Test 1 Flashcards
(112 cards)
1
Q
basic taxonomy classification
A
Life, Domain, Kingdom, Phylum, Class, Order, Family, Genus Species
2
Q
all living organisms are classified as either
A
prokaryotes or eukaryotes
3
Q
prokaryotes vs eukaryotes: unicellular or multicellular?
A
prokaryotes: uni
eukaryotes: multi
4
Q
prokaryotes vs eukaryotes: membrane bound organelles?
A
prokaryotes: no
eukaryotes: yes
5
Q
prokaryotes vs eukaryotes: DNA
A
prokaryotes: single circle in the cytoplasm eukaryotes: chromosomal DNA
6
Q
prokaryotes vs eukaryotes: cell division
A
prokaryotes: binary fission
eukaryotes: mitosis
7
Q
Binary fission
A
Asexual reproduction of bacteria. DNA attaches to the plasma membrane cell wall stretches so cell volume enlarges DNA replicates Cell wall and plasma membrane begin to pinch inward at the center of the cell DNA pulls apart Cytoplasm is equally distributed cell wall and plasma membrane complete growth inward at the center finally divides into two identical daughter cells
8
Q
prokaryotes vs eukaryotes: domains
A
prokaryotic domains: bacteria, archaea
eukaryotic domains: protista, animalia, plantae, fungi
9
Q
Nitrogen fixation
A
Certain bacteria and cyanobacteria can transform atmospheric nitrogen into other nitrogenous compounds that can be used as nutrients by plants
10
Q
prokaryotes vs eukaryotes: any other metabolic functions?
A
prokaryotes: nitrogen fixation, photosynthesis
eukaryotes: n/a
11
Q
Kingdom within Domain Archaea
A
Archaebacteria
12
Q
evolutionary theory of archaebacteria
A
it is thought that archaebacteria of domain archaea may be the oldest forms of life on earth, and domains bacteria and eukarya probably diverged from archaebacteria independently. Archaea were initially classified as bacteria but eventually were classified into their own group because they had their own distinct and unique properties from both bacteria and eukaryotes
13
Q
what make archaebacteria distinct?
A
- evolutionary theory about them
- there are no known pathogens
- they are extremophiles
- they use organic compounds (sugar, ammonia, hydrogen gas) or sunlight for energy
14
Q
what make archaebacteria distinct?
A
- evolutionary theory about them
- there are no known pathogens
- they are extremophiles (since they are survivors of ancient lines that have persisted in habitats that are like habitats from when bacteria first evolved. These habitats are extremely acidic, hot or salty)
- they are autotrophic
15
Q
Autotrophs
A
organisms that use organic compounds (sugar, ammonia, hydrogen gas) or sunlight for energy. Most autotrophs use photosynthesis to derive these organic compounds.
16
Q
Extremophiles
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organisms that are found in extreme conditions (i.e. hot springs, salt lakes, oceans, marsh lands, human colon, oral cavity, skin)
17
Q
kingdom within domain bacteria
A
kingdom bacteria
18
Q
what makes bacteria distinct?
A
- the most abundant, diverse and widely distributed organism
- they live in symbiotic relationships with plants and animals
- they can live in soil, water, acidic hot springs and in radioactive waste
- they are characterized based on morphology, metabolism and biochemistry
- Most divide by binary fission, but some do genetic recombination by conjugation
19
Q
what makes bacteria distinct?
A
- the most abundant, diverse and widely distributed organism
- they live in symbiotic relationships with plants and animals
- they can live in soil, water, acidic hot springs and in radioactive waste
- they are characterized based on morphology, metabolism and biochemistry
- Most divide by binary fission, but some do genetic recombination by conjugation
- some are pathogenic (can cause infectious diseases)
20
Q
Conjugation
A
some bacteria have genetic recombination via conjugation, in which all or part of the genetic material of one bacterium is transferred to another bacterium and a new set of genes is assembled
21
Q
differences in morphology of bacteria
A
3 basic shapes: bacillus (rods), coccus (circles), spirillum (spirals)
22
Q
differences in metabolism of bacteria
A
heterotrophic (some are decomposers- a type of heterotroph) or autotrophic
23
Q
decomposers
A
heterotrophic organisms that feed on dead organic matter and release nutrients locked in dead tissue- which is vital for recycling nutrients
24
Q
decomposers
A
heterotrophic organisms that feed on dead organic matter and release nutrients locked in dead tissue- which is vital for recycling nutrients
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difference in photosynthesis between bacteria and eukaryotes
photosynthesis in bacteria is diff from photosynthesis in eukaryotes because they don’t necessarily produce oxygen
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where is bacteria found in humans?
