Chapter 2 - Prokaryotes, Viruses, and Protists Flashcards
pathogen
a disease-causing micro-organism (e.g. bacteria, virus)
plasmid
a small loop of DNA often found in prokaryotic cells, containing a small number of genes
capsule
the protective outer layer of some bacteria; makes them appear shiny
3 common shapes of bacteria
coccus/cocci - round
bacillus/bacilli - rod shaped
spirillum/spirilli - spiral/corkscrew shaped
obligate aerobe
an organism that must have oxygen to survive
facultative aerobe
an organism that can live with or without oxygen
obligate anaerobes
organisms that cannot live in the presence of oxygen
Describe the process of binary fission
- chromosome duplicates
- cell elongates
- cell splits into 2 identical daughter cells
Describe the process of conjugation
- 2 cells join to exchange genetic information
- copy of plasmid is transferred to nearby cell through hollow pilus
Describe the process of transformation
- bacteria cell picks up and uses pieces of DNA from environment
- incorporates new DNA into chromosome
endospore
a structure highly resistant to extreme conditions that forms around the chromosome when under stress; will remain dormant until conditions improve
Name the six major groups of bacteria
- Proteobacteria (purple bacteria)
- Green bacteria
- Cyanobacteria (blue-green algae)
- Gram-positive bacteria
- Spirochetes
- Chlamydias
horizontal gene transfer
when one species picks up DNA from another species; AKA lateral gene transfer
List 4 reasons why viruses are considered to be non-living.
- They do not grow
- They cannot reproduce
- They do not produce/use energy
- They cannot maintain homeostasis
bacteriophage
a virus that infects a bacteria
5 stages of the lytic cycle
- ATTACHMENT to cell
- PENETRATION of viral DNA or RNA (at which point it may continue with lytic or lysogenic cycle)
- REPLICATION (biosynthesis) of new viral proteins and nucleic acids
- ASSEMBLY (maturation) of the new viruses
- RELEASE of new viruses into environment (cell lyses)
4 stages of the lysogenic cycle
- Phage DNA injected
- Viral DNA joins host DNA to form prophage
- Viral DNA replicated with binary fission
- May enter lytic cycle or stay dormant
viroid
small, circular RNA that only infects plants and does not have a protein coat (e.g. potato famine)
prion
an infectious protein, causing neurological diseases in mammals (e.g. Mad Cow disease)
gene therapy
a method of treating disease by introducing genes into a cell
retrovirus
contains RNA (e.g. HIV)
mutualism
a relationship between 2 species where each species benefits from the association
Name the 3 common shapes of bacteria.
Coccus (round), bacillus (rod), spirillum (spiral/corkscrew)
epidemic
a large scale (but confined) outbreak of disease
pandemic
widespread, global outbreak of a disease
endosymbiosis
a relationship in which a single celled organism lives inside the cell(s) of another organism
Difference between haploid and diploid
haploid: a cell containing half the usual number of chromosomes (n)
diploid: a cell containing two copies of each chromosome (2n)
zygote
a cell formed when a sperm fuses with an egg
sporophyte
a diploid organism that produces haploid spores
gametophyte
a haploid organism that produces haploid sex cells
alternation of generations
life cycle in which diploids produce spores that can create haploid individuals; haploids reproduce sexually to produce diploid sporophytes
Where do heterotrophic bacteria obtain their nutrients?
From carbon-containing organic compounds
In bacteria, the cell membrane is called the ____
plasma membrane
If a bacteria cell can pick up a stain, it has a _______, and is said to be ______.
It has a thick peptidoglycan layer (in the cell wall), gram positive
Name 3 shapes of viruses
Helical, Polyhedral and Complex
Explain antibiotic resistance. `
- When a bunch of bacteria are exposed to antibiotics, most bacteria will die, but resistant bacteria will survive
- The entire strain become resistant, and the antibiotics are no longer effective
Name 4 groups of euryarchaeota.
Methanogens, Halophiles, Extreme thermophiles, Psychrophiles
Characteristics of amoebas
- heterotrophs
- pseudopods
- hard outer skeletons
- most animal-like
Characteristics of euglenoids
- autotrophs
- unicellular
- have 2 flagella for movement
Characteristics of ciliates
- heterotrophs
- unicellular
- many cilia, but no cell walls
Characteristics of apicomplexa
- heterotrophs
- unicellular
- no cell wall
- ALL are parasites of animals
Characteristics of diatoms
- autotrophs
- unicellular
- move by gliding
- covered by glass-like silica shells
Characteristics of red algae
- autotrophs
- almost all are multicellular
- no cilia or flagella
- cell walls made of cellulose
Which protists are considered animal-like and which are considered plant-like?
Animal: amoeba, ciliates, apicomplexa
Plant: red algae, euglanoids, diatoms
