bio exam 3
Carries codons
mRNA
Binds to an amino acid
tRNA
Which of the following statements is true about RNA polymerase? a. RNA polymerase binds to promoter sequences in DNA to begin transcription. b. RNA polymerase produces strands containing T bases. c. RNA polymerase uses a RNA template to make DNA. d. RNA polymerase stops making new DNA sequences when it encounters a termination sequence. e. RNA polymerase uses the DNA template to make more DNA.
a.
Frameshift mutations a. cause a change in the reading frame of mRNA codons. b. are usually caused by base analogs. c. usually occur because of radiation exposure. d. cause a single amino acid change in the polypeptide chain. e. are usually the result of damage caused by free radicals.
a.
Free radicals a. form because of radiation exposure. b. form due to base analogs. c. form when atoms have paired electrons. d. are not reactive. e. are incorporated into DNA instead of normal bases.
a.
Mutations are only a. changes in the nucleotide sequence of DNA. b. changes in the amino acid sequence of proteins. c. changes in the nucleotide sequence of RNA. d. caused by mistakes in DNA replication. e. caused by environmental agents.
a.
Sickle cell anemia is caused by a. a single nucleotide mutation in DNA. b. a mutation that introduces an early stop codon. c. a deletion of a single amino acid from the normal protein. d. the deletion of many DNA nucleotides. e. the addition of a single nucleotide in the DNA.
a.
The complete set of genetic information of a human or other organism is called its a. genome. b. mutation. c. chromosome. d. phenotype. e. genotype.
a.
The three-dimensional shape of a protein is determined by the a. order of amino acids. b. temperature of the cells. c. amount of protein present. d. number of amino acids the organism possesses. e. the length of the protein.
a.
Translation is the process of a. making protein from RNA. b. duplicating DNA c. repairing mutations. d. cellular division. e. making pre-mRNA.
a.
What are the basic subunits of proteins? a. amino acids b. peptide bonds c. carboxyl groups d. nucleotides e. codons
a.
1. Approximately how many genes are there in the human genome? a. 20-25 b. 200-250 c. 2000-2500 d. 20,000-25,000 e. 200,000-250,000
d.
A cell that has accumulated a lot of mutations can have any of the fates below EXCEPT a. undergoing apoptosis. b. entering senescence. c. becoming cancerous. d. undergoing apoptosis then become cancerous. e. remaining in a dormant state.
d.
For the average American, _____ of radiation dose is due to background radiation. a. 19% b. 50% c. 70% d. 81% e. 99%
d.
Gene regulation is important because a. all genes have to be expressed in all cells. b. all the cells in the body have to express the same genes at the same time. c. genes are constantly changing due to mutation. d. different genes need to be expressed in different cells. e. no two cells in the body will express the same genes.
d.
How many different amino acids are found in proteins? a. 4 b. 10 c. 16 d. 20 e. 64
d.
Mutations a. are always easy to detect. b. always occur in the protein-coding region of genes. c. show up at a rate of about 6-7 mutations per child born. d. are usually only detected when there is a change in phenotype. e. are always harmful to an individual.
d.
The process where the information from DNA gets converted to RNA is called a. translation. b. mutation. c. initiation. d. transcription. e. elongation.
d.
Explain how base analogs cause mutations. What are the most common types of mutations caused by each mutagen?
Base analogs are chemicals that structurally resemble the bases (A, T, C, G) normally found in DNA. When DNA replicates, analogs in a replicating DNA strand can cause an incorrect base to be inserted into the newly synthesized strand, usually causing a single nucleotide substitutions.
Explain the difference between mutations that occur in body cells compared to mutations that occur in germ cells.
A mutation in a body cell will be passed on by cell division to other body cells, but it cannot be transmitted to future generations. And body cell mutations are underlying cause of cancer. Germ cell mutations can be transmitted to offspring
Most mutations in the DNA of cells are detected and repaired by each cell's DNA repair enzymes. However, on rare occasion, a mutation will be missed and remain in the DNA. What would happen if humans never developed any mutations? Please give TWO possible outcomes.