the gut and skin
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how can pathogenic bacteria be treated?
with antibiotics
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antibiotic sensitivity
how susceptible a bacteria is to a specific antibiotic
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Bacterial resistance-
the ability to resist an antibiotic that was once effective against it
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how to determine if an antibiotic is effective against a certain bacteria
with a sensitivity plate: o An agar plate is inoculated (grown) with bacteria and paper discs are soaked in different antibiotics and placed on the agar surface. After 24 hrs, the plate is examined and if an antibiotic disk is effective against the bacteria, it will destroy the bacteria surrounding it, resulting in a clear area around the disk (a.k.a. the zone of inhibition/ZOI.) Then, by comparing the diameters of the ZOIs of different antibiotic disks on the same agar disks we can determine the most effective antibiotic. If it is ineffective, there will be no ZOI.
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bacteria colony
when you grow bacteria, a visible growth of many identical bacterial cells from a single cell on the agar surface.
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how to grow bacteria in a lab
in either a tube of broth (liquid nutrient) or on the surface of a plate of broth mixed with agar (gelatinous polysaccharide)
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Gram positive bacteria
thick peptidoglycan cell wall, no outer envelope, retains purple die, more susceptible to antibiotics (easily killed with antibiotics)
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Gram negative bacteria
thin peptidoglycan cell wall, cell wall is surrounded by a rich outer envelope, does not retain purple dye, less susceptible to antibiotics (harder to kill with antibiotics)
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What is the gram stain procedure used for?
a procedure used to classify bacteria by susceptibility to an antibiotic:
PURPLE: gram positive/easy to kill VS PINK: gram negative/hard to kill
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what is the gram stain procedure itself?
crystal violet and iodine are applied to both the gram positive and gram negative bacteria. The thick peptidoglycan cell wall of the gram positive bacteria retains the purple dye, while the gram negative bacteria’s thin peptidoglycan cell wall does not. Alcohol is used to remove the stain from the surface of the gram negative cell walls that do not bind the stain. Safranin is then used to counterstain the gram negative cell with a red color so they’ll be more easily distinguishable from the gram positive cells.
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example of phylum of kingdom bacteria
cyanobacteria
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what is distinct about cyanobacteria's cells and structure?
1. cyanobacteria are multi-cellular (even though it is a prokaryote)
2. often surrounded by a jellylike sheath
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are cyanobacteria autotrophs or heterotrophs
autotrophs; they are photosynthetic
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what is distinct about cyanobacteria's pigmentation?
pigment: chlorophyll a: blue-green or brown-green
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how do cyanobacteria reproduce?
binary fission
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are algae and cyanobacteria related?
similar to algae but NOT related because cyanobacteria are prokaryotes while algae are eukaryotes
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what is the norm of how cyanobacteria live
most are free living and some live symbiotically
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symbiotic relationship
a relationship between two organisms where at least one organism benefits
(i.e.) Parasitic relationship a type of symbiotic relationship in which one organism benefits and the other organism is harmed
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what is distinct about kingdom plantae?
multicellular, autotrophic/photosynthetic organisms with cell wall
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what is distinct about kingdom animalia?
multicellular ingestive-feeding heterotrophs that lack cell walls and can respond rapidly to external stimuli
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what is significant about kingdom protista?
most are unicellular but some are multicellular, some are autotrophs and some are heterotrophs, some have a cell wall and some don't. basically, any microscopic organism that has a simple level of organization, is not an animal plant or fungi and that lives in a moist habitat
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how are protista classified?
They are thought to have given rise to plants animals and fungi so they are divided into groups depending on which of the other 3 kingdoms they are similar to: Algae (plant-like), Protozoa (animal-like) and Slime mold (fungus-like)
49
what is significant about kingdom fungi?
most are multicellular (mushrooms) heterotrophs with a cell wall made of CHITIN and which are in Hypha structures ---but some fungi are unicellular (yeast and mold)--
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how are fungi classified?
into 4 phyla based on their sexual structures
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how do fungi reproduce asexually?
