Chapter 7: Cell Structure and Function Lesson 3: Cell Structures & Functions

Cell Membrane The Cell Membrane is responsible for being selectively permeable, which means it only allows certain things in and out of the cell. The cell membrane is made up of a phospholipid bilayer. The cell membrane also has proteins and cholesterol (lipids) that have been inserted within the phospholipid bilayer.

Cytoplasm The Cytoplasm is made up of cytosol which is a clear jelly-like substance in the cell. The main function is to help intracellular movements and to provide protection to the organelles.

Microtubules and Microfilaments Microtubules and Microfilaments make up the cytoskeleton and have the responsibility of helping maintain the cell’s shape.

Rough ER The Rough Endoplasmic Reticulum (ER) is responsible for the transport of ribosomes (proteins) into and out of the cell. The Rough ER gets it’s name from the sandpaper-like appearance that the ribosomes causes. The Rough ER is known as the Cell Highway.

Smooth ER The Smooth Endoplasmic Reticulum (ER) is responsible for Lipid and Sterol production in the cell. It is called the Smooth ER because of its lack of ribosomes when compared to the Rough ER.

Ribosomes Ribosomes are the small, black dots found in high concentration in the Rough ER. Ribosomes are responsible for the production of proteins.

Lysosomes Lysosome’s main function is to seek out and digest (breakdown) unwanted bacteria and toxins within the cell. Lysosomes are most commonly found in animal cells.

Mitochondria The mitochondria is known as the Powerhouse of the cell. It’s main function is to provide energy for the cell. The mitochondria is an unique organelle because it has a double-membrane and can be mass produced (by the cell) if lots of energy is needed by the cell.

Vacuole The Vacuole is a membrane-bound sac that aids in digestion. Vacuoles are typically very small in animal cells.

Centrioles Centrioles help out with cell reproduction. The centrioles are made up of microtubules.

Peroxisomes Peroxisomes are organelles that protect the cell from toxins made by white blood cells. The white blood cells produce hydrogen peroxide to kill bacteria within the cell. That hydrogen peroxide is poisonous to the cell. The peroxisomes use enzymes to convert the hydrogen peroxide into harmless products (water and oxygen).

Golgi Apparatus The Golgi Apparatus (sometimes referred to as the Golgi Complex) is responsible for packaging proteins to be transported to different areas of the cell.

Nuclear Membrane The Nuclear Membrane (Also known as the Nuclear Envelop) consists of a double membrane. It’s functions is to protect the nucleus, more specifically to protect the DNA.

Nucleus The Nucleus is known as the brain of the cell. It’s main function is to control the activities within the cell. In the nucleus, the DNA double helix is packaged by special proteins (histones) to form a complex called chromatin. The chromatin undergoes further condensation to form the chromosome.

Flagella Cilia Cilia The Cilia and Flagella are two organelles that controls the modality of the cell. In other words, the cilia and flagella control the movements of the cell. Cilia are hair-like projections that are an extension of the cytoskeleton (made out of microtubules and microfilaments). These hair-like projections propels mucus in your throat, helps with hearing in your ears, and helps move food particles in your stomach. The flagella is a tail-like structure that is the main source of transportation for cells. An example of a cell with a flagella is a sperm cell.

Peroxisomes Plants and animal cells have many organelles in common. Lysosomes are only found in animals. The Cell Wall and Chloroplasts are unique to plant cells. Both animals and plants have vacuoles but the vacuole plays a greater role in plant cells. The next few slides are of a plant cell. You should be able to cell the difference between an animal’s vacuole and a plant vacuole. Also check out a chloroplast and a cell wall!

Vacuole The vacuole of a plant in far more important than the vacuole in an animal cell. Plants cannot move to go get water like animals can so plants like to store extra water in the vacuole. Notice that the size of a vacuole is far more superior in size in a plant.

Cell Wall The Cell Wall is a protective covering and major structural aid of a plant cell. The cell wall is found outside of the cell membrane and in made up of complex sugars (cellulose).

Chloroplasts The chloroplasts are only found in plants. Like the mitochondria, chloroplasts aid in the production of energy for the plant, have double membranes, and can be reproduced by the cell as needed.

How can we tell the difference between an animal cell and a plant cell just by looking at them? Be ready to discuss next class period! How can we tell the difference between a prokaryotic (left) and eukaryotic cell (above)?