question

Selective Media

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Inhibits growth of one bacteria over another. EG: McConkey is selective for gram negative and Mannitol Salt is selective for gram positive

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Enrichment Media

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All bacteria types can grow but only one will outgrow all the rest because of nutrients. EG: blood agar, fastidious microorganisms

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Differential Media

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Distinguish one microorganism type from another growing on the same media. McConkey is differential for lactose fermentation and mannitol salt agar is differential for mannitol fermentation

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Obligate anaerobe

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Microorganisms that live and grow in the absence of molecular oxygen. They gather at the bottom of the test tube to avoid oxygen. They do not have enzymes, and lack an electron transport chain. That is why we can't use oxygen to ...? These form endospores and are also thermophiles

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Facultative anaerobe

answer

These are not obligate. The anaerobe does not need oxygen to grow. Lack of oxygen does not hurt them. they can be found all along the test tube. They are adapting to variations. Have both enzymes (superoxide dismutase and catalase). Eg; E. coli and S. aureus

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Microaerophile

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Require oxygen but at a low concentration. So they will gather towards upper end of test tube, but not at bottom. Have little enzymes. Eg: Heliobacter Pylori - also a neutrophile and makes an enzyme called Urease which changes the pH from 3 to 7 so it can survive in the stomach. Causes ulcer.

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Obligate aerobe

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Oxygen-needing bacteria. Gather at the top of test tube in order to absorb max amount of O2. Has enzymes. Survival depends on their ability to detoxify O2 and successful gene expression. Eg: Bordetella Pertussis (whooping cough).

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Aerotolerant Bacteria

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Are not affected at all by oxygen. The are evenly spread along the test tube. They only contain the enzyme superoxide dismutase (SOD) Use Peroxidase to break down peroxide and superoxide.

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Describe the natural antioxidants in our bodies

answer

1. Superoxide dismutase (SOD) - removes the free radical from oxygen making o2 and H2O2 (hydrogen peroxide). (or the reverse?)
2. Catalase - Hurns H2O2 into O2 and H2O so now it can safely go into the body.

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Hemolysins

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Enzymes that break down red blood cells. Red blood cells carry oxygen.

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Lag phase of growth curve

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Early phase of bacteria population grown during which no signs of growth occur as bacteria are adjusting to their environment.

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Log phase of growth curve

answer

maximum rate of cell division during which growth is geometric in rate of increase. Also called exponential growth

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Death phase of growth curve

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End of the cell growth due to lack of nutrition, depletion of environment, accumulation of wastes. Population of cells begins to die. More cells are dying than dividing.

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Stationary phase

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survival mode, balance is equal between cells dividing and cells dying

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CFU - Colony-forming unit

answer

A measure of viable bacterial numbers. Unlike direct microscopic counts where all cells, dead and living, are counted, CFU measures viable cells. Results are given as CFU/ml for liquids, CFU/g for solids

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Gene

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The fundamental unit of heredity responsible for a given trait in an organism. A site on a chromosome that provides information for a certain cell function. A specific segment of DNA that contains the necessary code to make a protein or RNA molecule.

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Genotype

answer

Genetic makeup of an organism. The genotype is ultimately responsible for an organism's phenotype, or expressed characteristics.

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Phenotype

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The observable characteristics of an organism produced by the interaction between its genetic potential (genotype) and the environment.

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Chromosome

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The tightly coiled bodies in cells that are the primary site of genes.

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Nucleotide

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The basic structural unit of DNA and RNA; each nucleotide consists of a phosphate, a sugar (ribose in RNA, deoxyribose in DNA), and a nitrogeneous base such as adenine, guanine, cytosine, thymine (DNA), or uracil (RNA).

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Semiconservatism

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In DNA replication, the synthesis of paired daughter strands, each retaining a parent strand template. DNA copies itself just before cellular division by this process. Semiconservatism replication means that each "old" DNA strand is the template upon which each "new" strand is synthesized.

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mRNA

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Carries the message of DNA to the ribosome. Contains *codons*: a sequence of base pairs that code for an amino acid. Eg: AUG - you use the codon to determine the name of the amino acid.

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tRNA

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Adapter molecule to transfer RNA. Adapts the genetic code based on the base sequence of mRNA anticodon. Eg: AUG-UAC brings the amino acid from the cytoplasm into the ribosome.

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rRNA

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Not clear what it does but it is thought to synthesize ribosomes. A single-stranded transcript that is a copy of part of the DNA template.

