Chapter 4
What are the two types of Glycocalyx?
Capsule(neatly organized and firmly attached) and the Slime layer(loosely attached to the cell wall)
What two proteins penetrate the Plasma membrane?
Integral and Trans-membrane proteins
Describe the functions of the nucleus
It contains the majority of the cell's genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes.
What are some characteristics of the Acid -fast cell walls?
It has a waxy Lipid bound to Peptidoglycan They are similar to gram-positive cell walls Has Mycobacterium Has Nocardia Can stain with carbolfuchsin
What are three characteristics of Glycocalyx?
It is external to the cell wall It's viscous and gelatinous Made of polysaccharide and/or polypeptides
Define simple diffusion
Movement of a SOLUTE from an area of high concentration to and area of low concentration. This continues until molecules have reached equilbrium
Compare and contrast archaea and mycoplasmas
Mycoplasmas § Lack cell walls § Sterols in plasma membrane Archaea § Wall-less, or § Walls of pseudomurein (lack NAM and D-amino acids)
Describe the functions of the centrosomes?
Networks of protein fibers and centrioles From the mitotic spindle; critical role in cell division
What inhibits the peptide bridges in Peptidoglycan?
Penicillin
What is the composition of the cell wall?
Peptidoglycan(NAG and NAM) -polymers of repeating disaccharides in rows -Rows are linked by Polypeptides
What proteins are found on the surface of the plasma membrane?
Peripheral Proteins
What are some characteristics of the gram negative cell wall?
Periplasm between the outer membrane and the plasma membrane contains peptidoglycan Has two full lipid bilayers The outer membrane is very lacey like The outer membrane has lipopolysaccharides
What are the four types of flagella?
Peritrichous, Monotrichous, Lopotrichous, and Amphitrichous
What are some functions of the plasma membrane?
Permeability Has enzymes for ATP production
Describe the functions of the Golgi Complex?(In Eukaryotic cells only)
Transports organelles Modifies proteins from the ER Transports modified proteins via secretory vesicles to the plasma membrane
What color will the bacteria turn if it is gram positive? Gram negative?
Turns purple if positive Turns light pink and loses color if it's negative
Describe the functions of the lysosomes?
Vesicles formed in the Golgi complex Contain digestive enzymes
What are the different types of spiral bacteria?
Vibrio, Sprillium, Spirochete
What are protoplasts?
Wall-less, gram positive cell
What are Spheroplasts?
Wall-less, gram- negative cell
What is Penicillin's effect in Bacteria?
destroys bacteria by interfering with the formation of the peptide cross bridges of Peptidoglycan. This prevents the formation of a functional cell wall.
Identify the functions of the nucleoid and ribosomes in the prokaryotic cell.
nucleoid: Bacterial chromosome ribosomes: Protein synthesis § 70S § 50S + 30S subunits
Describe the functions of the peroxisomes?
oxidizes fatty acids, destroys h202
What does the gram negative cell wall protect itself from>
phagocytes, complement, and antibiotics
The antibiotic erythromycin binds with the 50S portion of a ribosome. What effect does this have on a prokaryotic cell? On a eukaryotic cell?
prokaryotes: will kill the cells - antibiotic will stop protein synthesis by attaching to the 50S eukaryotes: does not affect the cell at all because it does not have a 50S portion
What is the general function of inclusions?
reserve deposits, generally cells and accumulate certain nutrients and use them when the environment is deficient
Describe the functions of endospores
resting cells resistant to desiccation, heat, and chemicals. Highly durable dehydrated cells with thick walls, found in gram positive bacteria
Under what conditions do endospores form?
they form under harsh environments, form spores around DNA. cell dies off and DNA remains protected. can lie dormant for several years
Describe the structure and function of the glycocalyx
§ Outside cell wall § Usually sticky § Capsule: neatly organized § Slime layer: unorganized and loose § Extracellular polysaccharide allows cell to attach § Capsules prevent phagocytosis
What are the three parts of the flagella?
Filament-Outer-most region Hook- Attaches to the filament Basal Body- consists of rod and pairs of rings; anchors flagellum to the cell wall and membrane
What are the characteristics of the cell wall?
