Chapter 4 - Functional Anatomy of Prokaryotic and Eukaryotic Cells Flashcards
Coccus (cocci)
-spherical-shaped
-“berries”
-when they divide to reproduce the cells remain attached to one another
-streptococci, diplococci, staphylococci
Diplococci
-cocci that remain in pairs after dividing
-ie. Neisseria gonorrhoeae
Neisseria gonorrhoeae
-diplococci bacteria
-causes gonorrhoea
-a STI
-have fimbriae that help the microbe colonize to cause disease
Streptococci
-cocci that divide and remain attached in a chainlike pattern
-ie. Streptococcus pyogenes
Streptococcus pyogenes
-streptococci bacteria
-causes strep throat
Tetrads
-cocci that divide in two planes and remain in groups of four
Sarcinae
-cocci that divide in three planes and remain attached in cube-like groups of eight
Staphylococci
-cocci that divide and form grape-like clusters
-ie. Staphylococcus aureus
Staphylococcus aureus
-staphylococci bacteria
-causes MRSA and other skin infections
Bacillus (bacilli)
-rod-shaped
-“little rods”
-can be used as a scientific name OR a shape
-only divide across their short axis (= fewer groups)
-single bacillus, diplobacilli, streptobacilli
Single Bacilli
-single rods
Diplobacilli
-bacilli that appear in pairs after division
Streptobacilli
-bacilli that occur in chains
Bacillus anthracis
-bacillus bacteria
-causes anthrax
-have capsules
Spiral
-can be curved rods or curly string-like shaped rods
-vibrio, spirillum, spirochete
Vibrio
-spirals that look like curved rods
-look like a kidney bean
-ie. Vibrio cholerae
Vibrio cholerae
-vibrio (spiral) bacteria
-causes cholera
-uses a glycocalyx to help it attach to cells of small intestine
Spirilla (Spirillum)
-helical/corkscrew shape
-rigid but mobile body
-have flagella to move around
-ie ??
?? example
Spirochete
-helical
-flexible
-move by axial filaments (flagella that wrap from end to end)
-ie. Treponema pallidum
Treponema pallidum
-spirochete (spiral) bacteria
-causes syphilis
-have axial filaments
Monomorphic
maintain a single shape
Pleomorphic
can have many shapes depending on the species/environment
Coccobacilli (coccobacillus)
-neither cocci or bacilli
-oval shaped
-in between
Glycocalyx
-secreted by the organism on the outside of their cell wall
-a sugar coat (polysaccharide + polypeptide)
-the sugar makes it sticky
Capsule
-if the glycocalyx is organized and firmly attached to the cell wall
-capsule can be seen via negative staining
Slime Layer
-when the glycocalyx is unorganized and loosely attached to the cell wall
Glycocalyx Functions
-increase virulence
-prevent phagocytosis (capsules) by slipping away
-stickiness allows attachment
-prevents dehydration
-may inhibit nutrients moving out of the cell
Virulence
-disease causing capacity
Stroptococcus pneumonine
-have glycocalyx
-cause pneumonia
-vaccines don’t use whole bacteria, just the capsule material
Streptococcus mutans
-have glycocalyx
-attach to teeth
-cause dental decay and cavities
-use glycocalyx as a nutrition source (the sugars as energy)
Extracellular Polymeric Substance (EPS)
-a glycocalyx that helps cells in a biofilm attach to their target environment and to each other
-allows communication and survival between cells
Flagella
-appendages that are used for movement or attachment
-love to run but tumble when they hit a block/need to change direction
Atrichous
bacteria that lack flagella
Peritrichous
-when flagella are distributed around the entire cell
Monotrichous
-have a single flagellum at one pole
-polar
Lophotrichous
-a tuft of flagella coming from one pole
-polar
Amphitrichous
-flagella are at both ends of the cell
-polar
Polar
-flagella reside at one or both ends of the cell
Filament (Flagella)
-constant in diameter
-contains the flagellin protein that intertwine around a hollow core
-most not covered by a membrane/sheath
-filament is attached to a hook
-is straight, never curly
Hook (Flagella)
-protein structure of unknown name
Basal Body (Flagella)
-anchors the flagellum to the cell wall and plasma membrane
-small central rod inserted into a series of rings
Motility
-the ability of an organism to move by itself
-enables bacterium to move toward a favourable environment away from an adverse one
Taxis
-movement of a bacterium toward or away from a particular stimulus
Chemotaxis
chemical stimuli
Phototaxis
light stimulus
Archaella
-similar to flagella but in archaeal cells
-no basal-body anchor in pili
Axial Filaments (aka endoflagella)
-found in spirochetes
-anchored at one end of a cell
-propel bacteria in a spiral motion
-similar structure to flagella
Borrelia burgdorferi
-causes lyme disease
have axial filaments
Fimbriae
-hair-like appendages
-shorter, straighter, thinner than flagella
-can jet out from all regions of the cell
-range from 1-100+
-allow attachment to each other and surfaces
-can’t be stained
E. coli
