Test 2 Review Flashcards

Question

What is the **oldest & cheapest method** for culturing viruses?

Answer 1

Using embryonated eggs ## Footnote This method has been used for decades in virology.

Answer 2

Cell cultures ## Footnote Cell cultures allow for the study of viruses in a controlled environment.

Answer 3

Cell-free preparations ## Footnote CPFs are used in research to study viral properties without host cells.

Answer 4

* Electron microscopy * Serological tests * Molecular methods * Cell culture ## Footnote These methods help in detecting and identifying viral infections.

Answer 5

* Icosahedral head * Tail fibers * Base plate * Sheath * DNA genome * Parasitizes E. coli ## Footnote T-Even phages are a group of bacteriophages that infect bacteria.

Answer 6

* Lytic cycle: Virus replicates and destroys host cell * Lysogenic cycle: Virus integrates into host genome and remains dormant ## Footnote The lytic cycle leads to cell death, while the lysogenic cycle can remain inactive for a period.

Answer 7

* Attachment * Entry/Penetration * Biosynthesis * Maturation/Assembly * Exit ## Footnote Variations in animal viruses may include different entry mechanisms and latency periods.

Answer 8

* Eclipse period: Time between virus entry and new virion formation * Burst time: Time from infection to release of new virions ## Footnote These terms describe phases in the viral replication cycle.

Answer 9

* Latency: Dormant state of a virus * Prophage: Viral DNA integrated into bacterial genome * Provirus: Viral DNA integrated into host cell DNA * Temperate virus: Can enter lytic or lysogenic cycle * Transduction: Transfer of DNA between bacteria via a virus ## Footnote These concepts are essential for understanding viral behavior and interactions with hosts.

Answer 10

* Carbon * Hydrogen * Oxygen * Nitrogen * Phosphorus ## Footnote Nucleic acids contain phosphorus, which is not found in proteins.

Answer 11

* Sugar * Phosphate group * Nitrogenous base ## Footnote DNA contains deoxyribose, while RNA contains ribose.

Answer 12

* DNA: Deoxyribonucleic acid * RNA: Ribonucleic acid * GCATU: Guanine, Cytosine, Adenine, Thymine (DNA), Uracil (RNA) ## Footnote The 1'-5' primes indicate the directionality of nucleic acid strands, crucial for replication and transcription.

Answer 13

* It aids in remembering the base pairing rules for DNA and RNA ## Footnote The mnemonic simplifies the learning of nucleotide pairings.

Answer 14

* DNA strands are antiparallel; reading direction differs from synthesis direction ## Footnote This is fundamental for understanding DNA replication and transcription.

Answer 15

* Griffith: Transformation principle * Avery, Macleod & McCarty: DNA as genetic material * Chargaff: Base pairing rules * Hershey & Chase: DNA in viruses * Franklin & Crick & Watson: DNA structure ## Footnote Each scientist played a crucial role in uncovering the molecular basis of genetics.

Answer 16

* Helicase * Primase * DNA Polymerase III * DNA Polymerase I * Ligase ## Footnote DNA replication occurs in the S phase of the cell cycle, at the replication fork.

Answer 17

* Double helix: Structure of DNA * Base-pair: Complementary nucleotides * Hydrogen bonds: Hold base pairs together * Anti-parallel: Orientation of DNA strands * Replication fork: Site of DNA replication * Semi-conservative: Each new DNA has one old strand * Primers: Short RNA sequences for initiation * Leading strand: Continuous synthesis * Lagging strand: Discontinuous synthesis * Okazaki fragments: Short DNA segments on lagging strand ## Footnote These terms are essential for understanding DNA structure and replication mechanisms.

Answer 18

* Mutation: Change in DNA sequence * Spontaneous mutation: Occurs naturally * Classes of mutagens: * Chemical (e.g., benzene) * Physical (e.g., UV radiation) * Biological (e.g., viruses) ## Footnote Mutagens can increase the rate of mutations in organisms.

Answer 19

* Ames test: Assesses mutagenicity using bacteria * Auxotrophs: Require specific nutrients, indicating mutations ## Footnote The test uses the ability of mutants to revert to prototrophy to identify mutagens.

