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191 terms

Bio 151 Unit 3

covers the material for Dr. Crawford's Unit 3 test
STUDY
PLAY
What is the approximate age of the Earth?
4.5 billion years old
Approximately when did the earth's crust form?
4 billion years ago
How long ago was the first life on earth estimated to have formed?
3.8 billion years ago
How long ago was the first evidence of life on earth seen? How was this seen?
About 3.4-3.5 billion years ago with Prokaryotic fossils made by the layering of sediment
Macroevolution
the pattern of evolution over a long period of time
When did prokaryotic organisms begin to photosynthesize?
2.7 billion years ago
What prokaryotic organism was the first to photosynthesize?
cyanobacteria
Explain how Oxygen was first put into the earth's atmosphere.
Cyanobacteria began to split water during its light dependent reaction which produced copious amounts of Oxygen that saturated the earth's water bodies, combing with iron, thus laying down iron ore sediments (iron oxides). Once the iron was used up, Oxygen gas evaporated into the earth's atmosphere.
How did the introduction of Oxygen into the atmosphere affect the earth's prevalent anaerobic organisms?
this "poisoned" these organisms
Approximately how many years ago did the first single-celled Eukaryotes appear?
2.1 billion years ago
Approximately how many years ago did the first multicellular Eukaryotes appear?
1.5 billion years ago
Phylogenetic Tree
branching diagram that displays major episodes in the history of life on earth
What are the four different conditions/steps that simple cells originated out of?
1. Abiotic synthesis of small organic compounds or molecules (monomers)
2. Abiotic synthesis of polymers
3. Packaging of molecules into Protocells (Protobionts)
4. Origin of the earliest genetic material on earth (RNA) that led to inheritence
Oparin-Haldane hypothesis
hypothesis stating that the early earth atmosphere was a reducing atmosphere which allowed for the abiotic formation of simple organic molecules
What is the result of Miller and Urey's experiment to test the Oparin-Haldane hypothesis?
results proved that a reducing atmosphere consisting primarily of water, NH3, CH4, and H2 in high temperatures with electrical discharge is ample conditions for the abiotic synthesis of simple organic molecules. (supported the hypothesis)
What are some of the other theories on how life originated on earth?
-atmosphere was neutral; areas around volcanoes allowed abiotic synthesis of monomers
-hydrothermal vents in the ocean
-meteorites struck earth containing simple organic molecules
What type of reactions allow for the polymerization of the monomers?
dehydration reactions (synthesis)
What caused these monomers to polymerize?
came into contact with clay, rocks, or hot sand which act as catalysts for polymerization
Protocells/Protobionts
abiotically derived groups of molecules which achieve self-organization, self assembly, and reproduction.
How can some Protocells carry out metabolic pathways?
must be supplied with enzymes
What are 3 types of Protocells?
Liposomes, Microspheres, and Coacervates
Liposomes
type of protocell consisting of lipid droplets which exhibit self assembly in water and can reproduce, undergo swelling/shrinking, grow by engulfing other liposomes, and split into smaller liposomes.
Microspheres
-type of protocell
-when amino acids are placed on a hot surface, small proteins form, water is added to cool the solution and these proteins proteins form microspheres
-grow by absorbing more protein from solution then dividing when a certain size is reached
Coacervates
-type of protocell consisting of droplets that form when solutions of protein, nucleic acid, and polysaccharides are shaken.
-catalyze chemical reactions
-absorb materials from their environment
-secrete product
What was the first genetic material?
single-stranded RNA
What is the main advantage of single-stranded RNA?
it can replicate itself abiotically
single stranded RNA can assemble to form ________.
monomers
Single stranded RNA codes for its replication with low error rate, but error result in _______.
variety
What kind of form does single stranded RNA take on? Why?
a variety of 3D shapes due to the hydrogen bonding between nitrogenous bases
Ribozymes
protein formed by RNA that can catalyze peptide bond formation between amino acids
Explain how there is cooperation between RNA and the protein that it catalyzes.