1) we would essentially all be genetically identical. lacking in diversity.bad for the human species if a change in the environment occurs that we cannot tolerate very well 2)no genetic diseases (or no new genetic diseases) fewer people would be afflicted or die from these particular types of diseases, such as cancer.
proofreading
DNA polymerase
T/F---All mutations are harmful.
F
T/F---Both miRNA and siRNA prevent transcription from occurring.
F
T/F---Changing how tightly the DNA is wound around histone proteins does not affect gene expression.
F
T/F---Each child is born with 65-70 newly-mutated genes
F
T/F---Essential amino acids are produced by the body
F
T/F---Mutations only occur in body cells.
F
T/F---Sickle-shaped blood cells form because of interactions between cells.
F
T/F---The main source of radiation exposure for most of the U.S. population is exposure to cosmic radiation.
F
T/F---When genes are changed by mutations, this will never change the function of the proteins they encode.
F
How do mutations form?
Mutations are formed by mistakes during DNA replication and by agents called mutagens, such as chemicals and radiation, which can cause changes in DNA.
Forms between two amino acids
Peptide bond
Explain how chemicals in some pesticides cause mutations. What are the most common types of mutations caused by each mutagen?
Pesticides contain certain chemicals that can mix with and distort the shape of the DNA double helix and cause DNA polymerase to add an extra nucleotide during replication, creating a frameshift mutation
Consists of two subunits
Ribosome
Translation begins here
Start codon
Ends translation
Stop codon
T/F --Proteins have many functions within the cell.
T
T/F---A gene mutation can cause one amino acid of a protein to be substituted for another amino acid.
T
T/F---An mRNA molecule can move out of the nucleus and into the cytoplasm
T
T/F---Each child is born with 65-70 new mutations
T
T/F---Mutations are changes in the DNA nucleotide sequence.
T
T/F---Mutations in germ cells can be passed on to offspring
T
T/F---RNA polymerase makes mRNA from a DNA template.
T
T/F---Some mutations can provide an advantage to those who carry them.
T
T/F---Some mutations do not change the amino acids sequence of the protein.
T
T/F---The main source of radiation exposure for most of the U.S. population is exposure to radon.
T
A codon is a. located on miRNA. b. a group of nucleotides in mRNA that encodes the information for a specific amino acid in a protein. c. a group of nucleotides in a tRNA molecule . d. a chemical link formed between amino acids. e. the enzyme that carries out transcription.
b.
Base analogs a. often cause frameshift mutations. b. lead to single-nucleotide substitution mutations. c. resemble the sugars found in DNA nucleotides. d. cause breakage of DNA strands. e. resemble the phosphate groups found in DNA nucleotides.
b.
Beta globin a. combines with gamma globin to produce hemoglobin. b. comes in three versions. c. is absent in individuals with sickle cell anemia. d. is the only polypeptide present in hemoglobin. e. is present in a shortened, non-functional form in individuals with sickle cell anemia.
b.
Chemicals found in some pesticides a. resemble the bases found in DNA. b. can lead to frameshift mutations. c. change the structure of DNA bases. d. cause single-nucleotide substitution mutations. e. cause mutations by binding to the DNA polymerase.
b.
Exposure to radiation a. is easily avoidable. b. can cause the formation of free radicals. c. is entirely from exposure to natural background radiation. d. repairs mistakes made during DNA replication. e. for the average American is mainly due to dental x-rays.
b.
Hemoglobin is made up of a. four identical protein chains. b. two different protein chains. c. four different protein chains. d. three identical protein chains. e. none of these.
b.
RNA polymerase is the enzyme that a. makes protein from a DNA template. b. makes pre-mRNA from a DNA template. c. transports RNA from the nucleus to the cytoplasm. d. makes DNA from a RNA template. e. replicates DNA.
b.
The first codon in protein translation is called the a. stop codon. b. start codon. c. initiation sequence. d. promoter. e. termination sequence.
b.
The process of transcription requires a. transfer RNA. b. a DNA template. c. messenger RNA. d. DNA polymerase. e. ribosomes.
b.
The region on the DNA where the RNA polymerase initially binds is called the a. termination sequence. b. promoter. c. stop codon. d. start codon. e. message.
b.
