Cell Biology Overview

Cell Theory

• All living things are composed of cells.
• Cells are the basic units of structure and function in living things.
• All cells arise from pre-existing cells.

Cell Structures and Organelles

• Cells contain various structures (organelles) that perform specific functions.
• Plant and animal cells have different structures to fulfill their specific functions.

Plant and Animal Cell Differences

• Plant cells have cell walls and chloroplasts, which animal cells lack.
• These differences impact their functions and overall structure.

Cellular Membranes

• Cell membranes are selectively permeable.
• They regulate what enters and exits the cell.

Cytosis

• There are three types of cytosis: endocytosis, exocytosis, and transcytosis.

Diffusion

• Diffusion is the movement of molecules from a high concentration to a low concentration.
• It's crucial for transporting substances within cells.
• Examples include oxygen moving into cells from the blood.

Osmosis

• Osmosis is the movement of water across a selectively permeable membrane from a high concentration of water to a low concentration of water.
• Osmosis is important for maintaining cell shape and volume.
• Examples include water moving into a cell placed in a hypotonic solution.

Unicellular vs. Multicellular Organisms

• Unicellular organisms consist of a single cell (e.g., bacteria, amoeba).
• Multicellular organisms are composed of multiple cells (e.g., plants, animals).
• Different levels of organization (cells, tissues, organs, organ systems) allow multicellular organisms complexity and efficient division of labor.

Cellular Organization

• Cells → Tissues → Organs → Organ Systems → Organisms

Human Tissue Types (Example: Epithelial Tissue)

• Epithelial tissue covers body surfaces and lines body cavities.
• Function: Protection, secretion, absorption.

Organ Systems (Example: Cardiovascular System)

• Cardiovascular System: Transports blood, oxygen, and nutrients throughout the body.
• Major organs: Heart, blood vessels (arteries, veins, capillaries).

Solution Tonicity

• Hypotonic: Solution with a lower concentration of solutes than the cell, causing water to enter the cell.
• Isotonic: Solution with an equal concentration of solutes as the cell, resulting in no net water movement.
• Hypertonic: Solution with a higher concentration of solutes than the cell, causing water to leave the cell.

Osmosis/Diffusion Examples

• Saltwater vs. Freshwater Fish: Saltwater fish are adapted to maintain their water balance in saltwater; freshwater fish would swell and die due to osmosis if they were placed in saltwater.
• Skittles Diffusion: The different colors of Skittles disperse in water due to diffusion.
• Egg Osmosis: Placing an egg in a solution affects the egg's shape and volume based on osmosis.

Test your knowledge on cell theory, structures, and functions. This quiz covers the differences between plant and animal cells, cellular membranes, and the processes of diffusion and cytosis. Perfect for biology students seeking to understand fundamental cellular concepts.