acids to the site of protein synthesis? A. mRNA B. rRNA C. tRNA D. nRNA
C. tRNA
This diagram shows DNA fingerprints for a child and four adults. Which adult is most likely a parent of the child? A. Adult 1 B. Adult 2 C. Adult 3 D. Adult 4
D. Adult 4
How does DNA code for proteins in a cell? A. by creating a new double helix structure B. by using its phosphate and sugar molecules C. by adding more hydrogen bonds to its structure D. by arranging certain nitrogen bases of the cell in a particular order
D. by arranging certain nitrogen bases of the cell in a particular order
What is the function of a restriction enzyme? A. to control the movement of proteins into a cell B. to regulate blood sugar levels C. to produce hormones that regulate digestion D. to cut DNA at a specific nucleotide sequence
D. to cut DNA at a specific nucleotide sequence
What describes a mutation that is beneficial to a population? a. A mutation will be beneficial if it changes a protein in a way that increases the fitness of the offspring. b. A mutation will be beneficial if it results in an extra copy of a chromosome. c. A mutation will beneficial if it occurs in a noncoding region of DNA. d. A mutation will be beneficial if it occurs in response to a mutagen in the environment.
a. A mutation will be beneficial if it changes a protein in a way that increases the fitness of the offspring.
What most likely happen if tRNA malfunctioned during the assembly of a protein molecules? a. Amino acids would no longer be transported into the cell. b. Mutations would happen in the segment of mRNA as it formed. c. The wrong amino acids would be added to the new protein molecule. d. Bonds between the amino acids would no longer form inside the ribosome
a. Amino acids would no longer be transported into the cell.
How is DNA fingerprinting done in crime labs? a. DNA of suspects is compared to DNA isolated from hair, blood, or saliva at the crime scene. The DNA is cut into fragments, separated by gel electrophoresis, and then labeled with probes. b. DNA is isolated from the fingerprints of suspects and compared to DNA isolated from fingerprints at the crime scene. The DNA is cut into fragments and analyzed on a microarray by binding to labeled probes. c. Single-stranded DNA fragments from the crime scene are placed in a microarray plate. Genes that are expressed are labeled with cDNA probes. d. Single-stranded DNA fragments from suspects are separated by gel electrophoresis. Genes that are expressed are labeled with cDNA probes.
a. DNA of suspects is compared to DNA isolated from hair, blood, or saliva at the crime scene. The DNA is cut into fragments, separated by gel electrophoresis, and then labeled with probes.
How does the presence of tRNA in ribosomes allow ribosomes to manufacture proteins? a. It allows sequencing of amino acids based on an mRNA template. b. It allows for random distribution of amino acids. c. It stores chemical energy required for manufacturing proteins. d. It stores information about proteins already manufactured.
a. It allows sequencing of amino acids based on an mRNA template.
Which is the primary purpose of using restriction enzymes in gel electrophoresis? a. It allows the strands of DNA to be cut into various lengths for testing b. It restricts the number of base pairs that can be tested in a sample c. It makes the testing simpler by moving the strands into the gel faster d. It charges the DNA strands
a. It allows the strands of DNA to be cut into various lengths for testing
In an experiment, viruses were marked with radioactive DNA labeled with phosphorus-32, as shown on the left, or with radioactive protein, which was labeled with sulfur-35, shown on the right. After the viruses infected bacteria, radiation was found inside only the bacteria that had been infected by the virus that had radioactive DNA. What is the experiment called, and what is its significance? a. The Hershey-Chase experiment showed that the radioactive DNA is found inside the infected bacteria; therefore, DNA is the molecule that carries genetic information. b. The Hershey-Chase experiment showed that viruses with either radioactive DNA or radioactive protein can infect bacteria; therefore, both types of molecules can carry genetic information. c. The Franklin X-ray experiment showed that radioactive DNA forms a helical structure inside the infected bacteria; therefore, DNA is the molecule that carries genetic information. d. The Franklin X-ray experiment showed that either radioactive DNA or radioactive protein can form a helical structure inside the infected bacteria; therefore, both types of molecules can carry genetic information.
a. The Hershey-Chase experiment showed that the radioactive DNA is found inside the infected bacteria; therefore, DNA is the molecule that carries genetic information.
