Inside the cell...

Organelles formed of many different molecules vary enormously in size, shape and function interact to transport materials, extract energy from nutrients, build proteins, dispose of waste, and store information

The Animal Cell

The Plant Cell

NUCLEUS a large structure that controls the cell’s metabolism and stores genetic information (DNA in chromosomes). a round membrane-bound structure that serves as the control center for cell metabolism and reproduction if removed the cell dies

The Cell Nucleus

RIBOSOMES small particles that are sites of protein synthesis found lining the membranes of the endoplasmic reticulum and in the cytoplasm some are attached to the outer membrane surface of the endoplasmic reticulum

ENDOPLASMIC RETICULUM a system of fluid-filled canals, channels, enclosed by membranes canals serve as paths for the transport of material through the cell divides the cell into compartments

The Endoplasmic Reticulum Lined with Ribosomes

MITOCHONDRIA round or slipper-shaped organelles that release the energy in food molecules for use by the cell contain special proteins called enzymes surrounded by a double membrane sometimes called the cell’s powerhouse

The Mitochondria

GOLGI BODIES stacks of flattened membrane sacs serve as processing, packaging, and storage centers for the products released from the cell animal cells usually have only one golgi body plant cells may have several hundred golgi bodies

The Golgi Body

LYSOSOME small, saclike structures surrounded by a single membrane contain digestive or hydrolytic enzymes thought to be produced golgi bodies found in most animal cells, in some plant cells break down worn-out cells part of the body’s defense mechanism is some animals

CYTOPLASM watery material or jellylike substance lying within the cell between the cell membrane and the nucleus where many of the substances involved in cell metabolism are dissolved where many of the chemical reactions of cell metabolism take place contains a variety of organelles

CHROMOPLASTS contain the pigments that give certain colors to fruits, flowers, and leaves the most important type are the chloroplasts

Chloroplasts green structures found in plants and some one-celled organisms contain the green pigment chlorophyll capture light energy which is then used to produce food for the plant site of photosynthesis

The Chloroplast

VACUOLES storage sacs within the cytoplasm fluid-filled organelles enclosed by a membrane contain either waste or useful materials such as water or food plant cells vacuoles usually larger than animal cell vacuoles

CELL MEMBRANE thin structure that surrounds the cell made mainly of fats (lipids), with some proteins embedded throughout

Functions of the Cell Membrane separating the contents of the cell from the outside environment controlling the transport of materials - including waste products - into and out of the cell recognizing and responding to chemical signals

The Cell Membrane

How much have you learned? 1. Which structure is the boundary between a living cell and its environment? A. cell membrane B. cytoplasm C. vacuole D. ribosome

2. The structures labeled A,B,C, and D in the following diagram represent A. organelles B. organs C. nuclei D. mitochondria

3. The cell nucleus functions A. in obtaining energy for the cell B. in the storage of digestive enzymes C. as the center of control for the cell metabolism and reproduction D. in the transport of materials throughout the cell

4. The genetic material of the animal cell is found in the A. nucleus B. cytoplasm C. ribosomes D. vacuole

5. Current evidence indicates that ribosomes are most closely associated with A. contraction of the cytoplasm B. production of DNA C. synthesis of protein D. regulation of mitosis

6. Mitochondria are organelles in which A. digestive enzymes are stored B. secretory products are packed and stored C. the energy needed by the cell is released from the nutrients D. protein manufacture occurs

7. Which cell organelles are most closely associated with energy changes in a plant? A. mitochondria and chromosomes B. chloroplasts and mitochondria C. chromosomes and nucleus D. chloroplasts and nucleus

8. Which is the most accurate statement concerning protein synthesis in cells? A. Proteins are synthesized at the mitochondria in all living cells. B. Proteins are synthesized at the ribosomes in all living cells. C. Proteins are synthesized at the ribosomes in plant cell only. D. Proteins are synthesized by the nuclei in animal cell only.

Maintaining a Constant Cell Environment Homeostasis - the condition where the internal environment of a cell remains relatively constant at all times; when disrupted, a cell dies Cellular homeostasis - occurs even though the external environment may be different from the condition in the cell

Special Properties of the Cell Membrane Selective Permeability of the Cell Membrane certain types of substances pass through cell membranes more easily than others varies from one cell type to another