Bio 80 2 Exam

Prokaryotes

Single celled organisms that make up domains bacteria and archaea

Hypertonic environment

The net movement of water is out of the cell, due to the higher concentration of solutes outside the cell.

Hypotonic environment

The net movement of water is into the cell due to the higher concentration of solutes inside the cell

Isotonic environment

this condition the concentration of solutes is the same

inside and outside the cell, no net movement of water

Cell wall

maintains shape, protects the cell, and

prevents it from bursting in a hypotonic

environment

Most bacterial cell walls contain

______, a network of sugar polymers

cross-linked by polypeptides

peptidoglycan

Gram Stain

identifies bacteria by cell wall

composition

Gram-positive

simpler walls with a

large amount of peptidoglycan

Gram-negative

more complex walls

with outer membrane that contains

lipopolysaccharides and less

peptidoglycan

Many prokaryotes have a sticky layer of ______ or

protein surrounding the cell wall

polysaccharide

Capsule

if dense and well-defined

Slime layer

If not well organized

Endospores

Some bacteria form metabolically inactive endospores

when water or nutrients are lacking

Fimbriae

Hair like appendages that allow prokaryotes to stick to their substrates or other individuals in a colony

Pili

longer than

fimbriae and function to pull

cells together enabling the

exchange of DNA

Chemotaxis

is the movement toward or

away from a chemical stimulus

Flagella

are the most common structures

used by prokaryotes for movement

Prokaryotic cells lack

complex

compartmentalization

Nucleoid

region with no membrane that

holds chromosome

Plasmids

Prokaryotes may also have smaller

rings of independently replicating DNA

called

Genetic recombination

the combining of DNA from two sources, contributes to

prokaryote diversity

DNA from different individuals can be combined by

transformation,

transduction, or conjugation

horizontal gene transfer

Movement of genes between individual prokaryotes of different species

Transformation

: prokaryotic cells incorporate foreign DNA from surroundings

Transduction

phages (from “bacteriophages,”

viruses that infect bacteria) carry prokaryotic

genes from one host cell to another

Conjunction

DNA is transferred between two

prokaryotic cells

Antibiotics kill most bacteria, but not

those with _______, plasmids that

carry resistance genes

R plasmids

Proteobacteria

Gram negative, diverse in nutrition, and many of the heterotrophic bacteria are pathogens

Chlamydias

All species parasitize animal cells and

have gram-negative walls lacking

peptidoglycan

Spirochetes

Gram-negative heterotrophs

• Spiral through the environment by

rotating internal filaments

• Many are free-living, but others are

pathogens

Cyanobacteria

Gram-negative

photoautotrophs

• Plant chloroplasts likely

evolved from cyanobacteria

by the process of

endosymbiosis

Gram-positive bacteria

Diverse and gram-positive

Extremophiles

archaea that

live in extreme environments,

uninhabitable for most organisms

Extreme halophiles

tolerate

or require highly saline

environments

Extreme thermophiles

have

adaptations that make their

DNA and proteins stable at

high temperatures

Archaea and Eukarya are

Sister domains: most closely related

T A C K

A supergroup composed of the remaining,

closely-related clades of archaea

Methanogens

obligate anaerobes that

produce methane as a by-product of their

metabolism

Horizontal gene transfer (HGT) has

played a key role in the evolution of

prokaryotes

Significant portions of the genomes of

prokaryotes are mosaics of genes

imported from other species

metagenomics

used to

obtain entire prokaryotic genomes

from environmental samples

Prokaryotes

Oldest - 3.5 BYA. inhabits every environment to support life, new genomic advantages reveal extent of its diversity, originally classified by things like morphology, motility, gram staining, genetic analysis led to division of prokaryotes into bacteria and archaea

Biofilms

Cells of one or more

prokaryote species cooperate

to form surface-coating

colonies

common in

nature, but can cause many

problems for humans

including

Nitrogen fixation is isolated in

cells called

heterocysts

Facultative anaerobes

can use O2 if it is present or carry

out fermentation or anaerobic respiration if not

Obligate anaerobes

poisoned by O2 and live by

fermentation or use substances other than O2 for

anaerobic respiration

Obligate aerobes

require O2 for cellular respiration

Heterotrophs

require an organic nutrient to make other organic

compounds

Autotrophs

require CO2 or related compounds as a carbon source

Chemotropes

Obtain energy from chemicals

Phototrophs

Obtain energy from light

How do prokaryotes help recycle chemical elements?

• Decomposers (chemoheterotrophic prokaryotes) break down dead organisms and waste.

• This releases carbon and other elements back into the environment.

