BSC 111: Chapter 20, 21, 23, 25 Definitions and Key Concepts

Virus

noncellular parasitic agent consisting of outer capsid and innercore of nucleic acid

Obligate Intracellular Pathogens

replicate using the metabolic machinery of host cells

Outer layer of a virus

protein capsid contains genetic material that will attach to a host cell through tissue specificity, lock and key fit, or target immune response

Outer Membranous envelope

outer layer of a virus is derived from the host cell's plasma membrane

Attachment Step(Lytic Cycle )

virus gains based on proteins on a cell and virus (must match)
within the cells of specific living Organisms
-> determined by the structure of proteins in the naked capsid in the spikes of an enveloped virus

Penetration step (Lytic Cycle)

host cell engulfs virus or injects genome into cell

biosynthesis step (lytic cycle)

viral component synthesized using host cell

Released step(Lytic Cycle)

new viruses exit the host cell through lysis or budding to infect new host cells

Lysogenic Cycle

After penetration, bacterial cell is integrated into bacterial DNA and is passed on when bacteria reproduce. Causes the bacteria to go dormant and will be activited with the chnages in the enviroment

lytic cycle starts immediately

in animal viruses reproduction:

Seasonal FLu (RNA Virus)

-Influenza A-virus: host changes, caused epidhous
-Influenza B and C: only in humans
Rapid mutation rate

HIV/AIDS

Retrovirus:
Animal viruses with an RNA genome that is converted into DNA within the host cell by reverse transcriptase
->AIDS
->Human Immuno Deficiency

Emerging Viruses

Outbreak of previously unknown disease or known disease that increase in occurrence
-Mutated from existing RNA
-Expanded host range
-Antigenic shift
-vector born

Viral Diseases in Plants

-Can occur due to varroids
> 10,000 known viruses

Viroids

RNA with no capsid

Prions

misfolded proteins that can transmit their misfolded shape onto variants of the same protein

Fatal Neurovegetative Brain Disease

TSEs(transmissible spongiform encephalopathies) caused by prions
-Scrapie
-Chronic Waste Disease
-Kuru
-Mad Cow Disease

Prokaryotes

single celled, lacks membrane bound nucleus and the membranous organelles typical of eukaryotes
-> Evolved 3.5 BYA

Cell Wall

Provides support and shapes to a prokaryote cell

Capsule(Slime Layer)

helps parasitic bacteria protect itself from host cell defenses

Fimbriac

hairlike bristles that allow adhesion to surfaces

Flagellum

rotating filament that propels the cell

Conjunction Pilus

elongated, hollow appendage used to transfer DNA to other cells

Ribosome

site of protein synthesis (smaller than eukaryotes)

Nucleoid

single chromosome containing a few thousand genes that codes proteins

Plasmids

accessory rings that contain genes for antibiotic resistance

Binary Fission

Prokaryote reproduction where the cell splits and genetically identical sister cells
-allows rapid population growth because every individual our reproduce
- disadvantage: less genetic variation

transformation

Source of genetic variation where prokaryotes can absorb and express genetic material from environment

transduction

source of genetic variation where the process of transferring genetic material from one cell to another by a plasmid or bacteriophage

conjugation

source of genetic variation where genetic material transmitted by plasmids
-Cells connect by conjugation pilus
-donor cell passes DNA to recipient in the form of a plasmid

Peptidoglycan

Composition of Domain bacterial cell walls

gram-negative

indicates that a bacteria has a thin peptidoglycan wall and a extra LPS membrane layer

Spirilla

Spiral

Bacillus

rod shaped

coccus

circle

Strepto

chain

Stapho

clump

autotrophic

of or relating to organisms that can make complex organic nutritive compounds from simple inorganic sources by photosynthesis

heterotrophic

requiring organic compounds of carbon and nitrogen for nourishment

Bacterial Photoautotrophs

photosynthetic bacteria

Facultative anaerobes

bacteria is able to growing either the presence of absence of gaseous oxygen

Chemoautotrophs

bacteria that carry out chemosynthesis
-oxidize compounds to obtain the necessary energy to reproduce CO2 to an organic compound

Chemoheterotrophic

bacteria that obtain carbon and energy in the form of organic nutrients produced by other living things

Symbiotic relationship

close relationship between two different species

Mutualistic Symbiosis

both species benefit from the association

Parasitic Symbiosis

one species benefit, the other is harmed

Commensalism symbiosis

one species benefits whereas the other is unaffeced

Endospores

formed by pathogens within a cell wall
a copy of chromosome and cytoplasm shriveled into a dormant state, are encased by a heavy coat

Antibiotics

treatment that targets prokaryotes cell wall production in humans

cyanobacteria

Gram-negative bacteria that photosynthesize-> produces oxygen
Contains chlorophyll
Common in fresh and marine waters, soil, and on moist surfaces
Form lichens that can grow on rocks

Roles of Bacteria

Producers:
Responsible for the oxygen revolution
An important part of marine phytoplankton (food and oxygen production)