-Prevents osmotic lysis and protects the cell Membrane -Made of peptidoglycan(in bacteria) -Contributes to Pathogenicity
How many rings in basal body of flagella are found in the gram positive cell wall? Gram negative cell wall?
2 for the positive cell wall 4 for the negative cell wall
Compare and contrast acid-fast bacteria, archaea, and mycoplasmas
Acid-fast cell walls § Like gram-positive cell walls § Waxy lipid (mycolic acid) bound to peptidoglycan § Mycobacterium § Nocardia Mycoplasmas § Lack cell walls § Sterols in plasma membrane Archaea § Wall-less, or § Walls of pseudomurein (lack NAM and D-amino acids)
Identify the three basic shapes of bacteria
Bacillus(Rod-shaped) Coccus(Spherical) Spiral(variety because there are three kinds)
Why are drugs that target cell wall synthesis useful?
Bacteria have cell walls made of a protein called peptidoglycan that protects the cell from the exterior environment. Without the cell wall, the bacteria will be susceptible to destruction by chemicals outside the plasma membrane (which is just inside the cell wall of bacteria), and it will not be able to survive. Animal cells do not contain cell walls, so these drugs will only harm the bacteria and leave the cells in the body unharmed
Why are mycoplasmas resistant to antibiotics that interfere with cell wall synthesis?
Because they don't have cell walls
Why are bacterial capsules medically important?
Capsule: neatly organized Outside cell wall Protects from immune cells It gives encapsulated bacteria a potential advantage over the body's immune cells (impairs phagocytosis) Produce mucoid (sticky) colonies on agar
***Compare and contrast prokaryotic and eukaryotic cell walls and glycocalyxes.
Cell walls: Prokaryotic- -made of peptidoglycan, can be gram positive or gram negative -complex and rigid Eukaryotic- -much more simple, algae- cellulose, fungi-chitin, yeast- glucan and mannan Glycocalyx: Prokaryotic- slime layer or capsules Eukaryotic- layer of material containing sticky carbs -Strengthens cell surface, helps attach cells together, contributes to cell to cell recognition
What are some things that can damage the plasma membrane and cause leakage?
Detergents, polymixin antibiotics, alcohols,
Describe the functions of the Mitochondria?
Double Membrane Involved in cellular respiration Contain inner folds called cristae and fluid called matrix
Describe the function of sporulation
Endospore Formation
Differentiate flagella, axial filaments, fimbriae, and pili.
Flagella § Outside cell wall § Made of chains of flagellin § Attached to a protein hook § Anchored to the wall and membrane by the basal body Axial Filaments § Also called endoflagella simillar to flagella § bundles of fibrils that arise at one end of the cell beneath an outer sheath and spiral around the cell Fimbriae § Fimbriae allow attachment § Few to many per cell § Attach to each other and surfaces § Biofilm formation and surface colonization Pili § Longer than fimbriae § Usually 1 or 2 per cell § Used for gene transfer and motility § Facilitate transfer of DNA from one cell to anotheR
What protein is flagella made of?
Flagellum
Describe the structure, chemistry, and functions of the prokaryotic plasma membrane
Function The plasma membrane surrounds the outside of both Eukaryotic and Prokaryotic cells. It is made up of a double layer of phospholipids and controls the movement of various substances into and out of the cell, both passively and actively. It also allows cell identification. Structure Like all other cellular membranes, the plasma membrane consists of both lipids and proteins. The fundamental structure of the membrane is the phospholipid bilayer, which forms a stable barrier between two aqueous compartments. In the case of the plasma membrane, these compartments are the inside and the outside of the cell. Proteins embedded within the phospholipid bilayer carry out the specific functions of the plasma membrane, including selective transport of molecules and cell-cell recognition.
What is Glycocalyx?
Glue that hold cells in place
Is gram negative bacteria or gram positive bacteria less susceptible to Penicillin? Why?
Gram Negative because the outer membrane of gram negative bacteria forms a barrier that inhibits the entry of penicillin and other substances. Also, gram negative bacteria have fewer peptide cross bridges.
What are three differences between gram negative bacteria and gram positive gram bacteria?
Gram Negative: -Thin Peptidoglycan -Outer Membrane -Periplasmic Spce Gram Positive: -Thick Peptidoglycan -Cell walls -Teichoic Acids
What kind of toxins does the Gram positive cell wall make? Gram negative cell wall?