1. basic mitosis to produce 2 vegetative haploid cells called spores
2. Budding to produce smaller fungus than original one
3. Fragmentation to produce individual pieces, each of which are capable of undergoing mitosis to become their own fungus
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Budding
small cell of fungus undergoes mitosis, creating a protrusion that buds off from the fungus and eventually falls off to form its own cell. (An unequal distribution of cytoplasm eventually breaks off to become own cell that grows into a new hypha.) This bud is smaller than the original fungus because of an uneven distribution of cytoplasm. -----ALSO, The original cell stays in existence!
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Fragmentation
fungus breaks into a few individual pieces that break off, each of which are capable of undergoing mitosis and becoming their own fungus
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sexual reproduction of fungus
1. Genetic recombination- Hyphae of 2 genetically different individuals of the same species mate & their nuclei fuse (nuclear fusion)
2. Meiosis
3. Nuclear fusion- fusion of nuclei of 2 genetically different haploid hyphae
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Genetic Recombination in Fungi
Hyphae of 2 genetically different individuals of the same species mate, their nuclei fuse (nuclear fusion) which allows for genetic recombination, allowing for the mixing of genes in the next generation. [THIS IS THE FIRST TIME WE DISCUSS 2 GENETICALLY DIFF ORGANISMS OF SAME SPECIES MEET. BC they’re 2 genetically unique organisms, they produce a genetically different & new hyphae. Unlike Protists- which procreate by 2 genetically identical organisms meeting or reproduction by itself.
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Phylum Chytridiomycota (Chytrids)
- type of fungi
- Mainly aquatic saprophytes
- These organisms grow on freshwater algae
- Motile spore w/flagella
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Phylum Zygomycota
- bread mold fungi
- Appears dark from thousands of black sporangia
- Reproductive structure gametangia
- Most common genus is Rhizopus
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Phylum Ascomycota
- sac fungi
- Includes yeast (unicellular), mold and morels
- Reproductive structure: ascus: Have a microscopic, sac-shaped reproductive structure
- Mostly reproduce asexually by forming spores
- Common uses:
1. Penicillium- used to produce the antibiotic penicillin
2. Used in foods (i.e. yeast used in the production of wine and beer- saccharomyces cerevisiae)
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Phylum Basidiomycota
- (club fungi)
- Mushrooms, puffballs
- Some mushrooms are edible while other mushrooms are poisonous
- Site of sexual reproduction: "Basidia": external club-shaped structures on the surface of gills (gills= the lines on the underside the mushroom.)
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Lichens
- (an unclassified fungus group)
- 2 organisms that are born together, live together and die together in a symbiotic relationship (ascomycete from the phylum Ascomycota with a photosynthetic algae or a cyanobacteria)
- live on a variety of hard substances such as trees, rocks and firm soil
- reproduce asexually by releasing fragments of both fungus and algae cells (fragmentation)
- --- they both do fragmentation. When a piece of each breaks off, they join together and then live together and die together
- Brightly colored
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Types of Hypha
HYPHA (basic structure- filament composed of cytoplasm and nuclei enclosed by a cell wall); There are 2 types
1. SEPTATE HYPHA (fungi with divided cells)
- Septum walls separate cytoplasm and nuclei into cells. Organism is separated
2. COENTIC HYPHA
- Fungi that has incomplete or no septum
- Structure is multinucleate- consists of multiple nuclei
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mycelium
A collection of hyphae is called a mycelium
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What is significant about Algae?
1. they are autotrophic/photosynthetic plant-like protists
2. they are polyphyletic (come from diff ancestors)
3. major food source of ecosystem
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variations of cellular organization in algae
1. Unicellular: a single unattached cell that may or may not be motile
2. Filamentous: a multi cellular organism consisting of chains of cells attached to each other that can be branched or unbranched
3. Colonial: a multicellular organism that occurs as a group of cells attached to each other in a non-filamentous manner that can be a sphere, flat sheet, or other 3D shapes. Colonies are clonal (cells are identical)
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Algae's main roles within ecosystems
1. They are one of the major food sources of ecosystems- bottom of the food chain. If no algae, little fish die so big fish have nothing to eat and die too
2. Contain many useful chemicals that have pharmaceutical value
3. Necessary for global oxygen production/ help control pollution
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What is significant about protozoa?
