CHAPTER 7 MICRO REVIEW

What is nutrition?

The process by which chemicals are acquired from the environment and used in cellular activities.

What are nutrients?

Materials used to build new cellular components and needed for growth.

What are macronutrients?

Elements required in large amounts for cell structure and metabolism.

What are the six macronutrients?

Carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur (CHONPS).

What are micronutrients?

Elements needed in small amounts, often for enzymes and pigments.

Examples of micronutrients

Calcium, sodium, potassium, manganese, zinc, and copper.

What are the two types of nutrients?

Organic and inorganic.

What are organic nutrients?

Nutrients containing carbon and hydrogen that are often associated with living things.

Examples of organic nutrients

Methane, carbohydrates, lipids, proteins, and nucleic acids.

What are inorganic nutrients?

Materials that do not contain the typical carbon

Examples of inorganic nutrients

Metals, salts, oxygen, carbon dioxide, and water.

Is carbon dioxide organic or inorganic?

Inorganic.

What is the chemical breakdown of a cell?

About 70% of a cell is water, and proteins and about 96% of the cell are largely made from CHONPS.

What are the two ways microbes are classified by carbon source?

Autotrophs and heterotrophs.

What are the two ways microbes are classified by energy source?

Phototrophs and chemotrophs.

What is an autotroph?

An organism that uses inorganic carbon, mainly CO2, as its carbon source.

What is a heterotroph?

An organism that uses organic compounds as its carbon source.

What do autotrophs use for carbon?

CO2 or another inorganic carbon source.

What organisms can be autotrophs?

Plants, algae, and cyanobacteria are examples.

What do heterotrophs use for carbon?

Organic compounds such as carbohydrates, lipids, proteins, and nucleic acids.

What is a fastidious heterotroph?

A heterotroph that can use only a limited type or types of organic carbon.

What is an omnivorous heterotroph?

A heterotroph that can use a wide variety of organic carbon sources.

What is a saprobe?

An organism that obtains organic matter from dead organisms.

What is a parasitic heterotroph?

An organism that obtains organic matter from a living host.

What is an obligate parasite?

An organism that must live in a host for survival.

What is a phototroph?

An organism that gets energy from light.

What process do phototrophs use?

Photosynthesis.

What is a chemotroph?

An organism that obtains energy from chemicals.

What do chemotrophs use for energy?

Preformed reduced compounds or, in some bacteria, inorganic compounds.

What is a photoautotroph?

An organism that uses light for energy and CO2 for carbon.

Examples of photoautotrophs

Plants, algae, and many photosynthetic bacteria.

What is a photoheterotroph?

An organism that uses light for energy and organic compounds for carbon.

What is a chemoautotroph?

An organism that uses inorganic compounds for energy and inorganic carbon for carbon.

What is a chemoheterotroph?

An organism that uses chemicals for energy and organic compounds for carbon.

What is diffusion?

The movement of molecules from an area of higher concentration to an area of lower concentration.

Does diffusion require energy?

No.

What is facilitated diffusion?

Movement of substances from high to low concentration using membrane proteins.

What is a permease?

A membrane transport protein that helps move specific substances across the membrane.

What is osmosis?

The net movement of water across a selectively permeable membrane toward the area with higher solute concentration.

Does osmosis require energy?

No.

What is a solute?

The substance being dissolved.

What is a solvent?

The substance that dissolves the solute.

What are the two main types of transport?

Passive transport and active transport.

What is passive transport?

Movement of substances across a membrane without cellular energy.

What is active transport?

Movement of substances across a membrane using energy.

Does active transport require ATP?

Yes.

Why does active transport require energy?

It can move substances against their concentration gradient.

What is the sodium

potassium pump?

Is the sodium

potassium pump active or passive?

What is endocytosis?

A process where a cell takes material into the cell by forming a membrane vesicle.

What is exocytosis?

A process where a cell releases material outside the cell using a vesicle.

What type of endocytosis takes in solids?

Phagocytosis.

What type of endocytosis takes in liquids?

Pinocytosis.

What environmental factors affect microbial growth?

Nutrients, osmotic pressure, temperature, pH, oxygen/gas use, and other organisms.

Why is temperature important?

It affects the function of metabolic enzymes and therefore affects microbial growth.

What is minimum growth temperature?

The lowest temperature at which a microorganism can grow.

What is maximum growth temperature?

The highest temperature at which a microorganism can grow.

What is optimum growth temperature?

The temperature at which a microorganism grows best.

What is normal human body temperature?

About 37°C.

What are the major temperature groups?

Psychrophiles, mesophiles, thermophiles, and hyperthermophiles.

What are psychrophiles?

Microorganisms that grow best at cold temperatures.

What are mesophiles?

Microorganisms that grow best at moderate temperatures, including many organisms associated with humans.

What are thermophiles?

Microorganisms that grow best at high temperatures.

What are hyperthermophiles?

Extreme thermophiles that grow at very high temperatures, above about 67°C and sometimes much higher.

What organisms are often hyperthermophiles?

Archaea.

What happens to oxygen when it is used by cells?

It can form toxic oxygen products such as superoxide, peroxide, singlet oxygen, and hydroxyl radicals.

How do aerobes handle toxic oxygen products?

They use enzymes such as superoxide dismutase and catalase.

What is an aerobe?

An organism that requires oxygen for growth.

What is an obligate aerobe?

An organism that requires oxygen and may die if oxygen levels become too low.

What is a microaerophile?

An organism that grows best at oxygen concentrations below normal atmospheric levels, often around 2–10%.

What is an anaerobe?

An organism that does not require oxygen for growth.

What is an obligate anaerobe?

An organism that is harmed or killed by oxygen.

What is a facultative anaerobe?

An organism that can grow with or without oxygen but usually grows faster when oxygen is present.

Example of a facultative anaerobe

E. coli.

What is an aerotolerant anaerobe?

An organism that does not use oxygen but can survive its presence because it has enzymes that detoxify harmful oxygen products.

Example of an aerotolerant organism

Lactobacilli.

What is the pH scale?

A scale from 0–14 used to describe acidity and basicity.

What is neutral pH?

7.

What is acidic pH?

Less than 7.

What is basic/alkaline pH?

Greater than 7.

What ion concentration determines pH?

Hydrogen ion (H+) concentration.

What is another word for basic?

Alkaline.

What is a neutrophile

A microorganism that grows best around neutral pH, usually 6.5–7.5.

What is an acidophile?

A microorganism that grows in acidic conditions.

What is an obligate acidophile?

An organism that requires a pH below 3.

What is a facultative acidophile?

An organism that can grow below pH 3 but grows at about pH 3–6.

What is an alkalinophile?

An organism that grows in basic conditions, with a range around pH 7–11 and an optimum around pH 10.

What is osmotic pressure?

Pressure related to the movement of water across a membrane due to differences in solute concentration.

What type of environment do most microbes live in?

A hypotonic environment.

What is a halotolerant organism?

An organism that can tolerate moderate salt concentrations.

Example of halotolerant organism

Staphylococcus.

What is a halophile?

An organism that grows in high

Example of halophile

Many archaeans.

What is an osmophile?

An organism that grows in environments with high sugar concentrations.

Example of an osmophile

Xeromyces.

What is a nonsymbiotic relationship?

Organisms are free

What is synergism?

Microorganisms cooperate and share nutrients.

What is antagonism?

Some microorganisms inhibit or destroy other microorganisms.

How do bacteria reproduce?

Mainly through transverse binary fission.

What is binary fission?

One bacterial cell divides into two cells.