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DNA Polymerase

answer

Adds new nucleotides to a new strand of DNA modeled after an old strand of DNA. It is also for proofreading. Note that the nucleotides are not stable because DNA ligase has not been applied yet.

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RNA Polymerase

answer

Enzyme process that translates the code of DNA to RNA

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DNA Ligase

answer

seals in nucleotides (composed of a phosphate, nitrogenous base, and a sugar) after DNA Ligase is applied the nucleotides are stable

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DNA Gyrase

answer

located in Bacteria cells only.

"supercoiling" DNA

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Molecular Genetics

answer

When a message of DNA is turned into a protein. "Gene Expression"

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DNA Replication

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The semiconservative mechanisms that ensure precise duplication of the parent DNA strands. DNA fingerprinting.

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Transcription

answer

mRNA synthesis: the procss to which a strand of RNA is produced against a DNA template.

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Translation

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Protein synthesis; the process of decoding the messenger RNA code into a polypeptide.

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DNA ---> DNA

answer

Replication

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DNA ---> RNA

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Transcription

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RNA --- > Proteins

answer

Translation. Proteins are the functional products of DNA because they carry out the instructions of DNA.

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Mutation

answer

A Change in DNA sequence. Mutations can benefit the microbe, but in most cases it does not.

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Frameshift mutation

answer

Addition or deletion of one or more bases

CGC GGT --- > CGC

question

Base Substitution or Point Mutation

answer

One base is substituted for another base. CCT --- > CTT

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Induced Mutations

answer

Happen all the time. They result from exposure to known mutagens:

1. Chemicals
2. Radiation

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Spontaneous mutations

answer

Spontaneous mutations are very rare. Change in DNA arising from errors in replication, when there is an absence of an environmental agent.

question

Gene Expression: What are 3 ways to express a gene?

answer

Constitutive
Induction
Repression

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Constitutive

answer

Set of genes that's constantly on

question

Induction

answer

Set of genes that's turned on, so this means they are initially off. These are genes we don't need.
EG: Cancer cells

question

Lactose Operon -- Induction

answer

Turned on in the absence of glucose, does not make lactose, makes 3 enzymes that convert lactose to glucose. The repressor -- allosteric protein -- is what is causing the operon to be off. The lactose binds to the allosteric site causing the active site to change shape. So then the repressor comes off, allowing RNA polymerase to bind to the promoter and initiate transcription.

question

Secondary Messengers

answer

Secondary messengers tell the lactose operon whether or not it is needed.

question

Tryptophan Operon - Repression

answer

Makes tryptophan. When the conc. of tryptophan meets the max. threshold, Tryptophan binds to the allosteric site acting as a coil(?) repressor. The repressor protein changes shape and the conc of trypt goes down and the operon is turned off.

question

Types of Gene Transfer -- All-natural mutations

answer

Conjugation
Transduction
Transformation

question

Conjugation -- Gene transfer between 2 organisms by a pilus

answer

A pilus can only be formed by the F-plasmid (F+) which contains genetic information. F stands for fertility. An F+ donor cell and a F-recipient (F-) both contain a host cell genome. The F plasmid (F+) cell makes a copy of itself by DNA polymerase, ligase, helicase, gyrase, and semiconservatism which moves it over to the F-cell. When the F-plasmid moves over then it is no longer a recipient cell but a donor cell (F plasmid) survival of the species?

question

Transduction -- Gene Transfer between bacteria cells through a bacteriophage

answer

The virus, containing nucleic acid, enters cell A's genome and leaves with genes from cell A and enters into cell B. Cell A is destroyed. So the virus now contains nucleic acid and cell A's genes. When it goes into cell B it leaves behind part of c ell

question

Tranformation

answer

The uptake of naked DNA by another bacterial cell. In a host cell genome, inside of a bacteria cell, DNA comes out in fragments from the cell bursting. To make the cell burst it has to go under change in water availability (hypotonic) or temperature, or PH. This is how the DNA comes out of the cell. Then another bacteria cell can bring in one of the DNA fragments.

question

Classical Biotechnology

answer

Use living organisms to produce useful products to solve a problem. "invivo" testing - using a rat or some type of animal

question

Modern Biotechnology

answer

Use biological molecules to produce useful products or solve a problem. "Invitro" testing -- using a test tube with bacteria cells or human cells.

question

Genetic Engineering

answer

More specific terms of biotechnology. Manipulate the genes of an organism. Recombinant DNA technology.

