Golgi Apparatus

The Golgi apparatus, or Golgi complex is  a stack of membrane-bounded channels and vacuoles. They synthesize, package and secrete cell products.

This is the Golgi Apparatus.

Endoplasmic Reticulum

Materials are transported throughout the cell by a system of channels or canals called the endoplasmic reticulum (ER). Chemical reactions take place on the surface of the endoplasmic reticulum. In some places, it is smooth. The rough surface is due to the presence of ribosomes. Cells making proteins contain a large amount of endoplasmic reticulum.

This is the rough endoplasmic reticulum.

Nucleus and Nucleolus

The nucleus is a large structure located inside the cytoplasm of the cell. It is surrounded by its own membrane, called the nuclear membrane, and it contains other organelles (chromosomes and nucleoli). Cell activities are controlled by the nucleus. The nucleolus is located in the nucleus. It is involved in the production of ribosomes.

Cytoplasm

The watery cell fluid that contains the cell organelles is called the cytoplasm. The cytoplasm is located between the plasma membrane and the nucleus. Many life processes take place in the cytoplasm. The cytoplasm exists in two phases- a watery (sol) phase and a thicker (gel) phase.

Plasma Membrane

The plasma membrane is a double-layered structure that surrounds the cell. It provides a boundary between the cell and its environment. In animal cells, it is outside the cell border. In plant cells, it is located inside the cell wall. It's function is to control the passage of materials into and out of the call and to help maintain its shape. The plasma membrane is selectively permeable, which means it lets some materials into the cell while keeping others out.

Osmosis

Water moves freely across the plasma membrane (remember: the plasma membrane is selectively permeable, which means it lets some materials into the cell and keeps others out). Water will move to reach equal concentration on both sides of the cell's membrane. This movement if called osmosis- the diffusion of water across a selectively permeable membrane. The concentration of the substance that is dissolved ub the water controls which direction across the membrane the water will move. The water wants the concentrations of the substances to be equal on both sides. So, the concentration gradient controls osmosis. The water will continue to move across the membrane until the concentrations on both sides are equal.

Hypertonic Solution

The concentration of dissolved substances outside the cell is higher than inside the cell. The water wants the concentrations to be equal. The water will rush out of the cell to the area of higher concentration so that it is the same as the concentration inside the cell. But, the cell will shrink/shrivel up because there is less water inside the cell.

Hypotonic Solution

The concentration of dissolved substances is lower in the solution outside the cell than inside the cell. The water wants the concentration to be equal. So, the water will rush into the cell to lower the concentration outside the cell. But, there is so much water in the cell, so the cell will burst. Think of it this way. When you make kool-aid, there's sometimes more of the kool-aid mix at the bottom. So, what do you do in that situation? The easy thing to do is to add more water. Then, everything is perfectly mixed. This is a perfect example for a hypotonic solution.

Isotonic Solution

The concentration of dissolved substances is the same on the outside of the cell as it is on the inside. Nothing happens to the cell. See, water likes things to be even. For example, lets say we have sugar, and the amount of sugar is the same on the inside and on the outside. The water won't move, because everything is even and equal.

Cilia and Flagella

 Some cell surfaces have cilia and flagella, which are structures that aid in feeding. Cilia and flagella can be distinguished by their structure and by the nature of their action. Cilia are short, numerous, hair-like projections that move in a wave like motion. Flagella are long projections that move n a whip-like motion. Flagella and cilia are the major means of locomotion in unicellular organisms.

This is cilia.

And, this is flagella.

Mitochondria

Mitochondria are membrane-bound organelles in plant and animal cells that transform energy for the cell. It is folded, so it is easy to store. Those folds are called cristae.

Chloroplasts

Chloroplasts are cell organelles that capture light energy and produce food to store for a later time. Chloroplasts are only in plant cells. They turn light energy into chemical energy. Inside chloroplasts are chlorophyll, stroma, thylakoid and grana. Chlorophyll is a green pigment that traps the light energy. It gives leaves and stems their green color.

This is what a chloroplast looks like.

And, this is the color the chlorophyll makes plants.

Lysosomes

Lysosomes are organelles that contain digestive enzymes. They digest excess or worn out organelles, food particles and engulfed viruses or bacteria.

Vacuoles

Vacuoles are membrane-bound spaces used for temporary storage of materials. Vacuoles are larger in plant cells. This is because plant cells have to hold more water. It has so much water because it has to maintain its shape.

The blue thing in the middle is the vacuole. It's much smaller in animal cells. This is a plant cell.

The Cell Wall

The cell wall is in plant cells only. It is a fairly rigid structure located outside the plasma membrane. It provides additional support and protection.