RNA catalyzes the formation of the protein that then catalyzes RNA replication
How is natural selection displayed by RNA?
there is natural selection for the more efficient cooperatives between RNA and proteins
Eutherians
placental mammals
evolutionary trend
a general direction of evolutionary change; continuous change of character within an evolved lineage
exaptation
structures that evolve in one context but become co-opted for another function
Prokaryotes can be classified based up on what criteria?
cell shape, staining reactions, nutrition/metabolism, specific RNA base sequences
What are the various cell shapes of prokaryotes?
rods, cocci, spirilla, vibrios, spriochetes
In a gram stain, what species de-stain?
gram negative
In a gram stain, what species stay stained?
gram positive
Photoautotrophs
photosynthesize using light, carbon dioxide, and water
Chemoautotrophs
use carbon dioxide to build organic molecules
Photoheterotrophs
use light energy, but cannot use carbon dioxide as their sole carbon source. They use organic compounds from the environment to satisfy their carbon requirements. They use compounds such as carbohydrates, fatty acids, and alcohols as their organic "food".
Chemoheterotrophs
unable to fix carbon and form their own organic compounds. They obtain energy by the oxidation of electron donors in their environment.
True or False: Prokaryotes can undergo aerobic respiration but not anaerobic.
False! Prokaryotes can undergo BOTH aerobic and anaerobic respiration. (Fermentative or respiratory)
Types of polymers which can be digested and metabolized by Prokaryotes.
Basically any kind of organic molecule can be digested and metabolized by Prokaryotes. Some can digest and metabolize petroleum.
Genetic recombination
the bringing together of genes from different organisms into a single organism (two parents make a child that contains genes from each parent)
Prokaryotes exhibit a ________ transfer of DNA from donor cell to recipient.
unilateral
Bacterial conjugation
Genetic recombination in prokaryotes that is accomplished through cellular contact
Transduction
Genetic recombination in prokaryotes that is accomplished by viruses.
Bacterial transformation
ability of bacteria to alter their genetic makeup by uptaking foreign DNA from another bacterial cell and incorporating it into their own
permian extinction
The largest mass extinction in the history of life on Earth; it occurred 250 million years ago, driving up to 95 percent of the species in some groups to extinction.
cretaceous extinction
65.5 million years ago; eliminated over 50% of species( including dinosaurs)
extremophiles
A prokaryote that lives in an extreme environment. Extremophiles include methanogens, extreme halophiles, and extreme thermophiles.
stromatolites
layered rocks that form when certain prokaryotes bind thin films of sediment together
endosymbiosis
mitochondria and plastids (chloroplasts and related organelles) were formerly small prokaryotes that began living within another cell
Endosymbiont
a cell that lives within another cell known as the host cell
How would a heterotrophic host benefit from endosymbiosis?
it could use nutrients released from photosynthetic endosymbiont; an anaerobic host could benefit from endosymbionts that turn the oxygen to advantage.
Serial endosymbiosis
A hypothesis for the origin of eukaryotes consisting of a sequence of endosymbiotic events in which mitochondria, chloroplasts, and perhaps other cellular structures were derived from small prokaryotes that had been engulfed by larger cells.
Cambrian explosion
A relatively brief time in geologic history when large, hard-bodied forms of animals with most of the major body plans known today appeared in the fossil record. This burst of evolutionary change occurred about 535-525 million years ago.
continental drift
motion of continents about Earth's surface on plates of crust floating on the hot mantle
adaptive radiations
periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles, or niches, within their communities
heterochrony
an evolutionary change in the rate or timing of developmental events (ex: an organism's shape depends in part on the relative growth rates of different body parts during development)
How many mass extinctions have occurred in the Earth's history?
