Honors Bio 2 Chapter Ch24

what are bacteria

one of the three domains of life, consisting of single celled organisms without a nucleus. They have a cell wall made of peptidoglycan, typically have a single circular chromosome, and divide by binary fission

what are plasmids

in bacteria, a small circular molecule of DNA carrying a small number of genes that replicates independently of the DNA in the bacterium’s circular chromosome

what is peptidoglycan

a complex polymer of sugars and amino acids that makes up the cell wall in bacteria

what is horizontal gene transfer

the transfer of genetic material between organisms that are not parent and offspring

what is conjugation

the direct cell to cell transfer of DNA

what is transformation

the conversion of cells from one state to another, as from nonvirulent to virulent, when DNA released to the environment by cell breakdown is taken up by recipient cells. In recombinant DNA technology, the introduction of recombinant DNA into a recipient cell. Transformation is a form of horizontal gene transfer

what is transduction

the transfer of DNA between cells by means of a virus; a form of horizontal gene transfer. In cell biology, the passing of a signal from the outside of a cell to the inside, as in signal transduction

what are archaea

One of three domains of life, consisting of single celled organisms with a single circular chromosome and lacking a membrane bound nucleus. They divide by binary fission and differ from bacteria in many aspects of their cell and molecular biology

what is the carbon cycle

the network of biological and physical processes that shuttles carbon among rocks, soil, oceans, air, and organisms

what are cyanobacteria

a monophyletic group of bacteria capable of oxygenic photosynthesis; historically (and inaccurately) referred to as blue-green algae

what does oxygenic mean

producing oxygen

what does aerobic mean

utilizing oxygen

what does anoxygenic mean

not producing oxygen; anoxygenic photosynthetic bacteria do not use water as an electron donor and so does not generate oxygen gas

what is bacteriochlorophyll

a light-harvesting pigment found in photosynthetic bacteria; closely related to the chlorophyll pigments found in plants, algae, and cyanobacteria

what is fermentation

metabolic pathways in which the terminal electron acceptor is an organic molecule, in contrast to aerobic cellular respiration, in which the terminal electron acceptor is oxygen (O2). Fermentation produces ATP from the partial oxidation of organic molecules without oxidative phosphorylation. Two major types of fermentation are ethanol (alcoholic) and lactic acid fermentation

what are photoheterotrophs

an organism that uses the energy from sunlight to make ATP and relies on organic molecules obtained from the environment as the source of carbon for growth and other vital functions

what are chemoheterotrophs

a microorganism, such as a bacterium, that obtains its carbon by the fixation of carbon dioxide, using energy derived from chemical reactions, not from sunlight

what are primary producers

an organism that takes up inorganic carbon, nitrogen, phosphorus, and other compounds from the environment and converts them into organic compounds; a source of food for heterotrophic organisms in the local environment

what is assimilation

the process by which organisms incorporate nutrients obtained from the environment into more complex molecules

what is nitrogen fixation

the process by which some bacteria and archaea convert nitrogen gas (N2) into ammonia (NH3), a biologically useful to primary producers

what is nitrification

the process by which chemoautotrophic bacteria oxidize ammonia (NH3) to nitrite (NO2-) and then nitrate (NO3-)

what is denitrification

the process in which some bacteria use nitrate as an electron acceptor in respiration, releasing N2 to the environment

what is anammox

anaerobic ammonia oxidation; energy metabolism found in some bacteria in which ammonium ions are oxidized by nitrite, yielding nitrogen gas as a byproduct

what is a proteobacteria

the most diverse bacterial group, defined largely by similarities in rRNA gene sequences; it includes many of the organisms that populate the expanded carbon cycle and other biogeochemical cycles

what are gram-positive bacteria

bacteria that retain, in their thick peptoglycin walls, the diagnostic dye originally developed by Hans Christian Gram. Bacteria with thin walls, which do not retain dye, are said to be gram negative

