Structure of bacteria and virus

Topic 6

Bacteria

Bacteria

Small, single-celled prokaryotes with a cytoplasm lacking membrane-bound organelles and a single circular chromosome.

Prokaryotic Cells

Cells smaller than eukaryotic cells, with 70 S ribosomes, no nucleus, murein-containing cell wall, and mesosomes in the cell membrane.

Plasmids

Loops of DNA in prokaryotic cells, separate from the main chromosome, aiding in gene transfer.

Capsules

Structures like slime capsules in bacteria, protecting them from drying out and immune system attacks.

Flagella

Tail-like structures in prokaryotes enabling movement, with some having more than one.

Pili

Thread-like structures on bacteria surfaces for attachment to other cells or surfaces, involved in gene transfer.

Viruses

Non-cellular infectious particles with nucleic acid core, protein coat (capsid), and attachment proteins for host cell attachment.

Mycobacterium tuberculosis

Bacteria causing tuberculosis, transmitted through air droplets, affecting lungs and potentially other organs.

HIV

Human immunodeficiency virus containing RNA, infecting helper T cells, leading to decreased lymphocyte numbers and AIDS progression.

AIDS

Acquired immune deficiency syndrome resulting from HIV, leading to immunocompromise, opportunistic infections, and potentially death.