Cells and Organelles: Structure and Function

Cells and Their Organelles

• Organisms, including humans, are composed of individual units called cells.
• Cells of the same type working together form tissues.
• Tissues working together form organs.
• Organs working together form organ systems.

Organelles

• Specialized structures within cells, acting like "organs."
• Each organelle has a specific role in cell function.
• Examples include Nucleus, Ribosomes, Rough Endoplasmic Reticulum, Smooth Endoplasmic Reticulum, Mitochondria, Golgi Body, Lysosome, Centriole, and Cell Membrane.

Nucleus

• Contains cellular DNA, controlling cell functions.
• Surrounded by the nuclear envelope, which regulates what enters and exits the nucleus.
• Contains chromosomes (DNA) and chromatin.

Nucleolus

• Dense region within the nucleus.
• Contains RNA, crucial for protein synthesis (transcription).

Ribosomes

• Sites for protein synthesis.
• Can be found on the rough endoplasmic reticulum or freely in the cytoplasm.

Rough Endoplasmic Reticulum

• Location for protein synthesis and transport.
• Chemical reactions occur on the membranes.
• Composed of ribosomes connected to flattened sacs.
• Connected to the nuclear membrane.

Smooth Endoplasmic Reticulum

• Transport system for cell functions, and site of chemical reactions.
• Lipid synthesis and detoxification (drugs and alcohol)
• Composed of flattened sacs lacking ribosomes.

Mitochondria

• Produce energy (ATP) through aerobic cellular respiration.
• Glucose + Oxygen = Carbon Dioxide + Water + Heat + ATP

Golgi Body

• Packages molecules into vesicles for transport within or outside the cell.
• Also packages unnecessary/hazardous molecules into lysosomes.

Lysosome

• Double-membraned organelles that digest worn-out cell parts and hazardous chemicals using lysozyme.
• Produced by the Golgi body.

Centriole

• Creates spindle fibers for chromosome movement during cell division (mitosis and meiosis).

Cell Membrane

• Selectively permeable biphospholipid membrane.
• Controls substance movement in and out of the cell.
• Allows for cellular communication.
• Contains receptor sites for cell-specific chemicals (like hormones).

Cytoplasm

• Jelly-like substance filling the cell.
• Site for chemical reactions, including anaerobic respiration.
• Contains proteins, salts, ribosomes, and other organelles.

Animal Cell

• Contains various organelles.
• Some characteristics are not found in plant cells (e.g., centrioles)

Explore the fundamental units of life—cells—and their specialized components called organelles. Learn about the structure and function of key organelles such as the nucleus, ribosomes, and endoplasmic reticulum. Understand how these components contribute to overall cell function and the organization of life.