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what is the most basic unit of living things
cells
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what is the cells shape
tends to be spherical or cylindrical
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what is the internal contact of the cell and what is it surrounded by
- cytoplasm which is the liquid potion
- surrounded by cell membrane aka plasma membrane which is the outer boundary
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what do cells have
- chromosomes containing DNA
- ribosomes production of protein
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what is DNA
genetic material
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what are the two basic type of cells
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where are prokaryotes found
only in bacteria and archaea
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which cell is smaller
prokaryotes
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which cell has a nucleus? what does the other cell have?
- eukaryotic have nucleus
- prokaryotic DNA are housed in a nucleoid region
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which cell has organelles
- eukaryotic
- prokaryotic don't
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what are the properties of life
- heredity and reproduction
- growth and development
- metabolism
- movement and/or irritability
- cell support, protection, and storage mechanisms
- capacity to transport substances in and out of the cell
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chromosomes
long stands of DNA (the hereditary/genetic material) packed into discrete bodies
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where are the chromosomes in prokaryotes
loose in the nucleoid region not enclosed by a nuclear membrane
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what are the reproduction in eukaryotes
sexual and asexual reproduction
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sexual reproduction
offspring's are produced through the union of sex cells from 2 parents (usually un eukaryotes)
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asexual reproduction
- offspring's are produced through the division of a single parent cell into 2 daughter cells
- ex)mitosis
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mitosis******
a division of chromosomes used by MANY eukaryotic cells
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what is the reproduction in prokaryotes
asexual reproduction through the process called binary fission
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binary fission
a simple process of a cell splitting equally into 2
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metabolism
the chemical and physical life process occurring in a cell
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protein synthesis (metabolism)
cells make proteins using hundreds of tiny particles dispersed though out the cell called ribosomes
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motility
- the ability of self propulsion of movement
- notable sign of life, although not present in all cells
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what type of mobility do eukaryotic cell use
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what type of mobility do prokaryotic cell use
flagella and fibril
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what is flagella
whip like tails (single)
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what is cilia
hair on them
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what is pseudopods
- "false foot"
- take on all types of shapes
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fibrils
produce a gliding motion
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irritability
- the capacity to respond to chemical, mechanical, or light stimuli
- helps cells adapt to a changing environment and obtain nutrients
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what is a cells protection
cell wall
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cell wall
rigid structure that provides support and shape to most cells
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what eukaryotes have cell walls
plants, microscopic algae and fungi
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what eukaryotes don't have cell walls
animals, protozoa, humans
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what prokaryotes have cell walls
the majority of prokaryotes (bacteria) have cell walls
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what is the cells transport
cell membrane
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cell membrane
- semi permeable structure in both euk and prok that allows substance (nutrients) to come into the cell and wastes to be expelled out of the cell
- absolutely essential for cell survival
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what is allowed in the cell membrane
water and nutrients
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what is allowed out of the cell membrane
waste produces its creating
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what is not allowed in cell membranes
- virus
- foreign invaders
- toxin
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what is not allowed out of cell membrane
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external structure of a bacterial cell
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cell envelopes of bacterial cell
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internal structure of a bacterial cell
- cytoplasm
- ribosomes
- nucleoid/chromosomes
- endospores
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structures essential to all prokaryotic cells
- cell wall
- ribosomes
- cell membrane
- chromosomes (1 or a few)
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structures found in some but not all prokaryotes
- flagella, pili, fimbriae
- capsule, slime layer
- endospores
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what are the 2 major types of appendages
- flagella and axial filaments-those that provide motility
- fimbriae and pili-those that provide attachment or channels
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flagellum******
- singular
- a long whip-like "tail" extending from the surface of some bacteria that allows for self-propulsion
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polar
flagella attached at one or both ends
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what are the 3 subtype of polar
- monotrichous
- lophotrichous
- amphitrichous
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monotrichous
a single flagella
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lophotrichous
multiple flagella emerging from one site
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amphitrichous
multiple flagella come out of both ends
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peritrichous
flagella dispersed randomly around surface of the cell
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why use the flagella
because of chemotaxis and phototaxis
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chemotaxis
the ability to detect and move in response to chemical signals
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positive chemotaxis
movement of a cell towards a favorable chemical stimulus (usually a nutrient)
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negative chemotaxis
movement away from a repellent (potential harmful) compound
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phototaxis
movement of a cell in response to light (rather than chemical)
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what happens what polar flagellum rotates counterclockwise
cells swim forward (run)
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what happens when polar flagellum clockwise rotates clockwise
cell stops and changes direction (tumble)
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axial filament
- type of internal flagella that are enclosed in the space between the outer sheath and the cell wall peptidoglycan-(the periplasm)
- aka periplasmic flagella
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where are axial filaments seen
usually in corkscrews-shaped bacteria called spirochetes
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fimbria and pili******
- appendages that provide attachments or channels
- surface on the surface of bacteria that helps with interactions with other cells, but DO NOT provide locomotion
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fimbria
- singular of fimbriae (a fringe)
- small bristle like fibers that tend to stick to each other and to surfaces
- maybe the structures responsible for biofilms
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pilus
- singular of pili (a hair)
- aka sex pilus
- an elongated rigid tubular that is used in the "mating" process between cells called conjugation which involves partial transfer of DNA from one cell to another
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how can you tell the difference between cilia and fimbria
bacteria has fimbria not cilia
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glycocalyx****
an outer coating developed to protect some bacterial cells in response to harsh environment conditions
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what are the 2 types of glycocalyx
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slime layer
- loose shield that protects the cell from dehydration and loss of nutrients
- easily washed off
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capsule
- thicker more tightly bound layer
- not easily removed
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biofilm
a compact mass of microbes that forms thick living layers on various surfaces, natural or man made
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what are some natural places for biofilms
- scum in toilet or shower
- slimy slippery rocks in a stream
- plaque on teeth
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what are some man made places for biofilms
devices inside a human body (catheters, breast implants, placemaker)
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how do external structures (slime layer, capsules, fimbriae) play a role in the formation of biofilm
by allowing the microbes to aggregate and stick together
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