Bio 111 Exam 1 - Purdue University All Possible Questions and Answers with complete

Cell division requires what 3 things? - Answer-1. Replication of genetic material 2. Accurate segregation of genetic material 3. Divison of the cytoplasm between two cells Main difference between prokaryotes + eukaryotes? - Answer-Size and presence of membrane bound nucleus - prokaryotes are smaller, no nucleus / membrane bound organelles What is the term used to describe about 150 nucleotides of DNA wrapped around a core of histone proteins? - Answer-nucleosome Meiotic cell division plays a key role in which biological processes? - Answer-sexual reproduction A cell starts with 40 chromosomes (20 homologous pairs). After DNA replication how many chromosomes does that cell have? - Answer-40 (homologous pairs) During which phase of the cell cycle does the nuclear envelope reassemble? - Answer-Telophase How do bacteria divide? - Answer-Binary fission, asexual reproduction (one cell divides into two) Which proteins associate with the centromere of each chromatid? How? - Answer-Cohesion proteins - hold the sister chromatids together after DNA replication Kinetochore proteins - are the site of the microtubules attachment during cell division Process of binary fission - Answer-1. Single, circular bacterial chromosome is replicated 2. Replication begins at ori and proceeds in both directions to site of termination 3. New chromosomes separate and are partitioned to opposite ends of cell FtsZ proteins form a ring around the middle of the cell called a _______? - Answer-SeptumWhy is it critical that FtsZ is only produced during the day? - Answer-Dividing and replicating takes energy, only does it when sun is out to receive energy, evolutionary advantage Chromosome nomenclature - Answer-One (l) or two (X) chromatid chromosomes Centromere - area of repetitive DNA sequence, replicates during S phase What are telomeres? - Answer-Repetitive sequences of DNA at the ends of chromosomes Maintained by telomerase Shortened telomeres is associated with what? - Answer-Aging and disease In chromosomal compaction ______ has a (-) charge and ______ have a (+) charge - Answer-DNA, histones If a cell is actively dividing, does it have a higher or lower level of compaction? - Answer-High level of compaction, easily visible under a microscope What protein enzyme phosphorylates (add phosphate group to) other molecules? What enzyme dephosphorylates? - Answer-Kinases, phosphatases __________ are responsible for the progression of the cell cycle through the various checkpoints - Answer-Cyclins Why are cell cycle checkpoints important? - Answer-Could have insufficient environments, incomplete replication or damage of DNA, misaligned chromosomes. All could be lethal for cell What happens if a cell "fails the test" at any checkpoint in the cycle? - Answer-Cell division is halted for repairs or induced death of the cell Structure of DNA - Answer--Double stranded, double helix, sugar/phosphate backbone-Sides held together with covalent (phosphodiester) bonds, middle held together with hydrogen bonds (easily broken to separate for replication) Structure of a nucleotide - Answer-5 carbon sugar, phosphate group, nitrogenous base, free hydroxyl group, 5' and 3' ends Characteristics of parts of a nucleotide - Answer--5-c sugar: ribose / deoxyribose, determined by what is attached (OH = RNA molecule, H = DNA molecule) -Phosphate group: PO4, attached to 5' carbon sugar -Nitrogenous base: ATCG, thymine = DNA only, Urine = RNA only -OH(-): free hydroxyl group attached at the 3' carbon sugar What is semiconservative replication? - Answer-When each old DNA strand is used as a template for a new DNA strand The new complementary DNA strand is synthesized by what enzyme? - Answer-DNA polymerase III The new DNA strand grows from ______ to _______ while the template strand starts with the _________ and ends at the ___________ - Answer-5' to 3', 3' to 5' What are the enzymes required to replicated DNA? - Answer-Helicase, primase, DNA polymerase I & III, ligase