BIOL 2420 Exam 2

Nutrition

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

Essential Nutrients

Must be provided to an organism.

Macronutrients

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

Ex: proteins, carbohydrates, lipids

Micronutrients

aka "Trace Elements"

Micronutrients

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

Ex: Manganese, zinc, nickel

Organic Nutrients

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

Inorganic Nutrients

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

Carbon and Hydrogen

Organic nutrients contain ______ and ______.

Growth Factors

Organic compounds that cannot be synthesized by an organism because they lack the genetic and metabolic mechanisms to synthesize them.

70

Cell contents are ______% water.

Proteins

Most prevalent organic compounds in cells.

96

______% of cell is composed of

Carbon

Hydrogen

Oxygen

Phosphorus

Sulfur

Nitrogen

Atmosphere

The main reservoir of nitrogen is the ______.

DNA, RNA, and ATP

The primary sources of nitrogen for heterotrophs are ______, ______, and ______.

Inorganic

Some bacteria and algae use ______ nitrogen sources.

(nitrate, nitrite, or ammonia)

Fix

Some bacteria can ______ atmospheric nitrogen into a form that is usable by living organisms.

Living Organisms

Some bacteria can fix atmospheric nitrogen into a form that is usable by ______.

Ammonia

Nitrogen must be converted to ______ to be combined with carbon, in order to synthesize amino acids and other compounds.

20

Oxygen makes up ______% of atmosphere.

Oxygen

Essential to metabolism of many organisms.

Oxygen

Major component of carbohydrates, lipids, nucleic acids, and proteins.

Oxygen

Plays an important role in structural and enzymatic functions of cell.

Oxygen

Component of inorganic salts and water.

Hydrogen

Major element in all organic compounds and several inorganic ones.

Hydrogen

Major component in gases produced and used by microbes.

Hydrogen

Element responsible for maintaining pH.

Hydrogen

Acceptor of oxygen during aerobic cellular respiration.

Phosphate

Main inorganic source of phosphorus is ______ derived from phosphoric acid found in rocks and oceanic mineral deposits.

Phosphorus

Key component of nucleic acids, essential to genetics.

Phosphorus

Serves in energy transfers.

Sulfur

Widely distributed in environment, rocks, sediment.

Sulfur

Essential component of some vitamins and some amino acids.

Disulfide

Sulfur contributes to stability of proteins by forming ______ bonds.

Potassium

Essential to protein synthesis and membrane function.

Sodium

Important to some types of cell transport.

Magnesium

Component of chlorophyll; membrane and ribosome stabilizer.

Iron

Component of proteins of cell respiration.

Heterotroph

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

(proteins, carbohydrates, lipids, and nucleic acids)

Autotroph

Organism that uses CO2, an inorganic gas, as its carbon source.

Not nutritionally dependent on other living things.

Chemotrophs

Gain energy from chemical compounds.

(Such as organics like carbohydrates, or inorganic chemicals)

Phototrophs

Gain energy from light (through photosynthesis); transform it into chemical energy to be used for metabolism.

Photoautotrophs

Get energy from light, and carbon from CO2 (include algae, cyanobacteria).

Chemoautotrophs

Derive all energy totally from inorganic substances, such as hydrogen gas, sulfur, or iron, which they combine with CO2 and H2 to produce organic molecules and energy.

Methanogens

A kind of archaeon chemoautotroph; produce methane gas (by-produce) under anaerobic conditions by combining CO2 and H2.

Photoheterotroph

Get energy from light, carbon from chemicals (include "purple and green" photosynthetic bacteria).

Chemoheterotrophs

The majority of heterotrophs are ______.

Aerobic Respiration

Chemoheterotrophs use oxygen to break down organic compounds (carbon source) to produce energy.

Saprobes and Parasites

Two categories of chemoheterotrophic microbes.

Saprobes

Free-living microorganisms that feed on organic detritus from dead organisms; fungi and certain bacteria.