Answer 20

* DNA Polymerase 3: Synthesizes new DNA * DNA Polymerase 1: Replaces RNA primers * Excision repair: Removes damaged DNA * Photoactivation repair: Fixes UV-induced damage ## Footnote These processes are crucial for maintaining DNA integrity.

Answer 21

* It results from defective DNA repair mechanisms, leading to skin cancer ## Footnote This condition highlights the critical role of DNA repair in preventing mutations.

Answer 22

* Transcription: Initiation, Elongation, Termination * Translation: Initiation, Elongation, Termination ## Footnote Understanding these processes is essential for gene expression.

Answer 23

A sequence of three nucleotides that codes for a specific amino acid ## Footnote DNA triplets are the basis for codons in mRNA.

Answer 24

A sequence of three nucleotides in mRNA that corresponds to a specific amino acid ## Footnote Codons are read during translation to synthesize proteins.

Answer 25

A sequence of three nucleotides in tRNA that pairs with a codon in mRNA ## Footnote Anticodons ensure the correct amino acid is added during protein synthesis.

Answer 26

A DNA sequence that indicates where transcription of a gene begins ## Footnote The TATA box is a common promoter element in eukaryotic genes.

Answer 27

A segment of DNA that a repressor protein binds to, regulating gene expression ## Footnote Operators are part of operons in prokaryotic cells.

Answer 28

A gene that codes for a protein or RNA molecule ## Footnote Structural genes are essential for the synthesis of functional products.

Answer 29

A sequence of nucleotides that signals the end of transcription ## Footnote Terminators ensure that RNA synthesis stops at the correct location.

Answer 30

* E site: Exit site * P site: Peptidyl site * A site: Aminoacyl site ## Footnote These sites are crucial for the process of translation.

Answer 31

The process of moving the ribosome along the mRNA during protein synthesis ## Footnote Translocation occurs after peptide bond formation.

Answer 32

A covalent bond that links amino acids together in a protein ## Footnote Peptide bonds form during the process of translation.

Answer 33

It determines the protein's function and stability ## Footnote Misfolded proteins can lead to diseases, including prion diseases.

Answer 34

* Silent mutation * Missense mutation * Nonsense mutation ## Footnote Each type has different consequences at the polypeptide level.

Answer 35

Frameshift mutation ## Footnote Unless 3 nucleotides are deleted or inserted, frameshift mutations alter the reading frame.

Answer 36

* Transformation * Transduction * Conjugation ## Footnote Not all methods result in recombinants.

Answer 37

A protein that facilitates the movement of DNA across cell membranes ## Footnote These proteins are crucial for processes like transformation.

Answer 38

DNA that is not associated with proteins or other cellular structures ## Footnote Naked DNA can be taken up by bacteria during transformation.

Answer 39

A plasmid that carries genes for sex pili and allows for bacterial conjugation ## Footnote F+ plasmids enable the transfer of genetic material between bacteria.

Answer 40

A mechanism of plasmid replication that allows for the transfer of genetic material ## Footnote This method is often used in conjugation.

Answer 41

Hair-like structures that facilitate the transfer of DNA between bacteria during conjugation ## Footnote Sex pili are essential for the formation of mating pairs.

Answer 42

A bacterium that provides genetic material to another bacterium during conjugation ## Footnote Donors typically carry F+ plasmids.

Answer 43

A bacterium that receives genetic material from a donor during conjugation ## Footnote Recipients may become recombinants after DNA transfer.

Answer 44

An organism that has received genetic material from another organism ## Footnote Recombinants can exhibit new traits due to the acquired DNA.

Answer 45

A virus that infects bacteria ## Footnote Bacteriophages can transfer genetic material between bacteria.

Answer 46

A gene that is continuously expressed regardless of environmental conditions ## Footnote Constitutive genes are essential for basic cellular functions.

Answer 47

A cluster of genes under the control of a single promoter ## Footnote Operons are common in prokaryotic gene regulation.

Answer 48

* Repressible operon: Usually active, can be turned off * Inducible operon: Usually inactive, can be turned on ## Footnote This distinction is important for understanding gene regulation.

