Cell Structure Organelles

Recall the Characteristics of Life All Living things share the following: Cells Organization Energy use Homeostasis Growth/Development Reproduction

The Cell Theory All living things are composed of one or more cells. Cells are the only characteristic that cannot be found in non-living things. Because of their importance, much cell research has taken place and been compiled into the cell theory: All living things are composed of one or more cells. Cells are the basic units of structure and function in an organism. Cells come only from the reproduction of existing cells.

2 Levels of Organization Molecular and Cellular Macromolecules are organized into structures called organelles. Organelles working together make up a cell. One cell has all it needs to carry out all life processes. The organelles carry out all of the functions of life.

How is a single, tiny little cell able to do so much? Each organelle in the cell performs a specific function. Remember, all cells have A cell membrane DNA (genetic information) cytoplasm Only eukaryotic cells have a nucleus and other membrane-bound organelles.

Macromolecules Four macromolecules make up all the organelles: Proteins Lipids (fats) Nucleic Acids Carbohydrates

CELL MEMBRANE STRUCTURE: Organized in a bilayer. Outer portion is hydrophilic and inner is hydrophobic. Mostly made of lipids (phospholipids) and proteins. FUNCTION: the cell membrane surrounds the cytoplasm of a cell and physically separates the inside of the cell from the outside environment. Allows needed materials to pass through. Analogy: security guard or border control Found in: ALL cells (prokaryotic and eukaryotic)

Cheek Cell Cell Membrane Nuclear membrane Nucleus

CELL WALL Function: Gives cells Rigidity and Strength, and offers protection and overall provides skeletal support. Structure: Composed of cellulose, a type of carbohydrate. The structure is rigid, yet flexible, and it will bend rather than hold a shape, like when a plant wilts. Analogy: Brick walls of a builiding Found in: Prokaryotic and Plant cells

Cell Wall

The cytoplasm contains the organelles of a cell Structure: The cytoplasm is the region of the cell between the membrane and the nucleus. It consists of a gelatin-like fluid which “bathes” the organelles. It is a solution with dissolved salts, minerals, etc. Function: Region where most of the cell’s activities are carried out. Analogy: Jell-O with fruit pieces in it Found in: ALL Cells

Cytoplasm Cytoplasm

Mitochondria Structure: Mitochondria has two membranes. The outer membrane is smooth. The inner membrane is folded to allow more room for chemical reactions to occur. Function: Mitochondria break down compounds from food to release usable energy for the cell Analogy: Power Plant- converts energy to a usable form. Found in: Plant and Animal Cells

Cytoplasm Mitochondria Cell Membrane

Ribosomes Function-Ribosomes are responsible for translating code from mRNA and making proteins. Structure- Ribosomes are made up of proteins and RNA and consist of two parts, a large subunit and a small subunit. Some are attached to the endoplasmic reticulum; others float freely in the cytoplasm. Found in: ALL cells Analogy: Construction workers

Ribosome

Ribosomes

Endoplasmic Reticulum Structure: Membranous network of sac-like structures that are connected by cytoskeleton (Rough ER has ribosomes on it) Function: Transports materials within cells (an intracellular highway) -Rough ER has a role in protein synthesis -Smooth ER synthesizes (makes) lipids, breaks down toxic substances Analogy: factory; conveyor belts, machines, etc. Found in: Plant and Animal Cells

Golgi Body Structure: It is a network of flattened and stacked membrane-bound sacs found within cells Function: The golgi body stores, packages, and distributes the proteins and lipids made in the endoplasmic reticulum Analogy: shipping department, Post Office Found in: Plant and Animal Cells

Rough ER Ribosome Golgi Body Smooth ER

Lysosomes Structure- lysosomes are spherical organelles contained by a single-layer membrane containing digestive enzymes inside Function- Lysosomes contain the enzymes for breakdown of worn out cell parts.

Lysosomes Analogy: garbage/waste disposal. Found in: Plant and Animal Cells

Lysosomes

Cytoskeleton Functions- It maintains the cell’s shape and helps in the movement of the organelles. Structures- Flexible scaffold-like structure made up of microfilaments, microtubules, and proteins. Analogy: frame of a car/house. Found in: ALL cells

Cytoskeleton

Nucleus Structure: It has a double-layered membrane. It has large pores through which materials pass back and forth. Function: The nucleus directs all activity in the cell, controls the growth and reproduction of the cell, and contains the blueprints of the cell in the DNA. Analogy: county office that stores the original building blueprints. “Brain”, stores info and sends out messages. Found in: Plant and Animal Cells

Nuclear membrane Nucleus

Cilia FUNCTION: The cilia generate water currents STRUCTURE: In eukaryotic cells, cilia and flagella contain proteins and microtubules, which are composed of linear polymers of globular proteins called tubulin. Analogy: cilia are like fans Cilia found in: Animal Cells

Cilia

Flagella FUNCTION: Flagella are used primarily for movement of single cells. STRUCTURE: In eukaryotic cells, cilia and flagella contain proteins and microtubules, which are composed of linear polymers of globular proteins called tubulin. Analogy: flagella are like boat rudders Flagella found in: Animal and Prokaryotic Cells

Prokaryotic Bacterial Cell Flagella Animal Sperm Cell Prokaryotic Bacterial Cell

Animal and Plant Cells Share Many Structures in Common Animal Cell Plant Cell

Plant cells and Animal cells have some key differences: A cell wall Vacuole Plastids (Chloroplasts)

Vacuole Structure: Large sac surrounded by a membrane Function: Stores salts, minerals, nutrients, water, etc. and plays an important structural role for plants Analogy: Warehouse Found in: Plant cells and animal cells (very tiny)

Plastids (Chloroplasts) Structure: Surrounded by double-membrane, contains chlorophyll Function: contain pigments, capture energy from the sun to make organic compounds (food), may store food (starch) Analogy: solar panels Found in: Plant cells

Cell Wall Chloroplast

Cell Wall Nucleus