NU 545 Unit 7 Evolve 1

NU 545 Unit 7 Evolve 1. Which term describes the deoxyribonucleic acid (DNA) subunit of one deoxyribose molecule, one phosphate group, and one base? A. Polypeptide B. Double helix C. Nucleotide Correct A nucleotide consists of one deoxyribose molecule, one phosphate group, and one base. A polypeptide is a chain of proteins. The double helix is the twisted staircase presentation of DNA that was proposed by Watson-Crick. A codon is a triplet of amino acids. D. Codon . 2. 2.ID: 50 Which statement is true regarding termination codons? A. Eighty codons are possible. B. Three codons signal the end of a gene. Correct Three codons signal the end of a gene, and they are called stop or nonsense codons. C. Seventy codons specify amino acids. D. Each amino acid has one codon. . 3. 3.ID: 38 Which statement describes the function of DNA polymerase? A. Synthesizes ribonucleic acid (RNA) from the DNA template B. Synthesizes a polypeptide C. Performs base pairing in replication Correct The function of DNA polymerase is to assist with base pairing when replicating DNA. This enzyme travels along the single DNA strand, adding the correct nucleotides to the free end of the new strand. It also proofreads. Transcription is the synthesis of RNA from DNA. Translation is the formation of a polypeptide from RNA. DNA polymerase does not split DNA molecules. D. Splits DNA molecules . 4. 4.ID: 52 Which statement is true regarding base pairs? A. Adenine pairs with guanine. B. Guanine pairs with thymine. C. Cytosine pairs with adenine. D. Uracil pairs with adenine. Correct Uracil is structurally similar to thymine. Therefore the correct base pairs are adenine with thymine, guanine with cytosine, and uracil with adenine. . 5. 5.ID: 36 Which term describes the sequence for the beginning of a gene? A. Intron B. Exon C. Promoter site Correct Transcription of a gene begins when an enzyme called RNA polymerase binds to a promoter site on the DNA. A promoter site is a sequence of DNA that specifies the beginning of a gene. Many of the RNA sequences are removed, and the remaining sequences are spliced together to form the functional messenger RNA (mRNA) that will migrate to the cytoplasm. The excised sequences are called introns, and the sequences that are left to code for proteins are called exons. The anticodon is the sequence of three nucleotides that undergo complementary base pairing in translation. D. Anticodon . 6. 6.ID: 40 Which statement is true regarding chromosomes? A. There are three cell types. B. The somatic cells contain 46 chromosomes. Correct There are two cell types: somatic and gametes. Somatic cells are those that are not gametes (sperm and eggs). They have 46 chromosomes in the nucleus. These are also considered diploid cells. The gametes are haploid cells and have only 23 chromosomes. They are formed from diploid cells through meiosis. C. Gametes are diploid cells. D. Diploid cells are formed through meiosis. . 7. 7.ID: 46 Which term describes a cell that does not contain a multiple of 23 chromosomes? A. Aneuploid Correct The term aneuploid means that the cell does not contain a multiple of 23 chromosomes. Monosomy is the presence of only one copy of a given chromosome in a cell. Trisomy is the presence of three copies of a chromosome. Tetraploidy is a cell that contains 92 chromosomes. B. Monosomy C. Trisomy D. Tetraploidy . 8. 8.ID: 48 Which term describes an allele with an observable effect? A. Homozygous B. Heterozygous C. Dominant Correct Dominant alleles have effects that are observable. Homozygous is when two alleles at a locus are identical. Heterozygous is when the two alleles at a locus are different. Recessive alleles may be hidden. D. Recessive 9. 9.ID: 44 Which statement is true regarding autosomal dominant gene transmission? A. The affected parent transmits the gene to one-half of his or her children. Correct The affected parent will transmit the trait to (approximately) one-half of his or her children; in each match, a 50% chance exists that either a normal gene or an affected gene will be transmitted to the child. The affected gene is found equally in males and females, both sexes transmit the trait equally, and no skipping of generations occurs. B. The affected gene is found in males only. C. Generations are skipped for transmission. D. Females will transmit the disease more often than males. . 10. 10.ID: 54 Which statement is true regarding autosomal recessive inheritance? A. Parents will always display the trait. B. Approximately 50% of children will display the trait. C. Males and females are equally affected. Correct Males and females are equally affected by autosomal recessive traits. Generally, parents will not display the trait; that is, they are heterozygous themselves, but each will pass the recessive trait to 25% of their children. The child must be homozygous for the trait to express the recessive trait. D. An individual must be heterozygous to display a recessive trait. . 11. 11.ID: 56 Which statements are true regarding protein synthesis? (Select all that apply.) A. Protein synthesis takes place in the cytoplasm. Correct B. DNA replication occurs in the cytoplasm. C. Protein formation involves transcription and translation. Correct D. Ribonucleic acid (RNA) mediates transcription and translation processes. Correct Protein synthesis takes place in the cytoplasm, whereas DNA replication takes place in the nucleus. Protein formation involves transcription and translation. Both transcription and translation are mediated by ribonucleic acid (RNA). Chapter 5 1. What is the definition of incidence rate? A. Number of new cases of a disease reported during a specific period, divided by the number of individuals in the population Correct The number of new cases of a disease reported during a specific period of time (typically 1 year), divided by the number of individuals in the population, is the incidence rate. The proportion of the population affected by a disease at a specific point in time is the prevalence rate. The effect of a specific risk factor is the relative risk. Polygenic genes cause variation. B. Proportion of the population affected by a disease at a specific point in time C. The effect of a specific risk factor D. Variation is caused by the multiple effects of genes . 2. 2.ID: 40 Which statement is true regarding the risks of developing a disease? A. Empiric risks are based on assumptions. B. Recurrence risk is higher if more than one family member is affected. Correct Recurrence risk is higher if more than one family member is affected and usually decreases rapidly in more remotely related relatives. Empiric risks are based on observation. For diseases that have a threshold of liability, an individual usually does not have the disease below the threshold of liability. C. An individual below the threshold of liability for a disease will have the disease. D. The recurrence risk for disease usually increases rapidly in more remotely related relatives. . 3. 3.ID: 38 Which statement describes a monozygotic twin? A. Twins who share very few traits B. Twins who share all traits Correct Monozygotic twins divide from one embryo and actually share traits. They are natural clones. Twins from double ovulation are dizygotic and may not share traits. Monozygotic twins have the same rate across populations. Dizygotic or fraternal rates vary among populations. C. Twins who form from double ovulation D. Twins whose rates vary among populations.