Germ Theory

What are the primary components of a virus?

Proteins, nucleic acids, and sometimes lipids.

Why are viruses considered nonliving?

They are not made of cells and can only replicate inside the cells of living organisms.

What is the general structure of a virus?

A nucleic acid (DNA or RNA) core surrounded by a protein coat.

What happens during a lytic infection?

A virus enters a host cell, copies itself, and causes the cell to burst or lyse.

How does a lysogenic infection differ from a lytic infection?

The viral genetic material is inserted into the host's DNA and remains inactive without immediately damaging the host.

What was the 'Spontaneous Generation' theory?

The incorrect belief that life was randomly generated from non-living things.

What was the 'Miasma Theory' of disease?

The incorrect belief that disease was caused by 'bad air'.

What is the core principle of Germ Theory?

Disease is caused by the invasion of the body by microorganisms called pathogens.

What is a vector in the context of disease transmission?

An animal or insect capable of transmitting a disease to humans or other animals.

Who were the two primary developers of Germ Theory?

Louis Pasteur and Robert Koch.

What is the first of Koch's Postulates?

The pathogen must be present in all diseased cases but absent in healthy ones.

What is the second of Koch's Postulates?

The pathogen must be isolated and grown in a pure culture.

What is the third of Koch's Postulates?

The pathogen must cause disease when introduced to healthy subjects.

What is the fourth of Koch's Postulates?

The pathogen must be re-isolated from the newly infected host.

What is the purpose of pasteurization?

To kill microbes like bacteria in a liquid by heating it.

How did Louis Pasteur's S-shaped flask experiment disprove spontaneous generation?

It showed that bacteria only grew when the flask was open to the air, proving they did not spontaneously generate inside the liquid.

How do viruses produce disease in the body?

By disrupting the body's normal homeostasis.

What are vaccines composed of?

Weakened or inactive viral particles.

How do vaccines protect the body?

They stimulate the immune system to recognize and destroy specific viruses.

Besides vaccination, what is a key method for minimizing viral transmission?

Personal hygiene.

What are the three domains of life?

Bacteria, Archaea, and Eukarya

What is the primary difference between Eukarya and the other two domains?

Eukarya are eukaryotic and have a nucleus and membrane-bound organelles

Where are organisms in the domain Archaea typically found?

In extreme environments, such as hot springs or salt lakes

What are the three main roles of bacteria in nutrient cycling?

Decomposers, producers, and nitrogen fixers

What is the function of nitrogen-fixing bacteria?

They convert atmospheric nitrogen into a form usable by other organisms

What is the primary structural difference between Archaebacteria and Eubacteria?

They have different cell wall compositions and genetic structures

What substance is found in the cell walls of bacteria?

Peptidoglycan

What structures do bacteria use for movement?

Flagella or pili

What is the fastest form of bacterial asexual reproduction?

Binary fission

What is the process of bacterial conjugation?

A form of sexual reproduction where two cells exchange DNA to create genetic diversity

How do pathogens typically disrupt homeostasis?

By destroying cells or releasing harmful chemicals

What are the three basic shapes of prokaryotes?

Bacilli, cocci, and spirilla

What does the prefix 'staphylo-' indicate in bacterial arrangement?

Grape-like clusters

What does the prefix 'strepto-' indicate in bacterial arrangement?

Long chains

What does the prefix 'diplo-' indicate in bacterial arrangement?

Pairs

What is the role of Lactobacillus in the human body?

It helps digest food and supports immunity in the intestines

How are bacteria used in the food industry?

They are used to ferment foods like yogurt, cheese, and sauerkraut for flavor and preservation

What is an antibiotic-resistant 'superbug'?

A bacterium that is resistant to multiple antibiotics

What is MRSA?

Methicillin-resistant Staphylococcus aureus

What is a major human behavior that contributes to antibiotic resistance?

Overuse of antibiotics or failing to finish a full prescription

How does budding differ from binary fission in bacteria?

Budding is slower and involves one parent cell producing one daughter cell

What is the estimated death toll of the 1918-1919 influenza pandemic?

Between 20 and 40 million people.

What is the difference between a pandemic and an epidemic?

A pandemic occurs over a large geographic area, while an epidemic is contained to one region.

What is the function of macrophages in the immune response?

They digest viruses and infected cells.

What is the role of B cells in the immune system?

They produce antibodies that tag viruses or infected cells for destruction.

Why are antibiotics ineffective against viral infections?

Antibiotics only target bacteria, not viruses.

What is a virus?

A tiny infectious agent that is smaller than a cell and requires a host cell to reproduce.

What are the two types of genetic material found in viruses?

DNA or RNA, but never both.

What is the function of the viral capsid?

It is a protein shell that surrounds and protects the genetic material.

What are the five stages of viral infection in a host cell?

