Chapter 4 [BIO]
endosymbiosis
(lynn margulis) eukaryotic cells are the result of prokaryotic mergers
eukaryotic and prokaryotic similarities
1) both have genetic code (DNA) 2) both have biochemical pathways (glycolysis)
eukaryotes vs prokaryotes
1) prokaryote is size of organelle 2) eukaryote has a membrane bound nucleus 3) eukaryote has organelles (allow separation of biochemical and physiological functions)
bacteria is divided into __ groups with different thickness of ____
2, peptidoglycan
makeup of prokaryotic cells
70% H20, 26% macromolecules (nucleic acids, proteins, carbs), 4% small molecules (amino acids, sugars)
pili function
DNA exchange- plasmid
average size of prokaryotic cells
E. coli: 1µm x 2-6µm
plasma membrane
[cytoplasmic membrane] phospholipids- polar/hydrophilic end and nonpolar/hydrophobic end proteins- peripheral/outside and integral/inside (bacteria have a bilayer and archaea have a monolayer)
you have isolated a motile, gram-positive cell with no visible nucleus. you can assume this cell has... a. ribosomes b. mitochondria c. an endoplasmic reticulum d. a golgi complex e. all of the above
a
cytoplasm
all prokaryotes have this, 80% H20, 20% dissolved stuff
ribosomes
all prokaryotes have this, made of protein and ribonucleic acid (RNA), responsible for protein synthesis, 70S (smaller than eukaryotes)
nucleoid (nuclear region)
all prokaryotes have this, mostly double-stranded DNA, circular chromosome, NOT a nucleus
fimbriae
attachment to surfaces
glycocalyx
attachment to surfaces and protection from phagocytes
fimbriae function
attachment, prevents phagocytosis
glycocalyx function
attachment, prevents phagocytosis, and protects from drying out
which of the following pairs is mismatched? a, glycocalyx-adherence b. pili-reproduction c. cell wall-toxin d. plasma membrane-transport
b
simple diffusion vs facilitated diffusion
both allow materials to cross the plasma membrane from a high concentration to a low concentration without expending energy. facilitated diffusion requires carrier proteins.
active transport vs group translocation
both move materials across the plasma membrane with an expenditure of energy. in group translocation, the substrate is changed after it crosses the membrane.
active transport vs facilitated diffusion
both require enzymes to move materials across the plasma membrane. in active transport, energy is expended.
plasma membrane
cell wall formation and selective permeability
endospore formation is initiated by ____
certain adverse environmental conditions
____ and ____ were once bacteria
chloroplasts, mitochondria
3 major shapes of prokaryotic cells
coccus, bacillus, and spirals
size of the prokaryotic cell oscillatoria
cyanobacteria/blue-green algae: 8µm x 50µm
a pair of bacilli = ____; a group of bacilli = ____
diplobacilli; streptobacilli
a pair of cocci = ____; a chain of cocci = ____; a cluster of cocci = ____
diplococci; streptococci; staphylococci
a gram-positive bacterium ____ have a lipopolysaccharide-phospholipids-lipoprotein layer
does not
archaea has/doesn't have peptidoglycan
doesn't have (has psuedomuerin)
which of the following is not a distinguishing characteristic of prokaryotic cells? a. they usually have a single, circular chromosome b. they lack membrane-enclosed organelles c. they have cell walls containing peptidoglycan d. their DNA is not associated with histones e. they lack a plasma membrane
e
some organisms do not have mitochondria, instead they have ____
endosymbiotic bacteria (mixotricha paradoxa- 5 genomes)
(origin of eukaryotic cell) how did prokaryotic cells get in?
engulfment (cyanobacteria) and predatory bacterium (bdevellovibrio)
how do essential molecules enter cells through each wall?
essential molecules diffuse through the gram-positive wall. porins and specific channel proteins in the gram-negative outer membrane allow passage of small water-soluble molecules.
plasmids
extrachromosomal DNA, circular, contain nonessential/extra genes (ex. antibiotic resistance or toxin production)
formation of a new cell from an endospore is triggered by ____
favorable growth conditions
peritrichous
flagella are found around the entire surface of the cell
polar flagella
flagella are found at one or both ends of the cell
amphitrichous
flagella at both poles of the cell
lophotrichous
flagella on both ends of the bacteria
sporulation
formation of endospores (process) that contains only DNA, and small amount of other material necessary or resumption of metabolism [NOT REPRODUCTION]
formation of a new cell from an endospore is called ____
germination
which cell wall is toxic to humans
gram-negative
why is an endospore called a resting structure?
it provides a method for one cell to "rest", or survive, as opposed to grow and reproduce
axial filament characteristic
like a corkscrew
flagella characteristics
like a tail, made of the protein flagellin
pili characteristics
like long hairs, hollow (pilus)
fimbriae characteristic
like short bristles
symbiosis
living together
smallest size of prokaryotic cells
microplasmas: 0.2µm
cell wall
most prokaryotes have one, shape is dictated by cell wall, rigid, elastic, pathogenicity (due to some specific components), protects from changes in water pressure, strong
flagella
motility
pili
motility and transfer of genetic material
flagella function
movement (taxis)
axial filament function
movement in spirochetes
chemotaxis
movement toward (+) or away (-) from a chemical
phototaxis
movement toward (+) or away (-) from light
monotrichous
one flagella
the gram-negative bacterium initially retains the violet stain, but it is released when the ____ is dissolved by the decolorizing agent. after the dye-iodine complex enters, it becomes trapped by the ____ of gram-positive cells.
outer membrane, peptidoglycan
cell wall
protection from osmotic lysis
ribosomes
protein synthesis
endospore
resting
spores/endospores
resting structures, allows microbe to survive under adverse conditions (running out of something), (ex. bacillus anthacis produces spores)
plasma membrane function
retains the cytoplasm, site of metabolic processes (respiration/photosynthesis), contains receptor molecules ("eyes" and "nose"), and selectively permeable barrier
similarity between prokaryotes and chloroplasts/mitochondria
same size, surrounded by plasma membrane, contain 70S ribosomes, have their own DNA, grow and divide on own schedule, same pigments
simple diffusion
small molecules move from an area of high concentration to low concentration (not very efficient and not used much) DOESN'T REQUIRE ENERGY
osmosis
solvents move from high concentration to low concentration DOESN'T REQUIRE ENERGY
endospore formation is called ____
sporogenesis
glycocalyx characteristics
sticky like a spider web if tight = capsule if loose = slime layer
group translocation
substance is chemically altered during movement REQUIRES ENERGY
why does penicillin have no effect on most gram-negative cells?
the outer layer of the gram-negative cells prevents penicillin from entering the cells
of what advantage is an endospore to a bacterial cell?
the protective endospore wall allows a bacterium to withstand adverse condition in the environment
gram positive cells
thick layers of peptidoglycan, techoic acids (toxic component), single plasma membrane
gram negative cells
thin layer of peptidoglycan, lipopolysaccharide (LPS- toxic), two plasma membranes (sandwiched)
largest size of prokaryotic cells
thiomargarita namibiensis: 300µm
active transport
transport molecules against a concentration gradient (uses carrier integral proteins- organism can concentrate substances) REQUIRES ENERGY
facilitated diffusion
uses integral transporter proteins to move molecules across membrane (change in conformation of protein) DOESN'T REQUIRE ENERGY
flagella is used for ____ or ____
vaccines or identification
curved spirals = ____; corkscrew spirals = ____
vibrio; spirochete
germination
when the endospore gets a positive environmental cue allowing it to grow into a vegetative cell once again [EVENTUAL REPRODUCTION]
