Eukaryotic cell structure Section 7.3 Eukaryotic cell structure

Objectives Identify the structures and function of the parts of a typical eukaryotic cell. Explain the advantages of highly folded membranes in cells Compare and contrast the structures of plant and animal cells.

Cellular Boundaries As we know : the fluid mosaic model describes the plasma membrane as a flexible boundary of a cell but other things like plant cells, bacteria and fungi have additional boundaries like the cell wall

The cell wall is a fairly rigid structure located outside the plasma membrane that provides additional support and protection. A plants cell wall is made up of cellulose. Cellulose forms a thick, tough mesh of fibers. It does not select which molecules can enter into the cell.

Cell control The nucleus is the leader of the eukaryotic cell because it contains the directions to make proteins. All parts of the cells depends on proteins. So therefore, nucleus controls the activity of the organelles. Master set of directions for making protein is contained in the Chromatin, which are strands of DNA

Cell Control In the nucleus a prominent organelle call nucleolus, it makes ribosomes. Ribosomes are the sites where the cell produces proteins according to the directions of DNA . The are simple structures made of RNA and protein.

Cell Control When proteins are made, ribosomes leave nucleus and enter into the cytoplasm Before they enter the cytoplasm, blueprints of the DNA are translates into RNA and sent into the cytoplasm through the nuclear envelope. Nuclear envelope is a double membrane made up of two phospholipids bilayers containing small nuclear pores for substances to pass through. Cytoplasm is the clear, gel fluid inside of the cell.

Endoplasmic Reticulum (ER) The site of cellular chemical reactions. ER is arranged in series of highly folded membranes in the cytoplasm. Ribosomes in the cytoplasm attach to the surface called the rough endoplasmic reticulum where they carry out function of protein synthesis.

Endoplasmic Reticulum (ER) Smooth endoplasmic reticulum does not work with protein but is involved in biochemical activities like production and storage of lipids.

Golgi Apparatus A flattened stack of tubular membranes that modifies the proteins that were made. Sorts proteins into packages and packs them into membrane-bound structures called vesicles and sent to appropriate destination.

Vacuoles Membrane- bound compartments to temporary storage of materials. Is a sac used to store food, enzymes, and other materials needed by a cell. Animal cells usually don’t contain them but if they do its much smaller.

Lysosomes Are the organelles that contain digestive enzymes. Digest excess or worn out organelles, food particles, and engulfed viruses or bacteria. The membrane that surrounds a lysosome prevents the digestive enzymes from destroying the cell.

Cool fact: When a tadpole develops into a frog, lysosomes within the cells of the tadpole’s tail causes its digestion. Other molecules that are released are used to build different cells.

Energy Transformers Protein production, modification, transportation, and digestion requires energy!!!!!!! Energy providers are the organelles called chloroplasts and mitochondria.

Chloroplasts Are cell organelles that capture light energy and convert it to chemical energy. Has a double membrane that protects thylakoid membranes that the energy from sunlight is trapped by. (look like stack of coins)

Plastids Plant organelle that is used for storage that the chloroplast belongs to Some store starches or lipids. Plastids are named according to their color or the pigment they contain.

chlorophyll Traps light energy and gives leaves and stems their green color.

Mitochondria Membrane-bound organelle in a plant and animal cells that transform energy for the cell. This energy is then stored in the bonds of other molecules that cell organelles can access easily and quickly when energy is needed. Has an outer membrane and highly folded inner membrane.

Mitochondria

Cytoskeleton Forms a framework for the cell (like a skeleton) It is a constantly changing structure. It is a network of tiny rods and filaments called: Microtubules – thin, hollow cylinders made of protein Microfilaments- smaller, solid protein fibers

Microtubules & Microfilaments Together maintain shape of the cell and anchor and support many organelles. They also provide a sort of highway system through which materials move within the cell.

Centrioles Organelles found in the cells of animals and most protists. Occur in pairs are made up of microtubules Play an important role in cell division.

Cilia and flagella Organelles that are made up of microtubles that aid the cell in locomotion or feeding. Cilia are short, numerous projections that look like hairs. Flagella are longer projections that move with a whip-like motion.

Eukaryotic vs prokaryotic

Animal vs Plant cell

Questions over 7.3 How are highly folded membranes an advantage for the functions of cellular parts? Name an organelle that has highly folded membranes? If a cell synthesizes large quantities of protein molecules, which organelles might be numerous in that cell? Compare and contrast the functions of a cell wall to the functions of a plasma membrane. Compare the number of vacuoles in plant cells and animal cells.