Unit 1 Study Guide
Popular in Introductory Biology for Health Professions
Popular in Biology
This 12 page Study Guide was uploaded by Whitney Marie Halaby on Monday September 12, 2016. The Study Guide belongs to BIO 190 at Towson University taught by Dr. Elizabeth O'Hare in Fall 2016. Since its upload, it has received 50 views. For similar materials see Introductory Biology for Health Professions in Biology at Towson University.
Reviews for Unit 1 Study Guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/12/16
Unit 1 Study Guide DNA is… o Polymer/polynucleotide o Negatively charged o The basis of all life o Provides instructions for… Making RNA, proteins/molecules and the central dogma Carrying out daily activities Carry out cellular replication o Deoxy: the sugar molecule with the hydroxyl group that is replaced with a hydrogen atom o Nucleotides are linked together by dehydration reactions o Ribose: sugar – carbohydrate o Nucleic: refers to the location of the molecule – DNA is located in the nucleus o Big base always binds to small base o Made up of 4 nucleotides … Consists of sugar (5 carbon sugar), phosphate (negatively charged), and a base ( A & T, G & C) Held together in two ways: covalent bonds (link nucleotides together) and hydrogen bonds (link strands together) Thymine and Cytosine are single ringed nucleotides called pyrimidine – think the three y’s Adenine and Guanine are double ringed nucleotides called Purine – think Pure As Gold o DNA can be predicted because they are complementary o Because DNA has complementary pairs when the cell replicates it will have the same DNA o Adenine and Thymine are linked by 2 hydrogen bonds o Guanine and Cytosine are linked by 3 hydrogen bonds o The two strands run antiparallel o Hydrogen bonds are easily broken o Covalent bonds are much stronger they bond nucleotides together o Without covalent bonds hydrogen bonds would easily break apart o DNA runs in a 5 prime to 3 prime direction o Sugars are made up of complementary rings that will always go together o The specific sequence of nucleotides on chromosomes make us each unique A genome is… o a complete set of genetic material of an organism or virus Specific physical features of a DNA structure … o Double helix o Base pairs – complementary o 2 strands run antiparallel o sugar phosphate backbone o covalent bonds link nucleotides together o phosphate group, sugar group, base = nucleotide o each strand is made up of repeating nucleotides o hydrogen bond links A&T and A&G Watson & Cricke o Their discovery of the double helix would not have been possible without Rosalind Franklin (looking at her xrays gave them the head start they needed) o Chargaff helped determine base pairs AT and GC o Cricke received the most credit o Watson Cricke base pairing: A binds with T and G binds with C Repeating subunit monomer in DNA… o Nucleotides o Organic molecule o Provides structure for both DNA and RNA Complementary Base Pairing.. o Takes place in DNA and RNA o Adenine ALWAYS binds with Thymine o Guanine ALWAYS binds with Cytosine o In RNA Thymine is replaced with Uracil o The base pairs are a necessary aspect of nucleotides o Base pairs carry organisms genetic information o Without complementary base pairs nucleotides could not be formed and genetic information could not be passed down to offspring Hershey and Chase experiment … o 1952 o confirmed that DNA was genetic material by using T2 bacteriophage o two groups of bacteria were used – one group was infected with E. Coli which contains sulfur (sulfur is a component of protein NOT DNA) and the second bacteria had phosphorus (a component that protein does not have) – both groups were radioactive o prior to this experiment it was thought that proteins carried genetic information o Conclusion: Batch infected with Radioactive protein… radioactivity was mostly in the solution not in the pellet and radioactive solution contained mostly bacteriophages not bacteria Batch infected with radioactive DNA … radioactivity was mainly in the pellet and the radioactive solution is contained to the bacterial cells DNA carries genetic information not protein Two major functions of DNA… o Store genetic information o Pass on genetic information to offspring Differences between RNA and DNA … o RNA: Single stranded Uses U instead of T – A binds with U The sugar is ribose in the nucleotide Made from a DNA template Contains genetic information o DNA: Double stranded – double helix A binds with T G binds with C Sugar is deoxyribose Contains genetic information DNA Replication… o Also known as the semiconservative model o DNA replicates in the opposite direction o