-have fimbriae and sometimes pili that allow bacteria to adhere to small intesting lining
-causes watery diarrhea
-colonization can’t happen without fimbriae (no disease)
Pili (sex pilus)
-usually longer than fimbriae
-1 or 2 per cell
-involved in motility and DNA transfer
-form a bridge between cels
Twitching Motility
pilus extends by adding subunits of pilin and then retracts
Gliding Motility
-movement of pili bacteria
-allows microbes to travel in environments with low water content
The Cell Wall
-made of peptidoglycan
-surrounds and protects plasma membrane of prokaryotes
-prevents bacterial cells from rupturing when water pressure inside is greater than outside
-maintains shape of cell
-point of attachment for flagella
-contributes to ability of some to cause disease
-site of action of some antibiotics
Eukaryote Cell Wall
-some have cell walls
-chemical composition is different
-simpler in structure
-less rigid
Peptidoglycan (aka Murein)
-consists of repeating disaccharide connected by polypeptides to form a lattice around the cell
“Peptido”
-polypeptide portion that link adjacent disaccharide rows
-binds the sugar backbone together
-consists of a polypeptide chain & tetra-peptide cross-bridge
Tetra-peptide Side Chains
-4 amino acids attached to NAMs in the backbone
-don’t criss cross
Penicillin
-interferes with the final linking of the peptidoglycan rows by peptide cross-bridges
-cell undergoes lysis
“Glycan”
-the sugar backbone
-glucose converted into NAM and NAG which join together in an alternating pattern
NAM
N-acetylmuramic acid
NAG
N-acetylglucosamine
Gram-Positive Cell Walls
-many layers of peptidoglycan
-thick, rigid structure
-have periplasmic space
-have Teichoic Acid
Periplasmic Space (GRAM +)
-space between the cell wall and plasma membrane of gram-positive bacteria
-contains granular layer composed of lipoteichoic acid
Lipoteichoic Acid
-spans the peptidoglycan layer and is anchored to the plasma membrane
Teichoic Acids
-found in cell walls of gram-positive bacteria
-an organic acid
-made of an alcohol (glycerol or ribitol) and phosphate
-doesn’t anchor
Teichoic Acid Functions
-have a negative charge and may bind and regulate cation movement in and out of the cell
-attract positive ions into the cell
-cell growth
-provide antigen specificity (identity)
Gram-Negative Cell Walls
-one or very few layers of peptidoglycan
-has an outer membrane and inner plasma membrane
-no teichoic acid
-PG is anchored to lipoproteins in outer membrane
-more susceptible to mechanical breakage
Periplasm (GRAM -)
-gel-like fluid in periplasmic space
-region between the outer membrane and plasma membrane
-contains lots of degradative enzymes and transport proteins
Outer Membrane (GRAM -)
-consists of lipopolysaccharides, lipoproteins, phospholipids, porin proteins
-several specialized functions
-strong - charge evades phagocytosis
-barrier to chemicals that will cause breakdown
Porin Proteins
-in outer membrane
-form channels that selectively allow ions and molecules in/out
Lipoproteins
-anchor PG to outer membrane
Lip(opolysaccharide)
-lipid A is the fat portion that is in the top layer
-button structure
-house an endotoxin that is released when the cell dies
-Lipid A is what causes the signs and symptoms such as: fever, nausea, diarrhea, constipation
-leads to shock if not treated
Core Polysaccharide
-attached to Lipid A
-contains unusual sugars that provide structural stability
(Lip) O polysaccharide
-extends outward from the button core
-made of sugar molecules
-functions as the antigenic specificity
Atypical Cell Walls
-certain cell types have no walls or very little wall material
Mycoplasma (Atypical)
-Mycoplasma pneumoniae
-smallest known bacterial that can grow and reproduce outside living host cells
-have no cell walls
-pass through many bacterial filters
-plasma membrane gets solidified by lipids called sterols to protect them from rupture
Archaea (Atypical)
-either have no wall or a false wall with no PG
-contain a substance similar to PG called pseudomurein
-don’t cause diseases
Acid-Fast Cell Walls (Atypical)
-contain a waxy lipid called Mycolic acid in their cell wall
-prevents uptake of dyes
-can be stained with carbolfuschin
Mycobacterium tuberculosis
-have acid-fast cell walls
-cause TB
Mycobacterium leprae
-have acid-fast cell walls
-cause leprosy
Damage to Cell Walls
-chemicals that damage bacterial cell walls often don’t harm host cells
-via lysozyme or antibiotics
Lysozyme
-digests the disaccharide (glycan) in PG
=cell death
-occurs naturally in some eukaryotic cells
-found in mucus, tears, sweat, saliva, breast milk
Lysozyme on Gram +
-cuts the bridges between the sugars in the thick PG layer
-destroys the cell wall
Protoplast
-the cellular contents that remain
-wall less cell is a protoplast
-typically capable of carrying on metabolism
Lysozyme on Gram -
-outer and plasma membrane remain
