Chapter 9 Study Guide

Microbial Nutrition and Growth Lecture

What is Nutrition?

It’s the process by which chemical substances called nutrients are acquired from the environment and used in cell metabolism and growth

What is Essential Nutrient?

a nutrient that must be provided to an organism through food or enviornment

What are the nutrients for microbes?

carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur

What are MACRO nutrients?

they are required in large quantities, play principal roles in cell structure and

metabolism.

What are MICRO nutrients?

they are trace elements, needed in small amounts, help with enzyme and protein structure

What are 3 Sources that nutrients can come from?

organic sources, inorganic sources, or a combination

Parasites get nutrition from???

a host

Cell Composition: Water

70% of cell weight, most abundant of all components

Cell composition: Proteins

next most prevalent compound

96% of dry cell weight is composed of what?

CHONPS elements (carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur)

2 carbon sources?

heterotrophs, autotrophs

Heterotrophs

organism that gets its carbon in an organic form.

· Pseudomonas spp. can metabolize more than 100 different substrates

· Heterotrophs can be highly variable.

Autotrophs

organisms that uses inorganic CO2 as its carbon source

· "self-feeder"

· Algae, many archaea are autotrophs

Most nitrogen on earth is in the atmosphere as N₂, but this is inaccessible to

most organisms and must be transformed.

Some bacteria and algae can utilize inorganic nitrogen such as

NO₃- NO₂- NH₃

What is nitrogen fixation

bacteria converts N₂ into compounds that can be used by other organisms

components of organic compounds

major role in structural and enzymatic functions of the cell

Oxygen and Hydrogen

Hydrogen helps/serves

Serve as a source of free energy in oxidation- reduction reactions (involved in cellular respiration)

. Maintain pH, Form hydrogen bonds

Main inorganic source of phosphorus is

phosphate- found in phosphoric acid,

phosphate is a major component of many rocks and mineral deposits

Phosphate is a key component of nucleic acids.

Corynebacterium can store phosphate in

metachromatic granules

Sulfur is widely distributed in minerals, often in the form of

sulfate (SO42-)and sulfides (FeS, H2S),

Potassium

essential to protein synthesis and membrane function

used in cell transport

sodium

Calcium- What it’s for

stabilizes cell wall and endospores in bacteria

Magnesium- what it’s for

component of chlorophyll and stabilizes membranes and ribosomes.

Iron- what it’s for

used in cytochrome proteins used in cellular respiration

Zinc- what it’s for

necessary for eukaryotic gene regulation

What are the 3 nutritional types?

Photoautotrophs

Chemoautotrophs

Chemoheterotrophs

Photoautotrophs

- organisms that photosynthesize

· Algae, cyanobacteria

Chemoautotrophs

organisms that gain energy from chemical reactions involving simple chemicals in the environment.

inorganic chemicals———> energy

· Methanogens

Chemoheterotrophs

- derive carbon and energy from organic compounds.

· Some use aerobic respiration- using oxygen to break down organic compounds.

Extremophiles live in

"extreme" environments- cold, hot, salty, full of generally toxic environments

Hyperthermophiles

live in high-heat environments

This is used in PCR reactions

Thermophile DNA polymerase

Cell membrane

allows nutrients and waste to move across it selectively.

Diffusion

the natural tendency of molecules to move across a gradient.

Diffusion across the membrane is determined by the

concentration gradient and permeability of the substance.

Osmosis

the diffusion of water across a semi-permeable membrane.

Hypotonic Solution

ex: salt concentration INSIDE the cell is HIGHER than the salt concentration OUTSIDE the cell (water will diffuse into the cell due to higher concentration, causing CELL LYSIS)

Isotonic solution

same amount of salute inside and outside the cell

(salt example: same salt concentration in and out)

Hypertonic solution

salt example: too much salt outside, not enough water inside (causing a shriveled cell)

Facilitated diffusion

- transport that utilizes a carrier proteins that binds to a specific substance.

Carrier proteins

they only bind to one or a few molecule types.

