Microbiology Concepts for Exam 3

Flashcards for Microbiology Exam 3 covering various topics including pathogen identification, genetic concepts, and more.

Why is proper specimen collection important?

Incorrect collection or contamination can lead to false results and misdiagnosis.

What are key steps in identifying pathogens?

Collect from correct site, use aseptic technique, transport properly, and use lab methods.

What is specimen collection?

Obtaining samples (blood, urine, CSF) to detect infectious organisms.

What are general rules for specimen collection?

Aseptic technique, correct site, avoid contamination, quick transport, proper conditions.

Why can’t anaerobes be exposed to oxygen?

Oxygen can kill them or alter results.

Why shouldn’t CSF be refrigerated?

It can damage organisms and affect results.

What are microscopic methods for identification?

Gram stain, shape, arrangement of bacteria.

What are macroscopic methods for identification?

Colony size, color, shape on culture.

What are biochemical methods for identification?

Test metabolism and enzyme activity.

What are immunologic methods?

Detect antibodies/antigens (serology).

What is serology?

Study of antibodies in blood.

What are characteristics of Staphylococcus aureus?

Gram-positive cocci in clusters, skin flora, facultative anaerobe.

What is the key virulence factor of S. aureus?

Coagulase, which clots blood to protect bacteria.

What is the function of hyaluronidase?

Helps bacteria spread through tissues.

What is the function of hemolysins?

Destroy red blood cells.

What is the function of leukocidin?

Kills white blood cells.

What is the effect of enterotoxins?

Cause vomiting and diarrhea.

What effect does toxic shock toxin have?

Causes fever, rash, organ damage.

What is the pathogenesis of S. aureus?

Enters skin, spreads via enzymes, releases toxins.

What are prevention methods for S. aureus infections?

Hygiene, wound care, infection control.

What is MRSA?

Antibiotic-resistant Staphylococcus aureus.

Why is MRSA hard to treat?

It inactivates many antibiotics.

How is MRSA treated?

With alternative antibiotics.

What does Streptococcus pyogenes cause?

Impetigo and necrotizing fasciitis.

What is impetigo?

Contagious skin infection linked to poor hygiene.

What is necrotizing fasciitis?

Rapidly spreading, tissue-destroying infection.

What does Streptococcus pneumoniae cause?

Pneumonia and otitis media.

What are characteristics of Bacillus anthracis?

Soil bacteria, forms spores, causes anthrax.

What does Clostridium perfringens cause?

Gas gangrene (myonecrosis).

What is the treatment for C. perfringens?

Hyperbaric oxygen.

What does Clostridium tetani cause?

Tetanus, leading to muscle spasms.

What toxin does Clostridium tetani produce?

Tetanospasmin, which causes contractions.

How can tetanus be prevented?

Vaccination.

What does Clostridioides difficile cause?

Antibiotic-associated diarrhea.

What symptoms does Clostridium botulinum cause?

Blurred vision, swallowing difficulty, paralysis.

What are risks associated with Listeria monocytogenes?

Severe in immunocompromised individuals.

How can listeria be prevented?

Proper cooking and pasteurization.

How is Mycobacterium tuberculosis transmitted?

Respiratory droplets.

What is the treatment for TB?

Long-term multiple antibiotics.

What is the difference between latent and active TB?

Latent = inactive; Active = symptomatic and contagious.

What is DNA made of?

Nucleotides (phosphate, sugar, base).

What are the DNA bases?

A, T, C, G.

What is the shape of DNA?

Double helix.

What is a genome?

Total DNA in a cell.

What is a chromosome?

Packaged DNA.

What is the central dogma of molecular biology?

DNA → RNA → Protein.

Why are proteins important?

They perform cell functions.

What is the purpose of DNA replication?

To copy DNA.

What are the steps of DNA replication?

Unwind → add nucleotides → form 2 strands.

What is the role of DNA polymerase III?

Adds nucleotides and proofreads.

What is transcription?

Process of converting DNA into RNA.

Which enzyme is used in transcription?

RNA polymerase.

What are the steps of transcription?

Initiation, elongation, termination.

What is translation?

Process of converting RNA into protein.

What are the steps of translation?

Initiation, elongation, termination, folding.

What is a dominant trait?

Expressed with one allele.

What is a recessive trait?

Needs two alleles for expression.

What does autosomal refer to?

Non-sex chromosomes.

What does X-linked refer to?

Genes located on the X chromosome.

What is homozygous?

Having two identical alleles.

What is heterozygous?

Having two different alleles.

What does a square represent in a pedigree?

Male.

What does a circle represent in a pedigree?

Female.

What does a filled symbol indicate in a pedigree?

Affected individual.

What does a dot indicate in a pedigree?

Carrier.

What do Roman numerals represent in a pedigree?

Generations.

What do numbers represent in a pedigree?

Individuals.

What is a genetic disorder?

Disease caused by DNA mutation.

What is cystic fibrosis?

Condition characterized by thick mucus and lung issues.

What is Huntington’s disease?

Dominant disorder causing involuntary movements.

What is hemophilia?

A blood clotting disorder.

What is Down syndrome?

Condition resulting from an extra chromosome 21.

What is a mutation?

A change in DNA.

What is a point mutation?

One base change in DNA.

What is a silent mutation?

Mutation with no amino acid change.

What is a missense mutation?

A mutation that results in a different amino acid.

What is a nonsense mutation?

Mutation that creates a stop codon.

What is a frameshift mutation?

Mutation that shifts the reading frame of the gene.

What causes cancer?

Accumulated mutations in DNA.

What are proto-oncogenes?

Normal genes that promote cell growth.

What are oncogenes?

Mutated genes that lead to uncontrolled growth.

What are tumor suppressor genes?

Genes that slow down cell division.

What are biomarkers?

Indicators of cancer.

What is genomic medicine?

Using DNA for diagnosis and treatment.

What is a polygenic risk score?

A score that estimates disease risk based on multiple genes.

What is prenatal testing?

Testing to detect abnormalities in a fetus.

What is gene therapy?

Treatment that replaces defective genes.

What are some successful examples of gene therapy?

Treatments for sickle cell disease and hemophilia B.

What is pharmacogenetics?

The study of how DNA affects drug response.

Why do drugs affect people differently?

Due to genetic differences in metabolism and receptors.