Bacteria Good …or Evil?

What are bacteria? Single-celled organisms that lack a nucleus Prokaryotes – an organism whose cells lack a nucleus and some other cell structures. The genetic material in their cells is not contained in a nucleus.

Cell Structures

Bacteria Cell structures (cont.) cell wall - A thin membrane located outside the plasma membrane and within the capsule. plasma membrane - A permeable membrane located within the cell wall. It serves many functions for the cell, including energy generation and transport of chemicals.

Bacteria cell structures (cont.) cytoplasm - The jellylike material inside the plasma membrane in which the genetic material and ribosomes are located. DNA - The genetic material of the bacterium; it is located within the cytoplasm. ribosomes - Small organelles composed of RNA-rich granules that are sites of protein synthesis. The ribosomes are located within the cytoplasm.

Bacteria cell structures (cont.) flagellum - A long whip-like structure used for locomotion (movement). Some bacteria have more than one flagellum.

3 Basic Cell Shapes

What do bacteria need to survive? Food Energy

A Bacteria’s Diet: Bacteria have a wide range of diets. heterotrophs (they eat other organisms) Most heterotrophic bacteria are saprobes (they absorb dead organic material like rotting flesh). autotrophs (they make their own food). Autotrophic bacteria make their own food, either by photosynthesis (which uses sunlight, carbon dioxide and water to make food) or by chemosynthesis (which uses carbon dioxide, water and chemicals like ammonia to make food.

Respiration (Energy) Process of breaking down food to release energy.

Bacterial Reproduction

How do Bacteria Reproduce? Asexual Reproduction: Binary fission only one parent offspring identical to parent

How do Bacteria Reproduce? Sexual Reproduction: Conjugation 2 parents combine genetic material to produce new organism does not increase number of bacteria results in new bacteria, genetically different than parents

What are Endospores? Bacteria in “hibernation”, taking a rest Endospores are small rounded, thick-walled, resting cell that forms inside a bacterial cell. It contains the cell’s genetic material and some of its cytoplasm. When conditions are suitable, it opens up. Then the bacterium can begin to grow and multiply.

Bacteria: Good or evil? Evil: They make us sick Good: involved in oxygen and food production environmental recycling and cleanup health maintenance and medicine production