General Biology I

General Microbiolgy

Genetics

Chapter 7a: Microbial Genecs: Basics DNA structure and replicaon (video summary) 1. Describe the basic structure of a nucleode. (Slide 6) Nucleic acid is made of repeang units of nucleodes- Nucleodes are made of; phosphate, 5 carbon sugar, Nitrogenous base. 2. Describe the structure of DNA . (Slides 7-9) DNA is double stranded, complementary DNA strands are anparallel- 5’-3’;3’-5’. The strands bond together by complimentary nitrogenous bases. 3. Outline DNA replicaon in Prokaryotes. (Slides 11-22) 1. Bacteria replicate their DNA as the ﬁrst step in binary ﬁssion. 2. Each strand of nucleodes serves as a template for aa complimentary new strand. 3. The process is semiconservave because each new double helix is composed of nucleodes from the parent molecule and one newly-formed strand. when new strands are being made, they are called “leading” or “lagging” strands. Gene expression (video summary) 4. Outline the process of transcripon (Slides 24-35) Make mRNA from a DNA template by complementary base pairing. Only the secon of DNA that codes for a needed protein is copied. RNA polymerase aaches to a site called the promoter; then transcribes the DNA into mRNA. (DNA transcribed to RNA) 5. Outline translaon (Slides 37-50) Promoter- speciﬁc nucleode sequence at beginning of a gene; tells the RNA polymerase when to start transcripon. RNA Polymerase- binds to promoter by sigma factor that unwinds DNA. begins reading the DNA sequence on the on the template strand from 3’ to 5’; make Mrna in 5’ to 3’ direcon. Three steps; inhibion, elongaon, terminaon. (RNA translated to form polypepdes(proteins)) Regulaon of gene expression (video summary) 6. Describe the operon model of gene regulaon (Slides 52-53) Regulatory gene- codes for a repressor protein that controls process of transcripon. Promoter- DNA segment where RNA polymerase aaches to begin transcripon. Operator- DNA segment where the repressor protein binds. Structural genes- code for speciﬁc proteins. Repressor- block the ability of RNA polymerase to iniate transcripon; usually inacve unl acvator is present 7. Describe how the Tryptophan Operon works (Slides 54-58) It acts as a co-repressor that acvates the repressor and turn oﬀ it’s own producon. 8. Describe how the Lac Operon works (Slides 59-61) a. Describe how glucose modulates the acon of the Lac Operon (Slide 63) Contains genes that code for enzymes used in the hydrolysis of lactose. When there is no lactose, the lac repressor is acve and switches the lac operon oﬀ. When lactose is present, the repressor is inacvated and the lac operon in ON. NOTE – You may also want to check out the Core Curriculum Review for Exam 2 and the Microteaching opons on CANVAS. Also, the video summaries shown in class are on CANVAS. Chapter 7b: Microbial Genecs: Advanced Mutaons 1. List and describe the types of gene mutaons discussed in class. (Slides 3-7) -Point mutaons- most common, a sincle base at one point in the DNA sequence is inserted, deleted, or substuted by other base. 1. Silent mutaon- change in the codon but no change in amino acid; due to code redundancy. 2. Missense Mutaon- change in the codon changes the amino acid thus the protein. 3. Nonsense Mutaon- change in the codon change amino acid to “stop” codon. -Frameshiﬅ mutaons- nucleode triplets are displaced aﬅer the point mutaon, shiﬅs the “translaonal reading frame” a. List and describe common mutagens . (Slides 9-14) -Radiaon; Ionizing radiaons(X-rays and gamma rays); energizes electrons allowing them to escape from atom. The espaced atom strike other atoms causing ion formaons that react with DNA. Nonionizing radiaon(UV rays); causes thymine to crosslink resulng in thymine dimers, cause errors in replicaon and transcripon, most common type of mutaon. -Chemical; Nucleode analogs; can act as DNA nucleodes and enter DNA during replicaon. Nucleode-altering chemicals; alter structure of nucleodes.

