bacterial anatomy Flashcards

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1
Q

define amphipathic

A

hydrophilic and hydrophobic in different areas

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2
Q

Define passive diffusion (3)

A
  1. transporter independent
  2. the combined concentration of solutes passively tries to reach equilibrium
  3. uptake increases in a linear fashion, but will plateau when inside conc. reaches outside
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3
Q

define facilitated diffusion

A
  1. independent of membrane permeability
  2. example is a porin, which is proteins that make a hole through the membrane, allowing molecules up to a certain size through
  3. uptake levels will rise as outer conc rises, but will reach max saturation. uptake will plateau when inner and outer conc. reaches equilibrium
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4
Q

the lower the km,

A

the higher the affinity of the channel, more activity

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5
Q

is active transport dependent on a transporter?

A

yes

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6
Q

Define the kinetics of active transport

A

uptake will plateau at a point. however, concentration inside can go above outside concentration

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7
Q

what do uni-, sym, and antiporters have in common?

A

all are unidirectional, any kind of transport

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8
Q

define uniporters

A

They move one specific substance in one direction

Used for either facilitated diffusion or active transport

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9
Q

define symporters

A

They move two specific molecules in one direction at the same time
Used for either facilitated diffusion or active transport

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10
Q

define antiporters

A

Two specific molecules are transported in opposite directions
Used for either facilitated diffusion or active transport

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11
Q

what are two functions of the cell wall?

A

resist osmotic pressure caused by the entry of water, and define cell shape

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12
Q

define periplasm

A

gap between cell wall and interior plasma membrane

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13
Q

What is the difference between peptidoglycan units on gram positive and negative units?

A

Gram negative have DAP on their string of amino acids, while gram positive uses Lys in the same spot

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14
Q

bridges between layers of the peptidoglycan in gram negative

A

direct peptide bond between the amino acid chains of each layer

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15
Q

bridges between layers of the peptidoglycan in gram positive

A

indirect bonding between layers through a bridge of glycenes

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16
Q

how does the cell wall grow? (3 steps)

A
  1. preformed units are brought to the cell wall
  2. autolysin comes in and cuts the cell wall, allowing new units to be added to the cell wall
  3. bridges are then formed between the layers through transpeptidation
17
Q

how penicillin works

A

when the cell wall is growing, beta lactams in penicillin prevent new transpeptidation linkages between layers of the peptidoglycan layer.

18
Q

why does penicillin only work on gram + bacteria

A

Gram - bacteria have the glycocalyx that protects them from penicillin, since it is a large molecule

19
Q

how does lysozyme work?

A

it cleaves the beta 1-4 linkages between N-glucosamine and acetyl-muramic acid. it works on cell that are growing, and cells that are not. it cuts the linkages between peptidoglycan units

20
Q

What is the significance of Lipid A to the body?

A

only found on the LPS layer, no body cell have LPS, the body knows there is an intruder

21
Q

what is the LPS impermeable to?

A

larger proteins, ploysaccharides, and H+