Grade 11 biology - Prokaryotes, viruses and protists

Pathogen

A disease-causing agent, often a virus or micro-organism

Mutualism

A relationship between two species that live in very close association with each other, whereby each benefits from the association

Antibiotic

A substance that can kill or weaken micro-organisms; natural antibiotics are produced by bacteria or fungi, whereas synthetic antibiotics are manufactured

Plasmid

A small loop of DNA often found in prokaryotic cells; usually contains a small number of genes

Capsule

An outer layer on some bacteria; provides some protection for the cell

Coccus

A round bacterial cell

Bacillus

A rod shaped bacterial cell

Spirillum

A spiral or corkscrew-shaped bacterial cell

Inorganic chemical

A chemical that has an abiotic origin; some simple substances that are produced by organism are also classified as inorganic

Organic chemical

In biology, any chemical that contains carbon and is produced by living things; carbon dioxide is an exception—it is produced during respiration but is classified as inorganic

Obligate anaerobe

An organism that cannot survive in the presence of oxygen

Binary fission

The division of one parent cell into two genetically identical daughter cells; a form of asexual reproduction

Conjugation

A form of sexual reproduction in which two cells join to exchange genetic information

Transformation

A process in which a bacterial cell takes in and uses pieces of DNA from its environment

Horizontal gene transfer

The transfer of genetic information from one species into a different species

endospore

A dormant structure that forms inside certain bacteria in response to stress; protects the cells chromosome from damage

Virus

A small infectious particle containing genetic material in the form of DNA Or RNA within a protein capsule

Capaid

A protein coat that surrounds the DNA or RNA of a virus

RNA (ribonucleic acid)

A nucleic acid found in all cells and some viruses; usually carries genetic information that provides instructions for synthesizing protein

Epidemic

A large scale outbreak of disease; usually confined to a limited geographic region

Pandemic

An epidemic that occurs over a widespread geographic area, often globally

Bacteriophage

A virus that infects bacteria

Lysis

The rupturing of a cell; can occur when newly made viruses are released from a host cell

Lysogeny

A state of dormancy in which viral DNA may remain within a host cell’s chromosome for many cell cycle generations

Transduction

A type of gene transfer in which a virus transfers DNA from one bacterium to another

Gene therapy

A method of treating disease in which genes are introduced into cells to replace, supplement or repair a defective gene

Viroid

A very small infectious piece of RNA responsible for some serious diseases in plants

Prion

An abnormally shaped infectious protein responsible for some brain diseases of mammals, including humans

Endosymbiosis

A relationship in which a single-celled organism lives within the cell(s) of another organism; recent findings suggest this may be very common

Haploid

A cell containing half the usual complement of chromosomes

Zygote

A cell produced by the fusion of two gametes

Diploid

A cell containing two copies of each chromosome

Sporophyte

A diploid organism that produces haploid spores in an alternation of generations life cycle

Spore

A haploid reproductive structure; usually a single cell; capable of growing into a new individual

Gametophyte

A haploid organism that produces haploid sex cells in an alternation of generations live cycle

Alternation of generations

A life cycle in which diploid individuals produce spores that create haploid individuals; the haploid individuals reproduce sexually, producing sporophyte individuals and completing the cycle

Key features of proteobacteria (purple bacteria)

-some are photosynthetic but use a form of photosynthesis that differs from the of plants

-Ancient forms of these bacteria were the likely ancestors of eukaryotic mitochondria

-some are nitrogen fixing

Key features of Green bacteria

-they use a form of photosynthesis that differs from that of plants

-they are usually found in salt-water environments or hot springs

Key features of Cyanobacteria (blue-green algae)

-They use a form of photosynthesis similar to plants and other eukaryotes

-Ancient forms of these bacteria were the likely ancestors of eukaryotic chloroplasts

-They play major roles as producers and nitrogen fixers in aquatic ecosystems

-They form symbiotic relationships with fungi

Key features of Gram-positive bacteria

-They cause many diseases, including anthrax, strep throat, bacterial pneumonia, and meningitis

-They are used in food production (for example, lactobacillus is used in yogurt and probiotic products).

-Some have lost their cell wall

-One type—mycoplasmas—are the smallest known cells

Key features of Spirochetes

-their spiral-shaped flagellum is embedded in their cytoplasm

-They move with a corkscrew motion

-they cause syphilis

-Symbiotic spirochetes in termite intestines digest wood fibre

Key features of Chlamydias

-All are parasites that live within other cells

-they cause chlamydia, one of the most common sexually transmitted infections

-They cause trachoma, the leading cause of blindness in humans

key features of methanogens

-they live in low-oxygen environments, including

-sediments of swamps, lakes, marshes, and sewage lagoons

-digestive tracts of some mammals (including humans) and some insects

-they generate energy by converting chemical compounds into methane gas, which is released into the atmosphere

Key features of halophiles

-They are salt-loving organisms that can live in highly saline environments including the Dead Sea and foods preserved by salting

-Most are aerobic and get energy from organic food molecules

-some use light as a secondary energy source

Key features of Extreme thermophiles

-They live in extremely hot environments including hot springs and hydrothermal vents on the ocean floor

-Their optimal temperature range for growth is 70C to 95C

Key features of psychrophiles

-They are cold-loving organism found mostly in the Antarctic and Arctic Ocean’s, and cold ocean depths

-Their optimal temperature range for growth is -10C TO -20C