BIO | 205 | General Microbiolgy | exam | Chapter 7a: Microbial Genecs:

Micro_BIO250_Exam_1A.docx.docx-BIO250_Saylor_V5 • Unit 3: Tools of

Question 1 Correct 4.50 points out of 4.50 Flag question Question text histones amino acids The DNA of an organism is made up of subunits called. Select one: Question 2 Correct 4.50 points out of 4.50 Flag question Question 3 Correct 4.50 points out of 4.50 Flag question Feedback The correct answer is: nucleotides Question text A permanent, inheritable change in the genetic information is called . Select one: a. translation b. transcription c. a mutation d. an alteration e. regeneration Feedback The correct answer is: a mutation Question text c. nucleodes d. mRNA e. polymerases The duplication of a cell's DNA is called . Select one: Question 4 Correct 4.50 points out of 4.50 Flag question Question 5 Correct 4.50 points out of 4.50 Flag question a. mitosis b. replication c. transcription d. translation e. mutation Feedback The correct answer is: replication Question text Feedback The correct answer is: Transformation Question text c. Transformaon d. Cloning Transducon Conjugaon In Griﬃth's experiments with Streptococcus pneumoniae , rough nonencapsulated streptococci were converted into smooth encapsulated streptococci in the presence of the heat-killed smooth encapsulated streptococci. Which microbial process had Griﬃth idenﬁed? Select one: Question 6 Correct 4.50 points out of 4.50 Flag question Question 7 Correct 4.50 points out of 4.50 Feedback The correct answer is: the DNA strands run antiparallel to each other and the DNA polymerase can only add nucleotides to the 3' end of the growing strand. Question text The various techniques by which scientists manipulate DNA in the lab are termed . Select one: a. genetic engineering b. biotechnology c. recombinant DNA d. gel electrophoresis e. gene probes Feedback The correct answer is: genetic engineering a. the DNA strands run anparallel to each other and the DNA polymerase can only add b. one RNA primer aaches to the 5' end of the parent strand and the other primer to the 3' end. c. both RNA primers aach to the 3' end of the template strands, which are at opposite ends from d. both daughter strands can't extend toward the replicaon fork because there would not be room for two DNA polymerase enzymes. each other. nucleodes to the 3' end of the growing strand. The mechanism of DNA synthesis diﬀers between the two new daughter strands during replicaon. This is due to the fact that Select one:

BIO | 250 | Genetics | exam | Question 1 Correct 4.50 points

Question 2 Correct 4.50 points out of 4.50 Flag question Question text Eosin-methylene blue agar, or EMB, is a commonly used bacteriological medium for growing gram-negative bacteria from complex environments. It contains two dyes, eosin and methylene blue, as well as the sugar lactose. Eosin is a pH indicator that changes color when the medium is acidic, while methylene blue inhibits the growth of most gram- positive bacteria. If an organism consumes lactose, acid will be produced, causing the bacterial colonies to change color. Based upon this description, this medium is . Select one: a. reducing b. for enrichment c. selective d. diﬀerential e. diﬀerential and selective Feedback The correct answer is: diﬀerential and selective Question text • BIO250_Saylor_V5 • Unit 3: Tools of the Laboratory Question 1 Correct 50 points out of 4.50 Which scientiﬁc ﬁeld is involved in the identiﬁcation, classiﬁcation, and naming of organisms? Question 3 Correct 4.50 points out of 4.50 Flag question Question 4 Correct 4.50 points out of 4.50 Select one: a. Nomenclature b. Taxonomy c. Phylogeny d. Pathology e. Epidemiology Feedback The correct answer is: Taxonomy Question text Feedback The correct answer is: It is a process that is dependent upon enzyme (cellulase) production by gut microbiota. It is a very eﬃcient process the produces very lile undigested material in feces. It is a process that is dependent upon enzyme (cellulase) producon by gut c. It requires the acon of enzymes called kinases. d. It is linked to the digeson of glycogen. microbiota. Select the statement that most accurately reﬂects the process of plant material digeson in humans. Select one: Question 5 Correct 4.50 points out of 4.50 Flag question Question text Organic chemicals always have a basic framework of the element bonded to other atoms. Select one: a. carbon b. nitrogen c. oxygen d. hydrogen e. phosphorous Feedback The correct answer is: carbon Question text Feedback a. geomicrobiologist astrobiologist epidemiologist immunologist A scienst who studies the inﬂuence of microbes in the formaon of caves is called a(n) . Select one: Flag question Question 6 Correct 4.50 points out of 4.50 Flag question Question 7 Correct 4.50 points out of 4.50 Flag question The correct answer is: geomicrobiologist Question text All cells contain Select one: a. ribosomes for protein synthesis. b. cell walls made of cellulose. c. uracil in their DNA. d. organelles for compartmentalization. e. mitochondria to generate ATP. Feedback The correct answer is: ribosomes for protein synthesis. Question text The study of evolutionary relationships among organisms is called . Select one: a. biotechnology b. genetics c. recombinant DNA d. phylogeny