Which effect could a mutation in mRNA have on the production of proteins? a. The protein produced will have a different identity. b. The protein produced will have a coiled shape. c. The protein produced will produce excess nitrogen. d. The protein produced will produce excess water.
a. The protein produced will have a different identity.
Which of the following is not a practical use of DNA fingerprinting technology? a. identifying the best career for a person b. identifying the remains of deceased individuals c. establishing family relationships d. identifying the source of animal products
a. identifying the best career for a person
What are the subunits of DNA and their function? a. nucleotides that store information b. monosaccharides that provide quick energy for the cell c. lipids that store energy and provide insulation d. proteins that provide the building blocks for the structural components of organisms
a. nucleotides that store information
Which technology below would probably be the most important to a person who had diabetes and had to take insulin every day? a. using recombinant DNA to produce human hormones from bacteria b. testing parents for genetic disorders before they have children c. engineering fruits and vegetables that resist insects and other pests d. developing ways to identify criminals through DNA fingerprinting
a. using recombinant DNA to produce human hormones from bacteria
What is the relationship of cell specialization to the regulation of gene expression in multicellular eukaryotes? a. Cells are specialized because of the amino acids they produce, so they only need to express the genes for the tRNA molecules they use to stay alive and to carry out their specialized functions. b. Cells are specialized because of the proteins they produce, so they only need to express the genes for the proteins they use to stay alive and to carry out their specialized functions. c. Cells are specialized because of the genes that they contain, so they must eliminate the genes they do not need to stay alive and to carry out their specialized functions. d. Cells regulate gene expression in order to specialize their metabolism to take advantage of changing nutrients in their environment, such as lactose.
b. Cells are specialized because of the proteins they produce, so they only need to express the genes for the proteins they use to stay alive and to carry out their specialized functions.
Proteins are formed in the cytoplasm of cell using genetic instructions from DNA, which is located in the cells nucleus. Which of the following best explains how the genetic information gets to the site of protein synthesis? a. DNA is divided during mitosis, and one strand travels outside the nucleus to bind with RNA and form a protein b. DNA is copied to make mRNA. The mRNA leaves the nucleus and goes to the ribosomes, where the information is used to guide protein synthesis. c. Genetic information travels from DNA in the nucleus along a strand of mRNA that is connected to ribosomes in the cytoplasm where proteins are made. d. The genetic code is transferred to ribosomes on tRNA molecules, which can pass through the nuclear membrane.
b. DNA is copied to make mRNA. The mRNA leaves the nucleus and goes to the ribosomes, where the information is used to guide protein synthesis.
A student reads that deer mice that migrated to the hills of Nebraska originally had dark colored coats. Over many years, due to a mutation, the coat color of the mice changed to a lighter color to blend in easily with the sand. Which argument summarizes the mutation in deer mice? a. It is a harmful mutation as it caused a change in the original coat color of mice. b. It is a beneficial mutation as it helped the mice survive in their new surroundings. c. It is a neutral mutation as the change in coat color did not affect any body functions in the mice, and only helped the survival of the deer mice living in Nebraska. d. It is a neutral mutation as only the deer mice living in Nebraska were affected, and all other populations were unaffected.
b. It is a beneficial mutation as it helped the mice survive in their new surroundings.
A scientist irradiates seeds in an attempt to increase food production from a plant. How might radiation accomplish this goal? a. Radiation kills bacteria that harm the plant. b. Radiation causes mutations in the plant's DNA, increasing genetic variation. c. Radiation causes all living things to grow much larger. d. Radiation increases the rate of gene transcription.
b. Radiation causes mutations in the plant's DNA, increasing genetic variation.
