Microbiology Flashcards

A set of flashcards summarizing key concepts from microbiology lectures.

What are biofilms?

Communities of microbes attached to surfaces in a protective matrix.

Where can normal microbiota be found?

Skin, mouth, GI tract, and urogenital tract.

What did Pasteur’s swan-neck flask experiment prove?

Microbes come from other microbes, not spontaneously.

Name one benefit of microbes in medicine.

They produce insulin and vaccines using biotechnology.

What is spontaneous generation?

The disproven idea that life arises from non-living matter.

What is an ionic bond?

A bond formed by the transfer of electrons.

What is dehydration synthesis?

Building molecules by removing water.

What pH is considered acidic?

Less than 7.

Name the four major biomolecules.

Carbohydrates, lipids, proteins, nucleic acids.

What is ATP used for?

Storing and releasing energy in cells.

What is an atom?

The smallest unit of an element that retains its chemical properties.

What is a molecule?

Two or more atoms bonded together.

What are the three subatomic particles?

Protons, neutrons, and electrons.

What type of bond involves sharing electrons?

Covalent bond.

What is a hydrogen bond?

A weak attraction between a hydrogen atom and another electronegative atom.

Why do catheters increase infection risk?

Biofilms may form on them, resisting treatment.

Why are probiotics useful after antibiotics?

They restore normal microbiota balance.

Why do hospitals prevent biofilms on equipment?

Biofilms make infections hard to treat and remove.

How did Pasteur influence surgery?

His work led to sterile techniques, reducing infections.

Why is handwashing important in healthcare?

It removes harmful transient microbes.

Why must IV fluids be isotonic?

To prevent cells from swelling or shrinking.

Why do high fevers cause problems with enzymes?

They denature proteins by breaking hydrogen bonds.

Why is blood glucose monitoring important?

Excess glucose affects protein function and organ health.

Why do hydrogen bonds matter for living organisms?

They stabilize DNA structure and help proteins maintain their shape.

Why does water’s polarity make it vital for life?

It allows water to dissolve many substances and support biochemical reactions.

How can pH affect bacterial growth?

Some bacteria thrive in acidic or basic environments; pH can inhibit or promote growth.

Why are ionic bonds important in microbiology?

Ionic interactions stabilize enzyme structures and cell membranes.

Why is carbon central to organic molecules?

Carbon can form four covalent bonds, creating complex molecules necessary for life.

What are prokaryotic cells?

Simple cells without a nucleus or membrane-bound organelles.

What are eukaryotic cells?

Complex cells with a nucleus and organelles.

What shape is a coccus?

Spherical.

What shape is a bacillus?

Rod-shaped.

What arrangement is streptococci?

Chains of cocci.

What is the glycocalyx?

A sticky outer coating that helps with adhesion and immune evasion.

What are pili used for?

Attachment and DNA transfer (conjugation).

What is the function of flagella?

Movement or motility.

What makes up a Gram-positive cell wall?

Thick peptidoglycan and teichoic acids.

What is unique about Gram-negative bacteria?

They have an outer membrane with lipopolysaccharides (LPS).

What are endospores?

Dormant structures that help bacteria survive harsh conditions.

What is the plasma membrane made of?

A phospholipid bilayer with proteins.

What are the two major types of prokaryotic cells?

Bacteria and Archaea.

What structure helps bacteria move?

Flagella.

What structure allows bacteria to attach to surfaces?

Fimbriae.

What is a plasmid?

A small, circular piece of DNA in bacteria that can replicate independently.

What is peptidoglycan?

A substance in bacterial cell walls providing structural support.

Why are Gram-negative infections harder to treat?

The outer membrane blocks many antibiotics and contains endotoxins.

Why is knowing bacterial shape helpful in diagnosis?

Shape and arrangement help identify specific pathogens quickly.

How can bacteria move through tissues during infection?

Spirochetes use axial filaments to corkscrew through body tissues.

Why are endospores medically significant?

They make bacteria like Clostridium difficile extremely resistant to disinfection and heat.