question

Recombinant DNA technology

answer

Cutting and combining genes from 2 different organism. It involves modification of an organism's genome. Used to create genetically modified food that may have increased nutritional properties, be easier to grow, or may even vaccinate the person eating it against a host of diseases.

question

Tools of the Trade for Recombinant DNA technology

answer

1. Restriction Enzymes -- enzymes that recognize and cut DNA sequences. They learn things from bacteria cells.
2. Plasmids. Genest that can make bacteria resistant to antibiotics and can express genes from foreign organisms. 1. F-plasmid. 2. R-Plasmid, R-Resistance. Carry antibiotic resistance and are self-replicating.
3. DNA Ligase - seals in the gene.

question

Transposons

answer

Act Like Plasmids, mobile genetic elements -- "jumping Genes". They can jump from one plasmid or host cell genome in a DNA unit to the other and replicate itself. This causes instability in the cell.

question

Contributions to Biotechnology

answer

1. Gene Library -cloned DNA stored in yeast, viruses, or bacteria.
2. Polymerase Chain Reaction (PCR)-amplify DNA.
3.DNA Fingerprinting - analyze DNA/associated with replication, forensics, paternity testing, diagnostics
4. Medicines
5. Vaccines
6. Human Genome Project

question

Examples of Aerotolerant bacteria

answer

Lactobaccillus - Yoghurt
Acidophilus - Makes lactic acid to keep urogenital tract low PH.
Both of these are good bacteria cells that keep you from getting a yeast infection.

question

Aseptic Technique

answer

Methods of handling microbial cultures, and patient specimens in a way that prevents infection of the handler and others who may be exposed.

question

Operon

answer

Cluster of genes that regulate metabolism by controlling mRNA production.
1. Promoter - where RNA polymerase binds to start transcription. DNA sequence.
2. Operator -- a repressor binds to block transcription. On/Off switch. DNA sequence
3. Structural Genes -- encode for a set of enzymes.

question

Bacteriostatic

answer

Any process or agent that inhibits bacterial growth

question

Bactericidal

answer

Killing bacteria cells

question

Asepsis

answer

A safe level free of viable pathogenic microorganisms but is not sterile. You still may see microbial growth including endospores.

question

Sterilization

answer

Any process that completely removes or destroys all viable microorganisms, including viruses, from an object or habitat. Endospores are the indicators if something is sterile or aseptic. All sterile techniques are bactericidal.

question

Moist Heat

answer

Heat can be under pressure or not. Heat that is under pressure is steam and is sterile, killing endospores. Example is a Crock Pot. Heat that is not under pressure is boiling. Boiling is a bactericidal, aseptic technique -- does not kill endospores.

question

Dry Heat

answer

Sterile. Example: when we flame the loop in lab.

question

Cold Heat

answer

bacteristatic and aseptic

question

Mesophiles

answer

Grow at intermediate temperatures, warm loving. 37 degrees C. Eg: staph. aureus.

question

Psychrophiles

answer

Cold-loving bacteria, thrive at low temperatures (0-20 degrees C.)

question

Thermophiles

answer

Hot loving, 60 degrees C. or higher. Endospore forming bacteria. Obligate anaerobes.

question

PH affecting microbial growth

answer

Bactericidal and aseptic, because endospores can survive in too basic or too acidic condition.
• Acidophile --likes pH3
• Neutrophle -- likes pH7(our bodies)
• Alkalophile -- likes pH9

question

Water availability affecting Microbial Growth

answer

Cells are drying. Cells like an isotonic environment. Cells are bacteristatic but over time it becomes bactericidal and aseptic. It takes a while to kill the cells because of the water.

question

Halophile

answer

likes a hypertonic environment (salt-loving) Eg: staph aureus

question

Radiation affecting Microbial Growth

answer

UV Radiation and Gamma Radiation

question

Explain UV Radiation

answer

Starts bactericidal, but over time it becomes sterile. UV rays don't penetrate through clothes or plastic. Becomes sterile by Thymine Dimers -- fuse 2 thymine together, this blocks DNA Polymerase from reading it so the UV light can now destroy the cell.

question

Explain Gamma Radiation

answer

Sterile Technique. Can go through clothes, plastic. They form free radicals.

question

Filtration.

answer

Sterile technique that doesn't interfere with any cellular structures or processes and is mechanically removing bacterial cells from a solution. Once a solution goes through the filter it becomes sterile.

