The Cell Membrane: “Skin” that surrounds cell Selectively permeable Phospholipid bilayer Many cell organelles have membrane

Cytoplasm (Cytosol) The liquid inside the cell Helps to support cell structures Provide protective buffer

Cytoskeleton gives a cell shape holds organelles inplace Lets cell move in space by contracting and expanding (microfilaments made of protein actin). Holds organelles in place and anchor nucleus (intermediate filaments)

Mitochondrion The “powerhouse” of the cell Double-membrane Has its own DNA and ribosomes Use chemical energy from primarily sugar to make the energy for the cell to do various metabolic tasks. The main molecule that provides chemical energy is adenosine tri- phosphate (ATP).

NUCLEUS The control center of cell Source of genetic information Instructions for protein production which controls cell functioning. Almost always near center of cell.

NUCLEOLUS Dark area in center of nucleus Makes materials for ribosomes Defective nucleoli evident in Parkinson’s and Huntington’s diseases.

Endoplasmic reticulum Attached to the nucleus by its membranes. Two parts: the smooth endoplasmic reticulum (SER) and the rough endoplasmic reticulum (RER). SER releases lipids, such as hormones, that are used both in the cell and in other cells. RER looks rough because it is studded with ribosomes and functions in making proteins.

Golgi Apparatus Modifies proteins by adding signaling sugars onto surface of protein. Unmodified protein arrives at Golgi inside a transport vesicle. Fuses with Golgi and is modified as it travels through Golgi Golgi membrane pinches off with modified protein inside.

Protein Targeting & Disease Different types of proteins are housed in different parts of the cell where they can carry out their specific functions. Other proteins are secreted. If proteins end up in the wrong place or don’t get to the right place this can lead to abnormal cell function and/or serious diseases.

Perioxisomes Vesicles that contain oxidative enzymes Breaks down fatty acids, some amino acids, and toxic hydrogen peroxide. Look similar to lysosomes but bigger Found near mitochondria and chloroplasts while lysosomes can be found anywhere in the cell.

Found in many Animal Cells - Centrioles Organize the spindle during cell division. Consist of 9 groups of microtubules; each group has three microtubules. Therefore there are 27 microtubules in one centriole. Centrioles are always arranged perpendicular to each other.

Found in many Animal Cells -Flagella 9 + 2 arrangement of microtubules Used for cell movement

Found in many Animal Cells -Cilia Similar in structure to the flagella, but they tend to be shorter 9 + 2 arrangement of microtubules Found in groups on the cell surface. In single-celled organisms, they are used to move the cell. In the human body, used to move substances across the cell surface (e.g. cilia can be found on cells lining the trachea. These cells help to move mucus and trapped particles away from the lungs.

Found in animal cells - Lysosomes Recycling centers of cell. Contain hydrolytic enzymes which break nutrient particles into smaller pieces so that other organelles can use these fragments as a source of energy. They destroy bacteria and organic debris that enter cell from extracellular fluid. Break down damaged organelles, freeing components for re-use. Rarely found in plant cells because the central vacuole fulfills the recycling function in plant cells.

Found only in plant cells: Chloroplast Surrounds the outside of a plant’s cell membrane Attaches cells to neighboring cells. The wall is made of a rigid polysaccharide called cellulose Gives plant cells shape and structure . It prevents cell from bursting when too much water is available (e.g. rainy seasons). Turgor pressure is pressure that water puts on cell wall

Found only in plant cells: Central Vacuole Found near the middle of the cell. Stores water and other materials in these storage tanks, keeping them separate from cytosol. Central vacuoles perform the same functions as lysosomes, breaking down nutrients and organelles into usable energy components

The History of the Cell Theory