BIOL 1543 1st Edition Exam 2 Study Guide Downloads 8 11 Download 8 Nucleotide monomers are composed of sugar phosphate and a nitrogenous base DNA and RNA are polymers of nucleotides DNA has four kinds of nitrogenous bases 1 Thymine Py 2 Cytosine Py 3 Adenine Pu 4 Guanine Pu The two types are Pyrimidines and Purines How do we know its DNA The sugar is deoxyribose The nitrogenous bases are A T G and C How do we know its RNA The sugar is ribose The base Uracil is used in place of Thymine DNA is a double stranded helix With a sugar phosphate backbone Hydrogen bonds between bases hold the strands together A pairs with T G pairs with C Replication aka duplication The process of making two copies of a DNA strand Complicated process because part of the DNA has to untwist Happens very quickly and with few errors There is a proofreading enzyme There is a repair enzyme Genotype An organism s genetic makeup Phenotype The characteristics we see the manifestation of genetic information Gene A long line of nucleotides a hereditary unit of information GENES TO PROTEINS The DNA of a gene is transcribed into RNA and then translated into the polypeptide Two stages of expressing info in DNA o Transcription DNA RNA Happens in the nucleus Produces genetic messages in the form of RNA Three Stages Initiation Elongation Termination RNA that is used to make proteins is mRNA Messenger RNA carries the genetic message out of the nucleus o Translation RNA Proteins Happens in the cytoplasm Genetic information written in codons is translated into amino acid sequences A ribosome attaches to mRNA tRNA translates the message into a polypeptide Codons triplets of bases that specify the amino acid sequence of a polypeptide Mutations Something capable of causing genetic change Ex Radiation or Certain chemicals Cause by 2 things o Error in DNA o Mutagens Has varying effects on the organism 3 ways genes are altered o Base Substitution o Insertion of an extra o Base Deletion Eryth Red Cyte Cell Erythrocytes Red Blood Cells Chromo Colored Some Body Phago Eat Download 9 Viruses are genes packaged in proteins A phage aka a Bacteriophage o Means in attacks bacteria 2 Reproductive Cycles 1 Lytic Cycle a Phage DNA enters a lytic cycle inside a bacterium and then replicates transcribes and translates 2 Lysogenic Cycle a Phage DNA inserts into the host chromosome and is passed on to generations of daughter cells b 3 Possible Outcomes i Reproduces Asymptomatically ii Bacteria starts behaving in a different manner altering the host cell s function iii Can convert to the lytic cycle Some viruses can enter a cell and remain dormant for long periods of time with no effects Remain latent until stress or certain foods Others are immediately or intermittently harmful HemorrhagicFever When a person bleeds to death out of all of their orifices Caused by Ebola Antigenic Drif Genetic makeup changes over the years 3 Steps to Fighting the Flu 1 Get the vaccine 2 Take everyday actions 3 Take antiflu viral drugs if your doctor gives you a prescription Leading Causes of Viral Diseases Influenza Herpetic Viruses herpes o Human Herpes Virus 8 Kaposi s Sarcoma Plant viruses Have RNA Genomes and enter through wounds 3 Ways They Spread o Contaminated Farming Tools o Insects o Wind Some latent viruses steal a bit of host cell membrane as a protective envelope Called Envelope Viruses Ex AIDS and the mumps Emerging viruses New or newly studied viruses The Major Concerns are o RNA mutates faster than DNA o Changing Host Species o Globalization importing viruses H5N1 2004 o Bird Flu o No evidence of efficient human to human transmission or of airborne transmission o There was always physical contact with a contaminated bird o 60 Mortality Rate Coronavirus 2003 o SARS Severe Acute Respiratory Syndrome Retrovirus DNA is made on an RNA template AIDS caused by HIV Download 10 2 Basic Types of Reproduction Sexual Fertilization of sperm and egg produces offspring Asexual Offspring are produced by a single parent without the participation of sperm and egg o The offspring are genetic copies of the parent Cells only arise from preexisting cells Prokaryotic cells reproduce asexually by cell division o Binary Fission The process of asexual reproduction that involves the splitting of the parent into two approximately equal parts The single chromosome replicates moves apart grows membrane and then divides Most prokaryotes and protists no nucleus The Eukaryotic Cell and Mitosis Before the cell starts dividing the chromosomes replicate and produce sister chromatids Chromatids are joined at the centromere waist Each chromatid is a pair of daughter cells containing a complete and identical set of chromosomes Mitotic Phase 1 Mitosis The division of the genetic material 2 Cytokinesis The movement of the cytoplasm to the two new cells Interphase Growth 1 Synthesis Growth 2 Mitosis 1 Prophase a Formation of early mitotic spindle An array of G1 Synthe sis G2 microtubules and associated proteins that form between the opposite poles of the cell during mitosis b Centrosome The regulator of prophase produces and organizes the spindles 2 Prometaphase a Centrosomes are at the poles of the cells b Nuclear envelope is breaking down 3 Metaphase a The spindle is completely formed b Chromosomes are on the metaphase plate the middle of the cell 4 Anaphase a The sister chromatids are dividing b Each copy will go to each pole 5 Telophase a Nucleus starts to form 6 Cytokinesis a Cytoplasm starts to go to each cell Cytokinesis In animals it occurs by constriction of the cell o It will completely break apart into two separate cells o Complete cleavage of the cell In plants a cell plate forms and then a cell wall o They are still touching o Incomplete cleavage Mitosis has 3 functions 1 Growth a Multicellular 2 Replacement of damaged or lost cells a Multicellular 3 Asexual reproduction a Prokaryotes and protists Most animals cells only divide when stimulated and some not at all Most normal cells divide only when they are attached to the surface o Anchorage Dependence The cells must be attached to the surface before they divide o Density Dependent Inhibition When it gets so dense that all the cells are touching they stop dividing Growth Factors Proteins secreted by cells that stimulate other cells to divide They would grow in layers on top of themselves they don t cease dividing like normal This leads to cancer Apoptosis Programmed cell death Ex Unfertilized female egg Dead cell engulfed and