bio test 2 study guide chat gpt chapter 27

gram positive

thick peptidoglycan layer, no outer membrane, stain purple, more exposed peptidoglycan

gram negative

thin peptidoglycan layer, has outer membrane, stain pink, outer membrane contains lipopolysaccharides

capsule - functions of bacteria

protective outer coating around some bacteria, help avoid drying out, help attach to surfaces

fimbriae - functions of bacteria

start hairlike structures, helps attach to surfaces and host cells, can help form biofilms

sex pilus - functions of bacteria

connects a donor bacterium to another bacterium during conjugation, helps transfer DNA often plasmid between bacteria, can spread antibiotic resistant genes

nucleoid - functions of bacteria

region containing the bacterium main chromosome, stores most of the cells essential genetic information, not surrounded by a membrane

plasmid - functions of bacteria

small usually round DNA molecule separate from the main chromosome, replicates independently of the bacteria, often carries useful genes and can be transferred between bacteria

endospore - functions of bacteria

tough dormant structure formed by certain bacteria. allows survival under harsh conditions

r plasmid

plasmid that carries genes that make bacteria resistant to one or more antibiotics

importance of prokaryotes

nutrient cycling, human health, food production, environmental cleanup, medicine, oxygen production and food webs

why is protist not a taxon

it was traditionally used to group eukaryotes that were not classified as animals plants or fungi - protists does not form a single neural evolutionary group. protists have many different lineages that are not all each others closest relatives

endosymbiotic theory

states that some organelles in eukaryotic cells originated as free living bacteria that were taken inside another cell and eventually formed a mutually beneficial relationship

mitochondria and plastids share several features with bacteria

they contain their own DNA, they have bacterial like ribosomes, resemble bacterial fission, surrounded by membranes, genetic evidence links them

mitochondria ancestor

alphaproteobacterium

plastid ancestor

cyanobacterium

primary endosymbiosis

eukaryotic host cell engulfs bacterium, become organelle, process produced mitochondria and ancestors of primary plastids - primary plastids generally have two surrounding membranes

secondary endosymbiosis

eukaryotic host cell engulfs another eukaryotic cell that already has a plastid, the engulfed becomes a endosymbiont, the resulting plastid may have three or four surrounding membranes

four eukaryotic supergroups

excavata, SAR, Archaeplastida, unikonta

excavata

mostly unicellular, many have flagella for movement, not all members have the same structure - grove on cell surface

representative taxa of excavata

Giardia - intestinal parasite, Trypanosoma - disease causing parasite, euglena - flagellated organism that can photosynthesize

SAR

made up of three major lineages - Stramenopiles, Alveolates, Rhizarians

Stramenopiles

many have flagella with fine hair like projections at some life in stage - diatoms, brown algae, oomycetes (water molds)

Alveolates

have membrane bound sacs called alveoli beneath the cell membrane - dinoflagellates, ciliates, apicomplexans

Rhizarians

many have thing threadlike or branching pseudopodia - foraminiferans and radiolarians

Archaeplastida

includes photosynthetic eukaryotes with primary plastids, plastics originated through primary endosymbiosis, unicellular and multicellular

taxa archaeplastida

red algae - many contain red photosynthetic pigments, green algae - includes relatives of plants, land plants - mosses, ferns, conifers and flowering plants

unikonta

includes major lineages od amoebas animals and fungi, use pseudopodia

taxa unikonta

amoeba - pseudopodia, slime molds - amoebozoans with complex life cycles, fungi - absorbs surrounding nutrients, animals

charophytes

group of green algae and are considered the closest living algal relatives to land plants

shared characteristics between plants and charophytes

chlorophyll a and b, cellulose cell walls, chloroplast with similar features, formation of a cell plate

differences between charophytes and land plants

different habitat, have different embryos (plants have protected embryo) reproductive structures, adaptations to land

bryophytes

mosses, liverworts and hornworts. gametophyte is dominant generation

gametophyte n

haploid generation that produces sperm and eggs by mitosis

antheridium

male reproductive structure that produces sperm

archegonium

female reproductive structure that contains the egg

sporophyte 2n

diploid generation that produces spores through meiosis

why do bryophytes grow close to the ground

no vascular tissue, need water for fertilization, risk of drying out

traits of modern vascular plants

vascular tissue, lignified support and dominant sporophyte generation

vascular plants

ferns, club mosses, horsetails, gymnosperms and angiosperms

vascular tissue

allows plants to grow taller and transport resources over longer distance

xylem

transports water and minerals from the roots or lower parts of the plant

phloem

transports sugars and other organic nutrients throughout the plant

lignified supporting tissues

lignin strengths cell walls, structural support, grow upright and helps water conducting cells resist collapsing

dominant sporophyte generation

size and specialized tissue supports growth resource gathering and spore production

vascular plants vs bryophytes

vascular tissue, transport of water, size, true roots, dominant generation, sporophyte, fertilizatuon

homosporous

produces one type of spore, spores usually develop into gametophytes capable of producing sperm and eggs

heterosporous

process two types of spores

microspores

develop into male gametophytes

megaspores

develop into female gametophytes

sori

cluster of sporangia often on the underside of fern leaves

sporangia

structures where meiosis produces spores

zygote 2n

diploid cell formed when sperm and egg fuse

why was pollen an important adaptations for life on land

allowed plants to reproduce on Alan without needing water for sperm to swim to the egg

pollen grains

contain the male gametophyte or develop into it carrying the cells that deliver sperm

pollen tube

grows and delivers sperm to the egg

gymnosperms

coniferophyta, cycadophyta, gingkophyta, gnetophyta

coniferophyta

evergreens, produce cones

cycadophyta

similar to palm trees, large stiff leaves, produce cones

gingkophyta

one living species Gingko biloba, fan shaped leaves, popular tree

gnetophyta

Ephedra, welwitschia, gnetum, varied form and habitats

mature pine tree

sporophyte generation,

stamen

male reproductive part of a flower, anther and filament

anther

produces pollen grains, which contain male gametophyte

filament

stalk that supports and positions the anther

carpel

female reproductive structure - stigma, style, ovary, ovule,

stigma

sticker or receptive surface where pollen lands

style

connects the stigma to the ovary and provides a pathway for pollen tube growth

ovary

contains the ovules, after fertilization it usually develops into the fruit

ovule

contains the female gametophyte and egg, after fertilization it Tuens into a seed

petals

often colorful or scented to attract pollinators

sepals

usually green leaf like structures that protect the flower bud before it opens

how are fruits adapted to disperse seeds

wind, animals eat fruit/ carry seeds. water, dry fruits splitting and spraying seeds

how does human population growth threaten plant diversity

habitat destruction/fragmentation, climate change, pollution, invade species, over-harvesting

mycorrhizae

mutually beneficial associates between fungi and plant roots

why are mycorrhizae important

Improve plant nutrient and water uptake, Help plants grow and survive under challenging conditions, Contribute to nutrient cycling and soil ecosystems, Can help plants tolerate certain environmental stresses.