An anticodon is a. located on miRNA. b. a group of nucleotides in mRNA that encodes the information for a specific amino acid in a protein. c. a group of nucleotides in a tRNA molecule. d. a chemical link formed between amino acids. e. the enzyme that carries out transcription.
c.
Both miRNA and siRNA a. block DNA replication. b. block binding of RNA polymerase to the promoter. c. prevent translation of mRNAs. d. prevent processing of the pre-mRNA to mRNA. e. increase gene expression.
c.
Consider a stretch of 18 nucleotides on an mRNA molecule. If all 18 of these nucleotides are translated, how many amino acids will this account for? a. 3 b. 4 c. 6 d. 9 e. 18
c.
If the DNA sequence reads CGGATCAT, what will be the sequence of the RNA strand produced via transcription? a. GCCTAGTA b. GCCTAGUA c. GCCUAGUA d. GCCUAGTA e. GCCUACCC
c.
The mutation rates for different genes are affected by several factors. Which of the following statements about mutation rates for different genes is FALSE? a. Gene size affects mutation rates for genes. b. Nucleotide repeats found in some genes can increase in number with each generation. c. Genes with many adjacent A/T base pairs often have a high mutation rate. d. The smaller the gene, the lower the mutation rate. e. Nucleotide composition does not affect mutation rates of genes.
c.
The signal on the mRNA that causes translation to stop is the a. start codon. b. termination tRNA. c. stop codon. d. start methionine. e. termination sequence.
c.
What distinguishes amino acids from one another? a. different amino groups b. different carboxyl groups c. different R groups d. All of these distinguish amino acids from one another. e. None of these distinguish amino acids from one another.
c.
apoptosis
cell suicide
Which of the following statements about DNA repair is TRUE? a. All of the mistakes made in DNA replication are fixed by the proofreading activity of DNA polymerase. b. There is only one DNA repair system in humans. c. All mutations are detected and fixed by DNA repair systems. d. DNA repair systems recognize distortions in the DNA double helix. e. There is no DNA repair system to deal with damage caused by exposure to ultraviolet light.
d.
senescence
dormant cell
A change in the DNA nucleotide sequence is called a. an anticodon. b. translation. c. a tRNA. d. transcription. e. a mutation.
e.
All of the following are functions of proteins EXCEPT a. provide structure. b. receptors. c. carrier molecules. d. chemical messengers. e. storage of genetic information.
e.
All of the following are involved in translation EXCEPT a. messenger RNA. b. ribosomes. c. transfer RNA. d. AUG start codon. e. RNA polymerase.
e.
Environmental mutagens include certain molecules found in a. cigarette smoke. b. vehicle exhaust. c. some plants. d. some processed foods. e. all of these.
e.
Gene regulation can be achieved by all of the following EXCEPT a. the use of RNA interference. b. controlling access to the promoter regions of genes. c. chemically modifying histones. d. chemically modifying DNA e. controlling the rate of DNA replication.
e.
How might a change in DNA nucleotide sequence of a gene cause a genetic disorder? a. A change in one base pair in a gene can change a crucial amino acid in a protein. b. A mutation can change the three-dimensional shape of a protein and cause defective protein folding. c. A mutational change can cause a protein's subunits not to couple with each other properly. d. The change can lead to production of a shortened, non-functional protein. e. All of these are possible ways that changes in DNA could lead to genetic disorders.
e.
Types of mutations include all of the following EXCEPT a. single nucleotide substitutions. b. insertions. c. deletions. d. trinucleotide repeats. e. methylation of DNA.
e.
Which of the following statements about mutations is true? a. Mutations in body cells can be passed on to future generations. b. The only changes due to mutation are in the amino acid sequence of proteins. c. Mutations in body cells are not known to cause any phenotypic changes. d. All mutations are single-nucleotide substitutions. e. Mutations in germ cells can be passed on to future generations.
e.
Which of the following statements is true about sickle cell anemia? a. Affected individuals have a wide range of symptoms. b. It is inherited as an autosomal recessive trait. c. It can lead to early death if left untreated. d. It results from a mutation in the gene that encodes beta globin. e. All of these are correct.
e.
millirem
unit of measure of radiation dose
free radical
unpaired electrons