Micro-Biology 1-3 Exam

When did the scientific method start?

The 1600, scientist explained natural phenomena by : belief and superstitions

What is the scientific method?

a lengthy process of experimentation and analysis.

What is the hypothetico- deductive method?

A scientific approach to forming a hypothesis, accepting, testing, rejecting and refining until a conclusion is reached then process starts anew.

What are the differences between a hypothesis, theory, and law?

A hypothesis is an educated guess based on observation. A theory is and explanation developed through extensive observations, testing and retesting. Law is a statement of fact.

Who makes hypothesis?

Scientists, anyone

Who makes theories?

Scientific community

What is evolution ?

an accumulation of genetic changes that occur in organisms as they adapt to their enviorment

Why is evolution important for a class like microbiology?

Is important to understand antibacterial drugs, resistance and seasonal flu immune system

What is microbiology?

the study of living organisms too small to be seen with the unaided eye

What are the 3 MAIN groups of microbes? Know the characters.

Prokaryotes, Eukaryotes, Viruses

What are the two main types of cells? Know the characters.

Prokaryotes ( no nucleus, lacks organelles, small, all single celled, 2 types- Bacteria or archaea) , Eukaryotes ( has a nucleus, has organelles, some are single celled, 3 types- Helminths, protozoa, fungi)

What is the importance of microbes for human use?

they perform reactions for us like baking and antibiotics

What is the importance of microbes with regards to human diseases?

not all cause diseases but some do like pathogens (virus or bacteria)

How were microbes discovered?

microscopes help us to see what we already knew was there

What is the history of microbes discovery and who were the main scientists involved in their discovery?

Antonie Van Leeuwenhoek described bacteria, Robert Hooke was the first to see microorganisms, Schleiden and Schwann proposed cell theory (living things are made up of units of cells),

How was human disease linked with microbes?

the invention of pasteurization helped link human diseases to microbes

How are microbes used by humans to benefit us?

we use them for cheese, yogurt, baking, yeast, antibiotics and drugs like insulin

Who was Antonie Van Leeuwenhoek?

Dutch merchant, considered the father of microbiology, and described bacteria

Who was Robert Hook ?

English naturalist, first to see microorganisms, coined the word “cell”

Who was John Tyndall?

found that microbes in the dust and air have high heat resistance

Who was Ferdinand Cohn?

discovered and described bacterial endospores, sterile

Who was Robert Koch?

german physician, linked a specific microorganism with a specific disease, created a series of proofs verifying the Germ Theory of disease

Who was Oliver Wendell Holmes?

american physician, he studied the pattern of mortality in maternity wards connecting deaths with the lack of washing hands

Who was Ignaz Semmelsweiss?

the first to promote hand washing in maternity wards, collaborated with Holmes

Who was Joseph Lister?

first to utilize hand washing and misting operating rooms w/ antiseptic chemicals

Who was Lous Pasteur?

invented pasteurization, made the 1st vaccine, showed human diseases could arise from infectious microbes (yeast was responsible for fermentation)

What are Koch’s postulates? And why are they important?

1. microorganisms always in sick not well individuals

2. microorganisms can be isolated and grown

3. infecting a healthy individual with pure microbes will result in disease

4. re-isolate microorganisms from infected individuals

   shows how microorganisms can cause disease in a healthy individual

   (red flags of difficulty in steps 2 & 4, would be resolution)

What is nomenclature?

rules for naming new species

What are the levels of classification of organisms (from Domain to Species)?

Domain, Kingdom, Phylum/Division, Class, Order, Family, Genus, Species

What is a phylogeny?

types of taxonomic schemes based on natural relatedness, based on evolution

How has our perception of how the major living organisms are
related changed since Darwin?

