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Cell Wall of Prokaryotes
semi-rigid, premeable, made of peptidoglycan (carbohydrate w/ amino acid attached)
gives bacteria shape-- the design comes from the genome
protective "resting" structures
bacteria surrounded by durable cell wall
resistant to extreme conditions-in prokaryote
Asexual- thru Binary Fission
Sexual in the form of conjugations using plasmids
Reproduction of a Prokayote
autotrophs use photosynthesis or chemosynthesis
Heterotrophs including symbiotes
Energy Source Of a Prokaryote
Because of the widespread use (and misuse) of antibiotics some pathogenic bacteria have developed
•Survive 3000x more radiation than humans.
•Tolerate extreme dehydration, heat, and cold.
•Used to "chew up" toxic waste
•Exxon-Valdez oil spill
crawling sensation in the skin, tingling in the fingers, vertigo, ringing in the ears, headaches, hallucination, painful muscular contractions leading to convulsions, vomiting, and diarrhea. All of these symptoms are mentioned in the record of the Salem which trials.
the feeding network of a fungus (body)
- may be extremely large
-usually found underground or inside a decaying organism
-composed of wooden mesh of hyphae
the threadlike filaments of a fungus
-has a tubular cell wall that contains chitin
-surrounds the plasma membrane and cytoplasm
o A Structural polysaccharide of modified sugars
o Makes up insect excoskeletons & fungus cell walls.
o Polymer with glucose subunits and Nitrogen containing functional groups.
o ONLY in Fungi.
o Haploid cell which can grow directly into a hypha.
o Can be produced sexually and asexually.
Fungi which grow on living organism
One benefits from the other, the other suffers or dies
EX: Dutch elm disease, Corn smut, Athletes foot, jock itch, yeast infection
Fungi that live interdependently with photosynthetic organisms.
Symbiotic relationship, they both benefit.
Symbiotic relationship b/twn a fungal species and either a cyanobacteria or unicellular photosynthetic eukaryote.
• If separated they die.
symbiotic relationships b/twn fungi and the roots of a plant.
--Fungi help send the plant water, minerals and nutrients.
--Some of the sugars the plant produces are absorbed by the fungus.
a. Named for the sac which contains several haploid spores.
b. Candida yeast: good yeast—bread and beer,
i. Bad yeast: thrush, vaginal infections.
c. Sexual reproduction via spores produced in asci (sac-like cases).
d. Asexual reproduction via naked spores (conidia).
i. Both produce haploid spores.
e. Sources of many interesting chemicals.
i. Penicillium—the source of penicillin.
ii. Fungi make antibiotics.
a. Common mushroom, puffballs, stink horns, shelf fungi, plant-parasitic smuts & rusts.
b. * Usually reproduce sexually, septa present.
i. Honey mushroom- largest, oldest, heaviest living organism on plantet. Humongous fungus.
ii. A single clone of the honey mushroom Armillaria can cover more than 2,200 acres (1,600 football fields).
Basidia are generally found on the surface of gills
a. Named for the apparent complete lack of sexual reproduction in the life cycle.
b. Fungi whose sexual reproduction has not been observed.
i. Includes Athlete's foot fungus, Penicillium fungus, and Blue cheese fungus.
Undifferentiated embryonic cells (not specialized),
there are 2 types: apical and Lateral
Found at both ends of plants (roots and shoots).
Primary Growth", throughout life of plant, increases height
Ring-like structure in dicots and conifers.
"Secondary growth", later in life, responsible for thickening of branches and trunks.
Fibrous root (monocots) or taproot (dicots) systems.
o Grow at apical meristems.
o Protected by root caps: a lubricating layer secreting a slippery slime layer and regularly slough off to make penetration easier.
-Thin, no waxy cuticle. Separates inside from outside.
-Root hairs increase surface area, H20 uptake.
a. The fungus converts insoluble soil nutrients into simpler water-soluble compounds that root hairs can absorb and transport. The fungus obtain sugars and amino acids from the plant.
How does the Symbiont Mycorrhizae (fungus) help get nutrients
diffusion of water along a concentration gradient of free water molecules.
Water moves from High to Low
Cohesion- of water molecules makes them stick together, resist being pulled apart which is Hydrogen bonds
Tension- water s being pulled up
How does water move up a plant against gravity?
1. Water evaporates out of leaf stomata.
2. Leaf is "dry" so pulls water out of Xylem.
3. Water leaving Xylem pulls up the water behind it.
a. Unidirectional, controlled by opening/closing of stomata.
b. The rate of transpiration is controlled by opening and closing the stomata.
Moves from sources (things that make sugar like leaves) to sinks (things that use sugar like fruits)
Transport of Sugar
contains a high sugar concentration bc of sucrose moving from a source to a sink
-is directed by sugar production and use
Combines genes from 2 different parents, offspring genetically different from their parents.
After fertilization the zygote develops into the seed (plant embryo) which will grow into a new sporophyte.
Plant Sexual Reproduction
Earliest seed plants
nonflowering seed plants such as conifer, gnetophyte, cycad, or gingko
Wind pollination used for fertilization
Advantage: do not need biological help
Disadvantage: inefficient process
1. Sepals: sometimes colored, Attractors.
2. Petals: Colored, patterned to attract., advertise the location of the flower
3. Stamens: Male Reproductive parts that are Composed of filament and anther.
4. Carpels: Female Reproductive parts that are Composed of Stigma, style, and ovary.
-Attract pollinators using colors and scents
-Stop unwanted visitors
-ensure pollination is the goal
Angiosperm Gametophyte Development
• Develop inside sporophyte flowers, very small and parasitic ( can't live on their own)
• Pollen Grains: the Male gametophyte.
-Pollen develops within the pollen sacs.