Saprobes

Some ______ can become opportunistic pathogens or facultative parasites.

Opportunistic Pathogen

Normally nonpathogenic; cause disease in an immunologically compromised host.

Facultative Parasite

Not obligate; not restricted to a host.

Parasites

Benefit by deriving nutrients at the expense of the host.

Obligate

Parasite restricted to host.

Parasite

If a pathogen does not take nutrients, it is not considered a ______.

Extracellular Digestion

Process by which saprobes secrete enzymes, break down nutrients, then absorb smaller molecules.

Niche

Totality of adaptations organisms make to their habitat.

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.

Psychrophiles

Have optimum temperature below 15'C.

-5

Minimum temperature ('C) for psychrophiles.

20

Maximum temperature ('C) for psychrophiles.

Psychrophiles

Responsible for food spoilage in refrigerators. Rarely pathogenic.

Mesophiles

Have optimum temperature between 20-40'C.

10

Minimum temperature ('C) for mesophiles.

50

Maximum temperature ('C) for mesophiles.

Mesophiles

Most human pathogens are in this temperature adaptation group.

Thermophiles

Have optimum temperature greater than 45'C.

35

Minimum temperature ('C) for thermophiles.

60

Maximum temperature ('C) for most thermophiles.

Foodborne Infection

Caused by the ingestion of food containing live bacteria which grow and establish themselves in the human intestinal tract.

Foodborne intoxication

Caused by ingesting food containing toxins formed by bacteria which resulted from the bacterial growth in the food item. The live microorganism does not have to be consumed.

Toxic

As oxygen is utilized, it can be transformed into several ______ products that can damage or destroy cells.

Superoxide

______ ion requires 2 enzymes, superoxide dismutase and catalase, to convert it to a nontoxic chemical form.

Superoxide Dismutase

Superoxide ion requires 2 enzymes, ______ and catalase, to convert it to a nontoxic chemical form.

Catalase

Superoxide ion requires 2 enzymes, superoxide dismutase and ______, to convert it to a nontoxic chemical form.

Enzymes

If a microbe does not have the ______ required to convert toxic oxygen, it is forced to live in oxygen-free habitats.

Aerobe

Microbe which utilizes oxygen and can detoxify it.

Obligate Aerobe

Microbe which cannot grow without oxygen.

Facultative Anaerobe

Microbe which utilizes oxygen when present, but can also grow in its absence.

Microaerophilic

Microbe which requires only a small amount of oxygen.

Anaerobe

Microbe which does not utilize oxygen.

Obligate Anaerobe

Microbe which lacks the enzymes to detoxify oxygen, so it cannot survive in an oxygen environment.

Aerotolerant Anaerobe

Microbe which does not utilize oxygen, but can survive and grow in its presence.

Carbon Dioxide

All microbes require some ______ in their metabolism.

Capnophile

Microbe which grows best at higher carbon dioxide concentrations than normally present in the atmosphere.

6 and 8

Majority of microorganisms grow at a pH between ______ and ______.

Acidophiles

Microbes which grow at extreme acid pH.

Alkalinophiles

Microbes which grow at extreme alkaline pH.

Halophiles

Microbes which require a high concentration of salt; have significant modifications in their cell walls and membranes.

Hypotonic

Most microbes exist under slight ______ conditions (because their rigid cell walls withstand bursting), or isotonic conditions.

Osmotolerant

Microbes which do not require high concentration of solute such as salt but can tolerate it when it occurs.

Osmotolerant

Salt does not prevent all spoilage agents from growing on food, because many are ______ or halophilic.

Barophiles

Microbes which can survive under extreme pressure and will rupture if exposed to normal atmospheric pressure.

(Deep-sea microbes)

Symbiotic

Two organisms live together in a close partnership; required for survival by at least one member.

Mutualism

Obligatory, dependent; both members benefit.

Commensalism

One member benefits, other member not harmed.

Parasitism

One member is dependent and benefits; host harmed.

Nonsymbiotic

Relationship not required for survival.