Midterm 1.5

Question 1

Carboxysomes

Answer 1

Concentrate enzymes involved in carbon fixation - increases efficiency and reduces unwanted side reactions

Question 2

What do many microcompartments do?

Answer 2

Protect cell against toxic/reactive intermediates/bi-products

Question 3

Endospores

Answer 3

Highly differentiated, dormant cells that can survive starvation and very harsh environmental conditions

Question 4

Who usually produces endospores?

Answer 4

Members of the phylum Firmicutes that are gram +

Question 5

Vegetative cells

Answer 5

Normal, metabolically active, growing/dividing cells

Question 6

When do vegetative cells form endospores?

Answer 6

When subjected to nutrient depletion.

Question 7

How do you create a stable and resistant core of the endospore?

Answer 7

Dehydration of the core is key
Dipicolinic acid (DPA)
Small acid soluble proteins (SASPs)

Question 8

Explain the structures of the endospore

Answer 8

Core - where DNA/ribosomes are housed - will become the vegetative cell
Cortex - peptidoglycan layer
2 membranes
Coat - protective protein layer comprised of many different proteins
SOME spores produce a second protein layer called the exosporium

Question 9

Name all unique cell membranes of Archaea

Answer 9

Ether-linked lipids instead of ester-linked lipids of bacteria/eukarya

Lipids that make up bilayer are isoprenoid, not fatty acids

Lipids contain side branches and rings

Some produce transmembrane phospholipids - a lipid monolayer (similar to bilayer, but lipid tails are joined)

Question 10

How does the utilization of the S-layers differ for archaea and bacteria?

Answer 10

Archaea - proteinaceous S-layers act as the cell wall
Bacteria - S-layers act as supplementary structures, not generally thought of as part of the cell wall

Question 11

Pseudomurein

Answer 11

A component of the cell wall of archaea; it is similar to peptidoglycan in structure and function but contains different components

Question 12

Hamus

Answer 12

Fix cells to a surface or to other cells to mediate biofilm formation (archaea). Same thing as a grappling hook

Question 13

Explain archaea motility (!)

Answer 13

Swimming motility via an analagous flagellum-like apparatus (but functionally/evolutionarily distinct
Simpler (fewer proteins). Driven by ATP hydrolysis
Related to type IV pilus cuz it is built from inside out
Generally swim slower than bacteria

Question 14

Chemoorganotrophs

Answer 14

Organisms that harvest energy by oxidizing organic chemicals

Question 15

Chemolithotrophs

Answer 15

Organisms that obtain energy from the oxidation of inorganic compounds

Question 16

How do lysozymes affect cell wall synthesis

Answer 16

hydrolyze B (1,4) glycosidic bond between NAG and NAM

affects BOTH existing and growing bacteria

Question 17

How does penicillin affect cell wall synthesis

Answer 17

blocks transpeptidase enzyme (resp for linking peptide chains together)

affects ONLY growing bacteria as cell walls are still being built. it has no affect on already existing cells

most effective on gram positive because they have peptidoglycan, and no outer membrane for protection. they also lack B-lactamases