Five
homeotic genes
master regulatory genes that determine basic features
Cocci
spherical prokaryotes. They occur singly, in pairs (diplococci), in chains of many cells (streptococci), and in clusters resembling bunches of grapes (staphylococci).
Bacilli
rod-shaped prokaryotes. They are usually solitary, but in some forms the rods are arranged in chains (streptobacilli)
Spirilla
Spiral prokaryotes
peptidoglycan
a network of modified-sugar polymers cross-linked by short polypeptides
Vibrios
comma-shaped bacterial cells.
Spirochetes
corkscrew-shaped prokaryotes
What are the three most common shapes of prokaryotes?
spherical (cocci), rod-shaped (bacilli), and spiral (spirilla and spirochetes)
methanogens
archaebacteria that live in anaerobic environments and produce methane as a by-product of their metabolic processes
Archael cell walls contains a variety of polysaccharides and proteins but lack ________.
peptidoglycan
What is the difference in location of the peptidoglycan layer of gram-positive and gram-negative bacteria?
Gram-positive bacteria have a cell wall made of the peptidoglycan layer. Gram-negative bacteria have a thinner layer of peptidoglycan that is located between the plasma membrane and the outer membrane.
Gram-negative bacteria have an outer membrane that contains _________.
lipopolysaccharides (carbohydrates bonded to lipids)
capsule
a sticky layer of polysaccharides or protein that covers the cell wall of many prokaryotes. It enables prokaryotes to adhere to their substrate or to other individuals in a colony.
Fimbriae
hair-like structures that are shorter, thinner, and straighter than flagella - used for attachment, not movement (AKA attachment pili)
How do prokaryotic flagella differ from eukaryotic flagella?
prokaryotic flagella differ from those of eukaryotes in their molecular composition and their mechanism of propulsion. Prokaryotic flagella are much thinner and are not covered by an extension of the plasma membrane.
Endospores
A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions
plasmids
the small, circular segments of DNA that are found in bacteria and that stay separate from the bacterial chromosomes, carry accessory genes
halophiles
"salt-loving" archaea that live in environments that have very high salt concentrations
What allows prokaryotes to move?
flagella
What are the methods of genetic recombination in prokaryotes?
transformation, transduction, and conjugation
Earliest Eukaryotes had what 3 life processes?
mitotic, sexual, and meiotic processes
Genetic variability originated from _______ _______ of eukaryotic organisms.
sexual cycle
Every cell in gametes is ________.
haploid
Every zygote is ______.
diploid.
Syngamy
Fertilization of an egg and sperm (formation of a zygote)
Did the sexual cycle evolve as a reproduction strategy?
No, it evolved as a genetic recombination strategy
Haploid cells contain how many chromosomes?
23
Diploid cells contain how many chromosomes?
46
Karyogamy
the fusion of 2 haploid cells creating a diploid zygote
Haploid state is achieved by ______.
meiosis
What was the first type of sexual cycle to evolve?
zygotic life cycle
What cells can undergo meiosis?
Diploid cells ONLY
What type of protists are photosynthetic eukaryotes with cell walls?
Algae-- plant-like protists
Classification of Algae is based on what 3 things?
pigmentation, storage polysaccharides, and cell wall components
Diatom
-member of the stramenophile group
-unicellular plant-like protist (algae) with a glasslike cell wall made of hydrated silica embedded in an organic matrix (said to fit together perfectly like a shoe-box)
-yellow to brown in color
-reproduce asexually by mitosis most of the year
-can reproduce sexually, but is uncommon
-store energy in the form of a glucose molecule called laminarin
What are the primary producers of most aquatic ecosystems?
Algae
Dinoflagellates
-algae belonging to Alveolates group
-unicellular
-found mostly in marine habitats but also in freshwater
-whirl through the water
-red tide forms after dinoflagellate bloom
-some are bioluminescent
Describe how Dinoflagellates can be harmful.
Some secrete toxins. When these forms becomes too abundant (usually during a red tide), it can cause massive fish kills. Humans can get poisoning if eat shellfish that have been feeding on these blooms.
