Midterm 1

Question 1

Model gram negative microbe

Answer 1

Escherichia coli (E. coli)

Question 2

Model gram-negative microbe

Answer 2

Bacillus subtilis (B. subtilis)

Question 3

What is the phylogenetic tree of life composes of and based on?

Answer 3

Composed of 3 domains of evolutionary descent and based on sequenced genomes

Question 4

The target for antimicrobials is?

Answer 4

The cell envelope

Question 5

The cytoplasmic membrane key functions:

Answer 5

Permeability barrier – has selective permeability
Protein anchor – enzymes, transporters
Energy conservation – proton motive force

Question 6

Structure of the cytoplasmic membrane

Answer 6

Fluid mosaic model

Question 7

What helps to stabilize the cytoplasmic membrane?

Answer 7

• Hydrogen bonds and hydrophobic interactions
• Mg2+ and Ca2+ forming ionic bonds with negative charges on the phospholipids

Question 8

Outer surface of cytoplasmic membrane is characterized by?

Answer 8

Proteins that bind substrates or process large molecules for transport

Question 9

Inner surface of cytoplasmic membrane is characterized by?

Answer 9

Proteins involved in energy-yielding reactions, transport & secretion

Question 10

What do aquaporins do?

Answer 10

Enhance water transport

Question 11

Exceptions to membrane permeability (permeable substances)

Answer 11

Water, gases (O2, CO2, N2), ethanol, urea