General prokaryotic characteristics/Morphology and Arrangement

What does “prokaryotic” mean?

Simple cellular structure without a nucleus or membrane-bound organelles.

Do prokaryotes have a nucleus?

No, their DNA is in the nucleoid region.

Where is bacterial DNA located?

In the nucleoid region.

Do bacteria have membrane-bound organelles?

No.

What size ribosomes do bacteria have?

70S ribosomes.

How do bacteria reproduce?

Binary fission.

What structure surrounds most bacteria cells?

A cell wall made of peptidoglycan.

What is the plasma membrane?

A membrane that controls what enters and leaves the cell.

Why are bacterial structures important in medicine?

They are targets for antibiotics.

What is one major antibiotic target in bacteria?

Cell wall (peptidoglycan).

What is another antibiotic target?

Ribosomes (protein synthesis).

What enzymes are antibiotic targets?

DNA replication enzymes.

What cell structure is also targeted by antibiotics?

Plasma membrane.

Why do antibiotics work selectively on bacteria?

They target structures not found in human cells.

What are the three basic shapes of bacteria?

Cocci, bacilli, spirilli.

What are cocci?

Round-shaped bacteria.

What are bacilli?

Rod-shaped bacteria.

What are spirilli?

Spiral or curved-shaped bacteria.

What does “strepto-” mean?

Chains of bacteria.

Example of strepto- arrangement?

Streptococcus.

What does “staphylo-” mean?

Grape-like clusters of bacteria.

Example of staphylo- arrangement?

Staphylococcus.

What does “diplo-” mean?

Pairs of cells.

What are diplococci?

Pairs of spherical bacteria.

What are tetrads?

Groups of four cells arranged in a square.

What are sarcina?

Groups of eight cells arranged in cube-like packets.

What causes V-shaped bacterial arrangements?

Snapping division where cells remain partially attached.

What is palisade arrangement?

Side-by-side “picket fence” arrangement of cells.

What does “singles” arrangement mean?

Cells occur alone or randomly.