Microbiology Chpt. 9 Microbial Genetics – Flashcards
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| What is the smallest unit of heredity? |
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| Gene |
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| The nitrogen bases in DNA are bonded to the ? |
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| Deoxyribose |
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| DNA replication is semiconservative becasue the _______ strand will become half of the ______ molecule. |
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| Template, Finished |
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| In DNA, adenine is the complementary base for,_______, and cvtosine is the complement for _________. |
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| Thymine, Guanine |
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| Transfer RNA is the molecule that ? |
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| Adapts the genetic code to protein structure. |
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| As a general rule, the template strand on DNA will always begin with ? |
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| TAC |
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| The lac operon is usuallly in the ______ position and is adctivated by a/an _________ molecule ? |
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| Off, Inducer |
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| Which genes can be transferred by all three methods of horizontal gene transfer? |
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| Drug resistance |
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| Which of the following would occur through specialized transduction ? |
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| Transfer of genes for toxin production |
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| When genes are turned on differently under different environmental conditions, this represents a change in ? |
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| Phenotype |
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| True/False the DNA pairs are held together primarily by (covalent) bonds? |
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| False They are held together primarily by (HYDROGEN) bonds |
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| True/False Mutation usually has a negative outcome? |
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| True |
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| True/False The lagging strand of DNA is replicated in short pieces because DNA polymerase can synthesize in only one direction. |
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| True |
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| True/False Messenger RNA is formed by (translation) of a gene on the DNA template strand? |
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| False Is formed by (TRANSCRIPION) of a gene on the DNA template strand |
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| True/False A nucleotide is composed of a 5-carbon surgar, a phosphate group, and a nitrogenous base ? |
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| True |
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| genetics |
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| the study of heredity of living things -transmission of traits from parent to offspring -expression and variation of those traits -the structure and function of genetic material (structure of DNA) |
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| genetic study takes place on several levels what does microbiology focus on? |
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| cellular and molecular levels of study, the physiology, mutations and pathogenicity of microbes |
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| cells must self replicate, which occur in what 2 ways and describe? |
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| 1. binary fission (Bacteria) 2. Budding (yeast |
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| describe genome? |
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| All DNA present (biggest one) collection of all DNA present in organism Bacterial genomes=0.4-9.4 million nucleotides Human genosome=4 billion nucleotides |
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| Chromosome |
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| prokaryotes have one, which contain entire genome euksryotes may dividde genome into many |
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| Each cell contains how many feet of DNA? |
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| 6 feet of DNA |
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| _______are nonessential, circular pieces of DNA |
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| Plasmids |
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| What makes up a nucleotide? |
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| Phosphate deoxyribose sugar Nitrogenous base |
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| Nitrogenous bases What always pairs up Adenine always pairs up with Guanine always pairs up with? |
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| Adenine always pairs up with thymine Guanine always pairs up with cytosine |
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| Which of the following is not a pyrimide? a. Cytosine B.Thymine c. Adenine d. Uracil |
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| c. Adenine |
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| Enzymes of DNA replication Helicase (function) |
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| unzipping the DNA helix |
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| Enzymes of DNA replication Primase (function) |
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| synthesizing an RNA primer |
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| Enzymes of DNA replication DNA polymerase III (Function) |
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| adding bases to the new DNA Chain; profreading the chain for mistakes |
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| Enzymes of DNA replication DNA Polymerase I (function) |
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| removing primer, closing gaps, repairing mismatches |
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| Enzymes of DNA replication Ligase (function) |
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| final binding of nicks in DNA during synthesis and repair |
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| Three stages of DNA replication |
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| 1. initiation 2. elongation 3. termination |
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| Describe the intiation stage of DNA replication |
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| helicases seperate the DNA at the origin -primases produce RNA primers -DNA polymerase IIIbegins adding DNA nucleotides -Transcription performed by RNA polymers |
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| Describe Elongation stage of DNA repliciation? |
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| DNA polymerase III continues adding DNA basescan only be added to 3' end, |
