Biology Lecture Exam 3

What does DNA stand for?
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Define the role of DNA polymerase?It creates a new polymer of DNA. Binds the parent stand, reads each base + hydrogen bond compliment baseDefine the role of RNA polymerase?Binds each gene, reads the nucleotide, brings compliment baseDefine the role of DNA ligase?Binds the daughter strands to create phosphodiester bonds.What is rRNA, mRNA, and tRNA?rRNA: forms ribosomes, used to read RNA, signal for mRNA, signal tRNA. tRNA: Used to read mRNADefine TranscriptionThe first stage of gene expression, during which cells produce molecules of mRNA from instructions encoded within genes in DNADefine TranslationThe second stage of gene expression during which mRNA sequences are used to assemble the corresponding amino acids to make a protein.4 codons we must knowAUG - MET UAA - STOP UAG - STOP UGA - STOPWhat is the cell cycleG1 - enlarges and copies organelles S DNA replication G2 - gene expression for proteins needed in cell division, spindle fibers Prophase - spindles form Metaphase - sisters line up, each facing poles. Anaphase - Sisters separate into daughters Telophase - cleavage furrow Cytokinesis - cell splits and begins interphaseList the 3 cell cycle checkpoints and what occurs at each oneG1 - checks to make sure the cell is ready to divide, DNA integrity is checked G2 - Verify that DNA replicated correctly, any DNA damage will be sent back to S phase Mitotic Stage - checks that all sister chromatids are attached to the spindle fibers and ready for separationWhat are Telomeres?Telomeres are repeating DNA sequences at the end of every chromosomeWhat is contact inhibition?Where cells will stop dividing when they touch something externallyWhat is Apoptosis?Apoptosis is when cells are programmed to die. If the cell is dying, damaged and beyond repair, it will receive a signal to die. Keeps the amount of cells at a good level.What are the 5 characteristics of cancer cells?No contact inhibition Uncontrolled growth (tumor) Non Specialized cells Abnormal chromosomes No apoptosisWhy is cancer so hard to find a cure to treat?It is hard to treat because if you try to kill the bad cells, then you are also killing the good cells too.What is a Proto-oncogene?It codes for proteins that promote the cell cycle and inhibit apoptosis. It is normally off.What is a Tumor Suppressor gene?A tumor suppressor gene codes for proteins that inhibit cell cycle and promote apoptosis. They normally inhibit the cell cycle and prevent cells from dividing inappropriately. It is normally on.List the three cancer causing alleles and the condition that they causeBRCA 1 - Breast Cancer BRCA 2 - Breast Cancer RB Gene - Eye tumorWhat is a mutation?A change in a cell's DNA sequence.How can Telomeres be related to cancer?Because the telomeres eventually wears away, the DNA can become exposed.What are the differences between Germline and Somatic Line Mutations?Germline mutations will go through meiosis and somatic lines will go through mitosis.What is the difference between Anaphase 1 and 2?Anaphase 1 homologous pairs separate, anaphase 2 sisters separateDifference between haploid cells and diploid cellsHaploid - 1 copy of every chromosome Diploid - 2 copies of every chromosomeTetrad2 paired chromosomes. 4 total chromosomesDyad1 paired chromosome. 2 total chromosomesWhat is crossing over?The exchange of the genetic material between homologous chromosomes that occur during meiosis. It is important because it causes genetic diversityWhat is non-disjunction?It is the failure of chromosomes to separate at anaphase 1 or 2. If separations fails at anaphase 1, all gametes are incorrect. If it fails at anaphase 2, 50% are incorrect.