what are gram-negative bacteria

bacteria that do not retain diagnostic dye due to thin cell walls

what are hyperthermophics

an organism that requires an environment with high temperature

what is a methanogen

an archaeon that generates natural gas (methane, CH4) as a by product of anaerobic energy metabolism

what is symbiosis

a close, long term interaction between two different biological species

what is mutualism

a form of symbiosis that is mutually beneficial for both organisms, ex. gut bacteria

what is commensalism

a symbiotic relationship that benefits one organism without harming or helping the other organism

what is parasitism

a symbiotic relationship that benefits one organism while hurting the other

what are the three domains of life

bacteria, archaea, and eukaryotes

what are the 2 clades of prokaryotes

bacteria and archaea

what is the most known about prokaryote

bacteria

what can be learned from modern prokaryotes

information on original life forms, how evolution caused eukaryotes, and how prokaryotes were the only life forms 3.6-2.1

what are characteristics of bacterial cells

they outnumber eukaryotic cells, have no membrane bound nucleus, no energy producing organelles, and no sexual reproducing (leading to mutations from only mutations)

how does bacterial DNA function

it is a singular circular chromosome and also contains additional DNA (plasmids)

what can plasmids be used for

to make bacteria produce substances such as insulin via biotech companies

what occurs due to bacterial DNA being located in the cytoplasm

transcription and translation occur at the same place

where and how are cellular processes carried out by

the cytoplasm or in membrane of a bacterial cell by proteins that are free floating or membrane bound

how are bacteria classified

via a reaction to a gram stain that provides information about a cell wall

what are characteristics of gram positive bacteria

thick simple cell walls made of peptidoglycan that stain purple, like Staph

what are characteristics of gram negative bacteria

thin cells with less peptidoglycan, they lose the crystal violet stain, retaining safranin, appearing pink, tending to be more toxic like E coli

why is the small size of bacteria effective

it allows for nutrients via diffusion, resulting in a large surface area to volume ratio and the interior being closer to the environment, with larger cells struggling to get nutrition via diffusion alone

what are bacilli

rod shaped bacteria, like E coli

what are coccus

sphere shaped bacteria like staph

what are spirillum

bacteria shaped like squiggles (found in stagnant water)

what are spirochetes

spiral shaped bacteria like syphilis

what are club bacteria

club shaped bacteria like diphtheria

what are vibrio

bacteria shaped like beans with flagella like cholera

how do bacteria reproduce

a form of asexual reproduction like binary fission

what is binary fission

rapid genome duplication followed by cell fission, resultiing in many generations over short periods, optimally 1-3 hours, fast as 20 minutes, but usually 12-24 hours

how does genetic variation occur in bacterial cells

horizontal gene transfer, despite most genes coming from parent cells

how is horizontal gene transfer beneficial

it allows cells to gain beneficial genes from organisms distributed throughout the bacterial domain and beyond via conjugation, transformation, and transduction

how does conjugation work

DNA from a donor bacteria creates a pilus between the donor and the host, pulling the two cells together, where plasmids are transfered via a small opening

how does transformation work

DNA is released into the environment by dead cells, and new cell takes DNA from the dead donor in the external environment

transduction

a virus infected donor transfers DNA to a host via a virus

what is the difference between phototrophs and chemotrophs

phototrophs recieve energy from light vs chemotrophs recieve energy from chemical bonds

what is the difference between autotrophs and heterotrophs

inorganic carbon sources vs organic carbon sources

what kinds of organisms are photoheterotrophs

photosynthetic prokaryotes, some protists, and plants

what kinds of organisms are chemoautotrophs

some prokaryotes

what kinds of organisms are photoheterotrophs

some prokaryotes

what kinds of organisms are chemoheterotrophs

prokaryotes, protists, fungi, and animals

what is the normal carbon cycle

plants convert CO2 into carbohydrates, which animals then use to create CO2 from oxygen

what is anaerobic respiration

prokaryotes using different electron acceptors like NO3 and SO4 into forms of carbon used by anoxygenic photosynthesis to recycle the carbon