• Other organisms reuse these elements (like oxygen and nitrogen).

symbiotic

relationships

an ecological

relationship in which two species

live in close contact

Commensalism

one benefits,

the other is Unaffected

Mutualism

Both benefit

Parasitism

One benefits the other is harmed

Only bacteria, not archaea, are

pathogenic

Prokaryotes can also be used

in bioremediation which is…

the use of

organisms to remove

pollutants from soil, air, or

water

What has a nucleus and other membrane-

enclosed organelles

Eukaryotic cells

Protist

informal term used to refer to all

eukaryotes that are not plants, animals, or

fungi

Mixotrophs

combine

photosynthesis and heterotrophic nutrition

relationship between two species in which one organism lives

inside the cell or cells of the other organism (the host)

Endosymbiosis

Plastids

a small organelle

containing pigment or food (e.g.

chloroplasts)

The engulfed cell contains a

vestigial nucleus called

A nucleomorph

Four membranes surround

plasmid of chlorarachniophytes Which include

• 2 from engulfed cyanobacteria

• 1 from engulfed alga’s plasma

membrane

• 1 from heterotrophic

eukaryote’s food vacuole

In other protists, plasmids only

have 3 membranes

Indicates one of original 4

membranes has been lost

Excavata

asymmetrical, single-celled organisms with a feeding groove “excavated” from one side

The excavates include:

Organisms with modified mitochondria: the

diplomonads & parabasalids

• Organisms with unique flagella: euglenozoans

Diplomonads

Have mitosomes: reduced mitochondria

that generate energy anaerobically

Euglenids

• Have 1 or 2 flagella that emerge from a pocket at one end of the cell

• Can also change entire shape of body to move

• Have pellicle - stiff structure that helps keep shape

SAR – Stramenopiles

• Some of the most important phototrophs on Earth

• Most have a “hairy” flagellum paired with a “smooth” flagellum

• 3 important groups: diatoms, brown algae, and oomycetes

Diatoms

unicellular algae with a unique glass-like wall

of silicon dioxide made of silica in an organic matrix

Brown algae

are the largest and most complex

multicellular algae

SAR – Alveolates

• Have membrane-

enclosed sacs (alveoli)

just under the plasma

membrane

• 3 clades

• Dinoflagellates

• Apicomplexans

• Ciliates

Dinoflagellates

aquatic phytoplankton with 2 flagella, cellulose armor plates, and can be photosynthetic, mixotrophic, or heterotrophic.

SAR – Alveolates

• Nearly all apicomplexans parasitize animals

• Spread through host as tiny infectious cells

called sporozoites

• One end contains apical complex

• Non-photosynthetic

• Most have intricate life cycles with both sexual

and asexual stages

• Often require 2+ host species for

completion

• Ex. Plasmodium (causes malaria)

Ciliates

are named for their use of cilia to move

around and feed

Macronuclei

contains multiple copies of

the genome

Micronuclei

: may be diploid or haploid,

depending on life stage

SAR – Rhizarians

• Include forams and radiolarians

• Many are amoebas: protists

that move and feed using

pseudopodia, extensions of the

cell surface

Radiolarians

• Have delicate, symmetrical internal

skeletons typically made of silica

• Use reinforced pseudopodia to engulf

microorganisms by phagocytosis

Forams

• Have porous, multi chambered,

calcium carbonate shells called tests

Chlorophytes

: live in fresh and saltwater,

some are terrestrial

Charophytes

: include the algae most

closely related to plants

Unikonta

Amoebozoans

• Amoebas with lobe- or tube-shaped pseudopodia • Include slime molds,

tubulinids, entamoebas

Opisthokonts

a diverse group

including animals, fungi, and several

groups of protists

Protists play two key roles in

their habitats:

symbiont and

photosynthesizer

Plants

Multicellular terrestrial

organisms that are characterized by

photosynthesis, cell walls, and unique

life cycles and that evolved from within

green algae

Plants share traits with protists

• Multicellular, eukaryotic, photosynthetic autotrophs

• Red, brown, and some green algae

• Cell walls made of cellulose

• Green algae, dinoflagellates, and brown algae

• Chloroplasts with chlorophyll a and b

• Green algae, euglenids, and a few dinoflagellates

Shared traits plants and charophytes

Peroxisome enzymes

Flagellated sperm structure

Forms phragmoplast

Rose shaped complexes creates cell walls

Similar DNA

Differed traits between plants and charophytes

1. Alternation of generations that includes multicellular,

dependent embryos

2. Walled spores produced in sporangia

3. Multicellular gametangia

4. Apical meristem

archegonium

Female archegonium produce

egg cells

antheridia

Male antheridia produce and

release sperm

Bryophytes

informal term

referring to all nonvascular

plants

Seta

conducts nutrients to capsule,

which produce spores

Byroohyta

Moss

Hepatophyta

Liverworts

Anthcerophyta

Hornworts

Xylem

conducts most of the water and

nutrients

Phloem

distributes organic products