Attachment, penetration, biosynthesis, assembly, and release.

What are bacteriophages?

Viruses that specifically infect bacteria.

What is the primary outcome for the host cell in the lytic cycle?

The host cell bursts open and dies.

How does the lysogenic cycle differ from the lytic cycle?

In the lysogenic cycle, viral DNA is incorporated into the host chromosome and remains dormant until triggered.

What is the primary transmission method for the influenza virus?

Respiratory droplets.

How is the West Nile Virus transmitted?

Through mosquito bites.

What is the primary transmission method for Ebola?

Direct contact with blood or body fluids.

How do traditional vaccines work?

They introduce a weakened or killed form of the virus to stimulate the immune system to create antibodies.

How do mRNA vaccines function?

They trick cells into producing a piece of the virus so the immune system learns to recognize it.

What is the purpose of antiviral medications?

To slow or stop viral replication inside cells by blocking enzymes or preventing viral entry/exit.

What are spike proteins on a virus used for?

They help the virus attach to host cells.

What happens to memory B cells after an infection?

They remember the pathogen and produce antibodies quickly if it is encountered again.

What is the viral envelope?

An outer membrane found on some viruses, derived from the host cell.

Can the herpes virus be cured?

No, it remains in the body and can reactivate as cold sores.

What is the size range of viruses?

20 to 300 nanometers.

Can bacteria grow independently?

Yes, by increasing in size and dividing into more cells.

Do viruses have an organized cellular structure?

No, they consist only of genetic material inside a protein coat (capsid).

How do bacteria reproduce?

Primarily through binary fission, though they can also use budding and conjugation.

How do viruses reproduce?

They must enter a host cell and use the host's machinery to replicate.

Do bacteria and viruses have the ability to evolve?

Yes, both can mutate and adapt to new environments over time.

Do viruses possess a metabolism?

No, they do not use energy on their own.

Are viruses considered living organisms?

No, they do not meet enough characteristics of life.

What is the typical size range of bacteria?

0.5 to 5.0 micrometers in diameter.

What is the typical size range of viruses?

0.02 to 0.3 micrometers.

What is the primary medical treatment for bacterial infections?

Antibiotics.

How do antiviral medications work?

They slow down the process of viral reproduction.

What is the function of vaccines?

To prepare the immune system to fight off specific pathogens.

How is genetic material organized in bacteria?

As DNA located in a nucleoid region, not surrounded by a membrane.

What types of genetic material can viruses contain?

Either DNA or RNA, but never both at the same time.

What are the essential internal components of bacteria?

Cell membrane, ribosomes, cytoplasm, and DNA.

How does the host range of bacteria compare to viruses?

Bacteria can infect almost all living things, while viruses are highly specific to certain cell types or organisms.

Name three examples of bacterial infections.

Strep throat, urinary tract infections, and food poisoning.

Name three examples of viral infections.

Common cold, flu, and chickenpox.

How do bacteria contribute to human health?

They aid in digestion and the production of vitamins in the gut.

What is one beneficial use of bacteria in food production?

They are used to make yogurt, cheese, and fermented foods.

How can viruses be used in medical research?

They are used in gene therapy and to potentially treat antibiotic-resistant infections.

What is the principle of biogenesis?

The theory that life comes only from pre-existing life.

What was the Miasma Theory of disease?

The incorrect belief that disease was caused by inhaling bad air or foul-smelling vapors.

What are Koch's Postulates used for?

To identify the specific pathogen causing an infectious disease.

How did Louis Pasteur disprove spontaneous generation?

By using an S-shaped flask to show that microbes only grew in liquid when exposed to air-borne particles.

What was Edward Jenner's contribution to medicine?

He created the first vaccine by using cowpox to provide immunity against smallpox.

What is a vector in the context of disease?

An infected animal that carries disease-causing organisms from person to person.

Why are antibiotics ineffective against viruses?

Because viruses are nonliving and do not possess the cellular structures that antibiotics target.

What is the primary function of a vaccination?

To alert the immune system and prepare it to fight specific infections by building antibodies.

What is the structural composition of a virus?

A core of DNA or RNA surrounded by a protein coat called a capsid.

What is a bacteriophage?

A virus that specifically attacks and infects bacteria.

What happens to the host cell during the Lytic Cycle?

The virus injects DNA, destroys host DNA, replicates, and causes the cell to burst.

How does the Lysogenic Cycle differ from the Lytic Cycle?

Viral DNA merges with host DNA and replicates along with the host cell without immediately destroying it.

What is a retrovirus?

A virus like HIV that injects RNA to reverse engineer its own DNA and merge it with the host genome.

Where is DNA located in a bacterial cell?

In a region called the nucleoid.

What are the three main shapes used to classify bacteria?

Coccus (spherical), Bacillus (rod-shaped), and Spirochetes (spiral).