Bio 151 exam 2, Seth Blair, 2025 Questions And Answers

natural selection - ANS A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. cell doctrine - ANS All living things are composed of cells A single cell is the smallest unit that exhibits all of the characteristics of life All cells come only from preexisting cells primary protein sequence - ANS the linear sequence of amino acids nucleic acid sequence - ANS read from the sugar with 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 — Spontaneous generation - ANS Hypothesis stating that life could arise from nonliving matter. replication, transcription, translation - ANS on note card 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 and plant spores. Chargaff's Rule - ANS A=T and C=G transformation of bacteria - ANS genes transferred from one bacterium to another as "naked" DNA virus - ANS A tiny, nonliving particle that invades and then reproduces inside a living cell. bacteriophage - ANS A virus that infects bacteria 5' to 3' - ANS leading strand DNA replication is - ANS semiconservative; each of the two progeny double helices have one parental and one new strand helicase - ANS An enzyme that untwists the double helix of DNA at the replication forks. single stranded DNA binding proteins - ANS - bind to the unraveled strand preventing the re-association of the DNA strands & degradation of DNA by nucleases -Unpaired strands of DNA are very "sticky" so proteins are required to hold the 2 strands apart DNA polymerase - ANS Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule dNTPs - ANS deoxynucleotide triphosphates origin of replication - ANS Site where the replication of a DNA molecule begins, consisting of a specific sequence of nucleotides. replication bubble; replication fork - ANS a region of DNA, in front of the replication fork, where helicase has unwound the double helix Supercoiling - ANS Repeatedly coiling DNA molecule to make chromosome shorter and wider. Topiosomerase - ANS corrects "overwinding" ahead of replication forks by breaking, swiveling, and rejoining DNA strands RNA primer (primase) - ANS short segment of RNA used to initiate synthesis of a new strand of DNA during replication ligase - ANS An enzyme that connects two fragments of DNA to make a single fragment 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. Ozaki Fragments - ANS The fragments that make up the noncontinuous (lagging) strand Telomeres - ANS Repeated DNA sequences at the ends of eukaryotic chromosomes. Telomerase enzyme - ANS attaches many copies of DNA repeat sequence to the ends of chromosomes Telomere Overhang - ANS the extra nucleotides on the end of chromosomes that have no genetic info and buffer when strands get shorter polymerase chain reaction (PCR) - ANS A technique for amplifying DNA in vitro by incubating with special primers, DNA polymerase molecules, and nucleotides. messenger RNA - 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 similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription transcription unit - ANS A region of DNA that is transcribed into an RNA molecule. Promoter and terminator regions - ANS region of a gene in DNA where RNA polymerase binds and begins transcription region of a gene that signals the end of transcription transcription factors - ANS Collection of proteins that mediate the binding of RNA polymerase and the initiation of transcription. transcription unit - ANS the stretch of DNA that is transcribed into an RNA molecule transcription factor protein - ANS section of DNA upstream of RNA poly binding site that tells it where to bind - can allow or not allow the RNA poly to work to make an mRNA strand TATA box - ANS A promoter DNA sequence crucial in forming the transcription initiation complex. polyribosome - ANS A group of several ribosomes attached to, and translating, the same messenger RNA molecule. primary transcript - ANS The initial mRNA transcript that is transcribed from a protein coding gene. Also called pre-mRNA. messenger RNA - ANS 5' cap and poly-A tail - ANS Caps added to the mRNA as part of modification. They protect the mRNA segment, direct the mRNA out of the nucleus, and help ribosomes attach to the mRNA. exon and intron - ANS EXON: CODON THAT CODES FOR A SPECIFIC A.A. INTRON: JUNK DNA OR NONCODING RNA spliceosome - ANS A large complex made up of proteins and RNA molecules that splices RNA by interacting with the ends of an RNA intron, releasing the intron and joining the two adjacent exons.