Gram positive cell wall makes exotoxins only. The Gram negative cell wall makes both endotoxins and exotoxins
Compare and contrast the cell walls of gram-positive bacteria, gram-negative bacteria
Gram-Positive Cell Walls § Teichoic acids § Lipoteichoic acid links to plasma membrane § Wall teichoic acid links to peptidoglycan § May regulate movement of cations § Polysaccharides provide antigenic variation Gram-Negative Outer Membrane § Lipopolysaccharides, lipoproteins, phospholipids § Forms the periplasm between the outer membrane and the plasma membrane § Protection from phagocytes, complement, and antibiotics § O polysaccharide antigen, e.g., E. coli O157:H7 § Lipid A is an endotoxin § Porins (proteins) form channels through membrane
What is Fimbriae?
Hair-like appendages that allow for attachment
Describe the functions of the Vacuoles?
Important to plant cells Cavities in the cell formed from the Golgi Complex Brings food into cells; provides shape and storage
What are some characteristics of Archaea?
It is wall -less Has walls of pseudomurein(Lacks NAM and D-Amino Acids)
How do protoplasts differ from L forms?
L forms can return to a walled state
What is the endosymbiotic theory?
Larger bacterial cells engulfed smaller bacterial cells developing the first eukaryotes. Ingested Photosynthetic bacteria become chloroplasts Ingested aerobic bacteria became mitochondria
What links the cell wall to the plasma membrane in gram positive cell walls?
Lipoteichoic
Describe the functions of the chloroplasts?
Locations of Photosynthesis Contain flattened membranes(thylakoids) that contain chlorophyll
What is Pili?
Longer than Fimbriae Involved in motility(gliding and twitching) Conjugation Pili involved in DNA transfer from one cell to another
What hydrolyzes bonds in peptidoglycan?
Lysozymes
What are characteristics of the Fluid-Mosaic Model?
Membrane is as viscous as Olive oil Proteins move freely for various functions Phospholipids rotate and move laterally Self-sealing
What are the 7 types of Inclusions and what are their functions?
Metachromic Granules(Volutin)- Phosphate reserves Polysaccharide Granules- Energy reserves Lipid Inclusions- Energy Reserves Sulfur Granules- Energy Reserves Carboxysomes- RuBisco Enzyme for CO2 fixation during photosynthesis Gas Vacuoles- Protein covered cylinders that maintain buoyancy Magnetosomes- Iron oxide inclusions; destroys h202
How do bacteria move?
Motile Cells § Rotate flagella to run or tumble § Move toward or away from stimuli (taxis) § Flagella proteins are H antigens
What layer of the Plasma membrane encloses the cytoplasm?
Phospholipid bilayer
What is the outer membrane of the gram negative cell wall made of?
Polysaccharide, lipoproteins,and phospholipids
What is the susceptibility of penicillin to gram positive cell wall? Gram negative cell wall?
Positive cell wall will have a high susceptibility , while gram negative will have a low susceptibility
Osmotic Pressure?
Pressure needed to stop the movement of water across the membrane
Where is the DNA located in a prokaryotic cell? In Eukaryotic cell?
Prokaryotic cell: Nucleoid Eukaryotic Cell: In the Nucleus
What is the main feature that distinguishes prokaryotes from eukaryotes?
Prokaryotic cells have genetic material that is not contained in a nucleus
Differentiate prokaryotic and eukaryotic flagella.
Prokaryotic: - Double membrane, -Give cells movement. - Made up of the filament- flagellum, the hook, and the basal body- rod with a series of rings Eukaryotic - Structures that extend from the cell, anchored to plasma membrane by basal body - Consists of the 9+2 array of microtubules- made of tubulin
What are the differences between Prokaryotic and Eukaryotics?
Prokaryotic: -One circular chromosome; not in a membrane -No Histones -No Organelles -Bacteria: Peptidoglycan cell walls -Archaea: Pseudomurein Cell Walls -Divide by Binary fission Eukaryotic: - Paired Chromosomes in Nuclear Membrane -Histones -Organelles -Polysaccharide cell walls, when present -Divide by Mitosis
Compare and contrast prokaryotic and eukaryotic cytoplasms.