- Heterotrophic
- Protozoa is a term used to describe all the animal- like protists
- Structure: food vacuoles to digest ingested particles and contractile vacuoles to expel excess water
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how are protozoa classified?
classified by method of locomotion
• pseudopods
• flagella
• cilia ( three types of ciliated protozoa. They are free-swimming ciliates, crawling ciliates, and stalked ciliates. All of them use cilia for locomotion and capturing food)
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what is significant about slime mold?
heterotrophic fungi-like protists
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What is significant about supergroup Archaeplastida?
Have plastids; can be unicellular, colonial or multicellular
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Examples of groups within supergroup Archaeplastida
green algae, red algae
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What is significant about green algae?
- AKA chlorophytes
- live in fresh water
- classified under supergroup archaeplastida (so they have plastids + can be filamentous, colonial or unicellular)
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examples of green algae
chlamydomonas, spirogyra, cladophora volvox
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chlamydomonas
Unicellular Green Alga:
- Motile
- Live in soil, lakes and ditches (dirty fresh water)
- Simple structure; large chloroplast; structure involved in production and storage of starch
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Spirogyra and Cladophora:
```
Filamentous green algae:
-both live in fresh water
Spirogyra
-Slippery texture
Cladophora
-Coarse texture
```
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Volvox:
Colonial (multicellular) Green Algae
- Bound in a spherical matrix (like a ball).
- motile: Each sphere has 2 flagella extending outward from the surface of the colony
- Consists of many chlamydomonas-like cells (up to 50,000) but considered 1 multi-cellular organism bc the cells can’t survive alone
- Motile (synchronized beating of flagella spins the colony through water like a globe on its axis)
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Red Algae
- Live in warm marine/warm saltwater environments
- multicellular
- Pigment: phycobilins (red pigment)
- Can be filamentous or fleshy
- Can be attached to each other or free-floating
- Used as a food source
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what is significant about supergroup chromalveolata?
they contain kingdoms stramenopile (most w/plastids; unicellular and multicellular) and alveolate (alveoli support plasma membrane; unicellular), most have plastids, they are unicellular or multicellular
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Brown Algae
- classified under supergroup chromalveolata as a stramenopile
- Structurally complex
- multicellular
- Live in cool marine environments (cold saltwater)
- Important for marine ecosystem bc can act as a habitat or food for organisms
- Pigment: Fucoxanthin (brown pigment)
- Cellular organization: filamentous
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Diff genera (plural of genus) of brown algae:
1. Macrocystis (kelp) -100m long
2. Fucus- grows on top of rocks
3. Laminaria- used in food
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Diatoms
- classified under supergroup chromalveolata as a stramenopile
- Unicellular
- Pigment: fucoxanthin so it has a golden-brown color
- Photosynthetic
- Food source for a lot of aquatic life
- Has a hard cell wall made up of silicon dioxide (glass)
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Ciliates
- classified under supergroup chromalveolata as a stramenopile
- Identified based on presence of large numbers of cilia
- Many have 2 types of nuclei: micronuclei and macronuclei
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paramecium
an organism under supergroup chromalveolate under kingdom stramenopile that is free-living, freshwater, reproduce
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Alveolates
- a kingdom classified under supergroup chromalveolata
| - alevoli support the plasma membrane, unicellular
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dinoflagellates
- kingdom alveolate under supergroup chromalveolata
-Structure: oddly shaped cellulose plates; 2 flagella located perpendicular to each other
o Autotrophic AND heterotrophic
o unicellular
o Food source for fish and other organisms
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Vorticella
an organism under supergroup chromalveolate under kingdom stramenopile that has a contractile stalk, cell body with cilia, and is a filter feeder
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filter feeder
cilia beat rapidly to capture food particles
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what is significant about supergroup excavata?
organisms have a feeding groove; unique flagella; and are unicellular
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Euglenoids
kingdom under supergroup excavata
-Live in freshwater
-pigment:Chlorophyll b
-Considered plant-like bc is photosynthetic
-Structure: no cell wall; 2 flagella
-Red eyespot near base of flagella for light reception
-Can be autotrophic, heterotrophic and saprophytic (feed on dead or decomposing matter. Eukaryotic decomposer)
this Depends on the environment [This phenomenon illustrates why its so hard to distinguish from plants and animals on cellular level]
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Flagellates
kingdom under supergroup excavata identified based on presence of at least one flagellum; can be free-living or parasitic
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Trypanosoma
a flagellate that is pathogenic that can cause african sleeping sickness; lives in tropical conditions; is spread via infection from biting insects
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what is significant about supergroup amoebozoa?
