Microbiology exam 2

Nutrition

Process by which nutrients are acquired from the environment and used in cellular activities.

Macronutrients

Required in large quantities; play principal roles in cell structure and metabolism (proteins, carbohydrates)

Essential Nutrients

Must be provided to an organism. Two categories: macronutrients and Micronutrients (trace elements)

Organic Nutrients

contain carbon and hydrogen atoms and are usually the product of living things (methane, carbohydrates, lipids, proteins, and nucleic acids)

Inorganic Nutrients

Atom or molecule that contains a combination of atoms other than carbon and hydrogen (metals and their salts, gases and water)

Heterotroph

Must obtain carbon in an organic form made by other living organisms (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)

Chemotroph

Gains energy from chemical compounds

Phototroph

Gains energy through photosynthesis

Active Transport

Requires energy and carrier proteins; gradient independent. Forms of active transport: carrier mediated, group translocation, endocytosis/bulk transport. Note: transport is the movement of chemicals across the cell membrane.

Passive Transport

Does not require energy; substances exist in a gradient and move from areas of higher concentration toward areas of lower concentration. Forms of passive transport: diffusion, osmosis, facilitated diffusion. Note: transport is the movement of chemicals across the cell membrane.

Diffusion

The molecule passes from one side of the membrane with no assistance via protein or ATP. It is naturally traveling from an area of high concentration to low concentration

Osmosis

Water passes through the membrane from an area of high water concentration (low solute concentration) to an area of low water concentration (high solute concentration.)

Facilitated Diffusion

A molecule passes through a membrane with the help of a carrier protein. No ATP is involved and it travels from an area of high concentration to low concentration, but the molecule is too large, bulky, polar, or charged and cannot pass through the phospholipid portion of the membrane.

Carrier Mediated Transport

Special solute binding proteins pick up the molecule and bring them to a transporter protein located in the membrane. ATP is used to pump the molecule through the transporter protein.

Group Translocation

A molecule is captured by a protein carrier and modified as it passes through the membrane.

Endocytosis

The entire membrane makes a pocket and eventual vesicle and any molecules that are bound to the surface are brought inside the cell.

Binary Fission

The formation of two new cells of approximately equal size as the result of parent cell division. This occurs during the bacteria cell division cycle. The parent cell enlarges, duplicates its chromosome and forms a central transverse septum that divides the cell into two daughter cell causing an increase in population growth.

Phases of Bacterial Growth

4 major phases of bacterial growth as follows: (1) lag phase; (2) log phase; (3) stationary phase; and (4) death phase.

Turbidity

The cloudy appearance of media when bacterial growth is present. The amount of light that passes through the culture can be measured using a spectrophotometer. Degree of turbidity reflects the relative population size.

Fastidious

Bacteria that require growth factors and complex nutrients.

Obligate

An organism must have a certain environmental condition

Facultative

An organism is able to adjust to and tolerate the environmental condition, but it can also live in other conditions

Acidophiles

Grow best in very low pH (0.1-5.4) Ex: Lactobacillus closer to 5.4, Sulfur oxidizers to sulfuric acid pH 1.

Neutrophiles

Most disease-causing, grows best in the middle of the pH range (5.4-8.0)

Alkaliphiles

Grows best in very basic pH (7.0-11.5). Ex: Agrobacterium soil pH of 12

Psychrophiles

Grow best at very low temperatures Like temps around 15-20° C. Ex: Obligate (die at temps above 20°C) facultative (grows best under 20°C, but can grow at higher temps)

Mosophiles

Grow best at temps that range from room temperature to body temperature. Like temps around 25-40°C

Thermophiles

Thrive in high temps (50-60°C)

Aerobe

Utilizes oxygen and can detoxify it

Obligate Aerobe

Utilize oxygen, cannot survive in its absence due to back up in Electron Transport Chain

Facultative Anaerobe

Utilizes oxygen but can also grow in its absence

Microaerophile

Utilize oxygen, but requires only a small amount of oxygen because are unable to detoxify large amounts of oxygen free radicals

Anaerobe

Does not utilize oxygen