Unit 3 Cell Structure and Function quiz

The plasma membrane is “selectively permeable”

Oxygen can pass through the cell, water can move across the membrane, and nutrients can enter through transport proteins.

What happens during exocytosis

Cells transport materials out of the cell by packing them into membrane-bound vseicles.

Endocytosis

the process by which a cell takes substances into the cell. The plasma membrane surrounds the substance and pinches off to form a small sac called a vesicle. This process requires energy and is a form of active transport.

Phagocytosis

a type of endocytosis in which a cell engulfs large particles, such as bacteria. The cell membrane surrounds the particle and forms a vesicle inside the cell. Enzymes then break down the particle, helping the cell destroy harmful substances.

Pinocytosis

a type of endocytosis in which a cell takes in liquids and dissolved substances from its surroundings. The cell membrane folds inward and forms a vesicle containing the liquid. This process requires energy and is sometimes called “cell drinking.”

Receptor-mediated endocytosis

a type of endocytosis in which a cell uses receptors on its plasma membrane to recognize and take in particular substances. The membrane surrounds the substances and forms a vesicle that brings them into the cell. This allows the cell to take in specific materials, such as cholesterol, efficiently.

Integral membrane proteins

proteins that are embedded in the plasma membrane, often extending through the phospholipid bilayer. Help substances move across the membrane, act as receptors for chemical signals, help cells recognize and communicate with each other.

Characteristics of the phospholipid bilayer

a fluid, _____ layer, that forms the structural basis of cell membranes. It has amphipathic molecules with hydrophilic heads, and hydrophobic tails tucked inside. This organization creates a selectively permeable membrane which allows small molecules and blocks larger ones.

Osmosis

Movement of water across a selectively permeable membrane from an area of higher water concentration to an area with a lower one. It is a type of passive transport, meaning it does not require energy from the cell.

Photosynthesis

The process by which plants use sunlight to convert carbon dioxide and water into glucose and oxygen. Takes place in the chloroplasts where chlorophyll absorbs light energy

Cellular Respiration

The process by which cells break down glucose to release energy in the form of ATP, mainly takes place in the mitochondria when oxygen is avalible.

Diffusion

oxygen diffuses into cells from an area where oxygen concentration is higher to an area where it is lower

Facilitated Transport

The movement of substances across the cell membrane from high to low concentration using transport proteins. It does not require energy, so it is a type of passive transport.

Active Transport

The movement of substances across the cell membrane from low to high concentration, against the concentration gradient. It requires energy (ATP) and uses transport proteins.