Prokaryotic Cells

Question 1

What are the 7 components of a bacterial cell?

Answer 1

Cell wall, fimbriae/pili, plasma membrane, glycocalyx, ribosomes, flagella, nucleoid

Question 2

This is a single circular chromosome that has no nuclear membrane and is just restricted within a defined region of the bacterial cell.

Answer 2

Nucleoid

Question 3

These are small self-replicating DNA molecules that can be found in the cytosol (separate to the main chromosome)

Answer 3

Plasmids

Question 4

This is a rigid macromolecular layer that provides strength to the cell. It also confers shape and protection.

Answer 4

Cell Wall

Question 5

What is the cell wall of bacteria made of?

Answer 5

Peptidoglycan

Question 6

These are prokaryotes that lack cell walls - which are often a group of pathogenic bacteria

Answer 6

Mycoplasmas

Question 7

What are the 3 components that make up peptidoglycan?

Answer 7

NAG (carbohydrate backbone), peptide bond/cross-bridge, tetrapeptide sidechain

Question 8

What is the enzyme responsible for cross-linking the peptidoglycan chains to form cell wall?

Answer 8

Transpeptidase

Question 9

What are the 2 most common gram stain reference bacteria?

Answer 9

Staphylococcus aureus and Escherichia coli (E-coli)

Question 10

This stains a darker colour and indicates that a cell has a thicker layer of peptidoglycan between the outer and inner membrane of cell wall.

Answer 10

Gram-positive bacteria

Question 11

This stains a lighter colour (pink) and indicates that a cell has a thinner layer of peptidoglycan between the outer and inner membrane of cell wall.

Answer 11

Gram-negative bacteria

Question 12

This facilitates the movement of the cell in liquid medium. This acts like a propeller, cell rotates them to move.

Answer 12

Flagella

Question 13

This describes the movement of bacteria along a concentration gradient towards a chemical attractant or away from a chemical repellant.

Answer 13

Chemotaxis

Question 14

These are structures that cause bacteria to adhere to surfaces.

Answer 14

Fimbriae

Question 15

Why is fimbriae an inherited trait?

Answer 15

Because it is not essential for bacteria to live. Not all bacteria need to adhere to surfaces just to get their nutrients.

Question 16

Are fimbriae involved in cell motility?

Answer 16

No

Question 17

This attaches to other bacteria and is involved in the transfer of genetic material via Conjugation.

Answer 17

Sex pili

Question 18

What type of gene transfer is Conjugation?

Answer 18

Horizontal gene transfer

Question 19

This is a gelatinous polysaccharide and/or polypeptide out covering that forms a sticky meshwork of fibres meant to protect the bacteria.

Answer 19

Glycocalyx

Question 20

Glycocalyx organised into a defined structure and attached firmly to the cell wall

Answer 20

Capsules

Question 21

Glycocalyx disorganised without cell shape, and attached loosely to cell wall

Answer 21

Slime layer

Question 22

What are two main functions of capsules?

Answer 22

1) Virulence Factors - as they protect bacteria from phagocytosis and engulfment of immune cells

2) Prevent dessication

Question 23

This is when cells dry out.

Answer 23

Dessication

Question 24

These are formed during unfavourable growth conditions and germinate under favourable growth conditions. They are also resistant to heat/harsh chemicals/antibiotics/etc

It is a way of protecting cells from stress.

Answer 24

Bacterial endospores

Question 25

What two stressors trigger endospore formation?

Answer 25

Nutrient starvation
High cell density

Question 26

What are the 2 bacteria present in Gram Stain?

Answer 26

Staphyloccocus aureus (purple) and Ecoli (pink)