Biology Quiz: Cell Structure and Function

A living organism's smallest functional unit.

A theory stating that all living organisms are made of cells and their products.

This process creates new cells from existing ones.

The fluid inside the cell, containing water, electrolytes, and proteins.

The solvent for biological substances, maintaining cell temperature and acting as a substrate in some reactions.

Charged particles that contribute to osmotic potential, participate in metabolism, and transmit electrical impulses.

Proteins that have compact, folded structures and are essential for enzymatic reactions.

Proteins that form long filaments and provide structural support and movement.

Lipids are essential components of cell membranes. They include: phospholipids, which create membrane barriers, cholesterol, a building block for hormones, and triglycerides, which act as energy reserves.

The cell membrane, a thin structure surrounding the cell, is composed of a lipid bilayer—two layers of lipid molecules. This bilayer is selectively permeable, meaning it controls what enters and exits the cell.

Integral membrane proteins are embedded within the cell membrane, serving various functions like:

Carrier proteins facilitate the transport of specific molecules across the cell membrane. They act as shuttles, binding to the molecule and moving it across the membrane.

Glycogen is a complex carbohydrate stored in the liver and muscles, providing a readily available source of energy when needed.

Carbohydrates on the cell surface act as binding sites for molecules like hormones, allowing cells to respond to signals.

Certain carbohydrates on the cell surface trigger immune responses, helping the body recognize and defend against pathogens.

Carbohydrates on neighboring cells interlock, forming strong connections for tissue function.

The cell membrane regulates movement of water in and out of the cell, maintaining the internal environment.

The cell membrane acts as a barrier between the inside and outside of the cell, protecting its contents.

The cell membrane recognizes hormones and relays their signals inside the cell.

The cell membrane moves molecules across the cell, providing essential nutrients and removing waste products.

The cell membrane selectively allows certain ions to pass through, contributing to the generation and transmission of nerve impulses in excitable cells.

The net movement of water molecules across a semi-permeable membrane from a region of higher water concentration (dilute solution) to a region of lower water concentration (concentrated solution).

The pressure required to prevent the net flow of water into a more concentrated solution across a semi-permeable membrane.

The movement of substances across a membrane from an area of higher concentration to an area of lower concentration, without the need for energy. It requires a carrier protein.

The movement of substances across a membrane against their concentration gradient, requiring energy (usually ATP).

A type of active transport where the energy for movement comes directly from the breakdown of ATP.

A protein pump found in all body cells that pumps sodium ions (Na+) out of the cell and potassium ions (K+) into the cell, establishing a concentration gradient across the membrane.

The process where fluids are forced through a membrane or barrier by a pressure difference across the membrane. The amount filtered depends on pressure difference, surface area, and membrane permeability.

The movement of solutes along with the flow of solvent across a membrane. It has limited physiological significance.

The state of electrical charge difference across the cell membrane when a cell is at rest.

A specialized protein that actively transports sodium ions out of the cell and potassium ions into the cell, requiring ATP energy.

A type of membrane transport that uses the energy stored in the sodium ion concentration gradient created by primary active transport to move other substances across the membrane.

The process of transporting large molecules or particles into the cell by engulfing them in a membrane-bound vesicle.

A type of endocytosis where the cell engulfs small droplets of extracellular fluid.

A type of endocytosis where the cell engulfs large particles, such as bacteria or debris.

The process of transporting molecules or particles out of the cell by enclosing them in a membrane-bound vesicle and fusing it with the plasma membrane.

A protein complex that actively pumps calcium ions out of the cell or into intracellular organelles like the sarcoplasmic reticulum, requiring ATP energy.