BSC 108 University of Alabama Exam 3

What is the structure of a strand of DNA? - Correct Ans-double helix, twisted ladder What is DNA composed of? - Correct Ans-nucleotide subunits What is the backbone of DNA? - Correct Ans-deoxyribose and a phosphate group What is the backbone of DNA covalently bonded to? - Correct Ans-nitrogen-containing bases How many strands of DNA does a DNA molecule contain? - Correct Ans-two The two strands of DNA are: - Correct Ans-complementary What are the nitrogen-containing bases in DNA? - Correct Ans-adenine, guanine, thymine, cytosine How are the nitrogen-containing bases held together? - Correct Ans-hydrogen bonds What bases pair together? - Correct Ans-adenine=thymine guanine=cytosine How does DNA replicate? - Correct Ans-DNA molecule unwinds and each strand is a template for complementary base pairing; each daughter helix contains an intact strand from the parent helix and a newly synthesized strand therefore DNA replication is semiconservative One parent molecule is composed of two __________________ that separate. - Correct Ans-complementary strands Each strand is used as a ______________ to make a new strand. - Correct Ans template What are the two daughter molecules composed of? - Correct Ans-One "old" (parent) strand and one "new" (synthesized) strand Where do parent strands separate? - Correct Ans-origins of replication Where and how does synthesis of two new complementary strands occur? - Correct Ans-replication bubbles, using the parent strands as templates What do the replication bubbles do as DNA replication progresses in both directions at the replication forks? - Correct Ans-merge BSC108 BSC108 How does an organism's DNA lead to specific traits? - Correct Ans-by dictating the synthesis of proteins What is the structure of RNA? - Correct Ans-single-stranded nucleic acid RNA contains ________ instead of thymine. - Correct Ans-Uracil What sugar is used in RNA? - Correct Ans-ribose What is the function of mRNA (messenger RNA)? - Correct Ans-carries the genetic message from a gene (DNA) to ribosomes that translate it into a protein What is the function of tRNA (transfer RNA)? - Correct Ans-translates codons into amino acids Where does tRNA pair with mRNA? - Correct Ans-at the anitcodon What is the function of rRNA (ribosomal RNA)? - Correct Ans-to make up ribosomes with proteins What two processes do genes code for specific proteins? - Correct Ans-transcription and translation What is transcription? - Correct Ans-synthesis of mRNA under the direction of DNA Where does transcription occur? - Correct Ans-nucleus of a cell What is translation? - Correct Ans-synthesis of a polypeptide (which will become a protein) under the direction of mRNA Where does translation occur? - Correct Ans-on the ribosomes in the cytoplasm What is the structure of tRNA? - Correct Ans-three leaf clover, where one loop is the anticodon and the other end is where the amino acid attaches What is tRNA's role in translation? - Correct Ans-picks up amino acids and matches them to codons How does information flow in a cell? - Correct Ans-DNA - RNA - Protein DNA makes RNA through: - Correct Ans-transcription RNA makes protein through: - Correct Ans-translation What is a mutation? - Correct Ans-change in the genetic material of a cell BSC108 BSC108 What is a point mutation? - Correct Ans-change in one base pair of a gene What can a point mutation change? - Correct Ans-a gene's protein product What does change in the DNA molecule cause? - Correct Ans-altered mRNA to be transcribed and different amino acids to be added to the polypeptide chain What are frameshift mutations? - Correct Ans-mutations caused by insertions/deletions of a number of nucleotides not divisible by 3 What are potential effects of frameshift mutations? - Correct Ans-completely different translation, replication ending too soon, too-long chain What is a plasmid? - Correct Ans-small ring of self-replicating DNA separate from the larger chromosome(s) What is biotechnology? - Correct Ans-manipulation of organisms or their parts to produce a useful product What is recombinant DNA? - Correct Ans-molecule containing DNA from two different sources What is a genetically modified organism (GMO)? - Correct Ans-organism that has acquired one or more genes artificially What is a transgenic organism? - Correct Ans-a GMO that has received genes from an organism from another species What is a restriction enzyme? - Correct Ans-bacterial enzyme that cuts foreign DNA at one very specific nucleotide sequence What is a polymerase chain reaction (PCR)? - Correct Ans-technique used to obtain many copies of a DNA molecule What is a stem cell? - Correct Ans-a cell that generates replacements for nondividing differentiated cells What is an embryonic stem cell? - Correct Ans-cells in early animal/human embryo that differentiate during development to create all of the specialized cells in the body What is gene therapy? - Correct Ans-procedure intended to treat disease by altering an afflicted person's genes What is reproductive cloning? - Correct Ans-using a body cell to make one or more genetically identical individuals