organisms have pseudopods and are unicellular
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amoebas
kingdom under supergroup amoebozoa
- Live in marine and freshwater
- Identified based on presence of pseudopods (“fake feet” movable extensions used for locomotion and food gathering)
- polyphyletic
- Active consumers. Phagocytic- intake food via food vacuole
- Structure: no cell wall; no chloroplasts [Like animal cells]
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The cell cycle's phases
(A) Interphase:
1. G1: cell grows
2. S: DNA replicates
3. G2: cell preps for mitosis
(B) Cell division by Mitosis or Meiosis
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DNA is packed into _____
chromosomes
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how does DNA condense?
Specialized proteins help the DNA condense correctly and tightly
- Basic DNA double helix is wrapped around histone proteins
- The DNA helixes and histone proteins fold together a few times and form a structure called a nucleosome
- A strand of many nucleosomes wind together and form a chromatin
- Many tightly packed chromatin fibers make up a chromosome
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When DNA is copied and tightly packed/condensed:
- Each side is called a chromatid; the tip of each chromatid is called a telomere and it ends the chromosome
- The 2 sister chromatids are held together by a centromere
- Held together, they look like an X and they are called sister chromatids
- The male sex chromosome is an exception- it is shaped like a Y
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Homologous chromosomes
Each chromosome in a pair came from a different parent organism (1 from mother and 1 from father); Similar bc same gene but could have diff alleles so not exactly the same.
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Sister chromatids
when DNA doubles in the S phase, each chromosome copies itself and becomes a sister chromatid
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stages of mitosis
prophase, prometaphase, metaphase, anaphase, telophase
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product of mitosis
2 identical daughter cells
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prophase
sister chromatids codense and become visible, nuclear envelope begins to fragment, centrosomes begin to form spindles
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prometaphase
nuclear membrane completely fragmented, spindle fully formed, sister chromatids attach to spindle fibers by kinetochore microtubules
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metaphase
sister chromatids line up at the metaphase plate (in middle)
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anaphase
the kinetochore microtubules shorten which pulls the sister chromatids apart from one another to opposite poles of the cell
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telophase
nuclear membrane begins reforming around each set of DNA, chromosomes decondense and are no longer visible, cleavae furrow forms that separates the 2 sides into 2 identical daughter cells
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stages of meiosis
```
(A) DNA replication
(B) 2 rounds of cell division
1. homologous chromosomes split
2. individual chromosomes split up sister chromatids
2n --> 4n --> 2n --> n
```
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products of meiosis
Cell division that produces 4 unidentical haploid (n) daughter cells (gametes distinct from parent and unidentical to each other). that HAVE HALF DNA as compared to parent cell
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crossing over
-happens in prophase 1
-All the homologous chromosomes find their pair and align next to each other (“synapsis”) and form a structure called a “bivalent.” When they are bivalent, crossing over can occur
(1 piece of a chromosome can switch place with a piece of another chromosome)
-When this happens, the genes do not change, but the allele for that gene switches paces
-This process allows for genetic recombination- production of offspring with different combinations of traits than were found in either parent
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gametogenesis
the process in which cells undergo meiosis to form haploid daughter cells that mature into gametes
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spermatogenesis
formation of sperm
- Begins at puberty and is continuously happening and continuously making new cells
- 1 cell produces 4 sperm
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Oogenesis
formation of eggs
- Begins when baby is in her mother’s uterus- before she is even born!
- In UTERO, oogenesis proceeds through meiosis I and then PAUSES until girl reaches puberty
- When she reaches puberty, those cells continue doing meiosis and those are only eggs she has for whole life
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5 main differences between mitosis and meiosis
1. Mitosis produces identical daughter cells and Meiosis makes non-identical pairs
2. Mitosis: product has same # chromosomes as parent while Meiosis product cell has half # chromosomes as daughter cell
3. Mitosis produces 2 daughter cells and Meiosis produces 4 daughter cells
4. Mitosis has 1 cell division and Meiosis has 2 cell division
5. Mitosis is an asexual process and Meiosis is a sexual process