Purpose: cell production, wound repair, organismal growth (growth in size) o Replicated DNA must be an exact copy when it isn’t an exact match it is a mutation o Advantages: Makes sure all cells carry genetic info Have genetic instruction available for gamete development o Challenges: Complex coordination of multiple enzymes – proteins untwist – recruit nucleotides – solidify covalent bonds One out of one billion nucleotides is incorrectly paired Speed of the process – takes about one hour to copy the genome of e.coli and a few hours for a human 1. How does Replication happen so fast? Happens at multiple places along the chromosome The slower it goes the more prone it is to errors Ori: origin of replication DNA creates a bubble at ori and DNA replication occurs at multiple ori’s o How it happens … 2. Two strands of parental DNA separate Proteins attach to each ori causing a separation of the 2 strands – the opening DNA causes bubbles to form. Topoisomerase (an enzyme): unwinds DNA. Helicase (an enzyme): pry’s apart the double helix, breaks the hydrogen bond and makes the bubble bigger 3. Free nucleotides are going to bind to the parent strand following the base pairing rules DNA polymerase (RNA primer provides the location) adds nucleotides to 3 prime –OH the phosphate group (carbon 5) on the incoming nucleotide attaches to the –OH group (carbon 3) of the first nucleotide nucleotides are added in the 5 prime to 3 prime direction a. RNA primer is complementary to DNA sequence b. RNA primer laid down gives RNA polymerase a 3 prime OH to attach to a 5 prime phosphate c. Where there is RNA primer U will be used instead of T – but only there – it will eventually all be DNA only one or two nucleotides d. DNA made in a 5 prime to 3 prime direction but read templates 3 prime to 5 prime e. DNA polymerase requires a 3 prime hydroxyl group before synthesis can be initiated f. DNA polymerase has proof reading ability – changing nucleotides out that have been affected by radiation and toxic chemicals g. Leading strand: the strand that is continuously synthesized, works towards a forking point h. Lagging Strand: strand that is NOT continuously synthesized since new DNA is only made outward (5 prime to 3 prime) i. Okazaki fragments: DNA fragments – fragments are attached by DNA ligase j. A& C are the leading strands 4. Enzymes (ligates – blue) generate new sugar phosphate backbone – the phosphate of one nucleotide is linked to the sugar group of the adjacent nucleotide 5. Two identical daughter strands are formed – half of the parent strand half of the daughter strand – the daughter strand is called the semiconservative model Transcription … o Also known as protein synthesis o It is when RNA is made from DNA o Steps: 1. Initiation: RNA polymerase attaches to the promoter (this marks the beginning of RNA synthesis) – once attached RNA polymerase starts to synthesize RNA 2. Elongation: new RNA strand grows as RNA polymerase continues to add nucleotides – RNA nucleotides are linked together – free nucleotides form H bonds with bases of DNA template – as synthesis continues growing RNA molecules peel away from the DNA template, allowing the two separated DNA strands to come back together in the region already transcribed 3. Termination: when RNA polymerase reaches the terminator DNA sequence the RNA polymerase molecule detaches from newly made pre mRNA strands and the gene o First step to creating proteins o Prokaryote: bacteria, pro meaning before, karyo meaning no nucleus in the bacteria, transcription and translation take place in the cytoplasm o Eukaryotic: mammals, plants, transcription takes place in the nucleus and is then processed then exits into the cytoplasm and proteins are made off of mRNA – translation happens in the cytoplasm o Genes control phenotypic traits through expression of proteins o Genotype: genetic make up of organisms o Phenotype: physical manifestation of genotypes – genotypes are linked to phenotypes by proteins o Protein synthesis: genes that control phenotypic traits mRNA o Prior to nuclear export, mRNA is modified or processed o Addition to nucleotides (that are not encoded in the sequence) to end mRNA o Modifications to mRNA: Addition of extra nucleotides to end of premRNA that are not incorporated into peptide sequence Small cap: a modified form of a G nucleotide and the 5 prime end and 5 prime cap Large cap: a chain of 50250 A nucleotides at the 3 prime end (polyA tail) Facilitate export of mRNA from nucleus Protect mRNA from degradation by cellular enzymes Help ribosomes bind to mRNA RNA Splicing: Cutting introns out of the mRNA and the joining of exons together