Diversity and Biology of Bacteria 2

Question 1

Which of the following characteristics about the SYMPORT TRANSPORT SYSTEM are TRUE?

Requires no energy

Requires transport proteins

Simultaneous movement of protons and substrate into the cell

Modification of the substrate during the transport

quiz

Answer 1

-Requires transport proteins
-Simultaneous movement of protons and substrate into the cell

The symport mechanism is a form of active transport across the bacterial membrane in which a transporter protein couples the inward movement of a substrate and ions (typically Na+ or H+). The energy to carry out active transport is provided by the concentration gradient of the driving ion. An example of this type of transport is the uptake of lactose by H+ -driven lactose transporter in Escherichia coli.

Question 2

Which of these bacterial structures is involved in the surface-associated motility known as twitching?

Capsule

Flagella

Lipoteichoic acid

Pili

LPS

quiz

Answer 2

• Pili

Twitching motility is one of the different types of motility mechanisms that bacteria use to move. Twitching motility is a process that enables bacteria to move along solid surfaces and involves pili extension and retraction, which reflects pilin subunit polymerization and depolymerization events.
Pili are proteinaceous hair-like appendages that offer bacteria a wide range of functional adaptations.

Question 3

Which of the following statements about metabolism are FALSE?

Fermentation requires the presence of oxygen

Heterotrophic bacteria only use carbohydrates as a source of energy and carbon

Bacterial ATP synthase is a free-cytosolic enzyme

Fermentation of glucose yields more ATP than glycolysis

quiz

Answer 3

-Fermentation requires the presence of oxygen

-Heterotrophic bacteria only use carbohydrates as a source of energy and carbon

-Bacterial ATP synthase is a free-cytosolic enzyme

-Fermentation of glucose yields more ATP than glycolysis

Fermentation is an anaerobic process in which the final acceptor of electrons is an organic metabolic intermediate derived from a fermentable substrate (normally carbohydrates). Fermentation yields very little energy compared with aerobic and anaerobic respiration.
Heterotrophic bacteria use organic molecules, like carbohydrates, proteins, lipids, alcohols and amino acids among others, as a carbon/energy sources.
The ATPase or ATP synthase is a membrane-bound multicomponent protein that converts the kinetic energy of the flowing protons into chemical energy (ATP). The F0 channel is inserted in the membrane while the catalytic components (complex F1) are located in the cytosol.

Question 4

What are some characteristics/potential roles of plasmids?

Answer 4

1. circular or linear extrachromosomal DNA
2. Not essential for bacterial survival
3. Autonomous replication
4. Antibiotic resistance
5. bacteria can have one or two plasmids

Question 5

What are capsulated bacteria?

Answer 5

• Bacteria that have an amorphous polysaccaride slime around them
• Barrier to toxic hydrophobic molecules like detergents
• Capsule protects against immune system

Question 6

Whats an example of a capsulated bacteria and explain Fredrick Griffiths experiements’ result

Answer 6

Streptococcus pneumonaie-> its capsulated from can hide from immune system and cause disease

Griffith injected two strains of S. pneumonaie (one with capsule and one without) into mice and only the capsulated bacteria was deadly.

Question 7

Whats the role of pili/fimbrae?

pili are longer than fimbrae, and fimbrae more abundant per cell

Answer 7

• twitching motility (can be extended & retracted on solid surface)
• Sex pilus used for conjugation
• Fimbrae needed for adhesion

Question 8

Whats the role of the flagella?

Answer 8

Provide motility. Different than twitching motility because it rotates instead of inching forward like a worm