Learn: Unit 1 - Characteristics of Life, Cells and Cell Theory | Quizlet

Metabolism

Essential chemical reactions that take place within an organism to sustain life.

Response

An organism's ability to detect and react to internal or external environmental stimuli.

Homeostasis

The maintenance of a stable internal environment (e.g., regulating body temperature or water levels).

Growth

The process of growing and changing in size, shape, or structure over an organism's lifetime.

Reproduction

The process by which living organisms produce offspring, either sexually (combining DNA from two parents) or asexually (a cell dividing to create identical copies).

Excretion

The process of eliminating metabolic waste products from an organism.

Nutrition

The exchange of materials and gases with the environment to obtain energy and raw materials needed for growth and survival.

Cell Theory

The fundamental biological principle stating that 1. All living things are composed of cells or cell products. 2. Cells are the smallest units of life. 3. New cells are produced from existing cells dividing.

Unicellular

An organism made up of only one single cell that carries out all the functions of life (e.g., E. coli, Paramecium).

Multicellular

An organism made up of many cells working together (e.g., plants, animals, fungi).

DNA (Deoxyribonucleic Acid)

The genetic material containing instructions for cellular structure, function, and reproduction.

Chromosome

A threadlike structure made of one very long DNA molecule and associated proteins. They are circular in prokaryotic cells and linear in eukaryotic cells.

Prokaryotic Cell

A small, simple cell lacking a nucleus and membrane-bound organelles (e.g., Bacteria).

Eukaryotic Cell

A larger, complex cell that encloses its DNA inside a membrane-bound nucleus and contains specialized organelles (e.g., plant, animal, protist, and fungal cells).

Nucleoid Region

The area within a prokaryotic cell where its single circular chromosome floats (unbounded by a membrane).

Plasmid

Small, independent circular rings of DNA found in prokaryotic cells separate from the main circular chromosome.

Tissue

A group of similar cells that work together to perform the same function. (eg. muscle tissue)

Organ

A group of tissues that work together to perform a function. (eg. the liver)

Organ System

A group of organs working together to perform complex functions (e.g., the digestive system).

Vacuole

Membrane-bound sac used for storage of materials like water, nutrients, and waste; plant cells have a single large central vacuole.

Organelle

A membrane-bound structure inside a cell with a specific shape and specialized function.

Cytoplasm

The fluid-filled region inside the cell membrane where metabolic chemical reactions and cellular functions take place.

Cell Membrane (Plasma Membrane)

The outer boundary surrounding a cell that controls what enters and exits the cell.

Nucleus

A membrane-enclosed organelle in eukaryotic cells that stores linear DNA chromosomes.

Vesicle

Small membrane-bound sac used to transport materials inside or outside the cell.

Mitochondria

Organelle that carries out cellular respiration to produce ATP energy from glucose and oxygen.

Chloroplast

Organelle found in plant cells that performs photosynthesis to convert light energy into glucose.

Cell Wall

Rigid outer layer found in plant, fungi, and bacterial cells that provides structure, support, and protection.

Nucleus

Membrane-enclosed organelle that protects DNA and controls cellular activities.

Protein

An organic compound that is made of one or more chains of amino acids. Cells are mostly made of protein.

Nucleolus

Structure inside the nucleus responsible for producing ribosomes.

Ribosome

Microscopic cellular structure that synthesizes (builds) proteins. Some float free in the cytoplasm and some are on the Rough ER

Endoplasmic Reticulum (ER)

Network of membranes involved in processing proteins (Rough ER) and synthesizing lipids/membranes (Smooth ER).

Golgi Body/Apparatus

Organelle that finishes, sorts, packages, and ships proteins to their destinations.

Lysosome

Organelle containing digestive enzymes to break down food, old cell parts, and waste.

Cytoskeleton

Network of microtubule fibers providing structural support, organelle movement guidance, and chromosome separation.

Centrioles

Structures made of microtubules that help organize DNA division during animal cell division.

Cellular Respiration

Metabolic chemical reaction taking place in mitochondria that turns glucose and oxygen into ATP energy.

Photosynthesis

Process occurring in chloroplasts that uses sunlight, carbon dioxide, and water to produce glucose and oxygen.

ATP (Adenosine Triphosphate)

The primary molecular energy currency used by cells to perform life functions.

Specialized Cell

A cell adapted with specific structures to perform a unique function within a multicellular organism.

Flagella

A long, whip-like tail that helps in cell motility.