Bio 151 Exam 2 Questions And Answers

theory of natural selection - ANS Idea, first proposed by Charles Darwin, that species survive due to favorable characteristics cell doctrine - ANS 1. all living things are composed of cells and cell products 2. a single cell is the smallest unit that exhibits all the characteristics of life 3. all cells come only from preexisting cells protein primary sequence - ANS the sequence of amino acids linked by polypeptide bonds that go into determining a protein's function nucleic acid sequence - ANS read from the sugar with the free 5′-phosphate to the sugar with the free 3′-hydroxyl group; it is written using the letters of the bases: A C G T in DNA or A C G U in RNA transcription - ANS synthesis of an RNA stand from a DNA template translation - ANS process by which mRNA is decoded and a protein is produced theory of spontaneous generation - ANS Life arises spontaneously from non-living material (false) gene - ANS A segment of DNA on a chromosome that codes for a specific trait meiosis - ANS a type of cell division that results in four daughter cells, each with half the number of chromosomes of the parent cell, as in the production of gametes. virus - ANS A tiny, nonliving particle that invades and then reproduces inside a living cell. bacteriophage - ANS kind of virus that infects bacteria transformation of bacteria - ANS the process by which foreign DNA is introduced into a cell Chargaff's Rule - ANS A%=T% and C%=G% double helix with anti-parallel strands - ANS One strand of DNA runs 5' to 3' and the other runs 3' to 5' 5' and 3' ends of strands - ANS the 5' end usually has a phosphate group and the 3' end usually has a hydroxyl group base paring - ANS In DNA A bonds with T and C bonds with G; in RNA A bonds with U and C bonds with G semi-conservative DNA replication - ANS The original DNA molecule serves as a template but is unzipped before it copies, with each strand serving as a template for the creation of a new double strand. helicase - ANS An enzyme that untwists the double helix of DNA at the replication forks. single-strand binding proteins - ANS bind to the unpaired DNA strands, keeping them from re-pairing DNA polymerase - ANS Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA strand dNTPs - ANS deoxynucleotide triphosphates (A,T, C, G) RNA primer - ANS short piece of RNA needed for DNA polymerase to start primase - ANS An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template. ligase - ANS An enzyme required for the repair, replication and recombination of DNA; joins okazaki fragments together leading strand - ANS The new continuous complementary DNA strand is synthesized along the template strand in the mandatory 5' to 3' direction. lagging strand - ANS A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork. telomeres - ANS Repeated DNA sequences at the ends of eukaryotic chromosomes; shorten with each replication overhangs - ANS Unpaired single strands at the ends of a double-stranded nucleic acid telomerase - ANS An enzyme that catalyzes the lengthening of telomeres in eukaryotic germ cells. origin of replication - ANS Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides. replication bubble - ANS a region of DNA, in front of the replication fork, where helicase has unwound the double helix replication forks - ANS portions of DNA where the double helix separates during DNA replication supercoiling - ANS The coiling of the DNA helix upon itself; can cause disruption to transcription topoisomerase - ANS corrects "overwinding" ahead of replication forks by breaking, swiveling, and rejoining DNA strands polymerase chain reaction (PCR) - ANS A method of producing thousands of copies of DNA segment by cell lysis, DNA precipitation and purification messenger RNA (mRNA) - ANS RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell RNA polymerase - ANS enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template transcription unit - ANS the stretch of DNA that is transcribed into an RNA molecule promoter - ANS specific region of a gene where RNA polymerase can bind and begin transcription terminator - ANS A special sequence of nucleotides in DNA that marks the end of a gene. It signals RNA polymerase to release the newly made RNA molecule, which then departs from the gene transcription factor proteins - ANS Regulate gene transcription by promoting or inhibiting transcription TATA box - ANS A promoter DNA sequence crucial in forming the transcription initiation complex, upstream of transcription, tells RNA polymerase which direction to read and which strand of DNA is the template primary transcript (pre-mRNA) - ANS eukaryotic RNA before it has been processed 5' cap - ANS The 5' end of a pre-mRNA molecule modified by the addition of a cap of guanine nucleotide; stabilizes mRNA