prior to the mRNA leaving the nucleus – ONLY IN EUKARYOTES Provides a means to provide multiple polypeptides from a single gene into processing in eukaryotes Archibald Garrod o Worked to discover the relationship between genes and proteins o Broad hypothesis o Specific hypothesis o First person to link phenotype to genotypes o Studied pee Beadle and Tatum o Mold o Showed that each mutation had a mutation in a single gene o Proteins were malformed o One gene on an enzyme/protein synthesis Translation o Makes proteins that carry out cellular function o Steps of Translation 1. Initiation: brings together mRNA and tRNA bearing the first amino acid (Met) and the two subunits for a ribosome – establishes where translation will begin – initiation establishes exactly where translation will begin this ensures mRNA codons are translated into the correct AA sequence translation does not start on the exact end of the mRNA (ribosome looks for AUG [Met] start signal – initiation occurs in two steps 1. mRNA molecule binds to a small ribosomal subunit and anticodon of tRNA Met basepairs with a start codon 2. Initiator tRNA carries Met with anticodon UAC and basepairs with start codon AUG 2. Elongation: amino acids are added one by one to the previous amino acid (this occurs in a 3 step process) 1. The anticodon on incoming tRNA molecule is carrying the appropriate AA then pairs with mRNA codon in ribosomal A site 2. The growing polypeptide separates from old tRNA onto the P site and attaches by a new peptide bond to an AA carried by the tRNA in the A site ribosome catalyzes formation of the peptide bond 3. P site tRNA (which doesn’t have an AA) leaves the ribosome and the ribosome translocate (moves) to the other tRNA (holding the growing peptide) from A site to P site 3. Termination: occurs when a stop codon reaches the ribosome’s A site – stop codons are UAA, UAG, UGA which are not amino acids but they act as signals to stop translation – the completed polypeptide is then freed from the last tRNA – ribosome splits back into two subunits o mRNA is made into protein 3 letter ‘words’ of nucleic acids (codons) are converted to the amino acid ‘word’ proteins DNA RNA Protein Nucleic Acid Nucleic Acids Amino Acids o Purpose: produce polypeptides o Needs: mRNA: instructions for making the new polypeptide amino acid supply tRNA: a molecule used to interpret the instructions (mRNA) enzymes: for adding the amino acid to the tRNA ATP: used for energy to add the amino acid to the tRNA by the enzyme Ribosomes: a large protein structure in the cytoplasm that coordinates the functions of mRNA and tRNA and catalyzes the synthesis of polypeptides a big protein that is only in the cytoplasm because that is where translation occurs – it also coordinates the function of mRNA and tRNA o Two subunits o Large subunit: made up of proteins and a kind of ribosomal RNA (rRNA) o Small subunit: made up of proteins and a kind of rRNA o Two subunits come together and work as a vice/clamp holds tRNA and mRNA molecules close, allowing AA to be carried by tRNA molecule to be connected to a polypeptide o 20 different amino acids o tRNA: a special type of RNA that converts 3 letter ‘words’ of codons (nucleic acids) on mRNA amino acid ‘words’ of proteins – tRNA must carry out two functions o 1. Pick up the appropriate amino acid – one specific amino acid attaches to a specific tRNA (each AA is joined to the correct tRNA by a specific enzyme using a molecule of ATP as energy to drive the reaction) – 1 enzymes is specific for each different type of AA (although all tRNA molecules are similar, there is a slightly different variety of tRNA for each AA) o 2.Recognize the appropriate codon in the mRNA using the tRNA’s anticodon Anticodon: a special triplet of bases that is complementary to the codon triplet on the mRNA – during translation anticodons on tRNA recognizes a specific codon on the mRNA by using basepairing rules o Essential amino acid: amino acids we need to get from our environment to survive o Non essential amino acid: an amino acid that is not essential to be part of an individuals diet because the body can produce them on their own o 3 bases ( a triplet code) are encoded for 1 amino acid – the number 3 is needed which means 64 triplet possibilities o Genetic Code Marshal Nierburg: deciphered first codon, 1961, synthesized an artificial RNA molecule – experiment: add uracils to a test tube with ribosomes and other ingredients used to carry out translation this resulted in protein being composed of only one amino acid (phenylaline Phe) 3/64 triplets do NOT designate amino acids but serve as stop codons that mark the end