Now it’s not just plants and animals its the 5 kingdoms: monera, plants, fungi, animals, protists

What are the 2 kingdom scheme? What was the evidence and what scientists came up with the ideas?

plants and animals. based on morphological characteristics (how you look) made up by Charles Darwin and Ernest Haeckel

What are the 5 kingdom scheme? What was the evidence and what scientists came up with the ideas?

monera, plants, fungi, animals, protists. based on morphological similarity made up by Robert Whittaker

What are the 3 domain scheme? What was the evidence and what scientists came up with the ideas?

Archaea, Bacteria, Eukarya. proposed a separate taxonomic system made up by Carl Woese and George Fox

How do you write a scientific name?

organisms have a 2 name designation (Genus Species), Ex: species name is Escherichia coli; genus is Escherichia and coli is the species epithet

What is Taxonomy?

science rules of classifying living beings

What did Carl Von Linne do?

established taxonomic categories

What are the size variations in bacteria?

Largest: Thiomargarita nomibiensis, Mid: Mycoplasma, Smallest: Nanobacteria

What are the 3 main bacterial shapes?

Coccus, Bacillus, Spiral

What are the other arrangements of bacteria?

Diplococci (pairs), Tetrads (groups of 4), Staphylococci (irregular clusters), Streptococci (chains of a few to 100), Sarcina (cubical packet of 8’s)

What shape is the Coccus?

sphere, oval, bean

What shape is the Bacillus?

Cylindrical rods

What shape is the Spiral?

rigid, helix, spiral

What are the major groups of appendages, their structure and function?

Flagella is 2 or more threads provides motility, Fimbriae small bristle like attaches to each other, Pilus long rigid tubular attachment

Pleomorphism means?

variations in size and shape in cells of 1 species

Bacillus arrangements of pairs with their ends attached is …

Diplobacilli

Bacillus arrangements of chain like structure with their ends attached is …

Streptobacilli

Bacillus arrangements of side by side rows with their ends attached is …

Palisades

How do bacteria move?

“Run” counterclockwise turning, smooth linear direction or “Tumble” reverse direction causes cell tumble, short change direction, long stay in place

What is it that a bacteria might move to or away from?

towards chemical favorable (positive chemotaxis) or away from chemical harmful (negative chemotaxis)

What are the main parts of the bacteria cell envelope?

2-3 layers, cell membrane (cytoplasmic) , cell wall, outer membrane

How does the cell envelope differ between Gram positive and Gram negative cells?

Gram positive has a thick cell wall, and a cell membrane. Gram Negative has a thin cell wall, outer membrane and cell membrane

What does the S- layer do? (surface coating)

provides protection from environmental conditions , only produced in hostile environments

The slime layer is ..

loose around the cell, protects agaisnt water loss and nutrients

The capsule is..

tightly bound to the cell, thicker/denser, and protects the immune system from water loss and adherence

What is the structure of peptidoglycan that’s in the Glycocalyx?

They are made up of Glycan chains: polysaccharides that alternate between G:N-acetyl glucosamine and M: N- acetyl muramic acid, cross linking with short peptides

What are some non-typical cell walls?

Mycolic acid and mycoplasma

What are the structural features and characteristics of the Gram negative outer membrane?

Lipopolysaccharides, Endotoxin (stimulates fever and shock reactions), Lipoproteins (anchors outer membrane to peptidoglycan)

What are the functions of the cell membrane?

energy reactions, nutrient processing, synthesis, regulate transport

Know what is inside of a bacterial cell

cytoplasm, site for biochemical and enzymatic activities, bacterial DNA, ribosomes, inclusion bodies, cytoskeleton, endospores

How is the bacterial genome arranged?

a single circular chromosome located in nucleolid

How are endospores formed and what are their function? What is their medical significance?

they are formed within a bacterial cell, usually in response to hostile conditions. They are responsible for numerous lethal diseases.

