3.1 - The Bacterial Cell

Question 1

What is bacteria made up of?

Answer 1

Water (70%)
Protein (16%)
RNA (7%)
Membranes (4%)
DNA (1%)
Peptidoglycan (1%)
Metabolites (1%)

Question 2

How much of the dry mass of bacteria cell is protein?

Answer 2

Approximately 50%

Question 3

What do most bacteria contain?

Answer 3

(1) A thick complex outer envelope: The envelope protects the cell from environmental stress and mediates exchange with the environment.
(2) A compact genome: prokaryotic genomes are compact, with relatively little noncoding DNA. Small genomes maximize the production of cells from limited resources

Question 4

What may enable a high rate of reproduction in bacterial cells

Answer 4

Tighlt coordinated functions. The cell’s parts work together in a highly coordinated mechanism.

Question 5

What is included in the envelope?

Answer 5

(1) The outer membrane (gram negative only)
(2) The cell wall and periplasm
(3) Inner (cell) membrane also called the plasma membrane

Question 6

Composition of the plasma (cell) membrane

Answer 6

Mainly phospholipids and transporter proteins

Question 7

Composition of the cell wall

Answer 7

Composed of sugar chains linked covalently by peptides (peptidoglycan). It is flexible, but limits expansion of the cytoplasm, keeping the cell membrane intact when water flows in. In gram-negatives the cell wall lies within the periplasm

Question 8

Composition of the outer membrane (gram-negative bacteria)

Answer 8

Mainly phospholipids and LPS

Question 9

What is included in the cytoplasm?

Answer 9

Includes enzymes, mRNA extending out of the nucleoid and ribosomes. Ribosomes translate the mRNA to make proteins, which are folded by chaperones

Question 10

What is included in the nucleoid

Answer 10

Chromosomal DNA wrapped around binding proteins