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| Describe the termination stages of DNA replication |
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| Ligases link new DNA strands to a circle RNA pol Hits terminator DNA sequence and falls off |
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| Describe transcription ? |
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| The master code DNA is used to sythesize an RNA Molecule |
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| Describe translation? |
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| The information in the RNA is used to produce proteins (translation) |
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| What is central dogma |
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| +genetic information flows from DNA to RNA protein +the master code of DNA is used to synthesize an RNA molecule (transcription) +The information in the RNA is used to produce proteins (translation) +Exceptions : RNA viruses and retrovirses Rencently shown to be incomplete +In addition to the RNA that produces protein, other RNAs are used to regulate gene function +many of the genertic malfunctions that cause human disease are found in the regulatory RNA segements |
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| Know the flow of genertic information |
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| +transcription (DNA to RNA) + Translation (RNA to protein) (Not all RNAs are translated into protein;rRNA andtRNA used to produce protein) +Reserve transcription (RNA to DNA) (Only in retrovirus) |
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| RNA's Differ from DNA |
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| + single stranded molecule +Helical form +Contains uracil instead of thymine +the sugar is ribose |
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| wobble |
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| in many cases, only the first two nucleotides are required to encode the correct amino acid-throughout to permit some variation or mutation without altering the message |
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| chromosome male |
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| xy |
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| chromosome female |
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| xx |
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| number of chromosomes |
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| 46 or 23 pairs |
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| WIll antibotics effect the prokarotic or the eukarotic more? |
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| Prokarotic |
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| erthromycin |
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| used in sinus infections Binds to 50S portion and prevents translocation-movement of ribosome along mRNA |
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| tetracyclines |
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| used to trat acne. interfere with attachment of tRNA to mRNA-ribosome complex |
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| Steptomycin |
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| Given for Disease TB Changes the shape of 30S portion, causes code on mRNA to be read incorrectly |
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| Chloramphenicol |
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| Binds to 50S portion and inhibits formation of peptide bond to high of a dose effects blood ability to carry oxygen |
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| Antibotics affect transcription and translation Describe |
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| + certain drugs react with DNA, RNA or ribosomes and alter genetic expression +Growth of the infectious agent will be inhibited by blocking its protein-synthesizing machinery selectively +transcription-Target RNA polymerase +translation -ribsomes +antibotics often target the ribosome-inhibiting ribosome function and ultimately protein synthesis this is why the difference between bacterial and eukarotic ribosomes is so important |
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| Transfer RNA- the key to translation describe |
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| uniform in length (75-95 nucleotides long +molecule has a cloverleaf structur that then folds into a complex-3D helix +bottomloop of the clover exposes a triplet (the anticodon) that designates the specificity of the tRNA codons + at the opposite end of the molecule is a binding site for the amino acid that is specific to anticodon +for each 20 amino acids there is at least one specialized type of tRNA to carru it |
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| When interpreting the DNA code |
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| Read in triplets (codons) 4X4X4X= 64 possible 61 specify amino acids 3 stop translation |
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| Who discovered DNA Code |
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| James Watson- and Fransis Crick made of nucleic acid (A,C,G,T) two strand combined into double helix |
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| Eukaryotic chromosomes describe |
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| DNA molecule tightly wound around proteins located in the nucleus vary in number froma few to hundreds linear can occur in pairs or singles |
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| bacterial chromosomes |
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| histone-like proteins located in the nucleoid region of the cytoplasm |
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| genotype |
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| entire collection of genes in an organism |
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| phenotype |
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| the traits of an organism which are an expression of the genotype |
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| Structural genes |
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| code for proteins -make proteins -enzyme, cytoskeleton |
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| rRNA and tRNA genes |
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| translating or making of protein=protein synthesis |
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| regatory genes: |
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| Control gene expressions |
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| Describe nitrogenous bases |
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| purines and pyrimidines -span the center of the molecule and pair with complementry bases from other strands -the paired bases are joined by hydrogen bonds -easily broken allow the molecule to be "unzipped" |
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| General structure of DNA: sugar phoshate backbone |
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| nucleotides covalently bond to form sugar -phosphate linkage sugar phosphate backbone is represented by ribbon each sugar attaches to two phosphates- one bond is 5'carbon on deoxyribose the other a 3' carbon |
