Chapter 2: Cells and the Human Body

Flashcards covering cell structure, function, transport, and organization within the human body.

What is a cell?

The smallest structure that can perform life's functions.

What does the cell theory state?

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

What are the main components of a cell?

Cell membrane, cytoplasm, organelles, cytosol, cytoskeleton, and inclusions.

What is the function of the cell membrane?

Separates the cell contents from the environment and controls what enters and leaves the cell.

What is cytoplasm?

The jelly-like material inside the cell that fills the space between the nucleus and the cell membrane.

What is cytosol?

The liquid part of the cytoplasm where most metabolic reactions occur.

What are organelles?

Structures within a cell specialized for particular functions.

What is the nucleus?

The largest organelle, containing DNA and controlling the cell's structure and function.

What occurs at the ribosomes?

Where amino acids are joined together to make proteins.

What is the endoplasmic reticulum (ER)?

A network of membranes used for storage, support, synthesis, and transport within the cell.

What is the function of the Golgi body?

Modifies proteins and packages them for secretion from the cell.

What are lysosomes?

Small spheres containing digestive enzymes that break down large molecules and worn-out organelles.

What are mitochondria?

Spherical or sausage-shaped structures where cellular respiration occurs.

What are cilia and flagella?

Fine projections that can beat back and forth to move either the whole cell or substances over the cell surface.

What is the cytoskeleton?

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

What are inclusions?

Chemical substances found in the cytoplasm that are not part of the cell structure.

What is the fluid mosaic model?

A model explaining the structure and function of the cell membrane, composed of a phospholipid bilayer with embedded cholesterol and protein molecules.

What are the main functions of the cell membrane?

Acts as a physical barrier, regulates the passage of materials, is sensitive to changes, and helps support the cell.

What does it mean for cell membranes to be differentially permeable?

They allow certain ions and molecules to pass through but restrict the movement of others.

What are the main methods of transport across the cell membrane?

Diffusion, facilitated transport, and vesicular transport.

What is diffusion?

The spreading out of particles so that they are evenly distributed over the space available.

What is osmosis?

The diffusion of a solvent (usually water) through a differentially permeable membrane to balance the concentration of another substance.

What types of proteins are involved in facilitated transport?

Channel proteins and carrier proteins.

What is vesicular transport?

Involves the movement of substances across the cell membrane in membranous sacs called vesicles, requiring energy.

What is endocytosis?

Taking liquid or solids into the cell by vesicular transport.

What is exocytosis?

When the contents of a vesicle inside the cell are passed to the outside.

Why are cells so small?

A small cell has a larger surface-area-to-volume ratio than a large cell, making it more efficient at exchanging materials.

What are the four structural levels of the body?

Cells, tissues, organs, and systems.

What is epithelial tissue?

Covering or lining tissue, e.g., outer layer of the skin.

What is connective tissue?

Provides support for the body and helps to hold all the body parts together.

What are the four kinds of tissues?

Epithelium, connective, muscular and nervous.

What are the three types of muscular tissue?

Skeletal, smooth, and cardiac muscle.

What is nervous tissue?

Made up of specialized nerve cells called neurons.

What are organs?

Body structures that are made up of two or more types of tissue.

What is a system?

A group of organs that work together to carry out a particular task.

What is an organism?

All the body systems work together to meet the needs of a functioning organism.