Microbiology Lecture Notes Review

Vocabulary flashcards related to viruses, symbiosis, infectious diseases, epidemiology, innate and adaptive defenses.

Virus classification

Type of nucleic acid (DNA or RNA), shape of capsid, presence/absence of envelope, host range.

Obligate intracellular parasites

Viruses cannot reproduce or carry out metabolism on their own; they must use a host cell's machinery to replicate.

Viral genome

The virus's DNA or RNA, instructions for making copies.

Capsomere

Individual protein units that make up the capsid.

Capsid

Protective protein shell around the genome.

Envelope

Lipid layer stolen from the host cell membrane.

Spikes

Help the virus attach to and enter host cells.

Virion

A complete virus particle.

Viral Shapes

Helical, polyhedral/icosahedral, complex.

RNA Viruses

• Sense RNA acts like mRNA. – Sense RNA must be converted. Retroviruses use RNA to DNA via reverse transcriptase.

DNA Viruses

Replicates in host nucleus and is often more stable than RNA viruses.

Lytic Cycle

Fast. Virus replicates and bursts cell. Immediate symptoms.

Lysogenic Cycle

Slow. Virus DNA integrates into host DNA. No symptoms until triggered.

Attachment

Virus sticks to a specific receptor on the host cell.

Entry

Virus injects its genetic material into the host.

Biosynthesis

The host cell’s machinery is hijacked to make viral parts.

Maturation

Viral parts are assembled into new viruses.

Release

The host cell bursts, releasing hundreds of new viruses.

Prophage

Viral DNA inserted in bacteria.

Prions

Infectious proteins (no nucleic acid) affect humans and animals, causing brain protein to unfold.

Viroids

Plant pathogens, RNA only, no protein.

Symbiosis

A close association between two or more organisms, at least one benefits.

Mutualism

Both organisms benefit.

Commensalism

One benefits, the other is unaffected.

Parasitism

One benefits (parasite), the other is harmed (host).

Normal Microbiota (Flora)

Microbes that colonize the body without normally causing disease.

Resident Microbiota

Part of your normal microbiota for life in stable populations.

Transient Microbiota

Remain in the body for a short period.

Reservoir

A site where pathogens are maintained as a source of infection.

Zoonoses

Diseases spread from animals to humans.

Human Carriers

Infected people who may or may not show symptoms but can still transmit pathogens.

Skin

Outer layer is a barrier; pathogens can enter through cuts, hair follicles, or burrowing organisms.

Mucous membranes

Line body cavities open to the outside (respiratory, GI, urinary, reproductive).

Placenta

Normally blocks pathogens, but some can cross and infect fetus.

Parenteral Route

Not a natural portal, but refers to pathogens entering through breaks in the skin.

Contamination

Refers to the presence of microbes (including pathogens) in or on the body.

Infection

Occurs when microbes evade the body’s external defenses, multiply, and establish in the body.

Infection

Occurs when microorganisms invade the host, multiply, and establish themselves.

Disease

Occurs when an infection results in damage to the host’s body or disrupts normal function.

Morbidity

Refers to the state of being diseased.

Pathogenicity

The ability of a microorganism to cause disease.

Virulence

The degree of pathogenicity. Describes how severe or harmful the disease caused by a microbe is.

Symptoms

Subjective characteristics of disease felt only by the patient.

Signs

Objective characteristics of disease that can be observed or measured by others.

Syndrome

A group of signs and symptoms that occur together and characterize a particular disease or abnormal condition.

Antiphagocytic Factors

Prevent the immune system from destroying the microbe.

Antiphagocytic Chemicals

Secreted to disable or kill white blood cells.

Hyaluronidase

Breaks down hyaluronic acid, helping bacteria invade deeper tissues.

Coagulase

Triggers blood clotting, allowing bacteria to hide inside the clot.

Streptokinase

Breaks down blood clots, allowing bacteria to escape and spread.

Hemolysins

Lyse red blood cells to release iron.

Exotoxins

Proteins secreted by live bacteria, very specific in their effects.

Endotoxins

Part of the outer membrane of Gram-negative bacteria, released when the cell dies.

Neurotoxins

Target the nervous system, interfering with nerve signal transmission.

Enterotoxins

Target the intestinal tract, causing diarrhea, cramping, and vomiting.

Incubation Period

Time between exposure to the pathogen and the first appearance of signs or symptoms.

Prodromal Period

Short period of general, mild symptoms.

Illness (Invasive) Phase

Disease is at its most severe, with obvious and intense signs and symptoms.

Decline

Immune response kicks in, or treatment begins to work, and symptoms lessen.

Convalescence

Recovery period where tissues are repaired and strength returns.

Fomite

An inanimate object that can accidentally transmit pathogens to a new host.

Direct Contact

Person-to-person contact.

Indirect Contact

Spread via fomites.

Droplet Transmission

Pathogens carried in droplets less than 1 meter.

Airborne

Pathogens spread through dust or droplets that travel more than 1 meter.

Waterborne

Contaminated water.

Foodborne

Improperly cooked or stored food.

Biological Vector

Pathogen lives in the vector and reproduces inside it.

Mechanical Vector

Vector transports the pathogen on its body, not infected.

Communicable Disease

A disease that can spread from one host to another.

Contagious Disease

A highly communicable disease, spreads easily.

Noncommunicable Disease

Does not spread from host to host.

Epidemiology

The study of the distribution and spread of diseases in populations.

Morbidity Rate

The number of people who get sick in a population.

Mortality Rate

The number of people who die from a disease in a population.

Endemic

A disease that occurs routinely in a population or region.

Epidemic

A disease occurs at a higher-than-normal frequency in a population or area.

Pandemic

An epidemic that has spread across multiple countries or continents.

Prevalence

The total number of cases of a disease in a population at a given time.

Incidence

The number of new cases that develop in a given time period.

Descriptive Epidemiology

Involves collecting data about the time, place, and people affected.

Analytical Epidemiology

Uses data to find cause, source, or risk factors.

Experimental Epidemiology

Tests hypotheses about disease using controlled experiments.

Nosocomial Infections / HAIs

Infections acquired while receiving treatment in a healthcare setting.

Notifiable Disease

A disease that must be reported by healthcare providers to public health authorities by law.

Innate Nonspecific Defenses

Built-in responses that are present at birth, responding immediately with a general response.

Specific Adaptive Defense

Targets specific pathogens, develops over time, and has memory.

Innate Defenses Components

Physical barriers, chemical substances, cellular components, inflammation, and fever.

Mucus Secretions Protection

Mucus secretions trap microbes and prevent attachment.

Antimicrobial Peptides

Small proteins made by skin, immune cells, and mucosa disrupting microbe membranes.

Plasma

Liquid part of blood, making up 55% of total blood volume.

Cytokines

Coordinate immune responses, respond to viral infections, promote inflammation, and guide WBC movement.

Erythrocytes

Carry oxygen via hemoglobin.

Basophils

Release histamine; involved in allergy and inflammation.

Mast Cells

Release histamine in tissues; important in allergies.

Eosinophils

Target helminths and modulate allergic responses.

Neutrophils

Most abundant WBC; first responder; major phagocytes.

Dendritic Cells

Antigen-presenting cells link innate to adaptive immunity.

Monocytes

Mature into macrophages; professional phagocytes.

Lymphocytes

T cells, B cells, and NK cells, involve specific/adaptive response.