Biology - Unit 2 - Cells - Structure and Function of Prokaryotic Cells and Viruses

which organelles do prokaryotic cells (mainly bacteria) contain?

• cell wall

• slime capsule

• plasmid

• circular DNA

• flagellum

• cytoplasm

• cell membrane

• small ribosomes (70S vs 80S)

which organelles do prokaryotic cells not contain?

• any membrane-bound organelles

• mitochondria

• nucleus

• ERs

• golgi apparatus

• lysosomes

describe the structure of a prokaryotic cell wall

• made of murein, which is a glycoprotein (protein with carbohydrate attached) - peptidoglycan

describe the function of the cell wall

• physical barrier that protects against mechanical damage

• excludes certain substances from the cell

describe the structure and function of the slime capsule

• coats the cell wall, made up of secreted slime

• protects the bacteria from attack by cells of the immune system

• helps bacteria stick together

describe the structure and function of the flagellum

• has a rigid, corkscrew shape and a rotating base

• this helps the cell spin through fluids

describe the structure and function of prokaryotic enzymes

• smaller than eukaryotic - 70S type

• site of protein synthesis - can be inhibited by certain antibiotics

• the difference between prokaryotic and eukaryotic ribosomes allows antibiotics to selectively target prokaryotes 

describe the function of the circular DNA

possesses the genetic information for the replication of bacterial cells

describe the function of the plasmids

• can reproduce independently, so are used as vectors in genetic engineering

• possess genes that aid the survival of bacteria by producing enzymes that can break down antibodies

describe the structure of viruses

• they have a core of genetic material (DNA or RNA)

• this is covered by a protein coat called a capsid

• attachment proteins stick out from the capsid 

describe how viruses reproduce

• virus attaches to the host cell receptor proteins

• virus injects genetic material into the host cell

• genetic material and proteins are replicated by the host cell machinery - ribosomes, RER

• the viral components assemble 

• the replicated viruses are released from the host cell

• the attachment proteins on the virus require different receptor proteins, affecting which types of host cell viruses can infect