Chapter 7

Front 1

Microbial Nutrition: Nutrition!

Back 1

Process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities.

Front 2

Essential Nutrients

Back 2

Must be provided to an organism

* Two essential nutrients:

1) Macronutrients

2) Micronutrients

Front 3

Macronutrients

Back 3

* Required in large quantities; play principle roles in cell structure and metabolism.

* Proteins, carbohydrates- large part of you!

Front 4

Micronutrients (trace elements)

Back 4

* Required in small amounts; involved in enzyme function and maintenance of protein structure

- Manganese, zinc, nickel -vitamins & minerals.

Front 5

Nutrients:

Organic Nutrients

Back 5

- Contain carbon and hydrogen atoms and are usually the products of living things

* Methane (CH4), carbohydrates, lipids, proteins, and nucleic acids.

Front 6

Nutrients:

Inorganic Nutrients

Back 6

- Atom or molecule that contains a combination of atoms other than carbon and hydrogen

* Metals and salts (magnesium sulfate, ferric, nitrate, sodium phosphate)

* gases (oxygen, carbon dioxide) and water.

Front 7

Chemical Analysis of Cell Contents

Back 7

* 70% water

* Proteins

* 96% of cell is composed of 6 elements

SCHNOP! Carbon, Hydrogen, Oxygen, Phosphorous, Sulfur, Nitrogen.

CO2, H2, O2, S, PO4, N2

Front 8

Symbols: ******

Back 8

Carbon CO2 Calcium CA+

Nitrogen N2 Magnesium MG2

Oxygen O2 Zinc ZN

Hydrogen H2 Iron FE

Methane CH4

Ammonia NH3

Phosphorous PO4

Sulfur S

Potassium K+

Sodium NA+

Front 9

Growth Factors: Essential Organic Nutrients

Back 9

* Organic compounds that cannot be

synthesized by an organism because they lack the genetic and metabolic mechanisms to synthesize them.

* Growth factors must be provided as nutrient

- Essential: amino acids, vitamins.

Front 10

Nutritional Types: * Main determinants of nutritional types are: - heterotroph & autotroph

Back 10

Energy Source:

- Chemotroph - gain energy from chemical compounds (can be either autotroph or heterotroph)

- Phototroph - gain energy through photosynthesis (can be either autotroph or heterotroph)

Front 11

Sources of Essential Nutrients:

Chemotrophs: energy from chemical compounds.

Back 11

- Carbon sources:

- Heterotroph - must obtain carbon in an

organic form made by other living organisms such as proteins, carbohydrates, lipids, and nucleic acids

- Autotroph - an organism that uses CO2, an inorganic gas as its carbon source.

*Not nutritionally dependent on other living things.

Front 12

Manobolic Classification: All organisms

Back 12

Energy source:

-Phototrophs (energy from sunlight)

-Chemotrophs (energy from chemical compounds) you.

Carbon source:

- Autotroph (carbon from CO2)

- Heterotroph (carbon from organic compounds)

Phototrophs:

Autotrophs: Cyanobacteria, vascular plants.

Heterotrophs: Heliobacteria, Most green non-sulfur bacteria.

Chemotrophs:

Autotrophs: Sulfur-oxidizing bacteria, hydrogen bacteria.

Heterotrouphs: Most bacteria, All non-phototrophic eukaryotes-(you)

Front 13

Autotrophs and their energy sources:

* Photoautotrophs- energy from sunlight

Back 13

- oxygenic photosynthesis

- Anoxygenic photosynthesis.

Front 14

Chemoautotrophs (lithoautotrophs)

Back 14

- Survive totally on inorganic substances.

- Methanogens, a kind of chemoatotroph, produce methane gas under a anaerobic conditions (without air).

*mineral and gases.

Front 15

Heterotrophs and Their Energy Sources:

-Majority are chemoheterotrophs

Back 15

* Two categories: (aerobic respiration)

- Saprobes: free-living microorganism that feed on organic detritus from dead organism. *recycle, critical in recycling in this world.

- Parasites: derive nutrients from host.

* Pathogens,

* Some are obligate parasites

* one way street.

Front 16

If an organism is degrading large organic

molecules to get both carbon and energy, it would be best described as a

Back 16

Chemoheterotroph

Front 17

Transport

Back 17

Movement of chemical across the cell membrane.

Front 18

Passive Transport

Back 18

Does not require energy; substances exist in gradient and move form areas of higher concentration toward areas of lower concentration.

