Microbiology Unit 1

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Questions and Answers

Who is credited with developing the Germ Theory of Disease?

Louis Pasteur and Robert Koch (correct)

Antonie van Leeuwenhoek

Ignaz Semmelweis and Alexander Fleming

Florence Nightingale and Joseph Lister

What is the function of helicase in DNA replication?

To unwind the double helix (correct)

To synthesize new DNA strands

To join the okazaki fragments

To proofread and edit the newly synthesized DNA

What is the term for the process by which genetic information is passed from DNA to RNA?

Translation

DNA replication

Gene expression

Transcription (correct)

What is the primary function of flagella in prokaryotic cells?

To aid in movement and motility Signup and view all the answers

What is the type of fungi that can exist in two forms, depending on the environment?

Dimorphic fungi Signup and view all the answers

Which of the following microorganisms is an example of a eukaryote?

Saccharomyces cerevisiae Signup and view all the answers

What is the term for the ability of a solution to maintain a stable balance of solutes and water?

Isotonic Signup and view all the answers

What is the term for a gene's physical and chemical characteristics?

Phenotype Signup and view all the answers

What is the term for a sequence of three nucleotides that codes for a specific amino acid or stops protein synthesis?

Codon Signup and view all the answers

Which of the following is NOT a type of non-living microorganism?

Bacteriophage Signup and view all the answers

What is the term for the process by which an organism's genetic information is expressed as a trait?

Gene expression Signup and view all the answers

What is the purpose of a biofilm in microbiology?

To protect microorganisms from antimicrobial agents Signup and view all the answers

What is the primary goal of traditional recombinant DNA technology?

To introduce genetic material into a host organism Signup and view all the answers

What is the role of Taq polymerase in PCR?

To amplify DNA sequences Signup and view all the answers

What is the function of the guide RNA in CRISPR technology?

To recognize and bind to specific DNA sequences Signup and view all the answers

What is the primary difference between enveloped and non-enveloped viruses?

The presence of a lipid bilayer membrane Signup and view all the answers

What is the goal of phage therapy?

To treat bacterial infections Signup and view all the answers

What is the role of reverse transcriptase in HIV infection?

To convert viral RNA into DNA Signup and view all the answers

What type of immunity is acquired through vaccination or infection?

Natural immunity Signup and view all the answers

What is the primary function of helper T cells in the immune response?

To activate B cells and produce antibodies Signup and view all the answers

What is the role of MHC-1 proteins in the immune response?

To present antigens to T cells Signup and view all the answers

What type of vaccine uses a piece of genetic material to stimulate an immune response?

mRNA vaccine Signup and view all the answers

What is the difference between narrow-spectrum and broad-spectrum antibiotics?

Narrow-spectrum antibiotics target a specific type of bacteria, while broad-spectrum antibiotics target a wide range of bacteria Signup and view all the answers

Who is credited with the discovery of penicillin?

Alexander Fleming Signup and view all the answers

What is the primary difference between infection and disease?

Infection refers to the presence of a pathogen, while disease refers to the symptoms Signup and view all the answers

What is the term for the beneficial relationship between normal flora and their host?

Mutualism Signup and view all the answers

Which of the following is an example of a primary portal of entry?

All of the above Signup and view all the answers

What is the term for the ability of a pathogen to resist elimination by the host's immune system?

Evasion Signup and view all the answers

What is the purpose of Koch's postulates?

To determine the causality of a disease Signup and view all the answers

What is the term for an infection that is not severe enough to cause symptoms?

Subclinical Signup and view all the answers

Study Notes

Microbiology Study Notes

Protozoa and Helminths

Giardia: causes giardiasis, a diarrheal disease
- Moves using flagella
Trichomonas: causes trichomoniasis, a sexually transmitted infection
- Moves using flagella
Entamoeba: causes amoebiasis, an intestinal infection
- Moves using pseudopodia
Plasmodium: causes malaria, a blood-borne disease
- Moves using sporozoites
Flagyl: an antiprotozoal medication that works by inhibiting DNA replication

Fungi

Characteristics of fungi:
- Eukaryotic
- Heterotrophic
- Decomposers
Types of fungi:
- Yeast: single-celled, spherical
- Mold: multicellular, filamentous
Dimorphic fungi: can exist in two forms, such as yeast and hyphae
- Example: Histoplasma capsulatum
Mycosis: a fungal infection
Antifungal medications:
- Work by inhibiting fungal cell wall synthesis
- Work by inhibiting fungal DNA replication

Helminths

Types of helminths:
- Cestodes: tapeworms
- Trematodes: flukes
- Nematodes: roundworms
Examples of helminths:
- Taenia: tapeworm
- Clonorchis: liver fluke
- Dirofilaria: heartworm
- Enterobius: pinworm
Vermox: an antihelminthic medication that works by inhibiting worm muscle contraction
Helminthic therapy: using helminths to treat diseases, such as inflammatory bowel disease