Mycolic acid (non-typical cell wall) is in …

Mycobacterium and Nocardia

Mycoplasma is a non typical cell wall because..

it lacks a cell wall, no outer membrane, stabilized by sterols, and varies in size and shape

Bacterial DNA is…

one circular strand of bacterial chromosome in the nucleoid

Plasmids is…

a non essential separate small circle DNA in bacteria, duplicated and passed onto offspring

Ribosomes is …

made up of RNA and protein and dispersed throughout cytoplasm to make protein

Inclusion bodies are …

1 layered membranes, storage sites for nutrients and excess protein

Cytoskeleton is …

a long protein polymer, contributing to cell shape

Endospores are…

only in some bacteria, survive in hostile conditions, have 2 stages (vegetative cell and endospore)

What are the differences between Macro- and Micro-nutrients?

Macro means large quantities (metabolism) while Micro is small amounts ( enzyme function)

What are the two major categories of nutrients?

inorganic and organic

Define Heterotroph

organisms that consume other organisms for energy, simple enough for absorption , digested than absorbed.

Define autotroph

an organism that can produce its own food using light, water, carbon dioxide, or other chemicals, inorganic CO2, convert into complex carbon compounds

Define phototroph

are organisms that use light as their source of energy to produce ATP and carry out various cellular processes.

Define chemotroph

an organism that obtains energy from chemical compounds, either organic or inorganic, instead of light

Define chemoautotrophs

is an organism that takes inorganic chemicals and transforms it into energy.

Define lithoautotrophs

requires neither sunlight nor organic nutrients and rely on inorganic materials (oxidizing)

Define photoheterotroph

an organism that uses light energy to fuel its metabolic processes but obtains its carbon from organic compounds rather than from carbon dioxide.

Define chemoheterotrophs

organisms that obtain both their energy and carbon from organic compounds by consuming other organisms or organic matter.

What are saprobes ?

they are free living microorganisms that decompose plants, animals, and microbes (bacteria and fungi).

How does saprobes and parasites take up nutrients from the environment?

Saprobes release enzymes that break down and digest their food till they can transport the small pieces into the cell. Parasites derive nutrients from their host.

What are the differences between active and passive transport?

Active Transport moves molecules against a concentration gradient requiring energy while passive transport goes with the gradient requiring no energy.

What are the major environmental factors that influence microbial growth?

temperature, gases, pH, osmotic pressure, radiation

The 5 different associations between organisms are…

Mutualism (both benefit), Commensalism (one benefits, the other is unaffected), Parasitism (one benefits at the other's expense), Antagonism (both are harmed by vying for resources), and Synergism (neither organism is affected, but both can benefit).

What is a biofilm?

mixed communities (different species) of bacteria and other microbes stick to a surface , made of protein substances

What is its structure, and what are the features of a biofilm?

large complex community w/ different species, can change environment to to their growth advantage , harder to get ride of

What is binary fission?

Bacterial duplication so parent cell enlarges, chromosomes duplicate, cell envelope pulls together in the center, cells divide into 2 daughter cells

Explain the differences between an exponential growth curve and a normal growth curve.

Exponential growth curve shows cells doubling at a maximal rate under good conditions (only growth) while normal growth curve shows the 4 stages from slow growth to fast death

What are the 4 bacterial growth phases?

Lag phase, Exponential phase, Stationary phase, Death phase

“ Flat” growth period is the …

Lag phase ( adjustment, enlargement, synthesis)

“Max” growth rate is the …

Exponential phase

“Cell birth = cell death” is the …

Stationary phase ( nutrients and oxygen go down, waste goes up )

Rise in waste would be what phase?

Death phase (cells begin to die exponentially)

What are parasites?

are microorganisms that live on or in a living body and may cause harm.

Psychrophiles

Microorganisms that thrive in cold environments, typically 0–15 °C, and can survive below 0 °C.

Psychrotrophs

Bacteria that can tolerate cold, but don’t prefer it. Have an optimal growth range of 25 °C

Mesophiles

Microorganisms that grow best at moderate temperatures, optimum 30–40°C. Most human pathogens are mesophiles.

Thermoduric is …

can survive high temperatures (like pasteurization) but don’t necessarily grow at those temperatures.

Thermophiles

Microorganisms that thrive at high temperatures, typically 45°C