Answer 49

The repressor protein binds to the operator, preventing transcription ## Footnote The Lac Operon is typically off when lactose is absent.

Answer 50

Lactose binds to the repressor, allowing transcription of structural genes ## Footnote This operon is called inducible because it is activated by the presence of lactose.

Answer 51

The gene that codes for the repressor protein in the Lac Operon ## Footnote The I gene plays a crucial role in regulating lactose metabolism.

Answer 52

A protein that inhibits gene expression by binding to the operator ## Footnote Repressor proteins are key regulators in operons.

Answer 53

A DNA sequence where RNA polymerase binds to initiate transcription ## Footnote Promoters are essential for gene expression.

Answer 54

Genes that code for proteins or functional RNA ## Footnote Structural genes are essential for the synthesis of functional products.

Answer 55

A sugar that induces the expression of the Lac Operon when present ## Footnote Lactose is the substrate that activates the operon.

Answer 56

Through binary fission ## Footnote This method allows for rapid population growth.

Answer 57

The time it takes for a microbial population to double ## Footnote Generation time varies among different species.

Answer 58

A graphical representation of the growth of a microbial population over time ## Footnote It typically includes lag, exponential, stationary, and death phases.

Answer 59

* Lag phase: Adaptation to new environment * Exponential growth phase: Rapid cell division * Stationary phase: Nutrient depletion, waste accumulation * Log death phase: Decline in viable cells ## Footnote Understanding these phases is useful for managing microbial populations.

Answer 60

* Plate counts (cfus): Viable cell counting * Most probable number (MPN): Statistical estimation of viable cells * Direct microscopic count: Counting cells under a microscope * Turbidity (spectrophotometer): Measuring cloudiness * Electronic counts (Coulter counter/flow cytometry): Automated counting * Metabolism: Measuring metabolic activity * Dry weights: Weighing biomass ## Footnote Each method has advantages and disadvantages, and some provide estimates.

Answer 61

They dilute the sample to obtain a countable number of colonies ## Footnote TMTC stands for 'Too Many To Count'.

Answer 62

* Enrichment culture * Amplification techniques ## Footnote These methods help increase the detectable population of microbes.

Answer 63

The ideal conditions for maximum growth rate ## Footnote Optimal conditions vary by species.

Answer 64

* Minimum: Lowest temperature for growth * Maximum: Highest temperature for growth * Optimal: Temperature for fastest growth ## Footnote These temperatures define the growth range for microbes.

Answer 65

Microbes that thrive at low temperatures (0-20°C) ## Footnote Psychrophiles are often found in cold environments.

Answer 66

Microbes that grow best at moderate temperatures (20-45°C) ## Footnote Mesophiles include many human pathogens.

Answer 67

Microbes that thrive at high temperatures (45-80°C) ## Footnote Thermophiles are often found in hot springs.

Answer 68

Microbes that thrive in high salt concentrations ## Footnote Halophiles are often found in salt lakes and salt mines.

Answer 69

Microbes that thrive under high pressure ## Footnote Barophiles are often found in deep-sea environments.

Answer 70

Microbes that thrive in acidic environments (pH < 7) ## Footnote Acidophiles are often found in acidic hot springs.

Answer 71

Microbes that thrive in neutral pH environments (pH 6-8) ## Footnote Neutrophiles include many common bacteria.

Answer 72

Microbes that thrive in alkaline environments (pH > 7) ## Footnote Alkaliphiles are often found in soda lakes.

Answer 73

An organism that requires oxygen for growth ## Footnote Aerobes utilize oxygen for cellular respiration.

Answer 74

An organism that does not require oxygen for growth ## Footnote Anaerobes may even be harmed by oxygen.

Answer 75

An organism that can grow with or without oxygen ## Footnote Facultative anaerobes can switch between aerobic and anaerobic metabolism.

Answer 76

An organism that does not use oxygen but can tolerate its presence ## Footnote Aerotolerant anaerobes rely on fermentation for energy.

Answer 77

An organism that requires low levels of oxygen for growth ## Footnote Microaerophiles thrive in environments with reduced oxygen concentrations.

Answer 78

To cultivate anaerobic bacteria by removing oxygen ## Footnote Reducing media contains chemicals that bind oxygen.