question

Size of Filter Unit Pores

answer

.01um for bacteria and viruses
.10um for bacteria and viruses
.22um for bacteria but not viruses
.45um for some bacteria but mainly dirt

question

Chemical Factors of Microbial Growth

answer

Interfere with proteins and the plasma membrane. (mode of action)
•Alcohol
•Halogens

question

Describe the alcohol factor of microbial growth

answer

bacteriostatic and aseptic. 70% alcohol is more effective than 100% alcohol because the water content in the 70% helps it be absorbed faster.

question

Bleach

answer

Halogen that is aseptic and bactericidal. If it is used properly it is a sterile technique that interferes with DNA.

question

Iodine

answer

Halogen that is bactericidal and aseptic

question

Phenols/Phenotics

answer

Halogens that are bactericidal and aseptic.
Eg. LIsterine/Lysol/Triclosan

question

Surfactants

answer

Halogens that are bacteristatic and aseptic.
Eg. Hand Soap

question

Heavy Metals

answer

Halogens that are antiseptic, bactericidal, and antimicrobial (nickel, silver, mercury)

question

What are the physical factors of microbial growth?

answer

Temperature, pH, water availability, radiation

question

How is DNA, mRNA, and fRNA made?

answer

DNA -- 5' - 3'
-- 3' - 5'
mRNA 5' - 3', so the 3' - 5' from DNA is what we have to use because it is the opposite.
tRNA -- 3' - 5' because it is the opposite of mRNA

question

Example of Facultative Anaerobe?

answer

E. Coli and Staph. Aureus

question

Example of Microaerophile?

answer

Heliobacter Pylori

question

Example of Obligate Aerobe?

answer

Bordetella Pertussis

question

Where does transcription occur in Prokaryotic and Eukaryotic Cells?

answer

Transcription of DNA to RNA occurs in the nucleus of Eukaryotic cells and the nucleoid of Prokaryotic cells.

question

Where does Translation occur in Prokaryotic and Eukaryotic Cells?

answer

In the ribosomes.

question

Direct bacteria cell counts

answer

Using the eye to see bacteria. Also uses an instrument like a coulter counter. As cells pass through this device, they trigger an electronic sensor that tallies their numbers.

question

Indirect bacteria cell counts

answer

1. Metabolism - looking at by-products. Co2 and ATP are measured.
2. Dry weight - wet solution
3. Turbidity - cloudiness in the test tube.

question

Describe a mass spectrophotometer

answer

Used to measure indirect bacteria cells turbidity. You place a testtube in a slot where light is coming through. The light bounces off anything solid. We get the Optimal Density from this.

question

Inaccuracy of coulter counter and spectrophotometer

answer

There is no distinction between dead and live cells

question

Name examples of Obligate Anaerobes

answer

Clostridium Perfringens -- gangrene
Clostridium tetini -- tetanus
Clostridium botulinum -- botulism

question

What is the AMPr gene?

answer

Ampicillin resistance gene

question

Recombination in bacteria depends in part on the fact that bacteria contains...

answer

Extrachromosomal DNA - Plasmids -- interchanging genes

question

What is a Functional Product?

answer

Fu

question

What are the essential elements?

answer

Carbon, Hydrogen, Oxygen, Phosphorus, Nitrogen, Sulfur, Iron.
All living things require these elements.

question

Growth Factors -- Organic Nutrients

answer

Only required for fastidious organisms (organisms that require special nutritional or environmental conditions for growth). Eg: nisseria gonorrhea -- needs amino acids.
1.Amino acids. 2. Purines. 3. Pyrimidines.

question

What is the advantage of using Agar?

answer

Agar is a polysaccharide. It is heat stable meaning it can be heated up and it still works. Nutrients have to be placed in the agar.

question

What are the 2 categories of Agar?

answer

• Complex media - used in lab. We don't know or care the exact chemical composition.
• Chemically-defined agar (more expensive, unnecessary unless you're doing research, looking for particular stuff to grow or isolate)

question

Trace Elements, Inorganic?

answer

Micronutrients (Zinc, copper, Magnesium) that occur in small amounts and are involved in enzyme function and maintenance of protein structure. They are non-fastidious organisms (meaning they don't require special nutritional or environmental conditions for growth.

question

Repression

answer

Set of genes that are turned off. We need these genes, they are always on. They are controlled by a repressor. The repressor is not bound to the operator (so it is on) so we have to make the repressor bind to the operator to turn it off.

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