Microbiology and Cell Theory

Unit Review Sheet

Facts and Definitions

Lesson 1: Cell Theory

• A cell is the smallest independently functioning unit of life. Some organisms have only one cell.
• Cell theory is a set of generally accepted principles that describe the properties of cells.
• The principles of cell theory are that all living organisms are composed of one or more cells, the cell is the smallest and most basic unit of an organism, and all new cells come from already-existing cells.
• A single-celled organism has one cell.
• A multicellular organism has or consists of more than one cell.
• The cell membrane (also called the plasma membrane) is a layer or boundary that separates the interior of the cell from the outside world.
• Cytoplasm is a gel-like substance that fills the interior of a cell.
• The nucleus is the largest structure in a cell. It contains the cell's genetic material and sends signals to other parts of the cell. Not all types of cells have a nucleus.

Lesson 2: Introduction to Plant and Animal Cells

• An organelle is a specialized part of a cell that has its own function.
• Eukaryotes are cells that contain a nucleus. Plant and animal cells are eukaryotes.
• The mitochondrion (plural is mitochondria) is a membrane-enclosed organelle that is important for the production of energy necessary for cell activity.
• The cell wall is the outermost layer of a cell in plants (and some fungi, algae, and bacteria) that provides a supporting framework.
• A vacuole is a membrane-bound organelle that contains fluids that contribute to cell digestion and waste elimination. Vacuoles also provide structural support to some cells, especially plant cells.
• The chloroplast is an organelle in which photosynthesis occurs within the cells of plants and algae.
• Pigments are chemical compounds that reflect only certain wavelengths of visible light. We see different pigments in different-colored leaves and flowers.

Lesson 3: The Structures of Eukaryotic Cells

• Cilia (singular is cilium) are thin, hairlike threads that project from the side of some cells and aid in movement (not found in plant cells).
• The cytoskeleton is an internal network of protein structures (microtubules and microfilaments) that controls a cell's shape and movement. It also allows the cell to move organelles around within the cell.
• The flagellum (plural is flagella) is a whip-like structure that protrudes out of some cells and is used for movement.
• Ribosomes are small, round structures in which proteins are manufactured.
• Equilibrium is a state where biological processes are in balance within a cell or organism.
• Homeostasis describes the process or mechanisms that systems in an organism use to maintain stability and resist change from outside forces.
• Osmosis is the movement of water through a membrane; the water moves from an area of high water concentration to an area of low water concentration.

Lesson 4: Protists

• Protists are microorganisms that are typically one-celled and contain a nucleus. Examples include paramecium and amoeba.
• A microorganism (or microbe), is an organism that is too small to be seen with the naked eye — a microscope is required to be able to see it.
• Microbiology is the study of microorganisms.

Lesson 5: Prokaryotes

• Prokaryotes are microorganisms that lack both a nucleus and most organelles. Bacteria and archaea are the two main types of prokaryotes.
• Bacteria (singular is bacterium) are prokaryotes that contain flagella and pili (hair-like structures on the outside of the cell that allow bacteria to stick to things); many bacteria also contain a capsule (protective structure outside of the cell wall).
• Archaea are prokaryotes also known as extremophiles — microbes that live in an environment of extreme temperature or acidity.

Lesson 6: Understanding Microbes

• A virus is a microbe that consists of a small amount of genetic material wrapped in a protein coat. It is unclear whether viruses should be classified as "living" or "nonliving."
• A micrometer is a unit of measure that is one millionth of a meter.

Lesson 7: Specialized Cells

• Specialization is the adaptation of an organism or part of an organism to a specific function or condition.

Lesson 8: Mitosis

• Mitosis is the process by which a cell divides into two daughter cells, each of which has the same number of chromosomes as the original cell.
• A mother cell is a cell that gives rise to other cells by cell division.
• A daughter cell is either of the identical cells produced when a living cell divides.
• Chromosomes are rod-shaped structures, usually found in pairs in a cell nucleus, that carry the genes that an organism inherits from its parents. The genes determine how the organism will grow, develop, and function.
• The state of the cell prior to mitosis, when it prepares by copying its DNA, is called interphase.
• Prophase is the first phase in cell division when chromosomes condense and can be seen with a microscope.
• Metaphase is the second stage of cell division during which chromosomes line up in preparation for separation.
• Anaphase is a late stage of cell division during which chromosomes move to the poles of the spindle.
• A spindle is a structure consisting of a network of fibers along which chromosomes are distributed and drawn apart during mitosis.
• Telophase is the final stage of cell division in which daughter cell nuclei form around chromosomes at opposite ends of the dividing mother cell.

Lesson 9: Biological Hazards and Infectious Disease

• Parasites are organisms that live on or in another, usually larger, host organism in a way that harms or is of no advantage to the host.
• Contagions are illnesses that spread from one person to another, especially by physical contact between persons or contact with infected objects.
• A mutagen is an external agent that increases the rate of mutation of cells or organisms, e.g., radiation or some chemicals or viruses.
• A carrier is a person or animal that is infected with a disease without displaying any of the symptoms; a carrier can pass an infection to others.
• A vector is the term commonly used to describe the microbe or organism that introduces the disease into another organism. Viruses and animals can be vectors.

Lesson 10: On Their Shoulders

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Final Project: Outbreak Prevention

• A glycoprotein is a protein with a carbohydrate component.
• Hypoxia is a lack of oxygen in the body's tissues.
• A phosphoprotein is a protein that is bonded to a phosphorous-containing compound.
• RNA is ribonucleic acid, a macromolecule containing the genetic instructions for the synthesis of proteins.