Cell Structure and Function Overview

Cell Theory

All living things are made of cells; cells are the basic unit of life; all cells come from pre-existing cells.

Prokaryotic Cells

Cells without a nucleus; example: bacteria.

Eukaryotic Cells

Cells with a nucleus and organelles; example: plant and animal cells.

Nucleus

Organelle that contains DNA and controls cell activities.

Mitochondria

Organelle that produces energy (ATP) through cellular respiration.

Chloroplast

Organelle in plant cells where photosynthesis occurs.

Ribosomes

Small structures that make proteins.

Rough Endoplasmic Reticulum (Rough ER)

Has ribosomes; helps in protein synthesis.

Smooth Endoplasmic Reticulum (Smooth ER)

Makes lipids; does not have ribosomes.

Golgi Apparatus

Packages and ships proteins out of the cell.

Lysosomes

Break down waste and old cell parts.

Cell Membrane

Controls what enters and leaves the cell; maintains homeostasis.

Cell Wall

Provides support and structure in plant cells.

Cytoplasm

Jelly-like substance that fills the cell and holds organelles.

Cell → Tissue → Organ → Organ System → Organism

The correct order of biological organization in multicellular organisms.

Circulatory System

Transports oxygen, nutrients, and wastes throughout the body.

Respiratory System

Brings in oxygen and removes carbon dioxide.

Digestive System

Breaks down food into nutrients the body can use.

Nervous System

Sends electrical signals to control body functions and responses.

Muscular System

Works with the skeletal system to produce movement.

Skeletal System

Provides support and structure; protects organs.

Excretory System

Removes waste from the body (e.g., through urine).

Immune System

Protects the body against disease and infection.

Reproductive System

Enables organisms to produce offspring.

Endocrine System

Regulates body functions using hormones.

Structure and Function

The idea that a part's shape or structure is related to what it does.

Example of Structure & Function

Mitochondria's folded inner membrane increases surface area for energy production.