Bacteria Overview and Reproduction

Bacteria Overview

• Bacteria are prokaryotes.
• Bacteria are single-celled organisms.
• The plural form is bacteria, and the singular form is bacterium.
• Bacteria have various shapes: coccus (round), bacillus (rod-shaped), and spiral.
• They can reproduce very quickly through binary fission.
• Bacteria are found in a wide range of environments, including air, soil, water, and inside living things like humans.
• A single square centimeter of human skin can have around 100,000 bacteria cells.
• Some bacteria can live in extreme environments like hot springs and icy lakes.

Bacterial Reproduction

• Bacteria reproduce through a process called binary fission.
• In binary fission, a bacterial cell duplicates its DNA and then divides into two identical daughter cells.
• Each new cell is a clone of the original, having identical genetic material.

Importance of Bacteria

• Many bacteria are helpful, while some cause diseases in humans and animals.
• Some bacteria produce medicines like streptomycin.
• Bacteria aid in digestion.
• Bacteria are used to make foods like yogurt, tempeh, and sourdough bread.
• Bacteria help decompose dead plants and animals.

Bacterial Shapes & Arrangements

• Bacteria typically come in three basic shapes: coccus (round), bacillus (rod-shaped), and spiral.

Bacterial Cell Structure & Components

• Capsule: A protective layer preventing drying out and attack by other cells.
• Cell wall: Gives the bacteria its shape and protects it.
• Cell membrane: Controls what enters and exits the cell, anchors proteins, produces energy, and makes cell wall components.
• Cytoplasm: Holds important parts like DNA and ribosomes; site of cell growth, metabolism, and replication.
• Nucleoid: An area in the cytoplasm that holds the bacterial genetic material (DNA). It is not a nucleus.
• Flagella: Hair-like structures used for movement, beating in a propeller-like motion. They can be arranged in different patterns on the bacteria
• Ribosomes: Spherical structures that produce proteins.
• Pili: Used for DNA transfer (conjugation) and may be present in one or few numbers.
• Fimbriae: Assist in attachment to surfaces; numerous on a single cell.
• Plasmid: Small, circular DNA molecule separate from the main bacterial chromosome. It can carry genes for antibiotic resistance or other traits.
• Endospore: dormant, resistant structures produced under adverse conditions. This allows the bacteria to survive harsh environmental factors (lack of nutrients, extreme temperatures, and drying out)

Bacterial Cell Envelope

•  The cell envelope is the exterior covering of a bacterial cell. It includes the capsule, cell wall, and cell membrane.