- Diffusion

- Osmosis - diffusion of water - semipermeable membrane, concentration gradient.

- Facilitated diffusion - requires a carrier.

**Cell Membrane (phospholipids, proteins and sterols***

Front 19

Active Transport

Back 19

requires energy and carrier proteins; gradient independent.

- Active transport

- Group translocation - transported molecule chemically altered.

- Bulk transport- endocytosis, exocytosis, pinocytosis. *** requires energy ***

Front 20

Back 20

Isotonic Solution- Water concentration is equal inside and outside the cell, rates of equal diffusion on both sides.

Hypotonic Solution: Net diffusion of water is into the cell; this swells the protoplast and pushes it tightly against the wall. Wall usually prevents cell from bursting.

Hypertonic Solution: Water diffuses out of the cell and shrinks the cell membrane away from the cell wall; process is know as Plasmolysis

. ie* (too much fertilizer)

Front 21

Facilitated Diffusion (Passive Transport)

Back 21

Still going with a gradient like diffusion- just to big to go through, and pairs up with a carrier molecule- latches and takes it through or can without a carrier molecule.

Front 22

Carrier Mediated Active Transport

Back 22

Membrane-bound transporter proteins (permeases) interact with nearby solute binding proteins that carry essential solutes (sodium, iron, sugars)

Once binding protein attaches to a specific stie, an ATP is activated and generates energy to pump the solute into the cell's interior through a special channel in the permease. *NA & K+

Front 23

If a cell is in a concentrated glucose solution and the glucose is moving into the cell through a carrier protein, this would be an example of

Back 23

Active Transport

*Moving against the gradient.

Front 24

Environmental Factors that Influence Microbes

Back 24

* Niche: totality of adaptations organisms make to their habitat.

* Environmental factors affect the function of metabolic enzymes

- Factors include:

* Temperature

* Oxygen requirements

* pH

* Osmotic pressure

* Barometric pressure

***Some require temp, O2 and some don't**

Front 25

3 Cardinal Temperatures

Back 25

- Minimum temperature - lowest temperature that permits a microbe's growth and metabolism.

- Maximum Temperature - highest temperature that permits a microbe's growth and metabolism.

- Optimum temperature - promotes the fastest rate of growth and metabolism.

Front 26

* 3 Temperature Adaptation Groups

1) Psychrophiles

Back 26

Optimum temperature below 15 C; capable of growth at 0 C.

Front 27

2) Mysophilies

Back 27

Optimum temperature 20C-40C; most human pathogens.

Front 28

3) Thermophiles

Back 28

Optimum temperature greater than 45C

Front 29

Gas Requirements****Know!

Back 29

Oxygen:

*As oxygen is utilized it is transformed into several toxic products.

- singlet oxygen (O2), superoxide ion (O2-), peroxide (H2O2), and hydroxyl radicals (OH-)

* Most cells have developed enzymes that neutralize these chemical:

- Superoxide dismutes, catalase.

*** If a microbe is not capable of dealing with toxic oxygen, it if forced to live in oxygen free habitats.

Front 30

**Categories of Oxygen Requirements: Know!

Back 30

* Aerobic- utilizes oxygen and can detoxify it.

* Obligate aerobic - cannot grow without oxygen

* Facultative anaerobe - utilizes oxygen but can also grow in its absence.

* Microaerophilic - requires only a small amount of oxygen

* Anaerobe - does not utilize oxygen

* Obligate anaerobe - lacks the enzymes to detoxify oxygen so it cannot survive in an oxygen environment.

* Aerotolerant anaerobes - do not utilize oxygen but can survive and grow in its presence

Front 31

**Culturing by Oxygen Requirement

Back 31

Two different ways of culturing anaerobes:

- Use of a medium such as Thioglucollate broth (reducing agent) - note tube #4 and use of anaerobic environmental chambers.

* removes O2 from it.

Front 32

Carbon Dioxide Requirement:

All microbes require some carbon dioxide in their metabolism.

* Capnophile:

Back 32

grows best at higher CO2 tensions than normally present in the atmosphere.

*Loves CO2!

Front 33

Effects of pH! Know! ****

- Majority of microorganisms grow at a pH between 6 and 8 (neutrophils)- strong bases and/ or acids tend to decrease effectiveness or inactivate enzymes and other proteins.

Back 33

Acidophiles - grow at extreme acid pH.