Example of harmful dinoflagellate: Pfisteria piscidia
Zooxanthellae
type of beneficial dinoflagellate that lives in a mutualistic relationship with coral
Golden Algae
-AKA Crysophytes
-ex: Vaucheria
-algae belonging to the stramenophile group
-color results from yellow and brown carotenoids, carotene and xanthophyll accessory pigments
-most unicellular, some are colonial, some form cyst stages
-live in both freshwater and marine environments
-similar life cycle to water molds
Dinobryon
a freshwater colonial golden algae
Brown Algae
-AKA Phaeophyta
-protist of the stramenophiles
-largest multicellular algae and the most complex
-have a thallus comprised of leal-life blade section, stem-like stipe, and root-like holdfast. (NOT homologous to higher plant organs)
-flagellated sperm
-example: Laminaria (demonstrates alternation of generations)
Pneumatocyst
synonym for air bladder, a swollen hollow structure in brown algae, increases buoyancy
Red Algae
AKA Rhodophyta
-protist with presence of red pigment called phycoerytherin
-live at great depths, most common in tropical water, can be found in freshwater environments in soils
-have sperm that rely on water currents for movement
Green Algae
AKA Chlorophyta
-two groups: Chlorophytes and Charophytes
-algae most like plants in pigmentation and photosynthetic apparatus
-some unicellular and some multicellular/colonial
What life cycle is also called the alternation of generations life cycle?
Sporic Life Cycle
Trend in plant evolution has been towards reduction of the _______ stages.
haploid (or gametophyte)
Diplomonads
-Primitive Eukaryote of the Excavata clade
-lack functional mitochondria but have mitosomes instead that help it gain some energy via glycolysis
-have multiple flagella and 2 equally sized nuceli
-example: Giardia intestinalis (attacks animal intestines causing extreme diarreah)
What are the three types of protists?
algae (plant-like), Protozoans (animal-like), and Fungus-like protists
water mold
-heterotrophic fungus-like protist
-example: Phytophthora (cause of Irish Potato Famine)
-essentially goden algae that have lost capacity for photosynthesis
-most are decomposers that grow as cottony masses on dead algae and animals in mainly freshwater habitats
-white rusts and downy mildews live on land as plant parasites
-have multinucleate filaments known as hyphae
-mainly diploid
Current evolutionary thinking that the water molds evolved from the _______ algae.
golden
Spirogyra
a filamentous green alga with spiral chloroplasts. It accomplishes syngamy by conjugation. The haploid filaments merely grow close to each other and a conjugation bridge grows across. The protoplast of one cell crosses this bridge into the other cell to establish the zygote.
Ulva
"sea lettuce"
-produces nearly identical looking (isomorphic) sporophyte (2n) and gametophyte (n) generations
-exhibits the sporic life cycle
Chara
believed to have given rise to plants. They have similarity in chloroplast DNA, ribosomal RNA, and some nuclear genes. They are the only green algae with peroxisomes, and their cell wall structure is most similar to that of higher plants.
Volvox
colonial sphere of many green algae; flagellated; gametes for differentiation
Chlamydomonas
(of the motile colony series aka volvocine line) single biflagellated cells with a single "cup-shaped" chloroplast. Gametes are just like vegetative cells. Can form protective coating around itself in bad conditions.
What is the structural difference between the cell walls of archaea and bacteria?
Bacteria's contain peptidoglycan that Archaea's lack
What technique is used to classify many bacterial species into two groups based on differences in cell wall composition?
Gram Stain
What is the difference between cell wall composition of Gram-positive and Gram-negative bacteria?
Gram-positive has simpler cell walls with larger amount of peptidoglycan than Gram-negative
Where are the chromosomes of prokaryotes stored?
In the nucleoid
How many chromosomes are found in a typical prokaryotic cell?