How do pili contribute to the spread of resistance genes?

They allow bacteria to transfer plasmids carrying antibiotic resistance.

What role does the capsule play in infection?

It protects bacteria from being phagocytosed by immune cells.

Why can plasmids make bacteria harder to treat with antibiotics?

Plasmids can carry genes for antibiotic resistance.

Why are bacterial capsules important for infection?

Capsules help bacteria evade the immune system.

Why is knowing if a bacterium is Gram-positive or Gram-negative important in medicine?

It influences which antibiotics are effective.

Why might a bacterium with flagella be more dangerous in infections?

Flagella allow bacteria to move and spread through tissues.

Why do biofilms make infections harder to treat?

Biofilms protect bacteria from antibiotics and immune cells.

What is catabolism?

The breakdown of molecules to release energy.

What is anabolism?

The building of complex molecules using energy.

What is ATP?

The main energy currency of the cell.

What factors affect enzyme activity?

Temperature, pH, substrate concentration.

What is denaturation?

Loss of enzyme structure and function due to heat or pH changes.

What are oxidation-reduction reactions?

Transfer of electrons; oxidation loses electrons, reduction gains them.

What are the 3 stages of cellular respiration?

Glycolysis, Krebs cycle, and electron transport chain (ETC).

What is fermentation?

An anaerobic way to make ATP with end products like lactic acid or ethanol.

How many ATP are made from one glucose via aerobic respiration?

About 38 in prokaryotes.

What is metabolism?

All chemical reactions inside a cell.

What is a substrate?

A molecule that an enzyme acts on.

What happens in glycolysis?

Glucose is broken down into pyruvate, producing ATP and NADH.

What is aerobic respiration?

Energy production that uses oxygen as the final electron acceptor.

What is anaerobic respiration?

Energy production using a molecule other than oxygen as the final electron acceptor.

What is osmotic pressure?

Pressure caused by differences in solute concentration across a membrane.

What are obligate aerobes?

Bacteria that require oxygen to grow.

What are obligate anaerobes?

Bacteria that die in the presence of oxygen.

What are facultative anaerobes?

Bacteria that can grow with or without oxygen.

What happens during the lag phase?

Bacteria adjust to the environment but don’t divide yet.

What is the log phase?

Rapid, exponential cell division occurs.

What is the stationary phase?

Growth rate equals death rate; nutrients run low.

What is the death phase?

Cells die faster than they grow due to nutrient depletion and waste buildup.

What is a biofilm?

A community of microbes living together in a sticky, protective matrix.

What is turbidity?

Cloudiness of a culture; indicates cell density.

What are serial dilutions used for?

To estimate the number of bacteria in a sample.

What is binary fission?

The process by which most bacteria reproduce by dividing into two identical cells.

What is a generation time?

The time it takes for a cell population to double.

What is an operon?

A cluster of genes under coordinated control.

What is the lac operon?

An inducible operon activated when lactose is present.

What is the trp operon?

A repressible operon turned off when tryptophan is abundant.

What is a point mutation?

A change in one DNA base.

What is a frameshift mutation?

Insertion or deletion of bases that shifts the reading frame.

What are the 3 types of horizontal gene transfer?

Transformation, conjugation, and transduction.

What is genetics?

The study of heredity — how traits are passed from one generation to the next.

What is a chromosome?

A structure containing DNA that carries genetic information.

What is plasmid DNA?

Extra circular DNA found in some bacteria that can carry useful traits like antibiotic resistance.

What is transcription?

The process where DNA is used to make RNA.

What is translation?

The process where RNA is used to make a protein.

What is a mutation?

A permanent change in the DNA sequence.

What is recombination?

The exchange of genetic material between two different DNA molecules.

What is conjugation?

Transfer of DNA between bacteria through direct contact.

What is transformation?

Uptake of naked DNA fragments from the environment by a bacterium.

What is transduction?

DNA transfer between bacteria using a virus (bacteriophage).

Why is bacterial conjugation important in antibiotic resistance?

It allows bacteria to directly transfer resistance genes to other bacteria.