Human Biology - Cells and Systems

These flashcards cover key vocabulary related to human biology, particularly cells and their structures, functions, and important biological processes.

Cell

The smallest structure capable of performing life’s functions; the basic unit of all living organisms.

Cell Membrane

A thin barrier that separates the cell's contents from the outside environment.

Cytoplasm

The jelly-like substance within the cell, containing cytosol and organelles.

Cytosol

The liquid part of the cytoplasm, composed of 75-90% water and dissolved substances.

Cytoskeleton

A framework of protein fibers that gives the cell its shape and assists in cell movement.

Inclusions

Chemical substances not part of the cell structure but found within the cytoplasm.

Cell Theory

States that all organisms are made of cells, which are the basic unit of life, and that all cells arise from pre-existing cells.

Nucleus

The largest organelle in a cell, containing DNA and responsible for cell activities.

Ribosomes

Small spherical organelles where amino acids are assembled into proteins.

Endoplasmic Reticulum

Membrane-bound organelles that extend from the cell membrane to the nuclear membrane; involved in chemical reactions and material transport.

Golgi Body

A series of flattened membranes that modify and package proteins for secretion.

Lysosomes

Membrane-bound spheres containing digestive enzymes to break down large molecules.

Mitochondria

Sausage-shaped structures involved in cellular respiration, providing energy for the cell.

Diffusion

The spreading of particles to achieve an even distribution across a space.

Osmosis

The diffusion of water across a differentially permeable membrane.

Facilitated Transport

Transport of molecules across the cell membrane via protein channels.

Active Transport

Movement of substances against a concentration gradient, requiring energy.

Vesicular Transport

The movement of materials across the membrane in membrane-bound sacs.

Endocytosis

The process of taking large particles into the cell by engulfing them with the cell membrane.

Exocytosis

The process of expelling contents of vesicles from the cell to the outside.

Epithelial Tissue

Covering or lining tissue closely joined together, found throughout the body.

Connective Tissue

A tissue composed of cells separated by a matrix, providing support to the body.

Muscle Tissue

Tissue comprised of cells capable of contracting for movement, including skeletal, smooth, and cardiac muscle.

Nervous Tissue

Tissue made of specialized nerve cells transmitting signals for communication and control.

Metabolism

All chemical reactions occurring in a living organism.

Carbohydrates

Organic compounds made up of carbon, hydrogen, and oxygen, primarily serving as an energy source.

Proteins

Macromolecules made of amino acids, important for metabolism and cellular functions.

Lipids

Organic compounds consisting of glycerol and fatty acids; they serve as important energy sources.

Enzymes

Biological catalysts, usually proteins, that speed up chemical reactions without being altered.

Substrate

The specific reactant that an enzyme acts upon.

Cofactor

Non-protein substances that assist enzymes in catalyzing reactions.

Activation Energy

The minimum energy required to initiate a chemical reaction.

Rh Blood Group System

Classification of blood based on the presence or absence of the Rh factor.