of translation AUG has a dual function – it signals where translation occurs – codes for amino acid (Met) – provides a start signal for protein polypeptide chains 61/64 triplets code for amino acids DNA: TAC TTC AAA ATC mRNA: AUG (indicates start site for translation) AAG UUU UAG Protein (use the chart): met. Lys. Phe. Stop (not an amino acid) – Met. Lys. Phe. All are amino acids Nearly all organisms share the same genetic code, this allows scientists to create o Genetic therapies o Research purposes o Agriculture benefits o For fun The genetic code outlines that all organisms must share a common ancestor which means we are all related evolution 5 W’s of Replication: o Who: the semiconservative model o What: DNA replicates in the opposite direction – due to the nature of DNA polymerase o Where: the nucleus o When: during conception of any organism o Why: pass down genetic information 5 W’s of Translation: o Who: mRNA and tRNA o What: makes proteins that carry out cellular function o Where: nucleus o When: Interphase o Why: to change the language from nucleotide to amino acid 5 W’s of Transcription: o Who: protein synthesis o What: provide genetic messages in the form of RNA o Where: nucleus o When: during interphase – when RNA polymerase looks for the promoter to know where to start o Why: to create proteins Initial Research Assignment Notes: o Epigenetics: Similarities between yellow & brown mice: goodie gene Differences between yellow & brown mice: color, size, one fat one skinny Methyl groups create a second genome Epigenomes make cells in your body that have the same DNA different Old twins: hardly any yellow shows through this means epigenome difference occur – this occurs because of different lifestyle choices and experiences ( eat, smoke, drink) Key differences between epigenetics and genetics: eat drink smoke Epigenetics and Cancer Epigenetic changes: biochemical changes of histone proteins and DNA methylation ( a change on the DNA strand can also affect how genes are expressed) Epigenetics are relevant to cancer because when changes take place in the proteins that control epigenetic process this can affect the way genes develop into cancer. There are often cancer promoting genes that are usually inactive but can become active when genes that shut off cancer turn off The specific problem associated with MLL rearrange Acute Myelngenous Leukemia (AML) is that immature blood cells fail to develop properly because HOX genes become active Dot1 is an inhibitor that can be use to turn off HOX gene expression in MLL rearranged AML cells. This could help patients because it would reduce the number of active HOX genes The epigenetic switch that turns on HOX genes is leukemia cells Gene Editing Technology The CRISPR (CRISPRCase9) is when a bacteria takes action to protect themselves from virsuses CRISPR is a natural system. When bacterium detects a virus in the DNA it produces 2 types of RNA one of which matches the virus. Then Cas9 is formed (an enzyme that can cut DNA). When the guide RNA finds the target in the genome the Cas9 cute the target DNA which disables the virus. Guide RNA must match the target. Once it is in the nucleus it will lock to a short sequence known as the pan. Cas9 will unzip the DNA and match it to the target RNA. If the match is complete, the DNA will be cut with molecular scissors. The cell will try to repair the cut but this is not possible this leads to mutations that can disable the gene Gene Editing Technology Advantages of CRISPR: it is something bacteria does naturally, it is being used to answer basic questions about what genes do Researchers hope to use CRISPR for treating cataracts, liver disease, muscular dystrophy, answer basic questions about genes, eye disorders, blood disorder, HIV Positives: Editas one of the main CRISPR researchers just received $120 million from a company backed by Bill Gates, there are constant conference’s among the brightest biologists in the world who talk about the implications of genome engineering (this means they aren’t taking it lightly), US National Academy of Science created a set of recommendations for embryonic engineering Negatives: The molecular scissors could cause problems (cut the wrong things), it is unclear how CRISPR will affect the host genome, CRISPR doesn’t target embryos as well as it does in isolated cells CRISPR means clustered regularly interspaced short palindromic repeats CAS9 is the name of protein that makes CRISPR work In a sense humans were genetic engineering before they even knew what genetic engineering was ex. Sweet kernels of corn
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'