Chapter 17, 20, 24 Flashcards
What are the 3 domains of life?
Bacteria, archaea, and eukaryota. Eukaryota are animals, plants, fungi, and protists).
Capsid
The protein shell that encloses a viral genome. It may be rod-shaped, polyhedral, or more complex in shape.
How may a viruses genome be?
Double/single stranded DNA and double/single stranded DNA
Viral envelope
A membrane, derived from membranes of the host cell, that cloaks the capsid, which in turn encloses a viral genome.
Bacteriophage
A virus that infects bacteria; also called a phage.
Host range
The limited number of species whose cells can be infected by a particular virus.
Lytic cycle
A type of phage replicative cycle resulting in the release of new phages by lysis (and death) of the host cell.
Lysogenic cycle
A type of phage replicative cycle in which the viral genome becomes incorporated into the bacterial host chromosome as a prophage, is replicated along with the chromosome, and does not kill the host.
Virulent phage
A phage that replicates only by a lytic cycle.
Give a brief summary of the lytic cycle steps
1) Attachment 2) Entry of phage DNA and degradation of host DNA 3) Synthesis of viral genomes and proteins 4) Assembly 5) Release
Restriction enzyme
An endonuclease (type of enzyme) that recognizes and cuts DNA molecules foreign to a bacterium (such as phage genomes). The enzyme cuts at specific nucleotide sequences (restriction sites).
Temperate phage
A phage that is capable of replicating by either a lytic or lysogenic cycle.
Prophage
A phage genome that has been inserted into a specific site on a bacterial chromosome.
Phylogeny
The evolutionary history of a species or group of related species.
Systematics
A scientific discipline focused on classifying organisms and determining their evolutionary relationships.
Taxonomy
A scientific discipline concerned with naming and classifying the diverse forms of life.
Binomial
A common term for the two-part, latinized format for naming a species, consisting of the genus and specific epithet; also called a binomen.
How does the naming system go?
Genus —> species
Genus
taxonomic category above the species level, designated by the first word of a species’ two-part scientific name.
What is the order of the Linnaean system?
Kingdom –> Phylum –> Class –> Order –> Family –> Genus –> Species
What are Archaea?
These are ancient forms of bacteria that were originally grouped under the kingdom Monera (now defunct) as Archaeabacteria. They are single celled microbes that find their origins as the first organisms of life here on Earth. Hence we give them the prefix ‘archaea’, which in Greek means ‘ancient things.’ Archaea organisms are also different from other domains in that many are extremophiles, meaning they can live in intense environments with high temperature, high acid, and high salt levels. One type of extremophile is the methanogens, or those organism that produce methane as a product of their metabolism.
Who are Miller and Urey and what did they do?
Miller and Urey made early earth in a lab. They simulated the conditions on early earth. They simulated water evaporating, electors which equaled lighting and also prebiotic soup. Result: amino acids formed
Describe early earth
Early earth didn’t have clear water and oceans, it didn’t have plants, there was no life at all. The sun was weaker and the atmosphere was thicker and dominated by CO2.
What was the environment for first life?
Consisted of hydrogen sulfide.
What are the ingredients of life?
Hydrogen, oxygen, carbon, and nitrogen.
What are Cyanobacteria?
They are bacteria on top of stromatolites and they are blue/green. They use photosynthesis as energy. As stuff settles on top the bacteria move up. Cyanobacteria made oxygen to produce the oxygenated atmosphere on earth.
Talk about Cyanobacteria part 2
Cyanobacteria obtain their energy through photosynthesis.
Earth earth with oxidizing vs reducing
By producing gaseous oxygen as a byproduct of photosynthesis, cyanobacteria are thought to have converted the early reducing atmosphere into an oxidizing one, causing the “rusting of the Earth”[7] and causing the Great Oxygenation Event, dramatically changing the composition of life forms on Earth by stimulating biodiversity and leading to the near-extinction of anaerobic organisms (that is, oxygen-intolerant). Symbiogenesis argues that the chloroplasts found in plants and eukaryotic algae evolved from cyanobacterial ancestors via endosymbiosis.
Abiotic
Nonliving; referring to the physical and chemical properties of an environment.
Probiotic
Denoting a substance that stimulates growth of micro organisms, especially those with beneficial properties
Protocells
An abiotic precursor of a living cell that had a membrane-like structure and that maintained an internal chemistry different from that of its surroundings.
What are the earliest fossils?
They are of prokaryotes that lived 3.5 billion years ago
Simple cells were produced through what 4 main stages?
1) The abiotic (nonliving) synthesis of small organic molecules, such as amino acids and nitrogenous bases.
2) The joining of these small molecules into macromolecules, such as proteins and nucleic acids.