DNA and Genes

Structure of DNA:
- Double helix
- Composed of nucleotides
Gene:
- Segment of DNA that codes for a protein
- Expression: process of creating a protein from a gene
Genotype:
- Genetic makeup of an individual
Phenotype:
- Physical characteristics of an individual
Who determined the structure of DNA:
- James Watson and Francis Crick
Nucleotides:
- Building blocks of DNA and RNA
- Composed of sugar, phosphate, and nitrogenous base
Complementary base-pairing:
- Adenine pairs with thymine
- Guanine pairs with cytosine
Anti-parallel:
- Strands of DNA run in opposite directions
Chromosome:
- Single molecule of DNA and associated proteins
DNA replication:
- Process of creating a new DNA molecule
- Involves helicase, polymerase, and ligase
Gyrase:
- Enzyme that relieves DNA tension during replication
Helicase:
- Enzyme that unwinds DNA during replication
Polymerase:
- Enzyme that synthesizes new DNA strand
Ligase:
- Enzyme that seals gaps in new DNA strand

Gene Expression and Translation

Gene expression:
- Process of creating a protein from a gene
Transcription:
- Process of creating mRNA from DNA
- Involves RNA polymerase
Translation:
- Process of creating a protein from mRNA
- Involves ribosomes, tRNA, and mRNA
Codon:
- Sequence of three nucleotides that codes for an amino acid
Anticodon:
- Sequence of three nucleotides that complements a codon
Start codon:
- AUG, codes for methionine
Stop codons:
- UAG, UAA, and UGA, terminate protein synthesis
Ribosomes:
- Site of protein synthesis
mRNA:
- Template for protein synthesis
tRNA:
- Brings amino acids to ribosomes during protein synthesis

Genetic Engineering and PCR

Goal of traditional recombinant DNA technology:
- To introduce a gene into an organism
Steps of traditional recombinant DNA technology:
- Isolate DNA
- Cut DNA using restriction enzymes
- Insert gene into plasmid
- Introduce plasmid into host cell
- Select for transformed cells
Goal of PCR:
- To amplify a specific DNA sequence
Steps of PCR:
- Denature DNA
- Anneal primers
- Extend primers using Taq polymerase
- Repeat steps
CRISPR:
- A gene editing tool that uses a Cas-9 enzyme and guide RNA
- Discovered by Jennifer Doudna and Emmanuelle Charpentier

Viruses

Size range of viruses:
- 20-400 nanometers
Types of viruses:
- Helical: rod-shaped
- Polyhedral: many-sided
- Complex: combination of helical and polyhedral
Bacteriophage:
- A virus that infects bacteria
- Discovered by Felix d'Herelle
Plaques:
- Clear areas on a bacterial lawn where viruses have infected and killed bacteria
Phage therapy:
- Using bacteriophages to treat bacterial infections
Steps in the lytic cycle:
- Attachment
- Penetration
- Uncoating
- Replication
- Assembly
- Lysis
Steps in the lysogenic cycle:
- Attachment
- Penetration
- Uncoating
- Integration
- Replication
- Induction
- Lysogenic conversion
How viruses enter human/animal cells:
- Attach to receptors on host cells
- Enter host cells through endocytosis or membrane fusion
Acute infections:
- Cause symptoms that resolve quickly
Latent infections:
- Remain dormant in host cells for a long time
Persistent infections:
- Cause chronic symptoms

Immunology

Types of immunity:
- Natural
- Artificial
Helper T cells:
- Activate B cells and other immune cells
- Recognize antigens presented by MHC-II
Cytotoxic T cells:
- Kill infected cells
- Recognize antigens presented by MHC-I
Antigen-presenting cells (APCs):
- Dendritic cells
- Macrophages
- B cells
Interleukins:
- Cytokines that activate immune cells
Natural killer cells:
- Kill infected cells and tumor cells
- Don't require antigen presentation
Monoclonal antibodies:
- Laboratory-produced antibodies that target specific antigens
- Used for diagnosis and treatment of diseases

Vaccines and Antimicrobial Medications

Types of vaccines:
- Live, attenuated
- Inactivated
- Subunit
- Conjugate
mRNA COVID vaccines:
- Use mRNA to instruct cells to produce a protein
Penicillin:
- Discovered by Alexander Fleming
- Inhibits bacterial cell wall synthesis
Narrow-spectrum antibiotics:
- Effective against a specific type of bacteria
Broad-spectrum antibiotics:
- Effective against a wide range of bacteria
How antimicrobial medications function:
- Inhibit cell wall synthesis
- Inhibit DNA replication
- Inhibit protein synthesis
- Disrupt cell membranes

Microbiology and Disease

Pathology:
- Study of the causes and effects of diseases
Etiology:
- Study of the causes of diseases
Pathogenesis:
- Study of the development of diseases
Infection:
- Presence of pathogens in the body
Disease:
- Pathological state that results from an infection
Normal flora:
- Microorganisms that live on and inside the body
- Provide benefits such as fermentation and immune system development
Microbial antagonism:
- Competition between microorganisms for resources
Opportunism:
- Ability of microorganisms to cause disease in compromised hosts
Koch's postulates:
- Criteria for determining the cause of a disease
Communicable:
- Able to be transmitted from one person to another
Contagious:
- Able to be transmitted through direct contact
Noncommunicable:
- Not able to be transmitted from one person to another
Incidence:
- Number of new cases of a disease in a population over time
Prevalence:
- Total number of cases of a disease in a population at a given time
Sporadic:
- Occurs occasionally and randomly
Endemic:
- Continuously present in a population
Epidemic:
- Widespread outbreak of a disease
Pandemic:
- Global outbreak of a disease

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Description

Test your knowledge of microorganisms, including types, history of discovery, Germ Theory of Disease, and roles in environment, food production, medicine, and biotechnology. Learn about prokaryotes, eukaryotes, and non-living microorganisms. Identify the characteristics and diseases associated with each.