One
Plasmids
Small rings of separately replicating DNA found in a typical prokaryotic cell
Reproduction in prokaryotes draws attention to what three key features of their biology?
1. They are small
2. They reproduce by binary fission
3. They have short generation times
(this is why they can have such large populations)
heterocyst
A large, thick-walled cell type in the filaments of certain cyanobacteria that performs nitrogen fixation (when in a low oxygen environment)
actinomycetes
filaments bacterium found in the soil. Ex. Streptomyces
Bacterial transformation
ability of bacteria to alter their genetic makeup by uptaking foreign DNA from another bacterial cell and incorporating it into their own
Bacterial transduction
bacteriophages (viruses that infect bacteria) carry bacterial genes from one host cell to another
Bacterial conjugation
DNA transfer from one prokaryotic cell to another via direct contact
How do sex pili aid in bacterial conjugation?
The cell donating the DNA uses sex pili to attach to the recipient of the DNA. After contacting a recipient cell, each sex pilus retracts, pulling the two cells together and forming a "mating bridge" that provides an avenue for DNA transfer.
F factor
A fertility factor in bacteria
-DNA segment that confers the ability to form pili for conjugation and associated functions required for the transfer of DNA from donor to recipient
-may exist as a plasmid or be integrated into the bacterial chromosome.
HFR
High Frequency Recombination-Bacterial strains that can transfer their chromosome because they have an F-plasmid integrated into their genome
Cells containing the F plasmid, designated F+ cells, function DNA ______ during conjugation.
donors
Cells lacking the F factor, designated F-, function as DNA _______ during conjugation.
recipients
R plasmids
bacterial plasmids carrying genes that confer resistance to certain antibiotics
Some Cyanobacteria and methanogens convert atmospheric nitrogen to ammonia in a process known as _______ ________.
Nitrogen Fixation
Heterocytes
specialized cell that carries out only nitrogen fixation
Symbiosis
a relationship in which two different organisms live in close association with each other
mutualism
symbiotic relationship in which both species benefit from the relationship
commensalism
symbiotic relationship in which one member of the association benefits and the other is neither helped nor harmed
parasitism
A relationship between two organisms of different species where one benefits and the other is harmed
pathogens
parasites that cause disease (many are prokaryotic)
exotoxins
proteins secreted by certain bacteria and other organisms
Endotoxins
-lipopolysaccharide components of the outer membrane of gram-negative bacteria
-don't get released until bacteria dies and cell wall breaks down
-example: salmonella
Protist
mostly unicellular eukaryote that is not a plant, animal, or fungus (some are colonial or multicellular)
What is considered the simplest eukaryote?
single-celled protists
mixotrophs
Protists that combine photosynthesis and heterotrophic nutrition
Invagination of cell membrane gave rise to what cellular structures?
Endoplasmic Reticulum, Golgi Apparatus, and Nuclear Envelope (created cell with nucleus and endomembrane system)
What two structures developed as subsequent changes in eukaryotes organisms?
cytoskeleton and microtubular structures
_______ of eukaryotic organisms is an extension of cytoplasm surrounded by plasma membrane.
Flagella
What was the subsequent change in chromosomes in Eukaryotic organisms?
changed from a single chromosome to multiple chromosomes that consist of linear DNA with proteins
Eukaryotic cells divide by _______.
mitosis
The first eukaryotes resulted in the origin of the ________ cycle to accomplish genetic recombination.
sexual
The origin of the sexual cycle resulted in the origin of the _____ state.
diploid (2N)
Every gamete cell is ______.
haploid (1N)
Syngamy
fertilization
How is the diploid state achieved?
by syngamy
Karyogamy
fusion of 2 haploid cells during syngamy
The haploid state of the sexual cycle is accomplished by _______.
meiosis (reductive division of diploid cells)
How many sets of chromosomes do haploid cells have?
