Exam 1 – Microbiology Test Questions – Flashcards

the study of very small living things

a set of techniques for studying very small organisms

prokaryotic cells:

1. relatively simple cell structure
2. their DNA is located in a poorly defined region inside the cell
3. they are usually very small

eukaryotic cells:

1. more complex
2. their DNA is set apart from the rest of the cytoplasm enclosed in a double-layered membrane of the nucleus
3. their cells contain other membranous structures like mitochondria, endoplasmic reticulum, Golgi bodies, and lysosomes which are not found in prokaryotic cells

A scientific name consists of its genus (very similar organisms) and species (the exact type of organism in that group.)

When writing a scientific name, the genus is capitalized and the species name is not. It should be italicized - or if that's not possible, underlined.

i.e. Acomys carhirinus

various kinds of media are used to:

1. provide the microorganism with what it needs to multiply
2. to encourage growth of the one we want to study and discourage the growth of those we do not
3. to reveal the characteristics of the microorganism that will allow us to identify it, such as motility or differences in metabolism

agar slant - when a larger surface area is needed to inoculate

agar deep - usually used for "stabs", which is useful in determining if the organism will grow - or grows best - int he presence/absence of oxygen, and also for seeing if the microorganism is motile

agar plate - allow the bacteria to spread out more, so that that isolated colonies can be studied

broth tube - often used just to keep a culture growing, or with the addition of particular substances, to reveal differences in metabolism

standard - because our microscopes haven't been fitted with specialized lenses that allow flourescent, phase contrast, or DIC (differential interference contrast or Nomarski) microscopy

compound - 2+ lenses

light - because light is used to form the image that you see when you look through the lens

1. molecules and ions are different sizes
2. molecules have a shape
3. molecules and ions are always moving
4. electrical charge is very important

1. Whether or not a molecule can move in or out of a cell depends, in part, on how large it is. (i.e. large molecules like triglycerides, starches and proteins are too big to pass through openings in the cell's plasma membrane and must be broken down into their components [monomers], or digested, before they can cross the membrane.)
2. Each different protein has its own unique shape and it can do what it does because of the shape that it has (form = function)
3. The energy of movement can be used to work in a cell. This movement allows diffusion to happen, powers the movement of substances into and out of the cell, and brings molecules together so that they can react with each other - releasing energy and/or creating new substances needed by the cell. (Diffusion + chemical reactions cannot happen if the molecules/ions are not moving.) The warmer the molecules/ions are, the faster they move.
4. Anything with a charge will interact with anything with a charge.

H_²O

Hydrogen bonds

acidic: 0-6

basic: 8-14

carbohydrates

proteins

lipids

nucleic acids

monomers - monosaccharides, or simple sugars.

3 important ones: glucose (easily available energy for cells, formed by photosynthesis)

fructose (the same atoms arranged differently. plants convert some glucose to fructose)

galactose (found in milk)

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2 monosaccharide monomers can be joined to form a disaccaride (polymer)

disaccharides include sucrose and lactose

polysaccharides include starch, glucogen and cellulose

DNA + RNA

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Nucleotides

ATP (the RNA nucleotide with an adenine base)

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A small molecule can transfer energy from one chemical reaction to another. ATP is sometimes called the "energy currency of the cell".

monomer - amino acids

polymer - polypeptide

fatty-acid based lipids and sterols

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They include small molecules that can be joined together to make larger ones (not string shaped) and all of hem are hydrophobic, or significant part of the lipid molecule is hydrophobic.

Sterols are made by eukaryotes, most sterol molecules are found in membranes - scattered throughout the lipid bilayer between the phospholipid "tails" - where they keep the membrane from being either too fluid or too stiff.

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The sterol found in animal cells is cholesterol. Plants make phytosterols, and fungi make ergosterol. In humans, a small amount of cholesterol is modified to form the steroid hormones: estrogen, progestone, testosterone, cortisol, and aldosterone.