Bio - Unit 8 - Cells and Cellular Transport

What are the three parts of the cell theory?

All living things are made up of one or more cells; the cell is the basic unit of structure and function in living things; all cells come from pre-existing cells.

Define prokaryote and provide an example.

A single-celled organism whose cells lack a nucleus and other membrane-bound organelles; example includes bacteria.

Define eukaryote and provide an example.

A complex organism whose cells contain a nucleus and other membrane-bound organelles; examples include plants and animals.

What are the two categories of eukaryotes?

Plant and animal.

What is the structure and function of the nucleus?

A large, membrane-bound organelle containing DNA organized into chromosomes; it regulates cell growth, metabolism, and reproduction.

What is the structure and function of DNA?

Deoxyribonucleic acid (DNA) is a double helix polymer of nucleotides; it is the primary carrier of genetic information.

What is the structure and function of the rough ER?

A network of folded membranes covered with ribosomes; it is involved in protein synthesis and transport.

What is the structure and function of the smooth ER?

A network of folded membranes without ribosomes; it synthesizes lipids and detoxifies drugs.

What is the structure and function of ribosomes?

Small particles made of RNA and proteins; they are the site of protein synthesis.

What is the structure and function of the Golgi body/apparatus?

Made up of stacked, flattened membrane-bound sacs; it modifies and packages proteins.

What is the structure and function of vesicles?

Small, membrane-bound sacs involved in transporting substances within the cell.

What is the structure and function of mitochondria?

Bean-shaped organelles with two membranes; they are the powerhouses of the cell, converting glucose into ATP.

What is the structure and function of lysosomes?

Membrane-bound organelles containing digestive enzymes; they break down waste materials in cells.

What is the structure and function of the cell membrane?

A phospholipid bilayer with embedded proteins; it protects the cell and regulates entry and exit of substances.

What is the structure and function of the cell wall?

A rigid outer layer found in plant cells; it provides structural support and protection.

What is the structure and function of cytoplasm?

The jelly-like substance filling the cell; it holds organelles in place and is the site of metabolic reactions.

What is the structure and function of chloroplasts?

Oval-shaped organelles containing chlorophyll; they are the site of photosynthesis.

What are the three functions of the cell membrane?

Defines boundaries, regulates entry and exit of substances, and facilitates intercellular communication.

What does semi-permeable mean?

It means that some substances can pass through the membrane while others cannot.

What is the structure of a phospholipid?

Composed of a hydrophilic head and two hydrophobic fatty acid tails.

What does bilayer mean?

Two layers.

Why is the cell membrane made of two layers?

Due to the amphipathic nature of phospholipids, forming a stable bilayer.

What is a solution?

A homogeneous mixture of two or more substances.

What is a solute?

The substance that is dissolved in a solvent.

What is a solvent?

The substance that dissolves a solute.

What is the most common solvent?

Water.

What is passive transport?

The movement of substances across a cell membrane without energy expenditure.

What is active transport?

The movement of substances across a cell membrane against their concentration gradient, requiring energy.

What is diffusion?

The net movement of particles from high to low concentration.

What are two types of diffusion?

Simple diffusion and facilitated diffusion.

What is facilitated diffusion?

Movement of molecules across a membrane with the help of transport proteins, without energy.

What is osmosis?

The movement of water molecules across a semipermeable membrane from high water potential to low water potential.

How long does diffusion/osmosis occur?

Until equilibrium is reached.

What are three types of solutions?

Isotonic, hypertonic, hypotonic.

What is isotonic?

A solution with the same solute concentration as the cell's cytoplasm.

What is hypertonic?

A solution with a higher solute concentration than the cell's cytoplasm.

What is hypotonic?

A solution with a lower solute concentration than the cell's cytoplasm.

What is plasmolysis?

The process where a plant cell's cytoplasm shrinks due to dehydration.

Explain the sodium-potassium pump.

An active transport protein that pumps sodium out and potassium into the cell, using ATP.

Explain exocytosis and endocytosis.

Exocytosis is the release of materials from a cell, while endocytosis is the uptake of substances into a cell.

What is endocytosis?

The process where a cell takes in substances by engulfing them with its membrane.

How is the bilayer formed?

The bilayer forms spontaneously due to the amphipathic nature of phospholipids.

What would happen to a human cell if it was placed in a 1.5% NaCl solution?

The cell would shrink due to the hypertonic solution.

Explain the fluid mosaic model.

The model describes the cell membrane as fluid and composed of various components.

What is the function of cholesterol in a cell membrane?

Cholesterol maintains membrane fluidity by preventing too much rigidity or excessive fluidity.

What is the function of carbohydrates in a cell membrane?

Carbohydrates serve as recognition markers for cell communication and adhesion.