The transport of a substance is limited by the number of binding sites on the cell membrane is called

saturation

when two molecules can bind the same carrier protein, they compete- molecules

with the greater affinity to the carrier or molecules with greater concentration gradient will be transported for quickly into the cell. what is the term for this?

Competition

Active Transport-What is it?

Transport nutrients across the diffusion gradient or faster than diffusion allows

What requires presence of specific membrane proteins?

Active Transport

Active Transport requires…

the expenditure of energy

This process couples the transport of a nutrient with its conversion to a substance that is immediately useful inside the cell.

Group Translocation

Endocytosis

A form of active transport to bring in large molecules, particles, or liquids.

Phagocytosis

when cells ingest other cells or large solid matter

Pinocytosis

the endocytosis of liquids such as oils or solutions

Do you think medical grade saline is an isotonic, hypertonic or hypotonic solution?

Isotonic-Isotonic solutions have the same concentration of solutes as body fluids, meaning they don't cause cells to swell or shrink when introduced into the body

Microbes are unable to control their internal temperature so they must to able to

live within a range of different temps.

LOWEST temperature that permits microbial growth

Minimum temperature

HIGHEST temperature that permits growth.

Temperatures above that can cause permanent enzyme and nucleic acid breakdown

maximum growth

small range of temperatures that maximizes growth and metabolism

Optimum temperature

Psychrophile temp

optimum temperatures below 15 degrees celcius

Mesophiles temp

optimum temperatures between 20 and 40 degrees Celsius

Thermophiles

optimum temp. greater than 45 degrees

Most ______ cannot survive above 60 degrees.

eukaryotes

Microbes are one of three forms:

. Those that use oxygen and can detoxify it

. Those that neither use oxygen nor detoxify it

. Those that do not use oxygen but can detoxify it

can use gaseous oxygen and poses enzymes to neutralize toxic oxygen

Aerobes

This aerobe must have oxygen in their environment.

obligate aerobe

This aerobe does not require oxygen and is capable of growth without it.

Facultative aerobe

need small amounts of oxygen, but cannot grow with normal atmospheric oxygen

Microaerophile

lacks enzymes for using oxygen in respiration

Anaerobe

·Obligate anaerobes

cannot tolerate free oxygen in environment

Many _________ _______ are anaerobic.

gut/ oral bacteria

can tolerate oxygen but can break down toxic forms of oxygen.

. Aerotolerant anaerobes

Acidophiles

grow at extremely low pH

. Euglena mutabilis-alga that grows in low pH pools, first found near acidic waste pits from mining

Alkalinophiles

grow at extremely high pH

Halophiles

tolerate or require high salt concentrations

Facultative halophiles

- can live in high salt concentrations

· Staphylococcus aureus

Mutualism

when organisms live in a mutually beneficial relationship

· Usually obligatory

Commensalism

one organism benefits but the other is not affected.

Parasitism

- one organism benefits but the other is harmed.

Antagonism

- when species not in a symbiotic relationship compete.

. Microbes can excrete chemical substances that inhibit or destroy microbes into the same habitat

Synergism

- an interrelationship between two or more free-living organisms that benefits them but isn't necessary for their survival.

80% of chronic infections are caused by

biofilms

What are Biofilms

- communities of different kinds of bacteria and other microbes that are attached

to surfaces

Biofilms can sense and monitor their population by means of

quorum sensing.

They are also prevalent

the process of one cell becoming two

Binary fission

the time required for cells to double

Generation time

Some microbes reproduce extremely fast- E. coli.

exponential growth

Growth that doubles repeated

Populations typically demonstrate a

growth curve.

Look at this chart

Look at this chart

Chemostat

a device that allows for continuous culturing.

· Adds a steady stream of nutrients to prevent dying, siphons off old media and dead bacterial cells.

Turbidometry

measuring the turbidity of a solution of bacteria to estimate population size.

Direct cell count

- counting cells microscopically

can be counted or counted by a computer

special slide calibrated to accept a tiny sample spread over a grid

cytometer

Flow cytometer

measures cell sizes, cell count, and can tell the difference between live and dead cells