Characteristics of Bacteria Quiz

Criteria for Life

• Scientists define life based on criteria such as organization, metabolism, homeostasis, growth, reproduction, response to stimuli, and evolution.

Cell Structure and Organization

• Cells are the basic units of life, and are organized into tissues, organs, and systems.
• Homeostasis is the ability of cells to maintain a stable internal environment despite changes in the external environment.
• Cells are organized into three domains: Bacteria, Archaea, and Eukarya.
• Organelles are specialized structures within cells that perform specific functions.

Cell Membrane and Transport

• The cell membrane is the main means of transport of substances across the cell membrane in unicellular organisms.
• Cells take in nutrients through active transport, passive transport, and endocytosis.

Bacteria

• Bacteria are classified based on their reaction to the Gram stain, which distinguishes between Gram-positive and Gram-negative bacteria.
• Peptidoglycan (also known as murein) gives most bacteria support and contributes to their structure and shape.
• Bacteria can reproduce through a process called binary fission.
• Some bacteria, such as facultative anaerobes, do not need oxygen but can survive in its presence.

Unicellular Organisms

• Unicellular eukaryotes, such as protists, are typically between 10-30 micrometers in size.
• Protists are a diverse group of eukaryotic organisms that include protozoa, algae, and fungi.
• Examples of unicellular organisms include Paramecium, Amoeba, and Euglena.
• Unicellular organisms usually reproduce through binary fission or budding.

Eukaryotes and Prokaryotes

• The main feature that distinguishes prokaryotes from eukaryotes is the presence of a true nucleus.
• Prokaryotes lack a nucleus and are typically small, simple cells.

Kingdoms and Domains

• The kingdom Protista includes unicellular, eukaryotic organisms that live in aquatic habitats.
• The kingdom Plantae includes multicellular, autotrophic organisms that have cell walls made of cellulose.
• The kingdom Fungi includes non-motile, heterotrophic organisms with structurally different cell walls from plant cells.

Characteristics of Unicellular Organisms

• A defining characteristic of protists is their ability to perform both photoautotrophic and saprophytic nutrition.
• Protozoans are a group of protists that are characterized by their ability to move using flagella, cilia, or pseudopodia.
• Ciliates are a type of protozoan that are distinguished by their cilia, which are used for movement.
• Flagellates are a type of protozoan that are characterized by their flagella, which are used for movement.
• Heliozoans are a type of protozoan that are characterized by their axopodia, which are used for capturing prey.

Multicellular Organisms

• Multicellular organisms are distinguished from unicellular organisms by their ability to have more complex body processes.
• The primary energy source for diatoms is sunlight.
• The main function of the flagella in dinoflagellates is to provide movement.
• Dinoflagellates cause red tides due to their ability to produce toxins.
• Multicellular organisms are able to have more complex body processes due to their ability to specialize cells and tissues.