Nitrogenous bases are located on both strands of the DNA double helix. What is the significance of the nitrogenous bases? a. The number of adenines and cytosines determines the type of RNA that will be produced. b. The order of nitrogenous bases determines the order of amino acids in the proteins synthesized. c. The amount of thymine and guanine in the DNA molecules determines the length of the genes. d. The type of hydrogen bonding between the nitrogenous bases determines which amino acid will be added to the peptide chain.
b. The order of nitrogenous bases determines the order of amino acids in the proteins synthesized.
Sickle cell anemia is a genetic condition that occurs because of a single point mutation in the DNA gene for hemoglobin. How is this mutation expressed in humans? a. The carbohydrate coded by the DNA has a different structure. b. The protein coded by the DNA has a different amino acid sequence. c. The chromosome carrying this gene changes shape during cell reproduction. d. The hormones in the blood are changed by increased differences in genes.
b. The protein coded by the DNA has a different amino acid sequence.
Human bone, muscle and nerve cells all contain the same number of chromosomes with the same complement of genes. What enables these cells to perform specialized activities? a. The ability of some cells to remove unnecessary DNA sequences b. The regulation of gene expression within each cell type c. The mutation of genes within each cell type d. The use of different methods of cell division.
b. The regulation of gene expression within each cell type
How would translation be affected if transcription did not occur? a. Translation would slow down but continue. b. Translation would stop if no mRNA was formed. c. Translation would not be affected because they are two different processes. d. Translation would speed up because it would not have to wait for products from transcription.
b. Translation would stop if no mRNA was formed.
Recombinant plasmids are useful for producing human proteins in bacteria. In addition to the gene for the human protein to be produced, what else does a recombinant plasmid usually include? a. sequences complementary to the host genome and a gene for antibiotic resistance b. a start signal for DNA replication and a gene for antibiotic resistance c. target sequences for Cas 9 protein and a start sequence for DNA replication d. target sequences for Cas 9 protein and sequences complementary to the host genome
b. a start signal for DNA replication and a gene for antibiotic resistance
In the early 1900s a scientist hypothesized a link between DNA and the production of protein in the cytoplasm. However, the fact that DNA could not be found outside the nucleus led scientists to believe that another substance was also involved in the synthesis of protein in the cytoplasm. In the 1940s scientists performed an experiment that ultimately identified the site of protein synthesis. They also identified the molecule responsible for transporting information from the nucleus to the site of protein synthesis. What was the newly identified molecule? a. a gene b. mRNA c. ATP
b. mRNA
DNA replication is said to be semiconservative. What does semiconservative mean in the context of DNA replication? a. Only the important parts of the base sequence of the original DNA are conserved during replication. b. Only one strand of the double-stranded DNA is replicated. c. Both DNA molecules resulting from replication have one of the original strands and one newly synthesized strand. d. DNA replication occurs in only half of the chromosomes in each cell cycle.
c. Both DNA molecules resulting from replication have one of the original strands and one newly synthesized strand.
Mutations cause many disorders in humans. Cystic fibrosis (CF) is a disorder that can be passed on from generation to generation. Skin cancer is a disorder that sometimes originates in skin cells as a result of overexposure to the Sun. Which statement best explains the formation of the mutations that cause both cystic fibrosis and skin cancer? a. These mutations are a direct result of a change in the amino acid molecule that controls the formation of genetic codes in gametes. b. These mutations are caused by a change in the sugars that make up the genetic codes in all cells. c. Both of these mutations involve a change in the makeup of genes. d. Both of these mutations are a result of the incorrect synthesis of the proteins that make up DNA.
c. Both of these mutations involve a change in the makeup of genes.
