BIO EXAM 2

peptidoglycan

• prokaryotic cell wall

• protective mesh-like wall to maintain cell structure and shape

• also regulates different elements in the cell

gram stain

fimbriae

pili

nucleoid

plasmids

• present in prokaryotes

• small circular pieces of nonessential DNA

• aid in conjugation

transformation

• DNA taken up from the environment

transduction

• DNA transferred by viruses

• virus infection → accidental DNA packaging → gene transfer

conjugation

• direct DNA transfer between cells (via plasmids)

extremophiles

symbiosis

parasitism

mutualism

commensalism

halophiles

thermophiles

methanogens

bioremediation

basic characteristics of prokaryotes

• bacteria & archaea

• unicellular (stick together to form colonies)

• smaller

• no nucleus

• no membrane-bound organelles

• contains plasmids

• single circular double-stranded DNA located in a nucleoid region

• metabolic diversity (photosynthesis, nitrogen fixation, methane production, etc

shapes of prokaryotes

• coccus (spherical)

• bacillus (rod-shaped)

• spirillum (spiral)

shape → function → environment

ex. spirillum can twist to move through thick fluids like mucus in animal bodies

gram positive bacteria

• thick peptidoglycan

• purple color

gram negative bacteria

• thin peptidoglycan & outer membrane

• pink color

cellular + genomic components of prokaryotes

cellular + genomic components of eukaryotes

three key features in prokaryotic reproduction

__ is the major source of genetic variation in prokaryotes

how long ago did prokaryotes evolve

• oldest life form on earth (s.5 billion years)

• abundant for over a billion years before eukaryotes appeared

genetic recombination

• bacteria reproduce by cloning but gain new genes by sharing DNA

• three types: conjugation, transduction, & transformation

• horizontally gene transfer

horizontal gene transfer

• movement of genes among individuals from different species

• not reproduction

• bacteria cannot reproduce sexually but can exchange genes

processes of bacterial recombination

example of extremophile and the domain it belongs to

ecological functions of prokaryotes

symbiotic relationships of prokaryotes

mixotrophs

endosymbiosis

• eukaryotic organelles evolved from a consortium of symbiotic prokaryotes

• mitochondria were aerobic hetertrophic prokaryotes

• chloroplasts were photosynthetic prokaryotes

alternation of generations

algal bloom

basic characteristics of protists

• eukaryotic

• originally consists of all unicellular eukaryotes

• some multicellular ones (complex cells must perform all life function)

• refers to all eukaryotic organisms that aren’t plants, fungi, or animals

• major protist phyla are grouped into four major monophyletic supergroups

primary + secondary endosymbiosis of protists

excavata

• some have a feeding groove excavated in the side

• share similarities in cytoskeleton features & DNA sequences

• modified mitochondria

• spiral or crystalline rod inside flagella

• major groups: diplomonads, parabasalids, euglenozoans

• ex. euglena, trichomonas

“SAR” clade

• monophyletic supergroup

• named for the first letters of the three major clades: stramenopiles, alveolars, and rhizarians

• hairy and smooth flagella

• membrane-enclosed sacs (alveoli) beneath plasma membrane

• amoebas with threadlike pseudopodia

• major groups: diatoms, brown algae, dinoflagellates, ciliates, etc

• ex. paramecium, plasmodium. etc

archaeplastida

• organisms with chloroplasts by primary endosymbiosis for photosynthesis

• phycoerythrin (photosynthetic pigment)

• plant-type chloroplasts

• major groups: red & green algae, plants

• ex. mosses, ferns, flowering plants, ulva, etc

unikonta

• amoebas with lobe-shaped or tube-shaped pseudopodia

• highly variable

• major groups: amoebozoans, slime mods, entamoebas, & opisthokonts

• ex. animals, fungi

euglenazoans

• diverse clade including predatory heterotrophs, photosynthetic autotrophs, mixotrophs, and parasites

• spiral or crystalline rod inside their flagella

diatoms

• unicellular algae with a unique two-part, glass-like shell

• a major component of phytoplankton

• highly diverse

brown algae

dinoflagellates

ciliates

• large varied group of protists

• named for their use of cilia to move and feed

• ex. paramecium caudatum

radiolarians

• single-celled

• hard shell made of silica

foram(inifera)s

• single-celled

• shell made from calcium carbonate

red algae

• apart of archaeplastida

• red photosynthetic pigment: phycoerythrin (masks the chlorophyll)

• can live deeper (found at 260m in bahamas)

chlorophytes

• found in archaeplastida, green algae

slime molds

• found in unikonta

entamoebas

• found in unikonta

choanoflagellates

• found in unikonta

• resemble their close animal relatives, the sponges

which groups are closest relatives of land plants?

archaeplastida

which groups are closest relatives of fungi and animals?

unikonta

gametophyte

• haploid stage (n)

• produce gametes (sperm + eggs)

sporophyte

• diploid stage (2n)

• produces haploid spores by meiosis (grow into gametophytes, completing the cycle)

embryophytes

alternation of generations (proper terms + haploid/diploid)

1. sporophyte (2n) produces haploid spores through meiosis

2. spores grow into gametophytes (n)

3. gametophytes produces gametes

4. fertilization forms a diploid zygote

5. zygote grows into a new sporophyte

sporangia

archegonium

antheridia

cuticle

vascular tissue

• second major innovation

• ~425 million years ago

• transport of water and nutrients

• growth taller than bryophytes

• led to vascular plants

• reproduce using spores

seed

• third major innovation

• ~360 million years ago

• protect the developing embryo

• survive dry conditions

• disperse more effectively

• seed plants

bryophytes

• nonvascular plant

• not monophyletic

• rely on water

• swimming sperm + no transport system

• gametophyte dominant

lycophytes

pterophytes

gymnosperms

angiosperms

stomata

xylem + phloem

• vascular tissue

• transport of water & nutrients

microphylls

• small leaves

• only one unbranched vein

• found in lycophytes

• simpler leaves

megaphylls

• larger leaves

• have branched vascular tissue (veins)

• found in ferns & seed plants

• allow more efficient photosynthesis

homosporous

• most seedless vascular plants

• produce one type of spore that develops into a bisexual gametophyte

heterosporous

• all seed plants & some seedless vascular plants

megaspores

• produced by heterosporous species

• gives rise to female gametophytes

microspores

• produced by heterosporous species

• gives rise to male gametophytes

apical meristems

rhizoids

researchers have identified a lineage of green algae called
___ as the closest relatives of land plants

chloroplast ancestor

key features of plants

• stems

• roots

• leaves

challenges plants faced moving to land are

• relative scarcity of water

• lack of structural support against gravity

four key traits distinguish land plants from algae

purpose of the sporangia

to produce spores

process of reproduction in the gametophyte stages using proper terms: gametangia, egg, archegonium, antheridia, sperm, zygote, embryo

land plants can be informally grouped based on the presence or
absence of an extensive system of ______

3 phyla of bryophytes

How do gametophytes differ from sporophytes in bryophytes? which phase is dominant

why are Bryophytes best able to reproduce sexually in moist habitats?

three main traits that characterize modern vascular
plants

vascular plants can be split into 2 groups

how do gametophytes differ from sporophytes in vascular plants?

what is the purpose of the vascular tissue in plants?

what are the two clades of seedless vascular plants?

why are modern seedless vascular plants are most common in damp environments

in terms of size and complexity, leaves can be classified as
_____________ and ______________. Which plant groups have which leaves?

vascular plants have ________________, modified leaves that bear sporangiagia