LSU BIOL 1202 Exam 2: McCoy

two domains of prokaryotes

Bacteria and Archaea

prokaryotes

unicellular organisms that lack a nucleus, circular chromosomes

sphere

cocci

rods

bacilli

spirals

spirilla

cell wall

maintains cell shape, provides physical protection, prevents cell from bursting in a hypotonic environment

Gram stain

A staining method that distinguishes between two different kinds of bacterial cell walls.

Gram-positive bacteria

Bacteria that have a thick peptidoglycan cell wall, and no outer membrane. They stain very purple

Gram-negative bacteria

Bacteria have complex cell walls with less peptidoglycan but with lipopolysaccharides. They stain pink. They are more disease-causing due to toxic lipopolysaccharides on the wall.

cell surface structures

- capsules, slime layers, fimbriae, pili

capsule

Covers the cell wall in prokaryotes.

Fimbriae

attachment structures on the surface of some prokaryotes

motility of bacteria

Ability to move via flagella

Spirochetes have axial filaments which wrap around the cell causing it move in a corkscrew manner

Reproduction in Prokaryotes

binary fission, divide every 1-3 hours, asexual reproduction, produces identical daughter cells

bacterial conjugation

the direct transfer of genetic material (DNA) from one bacterial cell to another

Transformation

uptake of foreign DNA from the surrounding environment

Transduction

viruses transfer genes between prokaryotes, one host to another

obligate anaerobes

organisms that cannot live where molecular oxygen is present

obligate aerobes

require oxygen

facilitative anaerobes

can live with or without oxygen

nitrogen-fixing bacteria

bacteria that can use nitrogen in soil to make nitrogen compounds

Domain Bacteria

Proteobacteria

Chlamydias

Spirochetes

Cyanobacteria

Gram-positive bacteria

Archaeans

Group of prokaryotic, unicellular organisms that live in harsh environments

thermophiles

heat loving

barophiles

organisms that live under extreme pressure

Methanogens

A group of archaebacteria that produce methane as a by product of their metabolism. live in swamps & marshes

Halophiles

salt loving

Chemoheterotrophs

acquire energy and carbon from organic molecules

Protists

A eukaryotic organism that cannot be classified as an animal, plant, or fungus.

Photoautotrophs

contain chloroplasts, photosynthesize

Heterotroph

decomposers: absorb organic molecules

Mixotrophs

combine photosynthesis and heterotrophic nutrition

Endosymbiosis

symbiosis in which one of the symbiotic organisms lives inside the other.

Flagellates (Mastigophora)

motile through the use of flagella

include giardia, trichomonas, trymonas, trypanosoma, and leishmania

Cilitates

move by means of hair like projections cillia (type of protozoa)

Amobea

moves by means of pseudopodia

zygotic life cycle

haploid cells transform into gametes, gametes fuse to form zygotes. sexual and asexual: malaria

alternation of generations

life cycle that has two alternating phases—a haploid (N) phase and diploid (2N) phase, many algae and land plants

Conjugation

In bacteria, the direct transfer of DNA between two cells that are temporarily joined.

four supergroups of protists

1. Excavata

2. SAR

3. Archaeplastida

4. Unikonta

Excavata

diplomonads, parabasalids, euglenozoans

Dipolomonads

lack plastids, 2 nuclei present

Parabasalids

Flagellated members of the Excavata, some of which are parasites (e.g., Trichomonas), that possess unique fibers at the base of the flagella

Euglenozoans

kinetoplastids, 1 flagella, trypanosoma

SAR

Stramenopiles, Alveolates, Rhizarians

Stramenopiles

Clade of protists with "hairy" flagellum includes water molds, diatoms, and brown algae

Diatoms

single-celled organisms. found in salt and fresh water. producers. make up a large percent of phytoplankton. cell walls contain cellulose and silica (frigid and glasslike). used in silver polish, toothpaste, filter and insulation

brown algae

One of a group of marine, multicellular, autotrophic protists, the most common type of seaweed. Brown algae include the kelps.

Golden algae

Typically unicellular, biflagellated, algae with yellow and brown carotene and xanthophyll accessory pigments.