What is the likely effect of a mutation that changes a single base in a gene compared to a mutation that inserts a single additional base? a. Changing a single base will always change the amino acid specified by the codon. Inserting a base will not change the codon if it is inserted between two codons. b. Changing a single base will sometimes change the amino acid specified by the codon, but inserting a base will always change the single amino acid specified by the codon that receives the insertion. c. Changing a single base will sometimes change the amino acid specified by the codon, but inserting a base is a frameshift mutation that will change many of the codons that follow the point of insertion. d. Changing only a single base will never change the amino acid specified by the codon, but inserting a base is a frameshift mutation that will change many of the codons that follow the point of insertion.
c. Changing a single base will sometimes change the amino acid specified by the codon, but inserting a base is a frameshift mutation that will change many of the codons that follow the point of insertion.
What is the relationship between a protein, the cell, and DNA? a. DNA is produced by protein which is produced in the cell b. Protein is composed of DNA which is produced in the cell c. DNA controls the production of protein in the cell d. A cell is composed of DNA and protein
c. DNA controls the production of protein in the cell
Which technique would most likely be used by forensic scientists? a. gene cloning b. gene therapy c. DNA fingerprinting d. karyotyping
c. DNA fingerprinting
Mutations in an Organism's DNA may be either beneficial or harmful. Which of the following statements best describes the concept of DNA mutation? a. DNA mutation is an alteration in DNA replication that always results in phenotypic change. Mutations are usually due to radiation or other environmental factors. b. DNA mutation is a change in the way that Genes reproduce themselves, which may or may not affect phenotypic characteristics. Mutations are usually due to environmental factors or heredity. c. DNA mutation is a change in the Gene sequence, which sometimes results in phenotypic change. Mutations can be due to environmental factors, heredity, or a mistake in DNA replication. d. DNA mutation is an alteration in the nucleus of a Cell that makes certain Genes unable to be copied, and they result in phenotypic change. Mutations are usually due to viruses and environmental factors.
c. DNA mutation is a change in the Gene sequence, which sometimes results in phenotypic change. Mutations can be due to environmental factors, heredity, or a mistake in DNA replication.
All organisms contain DNA, and every organism's DNA is made of the same four nucleotides. The differences between organisms is simply based on the order of these nucleotides. Since all organisms have the same basic, universal structure for DNA, which of these must also be universal? a. All organisms have the same proteins. b. All living things must have the same amount of DNA. c. The codons in all organisms' DNA code for the same amino acids. d. The DNA blueprint varies based on how the nucleotides pair during replication.
c. The codons in all organisms' DNA code for the same amino acids.
In the early 1980s scientists were able to produce two biomolecules by splicing a human gene into the bacterium E. coli to make recombinant human insulin and growth hormone. Which statement best explains why this experiment was successful? a. Human cells are eukaryotic, and E. coli cells are prokaryotic. b. All living organisms share the same genome. c. The genes for all organisms are composed of the same building blocks. d. The human body contains many types of bacteria, including E. coli.
c. The genes for all organisms are composed of the same building blocks.
What carries the instructions for making amino acids in a protein? a. the nitrogen base on the tRNA b. the hydrogen bonding between nitrogen bases c. the sequence of nitrogen bases on the mRNA d. the nitrogen base bonding on the DNA molecule
c. the sequence of nitrogen bases on the mRNA
According to the genetic code, the mRNA codons UCU, UCC, UCA, and UCG all code for the amino acid serine. What does this fact tell you? a. The genetic code is the same for nearly all organisms. b. The genetic code does not dictate the amino acid sequence of proteins. c. A mutation in one base will always have a physical effect on the resulting protein. d. A mutation in one base could have absolutely no physical effect on the resulting protein.
d. A mutation in one base could have absolutely no physical effect on the resulting protein.
An original strand of DNA has the sequence: GGC ATG AAC. A point mutation results in a change in the sequence: GGC ATG AAT. Using the mRNA codon chart above, what is the most likely result from this change? a. One amino acid will change to asparagine. b. One amino acid will change to phenylalanine. c. All three amino acids in the sequence will change. d. All three amino acids in the sequence will remain the same.
d. All three amino acids in the sequence will remain the same.