Answer 79

Enclosed environments that maintain anaerobic conditions ## Footnote Anaerobic chambers are used for culturing anaerobic organisms.

Answer 80

An organism that requires elevated levels of carbon dioxide for growth ## Footnote Capnophiles are often found in the gastrointestinal tract.

Answer 81

Oxygen can produce reactive oxygen species (ROS) that damage cellular components ## Footnote ROS can lead to oxidative stress and cellular damage.

Answer 82

* Catalase: 2 H2O2 → 2 H2O + O2 * Superoxide dismutase: 2 O2- + 2 H+ → H2O2 + O2 ## Footnote These enzymes help detoxify harmful oxygen byproducts.

Answer 83

Certain anaerobic bacteria ## Footnote These organisms can utilize alternative pathways for detoxifying oxygen.

Answer 84

* Carbon * Nitrogen * Phosphorus * Sulfur ## Footnote Macronutrients are essential for cellular structure and function.

Answer 85

* Iron * Zinc * Copper * Manganese ## Footnote Micronutrients are required in smaller amounts for enzyme function and other processes.

Answer 86

Organisms that use light energy to convert carbon dioxide into organic compounds ## Footnote Examples include plants and certain bacteria.

Answer 87

Organisms that obtain energy from chemical reactions and use carbon dioxide as a carbon source ## Footnote Examples include certain bacteria and archaea.

Answer 88

Organisms that use light for energy but require organic compounds for carbon ## Footnote Examples include some purple non-sulfur bacteria.

Answer 89

Organisms that obtain both energy and carbon from organic compounds ## Footnote Most animals and many bacteria are chemoheterotrophs.

Answer 90

* H: Water and organic compounds * N: Amino acids and nucleotides * P: Phosphate salts * S: Amino acids and sulfate ## Footnote These elements are essential for macromolecule synthesis.

Answer 91

From added salts and minerals in growth media ## Footnote Trace elements are often included in nutrient agar or broth.

Answer 92

Yeast extract, beef extract, or specific vitamins ## Footnote Growth factors are necessary for the growth of fastidious organisms.

Answer 93

Organisms that do not rely on other organisms for survival ## Footnote Free-living organisms can thrive independently.

Answer 94

An organism that lives on or in a host and derives nutrients at the host's expense ## Footnote Parasites can cause harm to their hosts.

Answer 95

An organism that lives in close association with another organism ## Footnote Symbionts can be mutualistic, commensal, or parasitic.

Answer 96

An organism that feeds on dead or decaying organic matter ## Footnote Saprophytes play a crucial role in nutrient cycling.

Answer 97

An organism that benefits from another without affecting it ## Footnote Commensalism is a type of symbiotic relationship.

Answer 98

An organism that benefits from another while also benefiting the other ## Footnote Mutualism is a cooperative relationship between species.

Answer 99

An organism that competes with another for resources ## Footnote Antagonistic relationships can inhibit growth or survival.

Answer 100

An organism that works together with another to enhance growth or survival ## Footnote Synergistic relationships can lead to mutual benefits.

Answer 101

An organism that produces organic compounds from carbon dioxide through photosynthesis or chemosynthesis ## Footnote Primary producers form the base of the food chain.

Answer 102

An herbivore that feeds on primary producers ## Footnote Primary consumers are the second trophic level in an ecosystem.

Answer 103

An organism that feeds on primary consumers ## Footnote Secondary consumers can be carnivores or omnivores.

Answer 104

An organism that eats both plants and animals ## Footnote Omnivores occupy multiple trophic levels.

Answer 105

* Inoculation * Incubation * Isolation * Inspection * Identification ## Footnote These steps are essential for successful microbial culture.

Answer 106

Cell culture media ## Footnote Obligate intracellular pathogens require living cells for growth.

Answer 107

Ordinary numbers are standard numerical values; exponents represent repeated multiplication; scientific notation expresses numbers as a product of a coefficient and a power of ten ## Footnote Understanding these concepts is essential for scientific calculations.

Answer 108

Yes ## Footnote Metric conversions involve changing units within the metric system, such as centimeters to meters.

Test 2 Review Flashcards

(132 cards)