3) The packaging of these molecules into protocells, droplets with membranes that maintained an internal chemistry different from that of their surroundings.
4) The origin of self-replicating molecules that eventually made inheritance possible.
Stromatolites
Stromatolites are many of the oldest known fossils that are layered rocks that form the activities of certain prokaryotes.
Gram positive
Describing the group of bacteria that have a cell wall that is structurally less complex and contains more peptidoglycan than the cell wall of gram-negative bacteria. Gram-positive bacteria are usually less toxic than gram-negative bacteria.
Gram negative
Describing the group of bacteria that have a cell wall that is structurally more complex and contains less peptidoglycan than the cell wall of gram-positive bacteria. Gram-negative bacteria are often more toxic than gram-positive bacteria.
Gram positive bacteria with gram staining
Gram positive bacteria stain a darker color and have a thick cell wall made of peptidoglycan
Gram negative bacteria with gram staining
Gram negative bacteria have a thinner layer of peptidoglycan located between the plasma membrane and the outer membrane
Peptidoglycan
A type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides. Peptidoglycan encloses the entire bacterium and anchors other molecules that extend from its surface.
Endospores
A thick-coated, resistant cell produced by some bacterial cells when they are exposed to harsh conditions.
Capsule
(1) In many prokaryotes, a dense and well-defined layer of polysaccharide or protein that surrounds the cell wall and is sticky, protecting the cell and enabling it to adhere to substrates or other cells. (2) The sporangium of a bryophyte (moss, liverwort, or hornwort).
Endosymbiosis
A mutually beneficial relationship between two species in which one organism lives inside the cell or cells of another organism.
Role of RNA
First way of passing down and storing information information.
Transformation
(1) The conversion of a normal animal cell to a cancerous cell. (2) A change in genotype and phenotype due to the assimilation of external DNA by a cell. When the external DNA is from a member of a different species, transformation results in horizontal gene transfer.
Conjugation
(1) In prokaryotes, the direct transfer of DNA between two cells that are temporarily joined. When the two cells are members of different species, conjugation results in horizontal gene transfer. (2) In ciliates, a sexual process in which two cells exchange haploid micronuclei but do not reproduce.
Binary fission
A method of asexual reproduction by “division in half.” In prokaryotes, binary fission does not involve mitosis, but in single-celled eukaryotes that undergo binary fission, mitosis is part of the process.
Compare binary fission and conjugation
Both reproduce& replicate DNA, maybe plasmids, gene transfer, produce offspring
Contrast binary fission and conjugation
Conjugation: sexual reproduction (2 parents), 1 cell can’t continue species survival, reproduces slowly, has F-factor, produces different offsprings-genetic diversity
Binary fission: asexual reproduction (1 parent), produces identical offsprings, 1 cell can continue species survival, no F-factor, reproduces quickly
Quorum sensing
Instead of language, bacteria use signalling molecules which are released into the environment. As well as releasing the signalling molecules, bacteria are also able to measure the number (concentration) of the molecules within a population. Nowadays we use the term ‘Quorum Sensing’ (QS) to describe the phenomenon whereby the accumulation of signalling molecules enable a single cell to sense the number of bacteria (cell density). In the natural environment, there are many different bacteria living together which use various classes of signalling molecules. As they employ different languages they cannot necessarily talk to all other bacteria.
Bacteria
Bacteria are tiny living beings (microorganisms) - they are neither plants nor animals - they belong to a group all by themselves. Bacteria are tiny single-cell microorganisms, usually a few micrometers in length that normally exist together in millions.
How do antibiotics work?
Antibiotics work by blocking vital processes in bacteria, killing the bacteria, or stopping them from multiplying. This helps the body’s natural immune system to fight the bacterial infection.
What are antibiotics?
Antibiotics are medicines used to treat infections or diseases caused by bacteria (e.g. respiratory tract infections such as pneumonia and whooping cough).
Domain
(1) A taxonomic category above the kingdom level. The three domains are Archaea, Bacteria, and Eukarya. (2) A discrete structural and functional region of a protein.
Bacteria
type of prokaryotic organism
Identified by their: 1) shape 2) chemical nature of their cell walls 3) they ways they move 4) the
ways they obtain energy
How do bacteria reproduce?
1st way: binary fission
2nd way: conjugation
What do cladogram so use for grouping?
Cladograms use patterns of shared derived characters as the main criteria for grouping.
Describe the earliest life forms on earth
Prokaryotic cells with metabolism based on chemosynthesis
What are the steps to the formation of life on earth; as it involves Protocells
Protocells are cells that are the step before life that make a membrane bound structure. First thing made on earth were amino acids (monomers) which made polymers. Polymers then go to protobions which then go to prokaryotic structures and then to eukaryotic structures.
