Mcb Lect 4

Front 1

7 Basic Nutrients all Bacteria Need (besides water)

Back 1

1. an energy source
2. carbon source
3. nitrogen
4. sulfur
5. phosphate
6. trace elements
7. essential growth factors (vitamins)

Front 2

Oxygen

Back 2

Not every organism requires elemental oxygen - aka non combined oxygen or O2

Organisms used combined oxygen - oxygen attached to another element

Front 3

Why do living organisms need nitrogen?

Back 3

- Nitrogen is found in AA so proteins cannot be made without Nitrogen

- Nitrogen is also an important component of nuclei acids, DNA, and RNA, and cannot be made without nitrogen.

- Some modified sugars, such as those found in bacterial cell wall maaterial peptidoglycan, can also contain nitrogen atoms

Front 4

Common Nitrogen Sources

Back 4

Organic Nitrogen from amino acids, nucleotides, etc.

Inorganic Nitrogen: ammonia, NH3, Nitrate, Nitrogen, N2

Front 5

Phosphorus

Back 5

- Phosphorus is needed in the oxidized state for nucleotides and phospholipids
- Some protein molecules hve a phosphate group or two that are attached after translation, Addition of removal of these phosphate groups is a common way of controlling the activity of enzymes.

Front 6

Sulfur

Back 6

Sulfur is found in a reduced state (-SH) in the amino acid cysteine and in important vitamins that act as enzyme cofactors such as biotin, thiamine, and coenzyme-A.

Front 7

Hydrogen sulfide

Back 7

A gas, most of the sulfur that is found dissolved in water is in an oxidized state as either sulfate or sulfite anions. Most organisms can reduce sulfate and sulfite to a form that can be assimilated into organic molecules.

Front 8

Trace elements

Back 8

Inorganic elements are needed in small amounts, usually for enzyme cofactors

Front 9

Important Metals include

Back 9

Iron, copper, magnesium, and zinc

Front 10

Larger amounts of ions

Back 10

Calcium, Potassium, Sodium, and Choride -- are needed but are rarely limiting

Front 11

Growth factors are organic compounds including.....

Back 11

Vitamins, amino acids, fatty acids, etc.

Front 12

Trace elements and growth factors are neededd as....

Back 12

components of biological macromolecules or enzyme cofactors

Front 13

Autotrophic Organism

Back 13

Able to obtain the carbon needed for growth from an inorganic source -- usually carbon dioxide
PLANTS

Front 14

Heterotrophic organism

Back 14

Needs organic carbon to grow, organic compounds come from other living organisms.
ANIMALS

Front 15

Phototrophic Organism

Back 15

Can derive the energy needed to sustain it's metabolism from light

Front 16

Chemotrophic Organism

Back 16

Requires a certain mix of chemicals that allows it to conduct redox reactions that yield energy.

Front 17

Two Types of Chemotrophic Organisms

Organotrophs

Back 17

Derive energy from chemical reactions that use organic compounds
(Organotrophy is a synonym for chemoheterotroph)

- Aquire organic compouds required for energy producing metabolism from the environment

***fungi and protozoa****

Front 18

Two Types of Chemotrophic Organisms

Lilotrophs

Back 18

Derive energy from chemical reactions that do not require carbon based compounds.

Front 19

Who gets credit for developing many of the techniques that are used to grow pure cultures of microorganisms in the labratory?

Back 19

A. Antony Van Leewoenhoek
B. Ignaz Semmelweis
C. Louis Pasteur
D. Robert Koch
E. Carl Woese

Front 20

Why use solid media to grow bacteria?

Back 20

When bacteria grow in liquid culture they are free to move around and mix with eachother. On solid media the bacteria are unable to move and so freely and thus an isolated cell will grow and reproduce for many generations in 1 place.

- This can produce a pile of bacteria that all descended from a single cell and are thus all genetically identical.

Front 21

Colony

Back 21

A colony is a visible pile of bacteria that all descended from a single cell - a well isolated colony of a microorganism is a small pure culture.

Front 22

Agar

Back 22

Agar is a complex carbohydrate that is derived from cell walls of a certain type of sea weed.

It is indigestible by animals and most microorganisms and so by itself provides no nutritional value to the medium.

Front 23

Generation time equation

Back 23

1/Growth Rate

Generation time = time it takes for a bacterial population to double

Front 24

Psychrophile

Back 24

Cold-loving bacterium that grows best at less than 20 degrees C.

Front 25

Mesophile

Back 25

Loves the middle, a bacterium that grows best at temperatures that humans consider comfortable generally about 25-45 C.

Front 26

Thermophile

Back 26

Heat-loving, a bacterium that grows best at temperatures above 60 C.

Front 27

Thermoduric

Back 27

A bacterium that grows at a moderate temperature, but is not killed rapidly by high temperatures.

Front 28

Thermophilic

Back 28

A thermophillic bacterium grows at a high temperature

Front 29

Most microorganisms grow best when pH is...

Back 29

Near neutrality or slightly acidic

Front 30

Acidophiles

Back 30

Grow best at a low pH

Front 31

Alkinophiles

Back 31

Grow at a higher pH

Front 32

Capnophiles

Back 32

Grow best when the concentration of carbon is elevated

Front 33

Halophiles

Back 33

Grow best at high concentrations of salt

Front 34

Why is it possible to store maple syrup at room temperature?

Back 34

Maple syrup has a high concentration of sugar and thus a low water activity - Maple syrup is a hypertonic solution

If a cell were in a bottle of maple syrup- the water would diffuse out of the cell and into the surrounding solution.

- This would cause the cytopasm of the cell to shrivel up

Front 35

Culture

Back 35

A population of microorg. growing in some environment

Front 36

Medium

Back 36

The food that microorganisms are grown on

Front 37

Broth

Back 37

Liquid medium, there are many different recipies

Front 38

Agar

Back 38

An algal extract used to solidify media

Front 39

Colony

Back 39

A visible pile of microorganisms on a sollid medium

Front 40

Inoculate

Back 40

A deliberately introduce microorganisms into an environment

Front 41

Defined medium

Back 41

The microbiologist knows the complete chemical composition of the medium, ingredient examples:
gluclose, ammonium nitrate, ammonium, phosphate

Front 42

Complex Medium

Back 42

Contains substances that have not yet been chemically analyzed such as:

milk, blood, yeast extract, meat, eggs, plant extracts

Front 43

Broth

Back 43

Liquid Media

Front 44

Solid Media

Back 44

Has a solidifying agent - gelatin (that can be degraded by many bacteria, starch or celluloes, or agar

Front 45

General Purpose Media

Back 45

used to grow a wide variety of microorganisms - Rich

Front 46

Selective Media

Back 46

Some species of microorganisms grow, but others don't.

Front 47

Differential Media

Back 47

Used to reveal a metabolic diffrence between species

Front 48

Enrichment media

Back 48

Used to enhance the growth of some species over others

Front 49

EMB Agar is both a ____ medium and a _____ medium

Back 49

selective medium and a differential medium

Most gram positive bacteria such s as Staphylococcus do not grow on EMB

A gram negative bacterium that does not ferment lactose grows on EMB, but does not produce a dark color

A gram negative bacterium that ferments lactose grows on EMB agar and produces dark colored colonies

Front 50

Total Bacteria Count

Back 50

Count includes dead bacteria