BIO | 250 | Genetics | exam | Question 2 Correct 4.50 points

1 Bio 205: Exam 2 – Due Thursday, March 24 , start of class . The answers to these quesons are in your class notes and on PowerPoint . I will also be available to help with the answers . You do not need to write complete sentences. It is best to write the answers out by hand, however, I will accept typed responses. NO LATE WORK ACCEPTED . Chapter 6: Microbial Nutrion and Growth 1. What is binary ﬁssion ? List the steps in binary ﬁssion. (Slide 84) The division of a single enty into two or more parts and the regeneraon of those parts to separate enes resembling the original. Steps; 1. DNA replicaon 2. Cell elongaon 3. Septum formaon 4. Septum compleon leads to separaon or further division 5. Process repeats. 2. Draw a hypothecal graph of a closed bacterial populaon over me . List and describe the phases in the curve. In other words, what is happening to the populaon at each phase? (Slides 87-88) Lag phase- acquires cell mass, no reproducon. log phase- cell division staonary phase- cells stop growing, cells dividing and dying at same rate death phase- cells dying due to lack of nutrients and increased waste products. 3. List and describe the methods/devices used to measure microbial growth in lab. (Slides 92-99) Microscopic count; count microorganisms directly through a microscope. Electronic counters. Flow cytometry. Direct methods requiring incubaon; serial diluon and viable plate count. Membrane ﬁltraon. Most probable number. Indirect methods; turbidity. Metabolic acvity. Dry weight. Genec methods. 1 Countering Anmicrobial Drug Resistance 1. What are the eﬀects of drug combinaons in ﬁghng resistance (Slide 51) Synergism- occurs when the eﬀect of two drugs together is greater than the eﬀect of either alone (Penicillin + streptomycin). Antagonism- occurs when the eﬀect of two drugs together is less than the eﬀect of either alone (Penicillin + tetracycline) 2. List ﬁve (5) methods used to slow the rate of anbioc resistance by bacteria (Slide 54) 1. Limit use of anmicrobials- only prescribe to necessary cases, complete the prescribed regimen, toss outdated anbiocs; do not use others drugs. 2. High concentraon of drugs- maintain in paent for long enough me to kill all sensive cells and inhibit others long enough for immune system to destroy. 1 3. Use anmicrobial agents in combinaon- synergism vs. antagonism. 4. Develop new variaons of drugs. 5. Ban anbiocs in animal feed. 3. List the common misconcepon about anbiocs. (Slide 55) 1. Bacteria is responsible for infecons that become resistant, not people who become resistant to anbiocs. 2. Bacterial mutaons that may result in anbioc resistance, not anbiocs cause mutaons to make the bacteria resistant. 3. Resistant bacteria sll grow at the same rate as sensive bacteria, not bacteria that are resistant to anbiocs are stronger and grow faster than sensive bacteria.

All courses in BIO

Popular Documents