Micro Final Exam

What theory states that life can arise from nonliving matter?

Spontaneous generation

What type of relationship harms the host?

Parasitism

What is bacterial movement toward or away from chemicals called?

Chemotaxis

What is the size of eukaryotic ribosomes?

80S

What are the three types of RNA?

Transfer, ribosomal, and messenger RNA

What is the start codon for protein synthesis?

AUG

What is the formula for pH?

pH = –log[H⁺]

What type of transport moves substances from low to high concentration?

Active transport

What is the main function of fimbriae?

Attachment

What happens during a deletion mutation?

Nucleotides are removed from DNA

What are “jumping genes” called?

Transposons

What are infectious proteins called?

Prions

What are the steps of phagocytosis?

Attach → Ingest → Fuse with lysosome → Digest → Discard waste.

What are the steps of Gram staining?

Crystal violet → Iodine → Alcohol → Safranin.

What are the steps of binary fission?

DNA replicates → Cell elongates → Septum forms → Cells separate.

What is a holoenzyme?

A protein combined with cofactors.

When is the maximum rate of cell division?

Exponential (log) phase

What is pasteurization?

Killing microbes with high heat for a short time.

What does isoniazid inhibit?

Mycolic acid synthesis.

What does ciprofloxacin inhibit?

DNA gyrase (nucleic acid synthesis).

What is ethylene oxide used for?

Gas sterilization

What does “bacteriostatic” mean?

Inhibits bacterial growth but doesn’t kill

What does NAD⁺ do?

Acts as an electron shuttle.

What is sterilization?

The elimination of all microbes, viruses, and endospores.

What is a biofilm?

A community of mixed microbes living together.

What type of bacteria require oxygen?

Obligate aerobes.

What type of bacteria die in oxygen?

Obligate anaerobes.

What is a psychrotroph?

Grows from 0–30°C and can spoil food.

What do halogens do to microbes?

Oxidize cell components.

What does selective media do?

Promotes some bacteria, suppresses others.

What does differential media do?

Distinguishes microbes visually.

What is virulence?

Severity of disease after infection.

What are adhesins?

Virulence factors for sticking to host cells.

What biosafety level is Staphylococcus aureus?

Level 2 (BSL-2).

What happens in glycolysis?

Glucose → Fructose → 2 three-carbon molecules → Pyruvate
→ Produces 2 ATP, 2 NADH.

What is the intermediate step between glycolysis and Krebs?

Pyruvate → Acetyl-CoA.

What happens in the Krebs cycle?

Acetyl-CoA + Oxaloacetate → Citrate → Back to oxaloacetate
→ Produces 2 ATP, 6 NADH, 2 FADH₂.

What are the steps of PCR?

Melting → Extension → Annealing.

What enzyme is used in PCR?

Taq polymerase

Who promoted handwashing to prevent infections?

Ignaz Semmelweis.

Who discovered that specific microbes cause specific diseases?

Robert Koch.

What is a pandemic?

An epidemic that spreads to many countries.

What are dermatophytes?

Fungi that infect skin, hair, and nails.

What causes acquired resistance?

Mutation or resistance genes.

What causes hemolytic disease of the newborn?

Rh⁻ mother with Rh⁺ fetus.

What type of transplant is most compatible?

Autograft.

What is the most abundant antibody class in serum?

IgG.

What kind of molecule is histamine?

Vasoactive molecule.

What is the antibody concentration in serum called?

Titer.

What type of immunity results from injection of an antigen?

Artificially acquired active immunity.

Guillain-Barré syndrome is linked to what infection?

Campylobacter jejuni.

What receptor binds COVID-19?

ACE2.

What do perforins do?

Punch holes in target cells causing lysis.

What bacterium causes whooping cough?

Bordetella pertussis.

What causes the common cold?

Viruses.

What does an indirect ELISA detect?

Antibodies in a patient sample.

What is stridor?

Loud breathing caused by airway blockage.

Where is lysozyme found and what does it do?

Tears and saliva; breaks down bacterial cell walls.

What type of hypersensitivity involves IgG or IgM?

Type II hypersensitivity.

What bacterium causes scarlet fever?

Streptococcus pyogenes.

What is a recombinant vector vaccine?

Genetic material from a pathogen inside a harmless virus or bacterium.

What is the most common type of influenza?

Type A.

What is autoimmunity?

Immune system attacks self tissues.

What illness has a barking cough and stridor?

Croup.

What initiates the lectin complement pathway?

Mannose-binding proteins.

What initiates the classical complement pathway?

Antigen–antibody complexes.

What is antigenic drift?

Random mutations that change viral antigens.

Where do deletion mutations occur?

Deletion mutations occur when one or more nucleotides are removed from a DNA sequence.

What enzyme in sweat breaks down peptidoglycan?

Lysozyme.

What virus causes chickenpox and shingles?

Varicella-Zoster Virus.

What is shingles?

Reactivation of Varicella-Zoster Virus.

What virus causes oral herpes (cold sores)?

HSV-1.

What type of rash includes small raised papules + flat macules?

Maculopapular rash.

Which diseases commonly cause maculopapular rashes?

Measles, rubella, fifth disease, hand-foot-mouth disease.

What is the major pregnancy complication of rubella?

Congenital rubella syndrome (blindness, deafness, heart defects).

What virus causes fifth disease (slapped cheek syndrome)?

Parvovirus B19.

What causes roseola?

Human herpesvirus 6 & 7.

What causes hand, foot, and mouth disease?

Coxsackievirus A26 and Enterovirus 71.

What organism produces exfoliative toxins that cause scalded skin syndrome?

Staphylococcus aureus.

Which bacterium can cause necrotizing fasciitis and toxic shock?

Streptococcus pyogenes.

Which organism produces the blue-green pigment pyocyanin?

Pseudomonas aeruginosa.

What fungi cause ringworm (tinea)?

Trichophyton, Microsporum, Epidermophyton.

What organism causes yeast infections?

Candida albicans.

What is the leading cause of preventable microbial blindness?

Trachoma (Chlamydia trachomatis).

What is keratitis?

Inflammation of the cornea.

What organisms commonly cause bacterial keratitis?

Pseudomonas aeruginosa and Staphylococcus aureus.

What helminth causes river blindness?

Onchocerca volvulus.

What are the protective membranes around the CNS called?

Meninges.

What is inflammation of the meninges?

Meningitis.

What is inflammation of the brain?

Encephalitis.

What is meningoencephalitis?

Inflammation of both meninges and brain.

What is the function of the blood-brain barrier?

Restricts pathogen entry into CNS.

What bacterium causes meningococcal meningitis?

Neisseria meningitidis.

What bacterium causes pneumococcal meningitis?

Streptococcus pneumoniae.

What bacterium causes listeria meningitis?

Listeria monocytogenes.

What three organisms commonly cause neonatal meningitis?

Group B Strep, E. coli, Listeria.

What causes Hansen’s disease (leprosy)?

Mycobacterium leprae.

Which form of leprosy is contagious?

Lepromatous form.

What toxin causes flaccid paralysis?

Botulinum toxin.

How does botulinum toxin cause paralysis?

Blocks acetylcholine release → muscles cannot contract.