Micro M1 final flashcards

What are the six major groups of microbes?

Bacteria, archaea, fungi, protozoa, algae, and viruses

How do prokaryotic and eukaryotic microbes differ?

Prokaryotes lack a nucleus and membrane-bound organelles, while eukaryotes possess both

How do bacteria and archaea differ?

Both are unicellular prokaryotes, but bacterial cell walls typically contain peptidoglycan while archaeal cell walls do not

What are the main characteristics of fungi?

Eukaryotic heterotrophs with cell walls, including unicellular yeasts and filamentous molds

How do yeasts and molds differ?

Yeasts are usually unicellular and reproduce by budding, while molds grow as multicellular filaments and produce spores

What are protozoa and how do they move?

Mostly unicellular animal-like eukaryotes that may move using pseudopodia, cilia, or flagella

What are algae?

Photosynthetic eukaryotes that contribute to oxygen production and aquatic food webs

What are viruses and how do they reproduce?

Acellular infectious agents containing DNA or RNA in a protein capsid that require host cells to replicate

What are helminths and why are they studied in microbiology?

Multicellular parasitic worms studied because they cause infections, although they are not microbes themselves

What beneficial roles do microorganisms play?

Oxygen production, decomposition, nutrient cycling, fermentation, biotechnology, and normal microbiota functions

What is a pathogen?

An agent capable of causing disease

What did Antonie van Leeuwenhoek contribute to microbiology?

He used simple microscopes to observe and describe living microorganisms, including protozoa and bacteria

Why could Leeuwenhoek observe protozoa but not viruses?

Protozoa are much larger, while viruses are generally too small for his light microscopes

What did Carolus Linnaeus contribute to biology?

He developed a system for classifying organisms according to shared characteristics

What is spontaneous generation and what is biogenesis?

Spontaneous generation proposes life arises from nonliving matter, while biogenesis states living organisms arise from existing life

How did Francesco Redi challenge spontaneous generation?

He showed that maggots appeared on meat only when flies could access it

How did Pasteur's swan-neck flask experiment disprove spontaneous generation?

Sterilized broth stayed free of microbial growth when airborne dust was trapped, but growth occurred after contamination

What are the four major questions of the Golden Age of Microbiology?

Does spontaneous generation occur, what causes fermentation, what causes disease, and how can infections be prevented

What did Pasteur demonstrate about fermentation?

Microorganisms such as yeasts cause fermentation and chemical changes in organic substances

What is pasteurization?

Controlled heating that reduces harmful microorganisms and spoilage organisms in foods and beverages

What is germ theory of disease?

The principle that particular microorganisms can cause particular infectious diseases

What were Robert Koch's major contributions?

He linked specific microbes to diseases, developed pure-culture methods, and formulated Koch's postulates

What are Koch's four postulates?

Find the suspected pathogen in diseased hosts, isolate and culture it, reproduce disease in a susceptible host, and reisolate the same pathogen

Why do Koch's postulates have limitations?

Some pathogens cannot grow in pure culture, some require living host cells, and some infections occur without symptoms

What did Hans Christian Gram develop?

The Gram stain, which distinguishes bacteria based on differences in cell wall structure

What did Ignaz Semmelweis demonstrate?

Handwashing by healthcare workers can greatly reduce transmission of infectious disease

What did Joseph Lister contribute to infection prevention?

He introduced antiseptic practices in surgery to reduce microbial contamination

What did Edward Jenner contribute to disease prevention?

He pioneered vaccination against smallpox using cowpox exposure

What did Paul Ehrlich mean by a magic bullet?

A chemical treatment that selectively targets a pathogen, exemplified by Salvarsan for syphilis

What are four major questions driving modern microbiology?

How genes work, how we defend against disease, what roles microbes play in the environment, and what chemical reactions sustain life

What are the three subatomic particles and their charges?

Protons are positive, neutrons are neutral, and electrons are negative

What are atomic number, mass number, and isotopes?

Atomic number counts protons, mass number counts protons plus neutrons, and isotopes have different neutron numbers

What are valence electrons and why are they important?

Electrons in the outermost shell that determine how atoms form chemical bonds

What are the four most common elements in living organisms?

Carbon, hydrogen, oxygen, and nitrogen

How do ionic, covalent, and hydrogen bonds differ?

Ionic bonds involve attraction between charged ions, covalent bonds share electrons, and hydrogen bonds are weak attractions between polar groups

How do polar and nonpolar covalent bonds differ?

Polar bonds share electrons unequally, while nonpolar bonds share them approximately equally

Why is water essential for living organisms?

Its polarity and hydrogen bonding make it an excellent solvent, help stabilize temperature, create cohesion, and support chemical reactions

What are acids, bases, and the pH scale?

Acids donate hydrogen ions, bases accept hydrogen ions or release hydroxide ions, and pH measures hydrogen ion concentration

What does a low versus high pH indicate?

Low pH indicates higher hydrogen ion concentration and greater acidity, while high pH indicates lower hydrogen ion concentration and greater basicity

What is a buffer and why is it important?

A substance that resists pH changes by accepting or releasing hydrogen ions, helping enzymes and cells function

What are salts and electrolytes?

Salts are ionic compounds that can dissociate in water into charged ions called electrolytes

How do synthesis, decomposition, and exchange reactions differ?

Synthesis combines substances, decomposition breaks them apart, and exchange transfers components between substances

How do dehydration synthesis and hydrolysis differ?

Dehydration synthesis joins molecules while releasing water, and hydrolysis breaks bonds using water

How do anabolism, catabolism, and metabolism differ?

Anabolism builds molecules, catabolism breaks molecules down, and metabolism includes all chemical reactions in an organism

What are the four major classes of organic molecules?

Carbohydrates, lipids, proteins, and nucleic acids

What are the main carbohydrate types and functions?

Monosaccharides are single sugars, disaccharides contain two sugars, and polysaccharides are long chains used for energy storage or structure

What are the four major lipid types and their functions?

Fats store energy, phospholipids form membranes, waxes provide water resistance, and steroids support membrane function and signaling

How do saturated and unsaturated fatty acids differ?

Saturated fatty acids lack carbon-carbon double bonds, while unsaturated fatty acids have one or more

What are phospholipids and why do they form membranes?

Molecules with hydrophilic phosphate-containing heads and hydrophobic fatty acid tails that organize into bilayers

What are proteins made of and what are their four structural levels?

Amino acids joined by peptide bonds, with primary sequence, secondary local folding, tertiary overall folding, and quaternary multiple subunits

What are nucleic acids made of and how do DNA and RNA differ?

Nucleotide chains containing sugar, phosphate, and bases, with DNA using deoxyribose and thymine while RNA uses ribose and uraci