Which statement best describes the relationship that exists among proteins, DNA, and cells? a. Proteins combine to produce cells, which produce DNA b. Proteins are made up of DNA, which determines the cells that are produced. c. DNA is made up of proteins, which tell a cell how to function. d. Cells contain DNA, which controls the production of proteins.
d. Cells contain DNA, which controls the production of proteins.
Why is DNA important for protein synthesis? a. DNA is used as a source of amino acids to make a protein b. RNA molecules build a DNA strand that synthesizes a protein c. DNA interacts with the RNA to add amino acids during protein synthesis d. DNA is used as a template to produce RNA that is translated to a protein
d. DNA is used as a template to produce RNA that is translated to a protein
Which of the following accurately describes the difference between Transcription and Translation? a. In Transcription, a double helix DNA molecule is split into two separate single strands. Translation is the process of joining each single DNA strand with a single strand of matching RNA. b. In Transcription, an amino acid chain is encoded in a DNA molecule. Translation is the process of turning the amino acids into nucleic acids in an RNA molecule. c. In Transcription, the Genetic code of a DNA molecule is first encoded. Translation is the process of converting the DNA code into code that RNA can use. d. In Transcription, the Genetic code of a DNA molecule is transferred to a messenger RNA molecule. Translation is the process of creating an amino acid chain using the encoded messenger RNA.
d. In Transcription, the Genetic code of a DNA molecule is transferred to a messenger RNA molecule. Translation is the process of creating an amino acid chain using the encoded messenger RNA.
Which of the following is the major difference in the process of DNA replication in prokaryotes when compared with eukaryotes? a. In prokaryotes, only one strand of DNA is replicated, and in eukaryotes, both strands are replicated. b. In prokaryotes, replication proceeds in one direction from a starting point, and in eukaryotes, it proceeds in both directions. c. In prokaryotes, the telomeres are replicated with DNA polymerase, and in eukaryotes, a special enzyme called telomerase is used. d. In prokaryotes, replication proceeds from a single starting point, and in eukaryotes, replication proceeds from multiple starting points.
d. In prokaryotes, replication proceeds from a single starting point, and in eukaryotes, replication proceeds from multiple starting points.
What property of restriction enzymes allows them to be especially useful in making recombinant DNA? a. Restriction enzymes cut DNA into smaller pieces that can be analyzed by gel electrophoresis. b. Restriction enzymes create mutations in DNA. Scientists can then select for mutants with new traits. c. Restriction enzymes cut DNA at specific sequences, leaving sticky ends that can be rejoined and, therefore, can be used to remove genes. d. Restriction enzymes cut DNA at specific sequences, leaving sticky ends that can be used to join two pieces of DNA from different sources.
d. Restriction enzymes cut DNA at specific sequences, leaving sticky ends that can be used to join two pieces of DNA from different sources.
How does a substitution impact a gene differently than an insertion? a. Substitutions often change back but insertions do not b. Substitutions cause frameshift mutations but insertions do not. c. Substitutions change one chromosome for another but insertions just add more genes. d. Substitutions only affect one amino acid but insertions can affect every amino acid from that point.
d. Substitutions only affect one amino acid but insertions can affect every amino acid from that point.
Which activity would most likely increase the mutation rate in a culture of bacteria being grown in a laboratory experiment? a. adding more distilled water to the culture b. adding excess nutrients to the culture c. exposing the culture to a higher concentration of CO2 d. exposing the culture to ultraviolet radiation
d. exposing the culture to ultraviolet radiation
Which will most likely cause an increase in the frequency of genetic mutations in humans? a. increased exposure to mold spores in the air b. increased exposure to the rising levels of atmospheric CO2 c. increased exposure to bacteria in drinking water d. increased exposure to X-rays
d. increased exposure to X-rays
In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). This change in skin color provides evidence that - a. the inheritance of skin color is an acquired characteristic. b. albinism is a recessive characteristic. c. ultraviolet light can cause mutations. d. the environment can influence gene action.
d. the environment can influence gene action.
