Bio 190 Exam 1 Study Guide
Bio 190 Exam 1 Study Guide Bio 190
Popular in Intro Biology for Health Professions
Popular in Biology
This 7 page Study Guide was uploaded by Danielle Francy on Thursday February 11, 2016. The Study Guide belongs to Bio 190 at Towson University taught by Joseph Velenovsky in Fall 2015. Since its upload, it has received 68 views. For similar materials see Intro Biology for Health Professions in Biology at Towson University.
Reviews for Bio 190 Exam 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: 02/11/16
Bio 190 Study Guide for Exam 1 What are the main differences between RNA and DNA? RNA: ● Sugarribose ● Single stranded ● A,U,G,C DNA: ● Sugardeoxyribose ● Double stranded ● A,T,G,C Purines: ● Big bases ● Adenine and Guanine ● Two rings Pyrimidines: ● Small bases ● Thymine and Cytosine ● One ring Important people to know: Rosalind Franklin and Maurice Wilkins: 1. Xray diffraction of DNA ● Obtained the “all important” image of diffraction pattern of DNA. ● Made careful measurements of the pattern. ● DNA was a helix, constant width of 2nm. Erwin Chargaff: 1. Chargaff’s Rules ● Quantity of A=T ● Quantity of C=G 2. Chemical analysis of DNA Watson and Crick: 1. Confirmed 2 strands in helix 2. Strands are antiparallel 3. SugarPhosphate backbone on outside of helix 4. Bases facing each other inside helix 5. Hbonded in complementary pairs 6. Orientation of strands and bases maximized number of Hbonds. 5’ to 3’ 7. PurinePyrimidine 8. Functional groups Amino Acids: ● A simple organic structure containing both a carboxyl group and amino group. ● Both of these functional groups are covalently bonded to a central carbon atom. Functional groups: ● Affect a molecule’s function by participating in chemical reactions in characteristic ways. ○ Hydroxyl group ○ Carboxyl group ○ Amino group ○ Phosphate group ○ Methyl group Four Main Classes of Biomolecules: 1. Nucleic Acids ● monomer nucleotides ● polymer polynucleotide ○ DNA ○ RNA 2. Carbohydrates ● monomer monosaccharides ● polymer polysaccharides 3. Proteins ● monomer amino acid ● polymerpolypeptide 4. Lipids ● monomer glycerol and three fatty acids Monomer: A molecule that can be bonded to other identical molecules to form a polymer. Polymer: A macromolecule composed of many repeating subunits. 3 Parts of a Nucleotide: 1. Nitrogenous base(A,G,T,C,U) 2. 5 carbon sugar(ribose or deoxyribose) 3. Phosphate group Hershey and Chase experiment : Background of the experiment: 1. Bacterial viruses (phage) were used to demonstrate that DNA is the genetic material. 2. The phage had a DNA molecule surrounded by a protein coat. 3. When phage infect bacteria, they attach to the surface of the cell and inject their DNA into the cell (protein coat remains on the outside of the cell). Part one of the experimen : 1. Phage were produced in a medium containing S35 and radioactively labeled “amino acids”. 2. The radioactivity was found in the protein coat, not the DNA inside the phage. 3. When the phage attached to the surface of the bacteria cell, they injected DNA, but the DNA was not infected with the radioactivity, thus the bacteria cell was not infected. 4. The radioactivity was found on the outside of the cell. 5. The phage produced in these cells contained no radioactivity. Part two of the experimen : 1. Phage were produced in a medium containing P32 labeled “deoxyribose nucleotides”. 2. This resulted in radioactivity in the DNA of the phage and not on the protein coat. 3. The phages then attached themselves to the bacteria cell and injected their DNA. Conclusion The DNA, not the protein, carries the genetic information for a new generation of phage. ****Also, radioactivity is found in S35 was in the liquid above the pellet while the radioactivity in P32 was found in the pellet. Replication, Transcription, and Translation DNA has two functions 1. Control: Transcription and Translation 2. Heredity: Replication Replication ● Complementary nitrogenous base pairing ● Two nucleotide strands separate ● Parental DNA ● Complementary (daughter) strands ● Free floating nucleotides ● Nucleotides are added using enzymes ● 1 parental DNA molecule yields 2 identical daughter DNA molecules ● Semiconservative model How replication works 1. There is one parent DNA strand. 2. DNA helicase separates the two parent strands (untwists them). 3. There are now 2 DNA templates. 4. Free nucleotides come to complementary base pair to each parent strand with the help of DNA polymerase. 5. Two new daughter cells are formed (semiconservative because half of the parent cell is conserved). Three Important Enzymes in DNA Replication and their functions: 1. DNA Helicase: Untwists parent strands (separates them) 2. DNA Polymerase: Adds nucleotides to growing strands and also repairs (mismatches) 3. DNA Ligase: Connects lagging fragments together and also repairs (single strand breaks)(proofreads) ***Usually anything with “ase” is an enzyme Replication Bubbles: ● DNA Helicase untwists the DNA strands to open the replication fork. ● Every replication fork has a leading and lagging strand, and ultimately every fork is joined together by the formation of a replication bubble. ● Replication bubbles fuse identical daughter molecules. Translation: ● Initiation, elongation, and termination How translation works: Step 1: Initiation ● mRNA binds to small ribosomal subunit. ● Initiator tRNA binds to AUG