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Flashcards in Lecture 3 Cell Biology Deck (41)
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What are the size ranges for Prokaryotes and Eukaryotes?

Prokaryotes -0.2 um to 700+ um


Eukaryotes -10 um to 200+ um


Why is the small cell size so significant?

Surface to area volume

-smaller size = greater SA:Vol

-bigger size = smaller SA:Vol = can't take in as much nutrients


Growth Rates

-High Growth Rate = High Evolution Rate


What are the main cell morphological shapes?

1. Coccus = sphere

2. Bacillus = cylindrical

3. Spirillum = spiraled

4. Spirochete = cork-screw

5. Appendaged = with a stalk or hypha

6. Filamentous = clusters


What are the types of cell filamentous cluster types?

Diplo = pairs of only 2 cells

Strepto = Chains of 3+

Staphylo = Grouped together in clump not chain


What is the structure of a cytoplasmic membrane composed of and what is its function?

Structure composed of phospholipid bilayer Function is selective permeability and to separate the inside cytoplasm from the environment outside.


What are the types and characteristics of membrane proteins?

Types are integral and peripheral They are anchored in cytoplasmic membrane and have hydrophobic and hydrophylic regions


How are Archaeal membranes different from Bacteria membranes?

Linkage of glycerol head to fatty acids

-Archaea have ether bond, Bacteria have ester Fatty Acid Composition

-Archaea have more unsaturated Isoprene bonds Monolayer membranes only in Archaea

-Monolayer membranes have FA's connected


What are the functions of the cytoplasmic membrane?

Permeability barrier

Protein anchor

Energy conservation (proton motive force)


What are the types of transport proteins?


Group Translocation

Periplasmic (ABC)


Why are transport proteins so important?

They enhance the rate of uptake of needed solutes

-much greater than simple diffusion


What are the types of transport mechanisms?





What is an example of a simple transport protein?

Lac Permease (E. coli) -Symport transports lactose against its concentration gradient along with H+ Protons into the cell

-Uses energy of protons moving with concentration gradient to transport lactose against its concentration gradient


What is group translocation?

Transport mechanism where the substance transported is chemically modified

-Uses the phosphotransferase system

-Uses 5 proteins which gives more control of system

-Energy driven using phosphoenolpyruvate (PEP) to phosphorylate the 1st protein which phosphorylates each one down the cascade


What is Periplasmic (ABC) transport protein?

ABC = ATP-Binding Cassette System Occurs in Periplasm

-Between cytoplasmic and outer membranes Requires multiple proteins

-protein binds substrate which the binds to membrane transporter to transport substrate


What is Protein export?

Transport large molecules either:

1. across membrane inside-to-outside

2. inserts into membrane Translocase proteins do this

-Ex. Sec System


What do cell walls provide for bacteria and archaea?


-Bacteria have Gram (+) or Gram (-)


What are the functions of cell walls in bacteria?

Prevent osmolytic lysis (cell explosion) Give shape and rigidity to cell


What is peptidoglycan?

Only present in bacteria

-Both Gram (+) and Gram (-)

-Not found in Archaea or Eukarya


Polysaccharide made of 2 sugar derivatives

-Connected by B-1-4 Glycosidic Linkages

-For long chains (sheets) around cell

-Chains are linked by amino acid branches (peptide bonds)


How does peptidoglycan differ?

Many different types that differ structurally

-Same Sugar backbone

-Different Peptide cross-linked branches


How is peptidoglycan targeted/destroyed?

Lysozymes destroy peptidoglycan Penicillin prevents synthesis

-breaks a bigger and bigger hole until cell is lysed


What are the similarities between Gram (+) and Gram (-) bacteria?

Both have peptidoglycan Gram (+)

-cytoplasmic membrane

-THICK wall of peptidoglycan Gram (-)

-cytoplasmic membrane

-THIN wall of peptidoglycan


How do Gram (+) and Gram (-) bacteria differ?

Gram (+)

-THICK peptidoglycan and NO outer membrane

-Looks smooth under scanning electron microscope


Gram (-) bacteria

-THIN wall of peptidoglycan and outer membrane

-Looks rough under scanning electron microscope


What are the characteristics of Gram (+) bacteria?

Have Teichoic Acids

-Embedded in cell wall

-Negatively charged so attracts cations Negative charge of cell surface transports cations like Mg 2+ or Ca 2+


What are the characteristics of Gram (-) bacteria?

Outer membrane has second Lipid Bilayer (Outer membrane) Outer membrane has: 1. Lipopolysaccharide (LPS)

2. Lipoproteins

3. Porins


What are Lipoproteins?

Anchor the outer membrane to peptidoglycan layer


What is the periplasm?

Between the Cytoplasmic and outer membranes Contains different classes of proteins

-Hydrolytic enzymes: initial breakdown of food molecules

-Binding Proteins: Begin translocation process

-Chemoreceptors: Detect chemical gradients (chemotaxis)


What are Porins?

Channels for specific small molecule transport

-regulate whats in periplasm by size specificity


What are the functions and structural features of Archaea cell walls?

Prevents Osmotic lysis and give shape/rigidity to cell just like bacteria cell walls

Structural features

-No peptidoglycan

-Has other polysaccharides, proteins or glycoproteins


What is Pseudomeurein?

Similar structure to peptidoglycan found in Archaea

-Connected by B-1-3 Glycosidic linkage

-So it's not affected by penicillin


What purpose do Polysaccharides + Sulfate serve in archaea cell walls?

SO42- binds to salt


Found in extreme halophiles (live in extreme salt concentrations