BIO 123 Chapters 10-12 Lecture Notes
BIO 123 Chapters 10-12 Lecture Notes BIOL 123
Popular in Biology for Health Related Sciences and Non-Majors
verified elite notetaker
Popular in Biology
This 10 page Study Guide was uploaded by Amber Logan on Saturday December 5, 2015. The Study Guide belongs to BIOL 123 at University of New Mexico taught by Dr. Dorothy C. Scholl in Fall 2015. Since its upload, it has received 337 views. For similar materials see Biology for Health Related Sciences and Non-Majors in Biology at University of New Mexico.
Reviews for BIO 123 Chapters 10-12 Lecture Notes
These were really helpful...I'll be checking back regularly for these
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: 12/05/15
Chapters 10 -12 Lecture Notes DNA, Its Structure and Replication;; Th e Regulation of Gene Expression;; GMOs and Climate Change (10.1) The Discovery of DNA as Molecule of Heredity • Early 1900s – we knew that proteins and DNA were the major components of chromosomes, but didn’t know if the genetic material contained in genes was protein or DNA • 1952 – discovered that genetic material is DNA o found through experimentation w/ bacteria • Watson & Crick – credited w/ the discovery of the structure of DNA o Rosalind Franklin – had a huge role w/ her research in X-ray crystallography, but was not given credit (10.2) The Structure of DNA and RNA • DNA = deoxyribonucleic acid o Monomer = nucleotides (deoxyribonucleotides) § All nucleotides have: (see Image 1) 1) 5-carbon sugar 2) phosphate functional group 3) variable nitrogenous base o purines = double-ringed bases – adenine (A) and guanine (G) o pyrimidines = single-ringed bases – thymine (T) and cytosine (C) § NOTE: You can remember this by noticing that pyrimidine, thymine, and cytosine all have a “y” in them o purines always bond to pyrimidines by hydrogen bonds – A always bonds to T w/ 2 hydrogen bonds, G always bonds to C w/ 3 hydrogen bonds § We can tell that an A-T rich region is the beginning of a protein-coding gene because A’s and T’s are easier to break apart than G’s and C’s § Chargaff’s Rule = says that there is always a 1:1 ratio of purines to pyrimidines o Polymer = nucleic acids § Double-stranded helical structure – held together by hydrogen bonds between complimentary nitrogenous bases § Backbone is formed by dehydration synthesis reactions between the sugar and the phosphate (= phosphodiester bonds) § DNA is antiparallel – each strand has a 3’ and a 5’ end, and they always run opposite of one another • i.e.: 3’ --------------- 5’ 5’ --------------- 3’ Image 1 Image 2 • RNA = ribonucleic acid o Monomer = ribonucleotides o 3 main differences between RNA and DNA: § RNA contains ribose, DNA contains deoxyribose sugar § RNA uses uracil, DNA uses thymine § RNA is single-stranded § NOTE: To remember this, think “R U Single?” where “R” stands for ribose sugar, “U” stands for uracil, and “single” is referring to its being single-stranded J o RNA is not antiparallel – it doesn’t have a second strand to be antiparallel to (10.3) DNA Replication • Only occurs when a cell needs to divide o Every time a cell divides, you have to copy ~ 6 billion base pairs! o Cells in G 0do not replicate their DNA but they do still carry out transcription and translation in order to build proteins • DNA replication is semi-conservative (= when a cell divides, the 2 resulting daughter cells have 1 strand from the original/parental DNA and 1 strand of the new/copied DNA) • Key enzymes involved in DNA replication: (see Image 3) o Helicase – unwinds the double-helix structure of DNA o Topoisomerase – binds to newly unwound strands of DNA and keeps them from winding up again o Single-stranded binding proteins (SSBPs) – spacer molecules that hold the replication fork/bubble apart o DNA polymerase – builds new strand of DNA by putting in complimentary bases § Is a proofreader – finds mistakes in nitrogenous base sequence and fixes it • DNA repair o 3 steps in DNA repair: 1) Recognition – DNA polymerase recognizes mistake 2) Removal – DNA polymerase enzymatically digests wrong base 3) Replacement – DNA polymerase replaces w/ correct base o Viral vector = DNA vaccine where you attach the correct gene to a harmless virus so that the virus can “infect” cells w/ the correct