Module 2 Flashcards
Describe the origin of cell theory
Describe the endosymbiotic theory
What are the shapes and arrangements of bacteria?
Describe prokaryotic cells, their inclusions and “compartments”
Includes bacteria and archaea
-Do not have a nucleus enclosed in a nuclear membrane (have nucleoid)
-Come in various sizes (not all bacteria are microscopic), much smaller than eukaryotes
-bacteria can form endospores and contain pili, fimbriae and flagellum/flagella
-Archaea have archaellum/archaella, form monolayers
Inclusions and compartments:
-Inclusions: cytoplasmic Energy storage structures
-Gas vesicles: float in water
-Magnetosomes: orientation according to magnetic field
Describe a eukaryotic cell
-membrane enclosed nucleus
-Membrane-bound organelles
-Mitochondria
-Chloroplasts
-Flagellum
-Cilia
Describe endospores and the sporulation cycle.
-Bacteria generally observed as vegetative cells but some have ability to form endospores
What is the cell envelope?
Series of layers around the cytoplasm (diverse functions in prokaryotes and eukaryotes)
-Cytoplasmic membrane
-Cell wall
-Outer membrane
-S-layer
-Capsule
What does the cytoplasmic membrane do?
-Selective barrier
-Generating gradients
-Anchors proteins for sensoring, communicating and interacting
What is the composition of the cytoplasmic membrane in bacteria and eukarya vs archaea?
What is simple diffusion?
Energy independent
What is facilitated diffusion?
Describe active transport
Describe coupled active transport
Antiport:
-Moving two substances in opposite direction
-Using the gradient of one molecule moving down its gradient to move another against its gradient
Symport:
-Molecules are moving in the same direction
What is an ABC transporter?
ATP-Binding Casette
-Substrate binds to a substrate-binding protein, changing the conformation of carrier protein allowing ATP to bind to its respective region and carries substrate into membrane proteins
-Gram negative = substrate binding protein in periplasm
-Gram positive = substrate binding protein attached to outside cell membrane
What is group translocation?
-Substance being trasnported is chemically modified in the process so it does not require transport against unfavourable concentration gradient
-membrane phosphorylates the sugar as it enters the cell (required during early stages of metabolism making it an energy neutral system)
Describe the cell wall in bacteria and their association with gram staining
-Main component is peptidoglycan (murein) only found in bacteria
-Composed of layers of alternating NAG and NAM chains for structure, shape
Gram negative:
-tetrapeptide chains are directly cross-linked
-Much thinner peptidoglycan layer
-Periplasmic space between cell wall and plasma membrane
-Second lipid bilayer (outer membrane) external to peptidoglycan attached by merein lipoprotein
-outer leaflet of outer membrane contains lippolysaccharide (LPS) or “endotoxin” attached to serve as mechanical strength, immune evasion and protection
-Contains lipid A, core polysaccharide and O antigen
Gram positive:
-Tetrapeptide chains are linked by pentapeptide (peptaglycine) cross bridges
-Much thicker and embedded with teichoic acids to stabilize peptidoglycan and increase rigidity
Acid-fast:
-Gram positive composition but contain mycolic acids (long fatty acid/ wax layer) on outer peptidoglycan cell wall which hold fuschin dye
Describe the cell wall of archaea
-Do not contain peptidoglycan
-Cell wall (pseudomurein) contains NAT instead of NAM
What is unique to eukaryotic cell walls?
-Cellulose (plants)
-Chitin (fungi)
Describe the S layer in bacteria
What are slime and capsule layers?
capsules are difficult to stain, negative stain techniques are typically used
What are pili and fimbriae
What are arrangements of flagellum?
Differentiate flagellum vs archaellum
What is twitching and gliding?
What are taxis and chemotaxis?
What is swimming?