and translation begins. Step 2: ● Large subunit binds to small subunit, creating functional ribosome. Step 3: ● Initiator tRNA binds to the P site which holds the growing polypeptide. ● The A site is open for the next amino acid. Step 4: Elongation 1. Codon recognition ● anticodon pairs with mRNA codon in A site. 2. Bond formation ● Polypeptide separates from tRNA in the P site and a new peptide bond is formed with the amino acid in the A site. ● Ribosome catalyzes 3. Translocation ● P site tRNA leaves ribosome and ribosome translocates tRNA in A site to P site ● The mRNA and tRNA remain hydrogen bonded and more as a unit ● Next mRNA codon is now in A site Step 5: Termination ● At stop codon: ○ Release factor binds to stop codon (A site) signaling the end of translation. ○ ***Stop codons don’t code for amino acids, it signals it ● Complex disassembles ○ Finished protein is released into cell ○ Empty tRNA falls out of the complex and will be reloaded for the next job. ○ Ribosomal subunits come apart and will be reused for further protein synthesis. Jacob and Monod: ***Proposed the idea of an operon. ● segment of DNA in bacteria that includes: ○ promoter sequence where RNA polymerase binds ○ operator sequence where a repressor protein binds ○ a group of structural (protein coding) genes ● controlled by a regulatory gene elsewhere in a genome ○ codes for a repressor protein ○ always “on” (transcribed and translated)=repressor protein always made. ● Active form of repressor: ○ binds to operator site ○ physically blocks RNA polymerase from binding ○ no transcription of structural genes=no proteins available to use lactose ● Inactive form of repressor: ○ not able to bind to operator ○ released if previously bound ● ***What determines whether the form of a repressor gene is active or inactive? ○ presence of lactose ○ binding of lactose to the repressor protein Gene Mutation: ● Permanent change in the base sequence of DNA within a gene. ● Can involve large regions of a chromosome or just a single base pair. ***What are the two ways gene mutations can arise? 1. DNA replication errors not corrected by proofreading 2. Environmental mutagens: radiation, chemicals, viruses. Categories of Mutations: 1. Point mutationsnucleotide substitutions 2. Silent mutations when an mRNA codon changes from GAA to GAG, no change in the protein product will result because GAA and GAG both code for the same amino acid. 3. Missense mutationsany genetic mutation that changes an amino acid from one to another. 4. Nonsense mutations any genetic mutation that leads to the RNA sequence becoming a stop codon instead. 5. Frameshiftnucleotide insertions or deletions 6. Reading framea way of dividing the sequence of nucleotides in a nucleic acid(DNA or RNA) molecule into a set of consecutive, nonoverlapping triplets. Questions: 1. What types of macromolecules do genes code for directly? ● Proteins 2. What types of macromolecules do genes not code for directly? ● Sugars, fats, and lipids 3. What is a genome? ● An organism’s complete set of DNA including all of its genes. 4. What are the two main sources of mutations in cells? ● DNA replication errors not corrected by proofreading ● Environmental mutagens: radiation, chemicals, viruses. 5. Are all mutations heritable? ● Most are, but not all. 6. What molecules are involved in transcription and translation? ● Translationribosomes, tRNA, mRNA ● TranscriptionmRNA, DNA 7. What are the four macromolecules? ● Proteins ● Carbohydrates ● Lipids ● Nucleic Acids 8. What is ATP’s main function? ● Energy 9. Where does transcription take place? ● Nucleus 10. Where does translation take place? ● Cytoplasm 11. What are the three stages of elongation in translation? ● Codon recognition ● Peptide bond formation ● Translocation 12. What is the only start codon? ● AUG 13. What are the three stop codons? ● UAA, UAG, UGA 14. What does ORI stand for? ● Origins of Replication 15. Is the regulatory gene always “on” or “off”? ● Always on 16. If lactose is present, is the operon on or off? ● On 17. If lactose is absent, is the operon on or off? ● Off 18. What are the three important enzymes in DNA replication? ● DNA helicase ● DNA ligase ● DNA polymerase 19. What are their functions? ● Helicaseuntwists parent strands ● Ligaseconnects lagging fragments together and repairs ● Polymeraseadds nucleotides to growing strands and repairs 20. In the Hershey and Chase experiment, what was the question being asked? ● Is DNA or protein the true molecule for passing the heredity trait. 21. What did Hershey and Chase conclude? ● That DNA, not the protein,was the genetic material. 22. What is DNAs two main functions? ● Control and heredity 23. What is the monomer of DNA? ● nucleotides 24. What is the flow of genetic information in the cell? ● DNARNAproteins 25. What does telomerase do? ● It adds length to telomeres. 27. What are the three main differences of DNA and RNA? ● DNA: ○ sugardeoxyribose ○ double stranded ○ A,T,G,C ● RNA: ○ sugarribose ○ single strand ○ A,U,G,C 28. How many amino acids are there and how many nucleotides are there? ● There are 20 amino acids and 4 nucleotides. 29. What does UTR stand for? ● Untranslated region 30. Why are changes in the 3rd position less serious than changes in the 1st or 2nd? ● Because there’s still possibility that there will be the same codon.
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'