BIOL 1050Exam # 2 Study Guide Lectures: 9-18Lecture 9 (February 12)- What is DNA?o Deoxyribonucleic acid (Deoxy=lacking oxygen) (Ribo=sugar)- What is the structure of DNA and who discovered it?o DNA is a double helix made of two strands o Discovered by: James Watson, Frances Crick- What are the 3 main components of DNA?o Sugar (pair in each “rung”) (“Handrails”)o Phosphate group (backbone of DNA, no genetic info) (“handrails”)o Nitrogen containing base (backbone of DNA, no genetic info) (“rungs”)- There are _____ strands of nucleotides in DNAo 2 anti parallel- There is ___ DNA molecule in a chromosome (23 pairs)o 1- What does not have DNA?o Red blood cells and hair (only in roots)- Every nucleotide is identical, except for its base, name the 4 baseso Adenine (A) (always pairs with T) (2 hydrogen bonds)o Guanine (G) (always pairs with C) (3 hydrogen bonds)o Cytosine (C) (always pairs with G) (3 hydrogen bonds)o Thymine (T) (always pairs with A) (2 hydrogen bonds)- Hydrogen bonds cano Hold anti parallel strands in DNA molecules togethero Can predict the order of bases on other strand - Example of DNA molecule sequence written from 5 prime to 3 primeo 5’ATGCATAG3’o 3’TACGTATC5’- What are the steps for semiconservative DNA replication (copying DNA)o DNA molecule is split in halfo New nucleotides added to each side of the original moleculeo Enzymes called DNA polymerases link nucleotides togethero Result= 2 daughter DNA molecules identical to original DNA- How does DNA determine our traits by determining our makeup of proteins?o In two stages called transcription (in nucleus) and translation (in cytoplasm)o DNA provides instructions for building virtually every organism on earth- Transcription is o The process that uses the instructions in DNA to make RNA- What does RNA do?o Helps pass information from DNA ribosomes (where protein is made)o In RNA there is no Thymine, is replaced by Uracil Ex. DNA> CGTAGACAAGTG GCATCTGTTCAC RNA> GCAUCUGUUCAC- What does RNA stand for?o Ribonucleic acid (has oxygen that DNA does not)o RNA is formed 1 nucleotide at a time from DNAo Bones of RNA are complimentary to DNA strand just like 1 DNA strand is complimentary to its other strandLecture 10 (February 14)- What is translation?o The process that uses the instructions in the RNA to make proteinso The RNA leaves the nucleus acts as a “messenger” for the DNA o Just like RNA is formed from DNA, proteins are made from directions on RNA- What are chains of amino acids?o Proteinso Instead of each RNA base coding for one amino acid, the RNA bases are read in groups of 3  Groups of 3 RNA bases are called codons (which specify all the amino acids)- There are multiple codons that code for the same ______o Amino acids No codon codes for more than 1 amino acid- Genetic code is _____, it is used by all living organisms on the planeto Universal  Genes can be transferred from one species to another- What is a mutation?o Any change in the order of bases on a strand of DNA- Mutations can be caused byo Exposure to harmful conditionso Exposure to certain viruseso Errors while copying DNAo Inheritance (only if occurs in sex cells)- What are some effects of mutations?o No effect occurs when the mutation in the DNA does not change the amino acid that is called for (neutral mutation)o Sometimes bases are either added, deleted or substituted If one base is added or deleted you get a frameshift mutation (shifting over by 1) Every codon from that point until end of gene is wrong so usually harmful- A framshift at the beginning of the sequence will more likely lead to more problems than one at the end of a sequenceLecture 11 (February 17)- What is the smallest unit of an inheritable trait?o Geneo 1 gene=1 RNA transcript (protein)- How do cells become different from each other if they all have the same DNA (except gametes)o Certain genes in a cell are turned “on” while others are turned “off”o Genes that are “on” undergo transcription and translationo Genes that are “off” do not function o This determines the type of cello Proteins turn them off/ono Transcription factors regulate transcriptiono Each cell type has a different pattern of active genes- Are viruses alive?o No, they have genes but are not cellular and cannot reproduce on their owno Most viruses are made of DNA or RNA (or both) wrapped in protein coato Virus must infect living cell with genetic material so that cell will make more viruses, it takes a little bit of the cells membrane when it leaves- Describe viral replicationo After virus binds to the host cells membrane the viral DNA is taken into the cello Viral DNA is replicated into dozens of new copies, using the hosts metabolic machinery and energyo Viral mRNA is transcribed from viral DNAo New viral proteins are synthesized, again using the hosts protein production moleculeso The new viral DNA and proteins assemble, forming many new virus particleso *antiboitic drugs work against bacterial infections but not viruses- How do new viruses and forms of old viruses arise?o Through mutations and evolutiono RNA viruses mutate moreo Small pox was the most devastating virus and killed 1/3 of anyone infected  The first and only disease to be eradicated (killed millions)- What are some new dangerous viruses?o Ebolao SARSo New strains of the flu- Name some species specific viruseso Swine flu (pig is the accidental host)o Avian fluo These viruses swap genetic info and can then infect a different species- Retroviruseso Do not have viral DNAo Use viral RNA to make viral DNA in process of reverse transcriptiono Then viral DNA can insert itself into host’s DNA to go through transcription/translation to make copies of viruso RNA>DNA> inserts itself into hosts genome (permanent)(does this on purpose)- What is HIV?o Human Immunodeficiency viruso Made of RNA and proteinso HIV carries its genetic instructions in the form of RNA rather than DNA- How does HIV replicate?o Reverse transcriptase (enzyme) uses viral RNA to make viral DNAo Viral DNA enters host DNAo Transcription make new RNA (viral and host)o New virus particles are assembled and leave host cell- Describe process of HIVo HIV infects and kills cells used in immune system, the immune system successfully fights for a while, eventually fails and AIDS develops Immune system no longer able to support iself <200 t cells per micro LLecture 12