- Sperm cells
• Embryo Sac: Female gametophyte, produces egg cells. Sac development results in 7 cells.
-1 egg cell.
-1 Primary endosperm cell with 2 nuclei.
-5 Cells that degenerate.
1. Pollen lands on Carpel.
2. Tube grows from pollen down through carpel.
3. 2 Sperm go down tube to egg for double fertilization.
a. 1 Sperm fertilizes egg to from diploid zygote.
b. The other sperm fertilizes primary endosperm cell to form triploid tissue.
Pollination and Fertilization
1. Hypocotyl - root
2. Epicotyl -shoot
3. Cotyledon -seed leaves (dicots have 2, monocots have 1).
3 parts of plant embryo:
Cells elongate at different rates on opposite sides of plant, causing bending.
How does the plant bend?
1. cell membrane lipid structure
2. Cell Wall composition
3.rRNA subunit sequences
Difference in bacteria and Archaea
unclear differences between this and the rest of the Eukaryotes
i. Even simpler and smaller than viruses
ii. Fragments of single-stranded RNA with NO protein coat
iii. Hijack cells; infects primarily plant cells including citrus trees, potatoes, avocados
i. Unusual infectious particles
ii. Protein particle with no genetic material (DNA or RNA)
iv. consist of a protein that is folded incorrectly and makes other proteins fold wrong
v. Origin? Developed as a by-product of living organisms
postive taxis- mover toard something
negative taxis- swims away from something
positive chemo taxis- swis toward a beneficial chemical
positive photo taxis- swims toward light
negative photo taxis swims away from light
Unfused nuclei from different parents occupying the same unit of hypha
a. Written as n+n
b. This stage does not exist in animals
Asexual Reproduction Cycle of Fungi
1. Haploid (1n) spores are produced by mitosis
a. The spores are produced by the fungus taking haploid cells and using mitosis makes haploid spores
i. No variation produced through this process of asexual reproduction
b. spores are genetically identical to original mycelium
c. spores disperse and germinate to produce new mycelium
i. hopefully the spores move far away from "parent" fungus
ii. fungi have developed ways in which they try to spread out spores as far as possible from themselves so they don't compete
Sexual reproduction Cycle of Fungi
usually only under stressful conditions; spores are produced; many mating types are possible (essentially like having many different sexes or genders)
-the environment needs to change in someway
-plasogamy-the cells actually fuse together
-karyogamy-fusion of nuclei to produce zygote like structures
zygote like structures (2n)diploid
-meiosis - the zygote like structures then produce haploid spores through meisos
-then the spores are dispersed within the environment
**haploid spores may disperse long distances away from the fruiting body
-Ancient group - diverged earliest from the other fungi
-The only fungi with flagellated spores (zoospores)
-These spores can swim and require water for them to move around
-Decompose dead material
-Majority of them are saprobic
Phylum: Zygote Fungi
i.Sexual reproduction via zygosporangia (resistant heterokaryons) that produce genetically variable spores
1.During sexual reproduction this fungus creates cells that are called zygosporangium, hence the name
ii.Asexual reproduction via sporangia that produce spores
iii.Mostly saprobic decayers of organic matter, e.g. soft fruit rot fungi and black break mold
iv.Some are parasitic, e.g. single-celled microsporidia
Phylum clomeromycetes = arbusular mycorrhizae
230 species now
Associated with about 90% of plant species
-To help conserve endangered plants and threatened environments
-To learn more about the natural world
-To better harness the abilities of plants to provide us with food, medicines, and energy
-Studying plants informs us about our world
-Viruses were purifed from pants
Why study Plants?
Mendels study of Peas
helped us understand human diseases such as sickle cell anemia and hemophilia, as well as countless other human diseases that have a genetic contribution
laid the foundation for the sciences of plant genetics and plant breeding
one serious disease that threathens the worlds food supply
cause of the potato late blight, has re-emerged as a threat
Puccinia graminis tritici
one serious disease that threatens the world's food supply
i. The wheat stem rust fungus
ii. A new, highly pathogenic strain emerged in Uganda in 1999-its called ug99
iii. This is a global problem that needs global attention, does not stop at its borders
Development of the seed and fruit
a. The first mitotic division of the zygote is asymmetric
b. This asymmetry provides the first environmental difference experienced by the differentiating cells and established the root-shoot axis
c. The sporophyte embryo develops from the zygote
d. The endosperm develops from the triploid endosperm nucleus
e. The ovule integuments become the seed coat
f. Tissues of the ovary (and sometimes the receptacle) become the fruit
i. Function of fruit is to aid in seed dispersal
Mechanical- Will actually shoot the seed out from the plant
Wind dispersal- white puffs
Water dispersal- Coconuts
Different ways of dispersing seeds
i. One cotyledon
ii. Veins usually parallel
iii. Vascular bundles usually complexly arranged
iv. Fibrous root system
v. Floral parts usually in multiple of three
i. Two cotyledons
ii. Veins usually netlike
iii. Vascular bundles usually arranged in ring
iv. Taproot usually present
Has one main root with several branches breaking off from it
v. Floral parts usually in multiples of four or five
Terminal bud, node, internode, terminal bud of branch, vegetative branch, leaf (petiole and blade)stem,
1. Anchor the plant in the ground
2. Absorb water and minerals
3. Store surplus food, principally, carbohydrates, that were manufacures in the shoot during photosynthesis
4. Transport water, minerals, sugars and hormones to and from shoot
5. Produce some hormones
6. Interact with soil fungi and bacteria that help provide nutrients to the plant
1. support and seperate the leaves, lifting them into the sunlight and air
2. transport water and dissolved minerals from the roots up to the leaves
3. transport sugars
multicellular diploid form
the plants of gardens, orchards, forest and feilds that produce flowers
produces mother cells
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