one (one gene for each protein)
Zygotic life cycle
-the only diploid stage is the zygote (cell formed from syngamy)
-all other stages are haploid
-most likely 1st type of sexual cycle to evolve
-many algae and fungi have this type of life cycle
Gametic life cycle
-the only haploid stage are the gametes (cells which fuse in syngamy)
-all other stages are diploid
-this is a typical animal life cycle
Sporic Life Cycle
-produces haploid stages in addition to gametes and diploid stages in addition to zygotes
-typical of some algae and most plants
The trend in plant evolution has been towards the ______ of the haploid (gametophyte) stages.
reduction
True or False: Either haploid cells or diploid cells can divide by mitosis.
True!
*But only diploid cells can undergo meiosis*
gametophyte
haploid multicellular organism (or multicellular haploid stage)
sporophyte
diploid multicellular organism (or multicellular diploid stage)
Excavata
(the excavates) clade of protists that includes Diplomonads and Parabasalids
Parabasalids
-Primitive Eukaryote of the Excavata clade
-have hydrogenosomes instead of mitochondria
-example: Trichomonas vaginalis (STD)
Diplomonads and Parabasalids lack a true functioning _________. They have modified versions of this organelle instead.
Mitochondria
Slime mold
Fungus-like protist belonging to the Amoebozoan clade
-2 types known as Plasmodial slime molds and Cellular slime molds
Plasmodial Slime Mold
-type of slime mold
-example: Physarum
-brightly colored, often yellow/orange
-use cytoplasmic streaming to distribute oxygen/nutrient
-has a feeding stage which is a multinucleate plasmodium living in organic matter
-plasmodium dries up in harsh condition and forms sporangium for sexual reproduction
-sporangium undergoes meiosis forming haploid spores that are flagellated or amoeboid and fuse in syngamy
-diploid zygote is formed that undergoes mitosis forming the feeding plasmodium
Cellular Slime Mold
-type of Amoebozoan slime mold
-example: Dictyostelium
-During sexual reproduction, two haploid amoebas fuse to form diploid zygote that consumes haploid amoebas
-the giant diploid cell undergoes meiosis followed by mitosis
-new haploid amoebas are released
-During the feeding stage (asexual reproduction) haploid solitary amoebas act individually
-when food is depleted, solitary cells form an aggregate that functions as a unit
-aggregate forms a stalk that supports an asexual haploid fruiting body
-haploid spores are released
-haploid amoebas emerge from the spore coats
zoospore
asexual spore that uses a flagellum for locomotion
gametangium
cell or organ in which gametes develop
archegonium
female reproductive structure in some plants, including mosses and liverworts
One of the adaptations of plants to life on land is the formation of a waxy layer known as a _______ on surfaces exposed to air.
cuticle
Plants developed supportive tissues like ______.
fibers
Plants developed vascular tissues like _____ and ______.
xylem and phloem
Xylem
dead hollow cells with secondary cell walls thickened with lignin for transport of water and dissolved minerals upwards and outward
Phloem
living cells with only primary cell walls for transport of sugars and other organic matter in all directions
Apical meristems
localized regions of cell division at the tips of shoots and roots
Bryophytes
non-vascular embryophytes with dominant gametophyte (n) generation
The origin of vascular tissue like the xylem and phloem allowed for the development of ________ ______.
specialized organs (roots, stem, and leaves)
What is the earliest known vascular plant?
Aglaophyton
Phylum Lycophyta
The club mosses
-many extinct species which reached the size of modern tress. Only a few, low growing species remain. These have small leaves with only a single unbranched strand of vascular tissue (microphylls).
Lycopodium
a homosporous species
-sporophyte produces a single type of meiospore which germinates into a gametophyte with both antheridia and archegonia
Strobili
sporophyl clusters
Selanginella
a heterosporous species
-sporophyte produces 2 types of meiospores. Megaspores germinate into female gametophyte which produces only archegonia. Microspores germinate into male gametophyte which produces only antheridia.