Alveolates

dinoflagellates, apicomplexans, ciliates

Dinoflagellates

plant-like protist that causes red tide

Plasmodium

causes malaria; mosquitos

cilitates

move by means of hair-like projections (type of protozoa), macro & micro nucleus

Rhizarians

-Amoebas with threadlike pseudopodia

-Includes radiolarians, forams, cercozoans

Radiolarians

A protist, usually marine, with a shell generally made of silica and pseudopodia that radiate from the central body.

Foraminiferans

amoeba like protist that has a shell and looks like a snail.

Cercozoans

An amoeboid or flagellated protist that feeds with threadlike pseudopodia.

Archaeplastids

red algae, green algae, land plants

Red Algae (Rhodophyta)

marine algae in which the chlorophyll is masked by a red or purplish pigment

Green algae

Photosynthetic protists that include unicellular, colonial, and multicellular species with grass green chloroplasts; closely related to true plants.

Charophyta

closest relative to land plants

Supergroup Unikonta

amoebozoans and opisthokonts

Amoebozoans

A member of a clade of protists that includes amoebas and slime molds and is characterized by lobe-shaped pseudopodia.

plasmodial slime molds

a type of protist that has ameboid cells, flagellated cells, and a plasmodial feeding stage in its life cycle

cellular slime molds

A type of protist that has unicellular amoeboid cells and a multicellular reproductive body in its life cycle

Tubulinids

a diverse group of amoebozoans with lobe- or tube-shaped pseudopodia, found in marine and freshwater

Entamoebidae

no flagella or mitochondria, particle feeders, asexual reproduction

Opsithokonts

animals, fungi, and related protists

Cyanobacteria and protists

Existed on land 1.2 billion years ago

Small plants, fungi, and animals emerged on land

500 million years ago

1st forest appeared and oldest forest

385 MYA

Charophyceans

closest relatives of land plants

Key traits plants share with charophyceans

rose-shaped complexions, peroxisome, flagellated sperm, and formation phragmatoplasts

sporopollenin

a layer of durable polymer that prevents exposed zygotes from drying out

Great opportunity for adaptive radiation

sunlight unfiltered, abundance of co2, nutrient rich soil, few herbivores, and pathogens

Land also presented challenges:

scarcity of water, lack of structural support against gravity

Key traits of land plants

1. apical meristems

2. alternation of generations

3. tough, resistant spores from sporangia

4. special organs for production of gametes

roots

anchoring mechanism

xylem and phloem

anchoring mechanism

lignin

material that stiffens cell walls of vascular plants, it increases cell stiffness, and provides better support of leaves

cuticle

The waxy, waterproof layer that covers the leaves and stems of most plants.

Stomata

openings in the leaves of plants, particularly on the underside and opened and closed by guard cells, allowing gases to enter and leave the leaf

Nonvascular

bryophytes

Vascular

tracheophytes

Nonvascular plants

plant that absorbs water and other substances directly thorugh its cells

Liverworts

Phylum Hepatophyta

Hornworts

Phylum Anthocerophyta

Mosses

Phylum Bryophyta

Bryophyte Gametophytes

produce flagellated sperm in antheridia and ova in archegonia

Bryophyte Sporophytes

grow out of archegonia, and are the smallest and simplest sporophytes of all extant plant groups

Leaves

increase surface area for photosynthesis

Phylum Lycophyta

club mosses, spike mosses, quillworts

Phylum Pterophyta

ferns, horsetails, whisk ferns

Seeds

consists of an embryo and nutrients surrounded by a protective coat

Advantage of seeds

1. Multicellular layer of tissue that provides extra protection to the embryo.

2. Have a supply of stored food that allows gymnosperm seed to survive for even years.

3. Can germinate then under ideal conditions.

heterosporous

A term referring to a plant species that has two kinds of spores: microspores that develop into male gametophytes and megaspores that develop into female gametophytes.

reduced gametophytes

microscopic male and female gametophytes (n) are nourished and protected by the sporophyte (2n)

mosses and nonvascular plants

Gametophyte: dominant

Sporophyte: reduced, dependent on gametophyte for nutrition

Ferns and other seedless vascular plants

Gametophyte: Reduced, independent (photosynthetic and free-living)

Sporophyte: Dominant

Seed plants (gymnosperms and angiosperms)

gametophyte is reduced (usually microscopic), dependent on surrounding sporophyte tissue for nutrition, sporophyte is dominant