DNA • These mistakes can be caused by mutations from carcinogens (e.g.: UV light, gases, chemicals, etc.) o UV rays disable genes by causing thymine-to-thymine bonds (= thymine dimers) § XP gene – repairs DNA by breaking thymine dimers § The effect of UV light has a cumulative effect – visible damage in adult skin could have begun developing decades prior o Ligase – hooks/ligates okazaki fragments (= fragments of replicated DNA on the lagging strand) together • Steps in DNA replication: 1) Helicase unwinds DNA 2) DNA polymerase binds to unwound strands and builds new strand § This can only occur in 1 direction 3) Ligase puts fragments of lagging strand and new strands of DNA together • The 3’ ----- 5’ strand produces the leading strand, while the 5’ ----- 3’ strand produces the lagging strand Image 3 (10.4) Gene Expression (Transcription, Translation, and the Genetic Code) • Gene expression = the process where information stored in DNA is used to make a product (usually a protein) o Flow of information in a cell: DNA RNA protein (structural, antibodies, enzymes, etc.) o Cells are highly specialized (in what genes are being expressed) § This specialization is based on chemicals signals that cells receive in utero § Gene expression changes as you develop – this is why we don’t look like we did when we were babies • Transcription and translation are the 2 major steps in protein synthesis Transcription • Transcription = when a protein-coding sequence on DNA is copied to an mRNA o Takes place inside the nucleus o Gene = sequence of DNA that is transcribed into RNA § 3 types of RNA 1) messenger RNA (mRNA) – copies DNA and leaves nucleus 2) transfer RNA (tRNA) – brings amino acids to ribosome 3) ribosomal RNA (rRNA) – structural component of ribosome o RNA polymerase = key enzyme involved in transcription;; the DNA polymerase of transcription § Transcription begins when RNA polymerase binds to promoter region and stops when it reaches the terminator region • Transcription can occur in either direction, unlike DNA replication, which can only occur in 1 direction o Codon = unique sequence of 3 bases (64 total) § Start codon – AUG (methionine) § Stop codons – UAA, UAG, and UGA § The first and second letters are the most important – the third is considered “wobbly” o Intervening sequences = extra bases in the middle of a protein-coding sequence § Introns = intervening sequences – are removed from strand § Exons = code for making a protein – are stuck together by ligase (= RNA splicing) once introns are removed Image 4 Translation • Translation = when the language of a nucleotide is translated into the language of amino acids • Occurs in the ribosome • Involves ribosome, mRNA, and tRNA o mRNA brings protein-coding sequence from nucleus o tRNA brings amino acids to the ribosome from the cytoplasm based off of its anticodon sequence (= complimentary base sequence to mRNA that lets the tRNA bind to the correct amino acid;; 1 3 base-sequence per tRNA) • Begins when mRNA binds to a ribosome and tRNA binds to start codon on mRNA o There are 3 binding spots in a ribosome for mRNA à 3 tRNAs can bind at 1 time o tRNA moves through ribosome like a factory line, adding amino acids to the polypeptide 1 at a time • Once end codon is reached, the amino acid chain is released and travels to the Golgi Apparatus where it is packaged and sent off Structure of an Amino Acid Image 5 Image 6 The Genetic Code • The genetic code is… o Not ambiguous – there are 20 amino acids coded for by 64 codons o Redundant – multiple codon sequences code for the same amino acid o Virtually universal – used by all living things on Earth § This is a key piece of evidence of evolution (10.5) Mutations, Gene Duplications, and Chromosomal Rearrangements: The Ultimate Source of Variation • Mutation = any change in base sequence • Types of mutations: o Point mutations = when a single base is altered § e.g.: substitutions (= when 1 base is substituted for another) Image 7 o Frameshift = when the sequence of amino acids is altered § e.g.: insertions (= when base(s) is/are inserted into a sequence in the wrong position) and deletions (= when base(s) is/are deleted from a gene sequence) § results in reading the codon sequence in the wrong order § usually stops