-this part is called a spheroplast
Antibiotics
-ie. penicillin
-disrupt cross bridge formation in PG
-destroy the peptide part of PG
-most gram - aren’t as susceptible to penicillin
Plasma Membrane
-prokaryotic cell membranes are usually less rigid than eukaryotes (except for mycoplasma)
-selectively permeable
Phospholipid Bilayer
-main component
-have polar head on the surface that is hydrophilic (water loving), soluble in water
-non polar tails on the interior that are hydrophobic (water fearing), insoluble in water
Peripheral Proteins
-lay on inner or outer surface
-easily removed
-function as enzymes, support scaffolding, mediators of shape during movement
Integral Proteins
-removed from membrane only after a disruption
-aka transmembrane proteins
-may be channels for entry/exit of substances
Glycoproteins
-proteins attached to carbohydrates
-protect cell
-lubricate cell
-cell interactions
Glycolipids
-lipids attached to carbohydrates
-protect cell
-lubricate cell
-cell interactions
Plasma Membrane Functions
-selective barrier
-breakdown of nutrients
-energy production
Chromatophores
-pigments and enzymes involved in photosynthesis
Simple Diffusion
-net movement of ions from an area of high concentration to an area of low concentration
-movement occurs until equilibrium
-oxygen and CO2 usually
Facilitated Diffusion
-integral membrane proteins act as channels/carriers
-for ions or large molecules
-no energy expended
Osmosis
movement of water across a selectively permeable membrane from and area of high water to an area of lower water concentration
Osmotic Pressure
pressure required to prevent movement of water into a solution containing solutes
Isotonic Solution
-a medium where overall concentration of solutes equals the inside of a cell
Hypotonic Solution
-outside cell
-solute concentration is lower than inside the cell
Hypertonic
-higher solute concentration than inside the cell
Cytoplasm
-cell substances inside the plasma membrane
-water
-proteins
-cabs
-lipids
-ions
Cytoskeleton
-fibres inside the cytoplasm
Nucleoid
-contains bacterial chromosome
-all the info required for cell structure and function
-not surrounded by nuclear envelope
Ribosomes
-all eukaryotic and prokaryotic cells have
-where protein synthesis takes place
Endospores
-resting cells
-resistant to heat, desiccation, chemicals
-formed by Bacillus (specifically Bacillus anthracis) and Clostridium species
-gram + cells
Clostridium tetani
-causes tetanus
Clostridium perfingens
-causes gangrene
Clostridium botulinum
-causes botulism (food poisioning)
Clostridium difficile
-causes colitis
Exception of Endospores
-only 1 that is gram-negative
-Coxiella burnetti: causes Q-fever (form of pneumonia)
-spread by domesticated animals
Sporulation
-endospore formation
-within a vegetative cell
-during stressful times
-spore septum (ingrowth) begins to isolate replicated DNA
-cell membrane begins to isolate new DNA and plasma
-spore septum surrounds isolated portion
-PG layer forms between membranes
-spore coat forms
-endospore is freed from cell
Germination
-return to vegetative state
-triggered by heat
Eukaryotic Cell
-typically larger
-more structurally complex
-have a true nucleus enclosed in a nuclear membrane
-have organelles
-complex flagella
-glycocalyx present in some cells lacking cell walls
-chemically simple cell wall when present
-have larger ribosomes (80S) and 70S in organelles
mitosis and meiosis
-plant and animal cells
Flagella and Cilia (Eukaryotic Cell)
-enclosed by plasma membrane
-used for locomotion
-consist of 9 + 2 array of microtubules
Cell Wall and Glycocalyx (Eukaryotic Cell)
-cell wall is simpler than prokaryotic
-glycocalyx: strength, attachment, cell-cell recognition
Plasma Membrane (Eukaryotic Cell)
-similar to prokaryotic in structure and function
-carbohydrates: attachment site for bacteria and receptor sites
-sterols: strength
Cytoplasm (Eukaryotic Cell)
-substances inside p. membrane and outside nucleus
Ribosomes (Eukaryotic Cell)
-attached to RER and free floating
-site of protein synthesis
-most are 80S except for ones in organelles (70S)
Nucleus (Eukaryotic Cell)
-contains DNA
-surrounded by nuclear envelope
-nuclear pores allow nucleus to communicate with cytoplasm
Endoplasmic Reticulum (Eukaryotic Cell)
-RER: processing and sorting proteins
-SER: no ribosomes, phospholipid synthesis
Golgi Complex (Eukaryotic Cell)
-transport proteins synthesized by RER
Lysosomes (Eukaryotic Cell)
-formed from golgi complexes
-contain digestive enzymes
Vacuoles (Eukaryotic Cell)
-space in the cytoplasm
-storage
Mitochondria (Eukaryotic Cell)
-metabolism
Chloroplast (Eukaryotic Cell)
-algae and green plants
-photosynthesis
Peroxisomes (Eukaryotic Cell)
-similar, smaller than lysosomes
-oxidize organic substances (ie. alcohol)
-h2O2 by product decomposed by catalase
Centrosome (Eukaryotic Cell)
-role in cell division