* many molds/yeasts, acidic pools, coal piles. and some bacteria.

Alkalinophils - grow at extreme alkaline pH.

* Hot pools and soils with high levels of basic mineral. Bacteria that decompose urine increases alkaline conditions.

* (both acidophiles and alkalinophiles have developed enzymes and other proteins that are resistant to damage by strong acids and bases)

Front 34

Osmotic Pressure

* Most microbes exist under hypotonic or isotonic conditions.

Back 34

Halophiles - require a high concentration of salt. High salt!

Osmotolerant - do not require high concentration of solute but can tolerate it when it occurs. Tolerates salt!

* These organisms have developed modifications in their cell walls and to some extent membranes, to allow them to survive.

Front 35

The environmental Factors:

Back 35

Bariophiles - can survive under extreme

pressure and will rupture if exposed to normal atmospheric pressure.

* For example: deep sea prokaryotes and eukaryotes such as Forminifera sp

Front 36

Chlamydomonas nivlalis grows in Alaska glaciers and its photosynthetic pigments give the snow a red crust. This organism would best be describes as a?????

Back 36

Psychrophile.

Front 37

Ecological Association Among Microorganisms: Microbial Associations

Symbiotic -

Back 37

- Organisms live in close nutritional relationships, required by one or both members

* Mutualism - Obligatory, dependent, both members benefit.

* Commensalism - The commercial benefits; other member not harmed.

* Parasitism - Parasite is dependent and benefits; host harmed.

Front 38

Microbial Associations: Nonsymbiotic

Back 38

- Organisms are free-living relationship not required for survival.

* Synergism - members cooperate and share nutrients.

* Antagonism - Some members are inhibited or destroyed by others.

Front 39

Interrelationships between Microbes and Humans

Back 39

* Human body is rich habitat for symbiotic bacteria, fungi and a few protozoa- normal microbial

flora.

* Commensal, parasitic, and syngergistic relationship.

* Where? Penis-urethra.

Example: how to get a clean urine sample. clean penis, urinate some, everyone has flora.

Front 40

Microbial Biofilms

Back 40

* result when organisms attach to a substrate by some form of extracellular matrix that binds them together in complex organized layers.

* Dominates the structure of most natural environments on earth.

Front 41

*The study of Microbial Growth*

Back 41

Growth occurs at two levels: growth at a cellular level with increase in size, and increase in population.

* Division of bacterial cells occurs mainly through Binary Fission (transverse)****(know)

- Parent cell enlarges, duplicates its

chromosome, and forms a central transverse

septum dividing the cell into two daughter cells.

Front 42

**Binary Fission-Prokaryotes**

Back 42

1) A parent cell at the beginning of the cell cycle:

What cannot be seen is the synthesis and activity gearing up for cell division.

2) Chromosome replication and cell enlargement: The parent cell duplicates the chromosomes and synthesizes new structures that enlarge the cell in preparation for the daughter cells.

3) Chromosomes division and Septation: the chromosomes affix to the cytoskeleton and are separated into the forming cells. The cell lays down a septum that begins to wall off the new cells. Other components (ribosomes) are equally distributed to the developing cells.

4) Completion of cell compartments: the septum is synthesized completely through the center, and the cell membrane patches itself so that there are two separate cell chambers.

5) End of cell division cycle: daughter cells are now independent units. Some species will separate completely as shown here, while others will remain attached, forming chains or pairs, for

example.

Front 43

**Rate of Population Growth**

Back 43

* Time required for a complete fission cycle is called the generation, or doubling time.

* Each new fission cycle increases the population by a factor of 2 - exponential growth.

* Generation times vary from minutes to day.

Front 44

**The population Growth Curve:**

Back 44

In laboratory studies, populations typically display a predictable pattern over time - growth curve

- Stages in the normal growth curve:

1) Lag phase - "flat" period of adjustment,

enlargement; little growth>

Front 45

The Population Growth Curve:

Back 45

Stages in the normal growth curve:

1) Lag phase

2) Exponential growth phase

3) Stationary phase - rate of cell growth equals rate of cell death caused by depleted nutrients and O2, excretion of organic acids and pollutants.

4) Death phase - as limiting factors intensify, cells die exponentially.

Front 46

Methods of Analyzing Population Growth:

Back 46

* Turbidometry - Most simple

* Degree of cloudiness, turbidity, reflects the

relative population size.

****way of measuring cloudiness.