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BIO 425: Microbiology > Lecture 3 Cell Biology > Flashcards

Lecture 3 Cell Biology Flashcards

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1
Q

What are the size ranges for Prokaryotes and Eukaryotes?

A

Prokaryotes -0.2 um to 700+ um

Eukaryotes -10 um to 200+ um

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2
Q

Why is the small cell size so significant?

A

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

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3
Q

What are the main cell morphological shapes?

A
  1. Coccus = sphere
  2. Bacillus = cylindrical
  3. Spirillum = spiraled
  4. Spirochete = cork-screw
  5. Appendaged = with a stalk or hypha
  6. Filamentous = clusters
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4
Q

What are the types of cell filamentous cluster types?

A

Diplo = pairs of only 2 cells

Strepto = Chains of 3+

Staphylo = Grouped together in clump not chain

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5
Q

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

A

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

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6
Q

What are the types and characteristics of membrane proteins?

A

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

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7
Q

How are Archaeal membranes different from Bacteria membranes?

A

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
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8
Q

What are the functions of the cytoplasmic membrane?

A

Permeability barrier

Protein anchor

Energy conservation (proton motive force)

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9
Q

What are the types of transport proteins?

A

Simple

Group Translocation

Periplasmic (ABC)

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10
Q

Why are transport proteins so important?

A

They enhance the rate of uptake of needed solutes

-much greater than simple diffusion

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11
Q

What are the types of transport mechanisms?

A

Uniport

Symport

Antiport

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12
Q

What is an example of a simple transport protein?

A

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

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13
Q

What is group translocation?

A

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
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14
Q

What is Periplasmic (ABC) transport protein?

A

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
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15
Q

What is Protein export?

A

Transport large molecules either:

  1. across membrane inside-to-outside
  2. inserts into membrane Translocase proteins do this
    - Ex. Sec System
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16
Q

What do cell walls provide for bacteria and archaea?

A

Structure

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

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17
Q

What are the functions of cell walls in bacteria?

A

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

18
Q

What is peptidoglycan?

A

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)
19
Q

How does peptidoglycan differ?

A

Many different types that differ structurally

  • Same Sugar backbone
  • Different Peptide cross-linked branches
20
Q

How is peptidoglycan targeted/destroyed?

A

Lysozymes destroy peptidoglycan Penicillin prevents synthesis

-breaks a bigger and bigger hole until cell is lysed

21
Q

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

A

Both have peptidoglycan Gram (+)

  • cytoplasmic membrane
  • THICK wall of peptidoglycan Gram (-)
  • cytoplasmic membrane
  • THIN wall of peptidoglycan
22
Q

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

A

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
23
Q

What are the characteristics of Gram (+) bacteria?

A

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+
24
Q

What are the characteristics of Gram (-) bacteria?

A

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

  1. Lipoproteins
  2. Porins
25
Q

What are Lipoproteins?

A

Anchor the outer membrane to peptidoglycan layer

26
Q

What is the periplasm?

A

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)
27
Q

What are Porins?

A

Channels for specific small molecule transport

-regulate whats in periplasm by size specificity

28
Q

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

A

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

Structural features

  • No peptidoglycan
  • Has other polysaccharides, proteins or glycoproteins
29
Q

What is Pseudomeurein?

A

Similar structure to peptidoglycan found in Archaea

  • Connected by B-1-3 Glycosidic linkage
  • So it’s not affected by penicillin
30
Q

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

A

SO42- binds to salt

Found in extreme halophiles (live in extreme salt concentrations

31
Q

What is the S-Layer in Archaea cell walls?

A

Paracrystalline Surface layer

32
Q

What are capsules and slime layers?

A

Capsules and Slime Layers found on cell surface of Archaea/Bacteria cell walls

  • Sticky material on cell surface
  • Ataches to surface, avoids phagocytosis and avoids dessication
33
Q

What are pili?

A

Cell surface structure found on bacteria/archaea cell wall

  • Protein filaments
  • Many short = fimbriae
  • Few long = Pili

Functions

  • Attach to surfaces
  • Genetic exchange
  • Colonization
34
Q

What kinds of things are stored inside Bacteria/Archaea (Inclusions)?

A

Carbon Storage Polymers

-store carbon and energy

Polyphosphate, Sulfur and Carbonate Minerals

-store inorganic molecules

Magnetosomes

-Store magnetic materials which help with direction/depth

35
Q

What are Gas Vesicles found in Archaea/Bacteria?

A

Spindle shaped proteins

Aid in Buoyancy and Flotation

-important in planktonic microbes

36
Q

What are Endospores?

A

Highly resistant bacterial seeds

  • Enable bacteria to survive harsh conditions
  • Vegetative cell = active cell
  • Spore = inactive cell
37
Q

How are endospores so resistant?

A

Physical Protection

-Spore coat (protein) and Cortex (Peptidoglycan)

Chemical Protection

-Dipicolinic Acid and Small Acid Soluble Proteins

38
Q

What is the sporulation and germination of Endospores?

A

Sporulation

-Formation of spores

Germination

  • Incative Spore -> Active Cell
  • Triggered by environment
39
Q

How do Archaea and Bacteria move (locomotion)?

A

Swimming Motility

  • Flagella
  • Two types: Polar (one region) and Peritrichous (all over)

Gliding Motility

  • Movement without flagella (must contact solid surface)
  • Two Types: Slime extrusion or Twitching (Pili)
40
Q

How are Polar and Peritrichous movement different?

A

Polar (Flagella in one region)

  • Reversible flagella: CW or CCW rotation changes direction
  • Unidirectional Flagella: One rotation, just stops and reorients to change directions

Peritrichous (Flagella all over)

  • Rotate to move then flails flagella to change direction
  • Run+Tumble
41
Q

What are the taxes for motility?

A

The reasons for motility are they are looking for:

Chemotaxis

-Chemical gradients

Phototaxis

-Light Gradients

BIO 425: Microbiology (22 decks)

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