protein synthesis/translation before it is completed Image 8 o Silent mutations – cause no change in structure of protein § Usually occur when the 3 base of a codon is mutated (because the 3 base is rd “wobbly”) • Some mutations can be beneficial – over time, these can be selected for and cause evolution in a population (11.1) Prokaryotes Use Operons to Regulate Gene Expression Prokaryotic DNA vs. Eukaryotic DNA • Bacteria have a single circular chromosome • All genetic material is in the nucleus • Has very little noncoding DNA à is much • Has a lot of noncoding DNA (junk more efficient at transcription and translation DNA, switches, etc.) o Genome is organized by function o Spacer DNA = coding • During gene replication, bacterial DNA sequences between protein- doesn’t have to wrap around histones for coding genes organization o Transposons = sequences that • Gene expression – bacteria can reorganize move from 1 position on a gene expression to adapt to environment chromosome to another – may o Operon = sequence of DNA that disrupt gene’s function includes groups of genes to make o Regulatory DNA = control gene different proteins plus their control expression sequences o Structural DNA = have an § Control sequences - gene architectural function (e.g.: centromere) promoters (= regions of DNA that are on/off switches for • During gene replication, genes wrap transcription) around histones § Allows bacteria to turn gene • Gene expression – we can change expression on/off very quickly which genes are expressed through a and do transcription and series of internal and external translation simultaneously (environmental) cues o Transcription factor = regulatory proteins that interact w/ the environment and regulatory DNA to control gene expression • Have housekeeping genes (– play essential role in flow of information in a cell) o These genes are highly conserved (= don’t change much over time) Image 9 (12) Bonus Question Topics • GMO = genetically modified organism o Transgenic organism = one that has had the genes of 1 organism inserted into it • Climate change = changes in the average weather for a region over time o Earth’s climate has been getting warmer o Greenhouse effect = the trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun Image 9 Big Picture Concepts from Previous Chapters • Biology = the study of life o Cell theory: § All cells come from preexisting, living cells § All cells have DNA as molecule of heredity § All living things are composed of 1+ cells – what does it mean to be alive? o All cells have… § Plasma membrane § Ribosomes § Enzymes o Emergent properties of life – idea that the cell is the basic unit of life • Scientific method – how to do science 1) Observation 2) Hypothesis § Null hypothesis = “of no effect;;” the independent variable will not have an effect § Alternative hypothesis = the independent variable will have an effect 3) Experimentation § Independent variable = the thing you manipulate;; given to the experimental group § Dependent variable = the thing you measure/your results § Experimental group = receives the independent variable § Control group = does not receive the independent variable 4) Data collection/analysis § Biostatistics – a p-value ≤ 0.05 indicates statistical significance 5) Conclusion • Evolution by natural selection o Natural selection = theory that individuals who are best adapted to their environment will be more likely to survive and reproduce § Key to survival of healthy genes o Bacteria and antibiotic resistance Picture Credit: Image 1: http://science.howstuffworks.com/life/cellular-microscopic/dna1.htm Image 2: http://www.chemguide.co.uk/organicprops/aminoacids/dna1.html Image 3: http://floxiehope.com/2015/04/27/studies-link-topoisomerase-interrupting-drugs-to-autism/ Image 4: http://socratic.org/questions/what-are-exons-and-introns-what-is-the-difference-between- them Image 5: http://study.com/academy/lesson/what-are-amino-acids-definition-structure-quiz.html Image 6: My personal lecture notes Image 7: http://classes.midlandstech.edu/carterp/Courses/bio101/chap15/chap15.htm Image 8: Dr. Scholl’s Chapter 10 & 11 PowerPoint Image 9: https://notesfromthegreenhouse.wordpress.com/tag/greenhouse-gas/
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'