what is fermentation

a form of carbon recycling occuring in chemoautotrophs (not a major pathway)

what are obligate aerobes

prokaryotes that require aerobic respiration like us

what are obligate anaerobes

prokaryotes poisoned by oxygen that fermentation/glycolysis, with no Krebs cycle

what are fatultative anaerobes

prokaryotes that are areobic and anaerobic

Where does glucose come from

Gluconeogenesis

What is a microbial mat

A group of microorganisms in the oceans matted up in multiple layers

What is the blue-green layer in microbial mats

Cyanobacteria, appear on top in well lit and oxygen rich areas

What is the purple layer in a microbial mat

Purple bacteria, an anoxygenic photosynthetic bacteria that lives in areas with light but no oxygen

What is in the black layer of a microbial mat

Bacteria that require anaerobic respiration and fermentation to support populations

What organisms live around hydrothermal vents

Chemoautotrophs that gain carbon by reducing CO2 to form carbohydrates

Where do chemoautotrophs get energy

From chemical reactions using molecules and ions such as H2, H2S, and Fe2+ to generate ATP, reducing energy needed to put CO2 in organic molecules

What is the main component of the sulfur cycle

Anaerobic respiration by bacteria and archaea reduces So42- into H2S which is then metabolized by chemoautotrophs and photosynthetic bacteria into SO42-

What is assimilation

When primary producers turn SO42- into organic S found in proteins

What is decomposition

When fungi and bacteria convert organic S molecules into H2S

What is nitrogen fixation

When bacteria and archaea turn N2 into ammonia (NH3/NH4+) which then goes into assimilation, nitrification, or annamox (fix N2 into a biologically available form)

What is nitrification

When ammonia is converted into Nitrite (NO2-) and then into Nitrate (NO3-), later goes into denitrification or assimilation (oxidized by bacteria)

What is denitrification

When nitrates (NO3-) are converted into nitrogen gas N2

What is anammox

NH4+ + NO2- → N2 + 2H2O

An anaerobic ammonia oxidation into Nitrogen gas, which provides a small amount of energy but is important for bacteria and archaea in oxygen poor environments (where prokaryotes gain energy)

What is assimilation in the nitrogen cycle

When plants take nitrates or ammonia and convert them into Organic Nitrogen, which is then decomposed into ammonia

What is true about diversity of prokaryotes

It is mostly unknown, but consists of most of life

How is the bacterial diversity in the oceans.

There are thousands of species found in the oceans, many are common, but there are enormous and diverse portions of the rare biosphere

What are proteobacteria

An extremely diverse group that contains nitrogen fixers as well as pathogens including salmonella, Neisseria gonorrhoeae, typhus, cholera

What are spirochetes

Heterotrophs that move by rotating internal flagella, including taxa responsible for syphillis and Lyme Disease

What are common traits of gram positive bacteria

A diverse group that contains pathogens like (clostridium, Bacillus anthracite, Leprosy, streptococcus, Staphlococcus) which also secrete compounds that kill bacteria and fungi like tetracycline and streptomycin

What are traits of Cyanobacteria

They generate oxygen by photosynthesis and are the origin of chloroplasts

How many clades of archaea are there

4

What are extremophiles

Archaea that can survive and extreme conditions

What is a halophile

Archaea that require high salt concentrations; like species living in the Great Lakes

What are thermophiles

Archaea that require high temperatures; like species living in hot springs (near boiling water)

What are methanogens

Archaea that use CO2 and H2 to create methane, they are obligate anaerobes in marshes and are mutualists with protozoa in termite and ruminant guts

What kind of symbiosis are only in bacteria

Parasitism, they make up half of human diseases like cholera, tuberculosis, botulism, food poisoning, and Lyme disease

What is the first step of controlling bacterial pathogens

Washing, Germ theory that pathogens come from microorganisms

What is the second big step in controlling pathogens

Antibiotics, drugs that target prokaryote traits, wont harm us

What drug targets the cell wall

Penicillin, as peptidoglycan is not found in eukaryotes