Domain Archaea

bacterial cells with pseudopeptidoglycan cell walls
Extremophiles: live in conditions of acidity, pressure, temp, salinity that would kill most other cells

Extreme Halophiles

archaea that live in extreme salt conditions

extreme thermoacidophiles

archaea that thrive in hot acidic environment

Methagenes

archaea that generate methane
-> exist in swamps and animal intestinal tracts

Protists

eukaryotes that are not animals, fungi, or plants
Single-celled, but some exist as colonies of cells or are multicellular

Endosymbiotic theory

proposes that eukaryotic cells acquired mitochondria and plastics(including chloroplasts) by engulfing a free-living bacterium that developed a symbiotic relationship within the host cell
-Mitochondria derived first from the endosymbiosis of an aerobic bacterium

mitosis

protists will reproduce asexually by

sexually

protists reproduce how when environmental conditions are unfit

giardia

protist parasite causing serious disease

dinoflagellate

Single celled phototrophs
important component phytoplankton
Cellulose plates surround two flagella
Causes Algae blooms: population explosion cause tides
-water turns red or brown due to pigments

plasmodium

protist that causes malaria
performs antigen switching

inside the insect vector

the sexual stage of plasmodium occurs

in human blood cells

the asexual stage of plasmodium occurs

Diatoms

A type of algae
Single-celled phototrophs
Part of phytoplankton as a source of oxygen and food in aquatic ecosystems

Diamtaxous earth

fossilized diatoms used in abrasives

brown algae

true algae
-Multicellular phototrophic
-Kelp
-Homoplastic with plants due to convergent evolution

oomycetes

fungus like protists
water molds with a filamentous body, chitin cell walls instead of cellulose

Entamoebas

-parasite
Used pseudopods to ingest cells-> uses a temporary arm like projection of a cell to move organisms
Acquired through contained water and soil
Causes amoebic dysentery

Slime molds

Important decomposer of dead plant material, fungi, and bacterial
Reduce spores but homoplasy with fungi is due to convergent evolution
Amoeboid movement using cytoplasmic streaming

red algae

Multicellular photoautotrophs (seaweed)
Red and blue accessory pigments in addition to photosynthetic chlorophyll
Pigments allow for us of the wavelength of light present in deep water

green algae

algae
Phototrophs
Most are multicellular, but some are unicellular
Contain chlorophyll, scratch, and a cell wall with cellulose
Charophytes: first closet relatives to modern land plants

Algae

photosynthetic organisms in freshwater habitats that re most closely related to land plants
Transition between protist and landplants

Aquatic

the vast majority of green algae are

green plants (virdiplantae)

green algae + land plants

-water cuticle
-stromata
-Vascularity

Land Plant adaptions to water loss

Stromata

pores in land plants that open and close to regular water and gas exchange

vascular tissue

tissue that conducts water and nutrients through the plant body in higher plants

tracheid

long tubular cell peculiar to xylem, conduct water upward from roots

Flavonoids

An adaption land plants made through pigments that absorb UV rays

Dominate diploid generation

Shift to this minimizes the effect of genetic mutation in plants due to UV rays by having two copies of the same gene

Haplodiplontic life cycle

multicellular haploid and diploid life stages

alternation of generations

a life cycle that alternates between two distinct multicellular haploid and diploid stages

Haploid (n)

cell condition in which only one of each type of chromosome is present,

gametophyte generation

haploid generation of the alternation of generations that produces gametes that unite to form a diploid zygote
->al spores divide by mitosis to produce the gametophyte
-> produces gametes by mitosis

Diploid (2n)

cell condition in whcih two of each type of of chromosome are present

sporophyte generation

diploid generation that produces haploid spores that develop into the haploid generation
->produces 4 haploid spores

sporangium(2n)

organ containing or producing spores

spore(n)

asexual reproductive cell capable of developing into a new organism without union with another cell. Within the gametocyte part of alteration of generation

gametangia

male and female gamete producing regions

Antheridia

male gametangia; produce sperm

archegonia

female gametangia; produces eggs

Gametophyte Dominant

What generation is dominnst in mosses

microscopic

When a sporophyte gains dominance the gametophyte is

Sporophyte dominance

In Vascular plants, what is the dominate generation

non-tracheophytes

all non-vascular plants -> Dominant gametophyte generation -> restricted to living in a wet environment

Phlyum Bryophyta(non-tracheophytes)

Mosses -> typically low laying -> superficial leaves, roots, and stems -> multicellular gametangia form at the tips of gametophytes

Phlyum Marchantiophyta (non-tracheophytes)

Liverworts -> flattened gametophytes with liver like lobes -> microscopic sporophyte -> can produce sexually or asexually

Gemma cups

Asexual reproduction done by liverworts; contain a fragment of parent plant. When water fills the cup, the fragments spread tne reproduction occurs

Phylum Anthocerotophyta(non-tracheophytes)

Hornworts
-> Sporophytes are photosynthetic and embedded in the gametophyte tissue