Prokaryotic: -The substance is inside the plasma membrane -80% water plus proteins, carbohydrates, lipids, and ions -Consists of cytoskeleton Eukaryotic: -The substance is inside the plasma and outside the nucleus Consists of Cytosol, cytoskeleton, and cytoplasmic streaming
Compare the structure and function of eukaryotic and prokaryotic ribosomes
Prokaryotic: Sites of Protein Synthesis Made of Protein and Ribosomal RNA 70s -50s and 30s Subunit Eukaryotic: Sites of Protein Synthesis 70s(found in mitochondria and chloroplasts) 80's(free in cytoplasm) -60s and 40s subunit
Differentiate protoplast, spheroplast, and L form.
Protoplast is a wall-less cell - Spheroplast is a wall-less gram-negative cell - Protoplasts and spheroplasts are susceptible to osmotic lysis - L forms are wall-less cells that swell into irregular shapes
What are two things that are susceptible to Osmotic Lysis?
Protoplasts and Spheroplasts
Define Active Transport
Requires a transporter protein and ATP; goes against gradient
Define group translocation
Requires a transporter protein and Phosphoenolpyruvic acid. The substance is altered as it crosses the membrane
Describe the function of endospore germination.
Returns to the Vegetative State
How do rough and smooth ER compare structurally and functionally?
Rough ER: Studded with ribosomes; sites of protein synthesis Smooth ER: No ribosomes; synthesizes cell membranes, fats, and hormones
Define Facilitated diffusion
SOLUTE combines with a transporter protein in the membrane. Transports ions and larger molecules across a membrane with the concentration gradient
Compare and contrast prokaryotic and eukaryotic plasma membranes.
Same: phospholipid bilayer w/proteins(peripheral and integral) Differences: Eukaryotes contain carbs attached to proteins and sterols (steroid alcohols like cholesterol) , which is not found in prokaryotes (except mycoplasma bacteria Eukaryotic plasma membrane also move materials across plasma membrane by passive, active, and endocytosis processes (phagocytosis & pinocytosis)
Bacteria is mainly divided by...
Shapes
How are simple diffusion and facilitated diffusion similar? How are they different?
Simple diffusion: movement of a solute from an area of high concentration to an area of low concentration Facilitated diffusion: solute combines with a transporter protein in the membrane
What are three ways that bacteria is distinguished?
Size, Shape, and arrangement
Hypotonic Solution?
Solute concentration is lower outside than inside the cell(Water moves into the cell)
Isotonic Solution?
Solute concentrations equal inside and outside of the cell.
Hypertonic Solution?
Solute concentrations is higher outside than inside the cell.(Water moves out of a cell)
What is something that some plasma membranes have?
Some membranes have photosynthetic pigments on foldings called chromatophores
How can you identify streptococci with a microscope?
Streptococi - single plane, chains cocci that divide and remain attached in chainlike patterns
Define Passive Processes
Substances moving from high concentrations to low concentrations. NO ENERGY.
Define Active processes?
Substances that move from low concentrations to high concentrations. USING ENERGY.
What is the gram positive cell wall made up of?
Teichoic Acids
What are three characteristics of the gram positive cell wall?
Teichoic acid links the peptidoglycan Carries a negative charge Regulates the movement of cations
How can flagella show whether or not it is gram positive or gram negative?
The basal body has rods, which has rings that can show whether or not it is gram positive or gram negative.
What attaches to flagella to bacteria?
The hook of the flagella
Define Osmosis
The movement of WATER across a selectively permeable membrane from an area of high water to an area of lower water concentration.
What are Atypical cell walls?
They are cell walls that do not fit in the gram positive cell wall, nor will they fit in the Gram negative cell wall
What are L-Forms?
They are wall-less cells that swell into irregular shapes
What are some characteristics of Mycoplasmas?
They lack cell walls. They have sterols(Lipid molecules) in their plasma membrane.
What are axial Filaments?
a filament that wraps around the cell and makes the cell move in a cork screw movement -Also called endoflagella -Found in Spirochetes -Anchored at one end of the cell -Rotation causes cell to move like a corkscrew
Which agents can cause injury to the bacterial plasma membrane?
alcohol, quaternary ammonium (detergents), polymyxin antibiotics
