THE BASIC STRUCTURE OF LIFE THE CELL THE BASIC STRUCTURE OF LIFE

THE CELL THEORY ALL LIVING THINGS ARE MADE OF CELLS. ALL LIVING THINGS FUNCTION THROUGH THE ACTIVITIES OF THEIR CELLS (METABOLISM). CELLS COME ONLY FROM PRE-EXISTING CELLS.

“CELL PEOPLE” Schleiden-Plants are made of cells Schwann-Animals are made of cells Virchow-Cells come only from cells Hooke-named the cell van Leeuwenhoek-invented a crude microscope; first to see living cells Brown-discovered the nucleus

Structure and Function Nerve cells have long processes to transmit information over long distances.

Epithelial Cells (Skin) Epithelial cells are flat and platelike in order to form a protective covering over the organism.

PROKARYOTIC CELL

PROKARYOTIC CELLS LACK AN ORGANIZED NUCLEUS LACK MEMBRANE-BOUND ORGANELLES HAVE A CELL WALL SOME HAVE A SLIME LAYER (CAPSULE)

PLANT CELLS HAVE A CELL WALL CONTAIN A LARGE CENTRAL VACUOLE USUALLY CONTAIN CHLOROPLASTS

ANIMAL CELLS DO NOT HAVE A CELL WALL HAVE CENTRIOLES HAVE SMALLER VACUOLES

THE CELL WALL MADE OF CELLULOSE GIVES SUPPORT TO THE PLANT CELL GIVES STRENGTH TO THE PLANT CELL IS PERMEABLE

PLASMA MEMBRANE CONTROLS WHAT ENTERS AND LEAVES THE CELL MADE OF A PHOSPHOLIPID BILAYER FOUND IN BOTH PLANTS AND ANIMALS

CYTOSOL The area of the cytoplasm outside of the individual organelles is called the cytosol. The cytosol contains thousands of enzymes The cytosol takes molecules and breaks them down, so that the individual organelles can use them.

THE NUCLEUS CONTAINS THE CELL’S DNA IS SURROUNDED BY ITS OWN NUCLEAR ENVELOPE OFTEN REFERRED TO AS THE “CONTROL CENTER” OF THE CELL

DNA THE GENETIC MATERIAL IN THE NUCLEUS DOUBLE HELIX FORMS CHROMATIN (working DNA) & CHROMOSOMES (nonworking DNA)

NUCLEOLUS The nucleolus is an approximately spherical region within the nucleus of eukaryotic cells. It stores RNA and ribosomal subunits.

MITOCHONDRIA Mitochondria generate the cell’s energy through cellular respiration. Usually they are rod-shaped, however they can be round. The inner membrane is thrown into folds or shelves called cristae.

Mitochondria Mitochondria have their own DNA and ribosomes. They are capable of reproducing themselves. Humans inherit mitochondrial DNA only from the mother.

Mitochondria Powerhouses of the cell Site of cellular respiration Breakdown of food to release energy and generate ATP

CHLOROPLASTS

Chloroplasts Chloroplasts are the site of photosynthesis, the process by which autotrophs make food. Chlorophyll is the light-trapping pigment in the chloroplast.

Chloroplasts Stroma is the semi-fluid filled space Contains enzymes Thylakoids are hollow sacs Provide membrane for photosynthetic reactions Grana are stacks of thylakoids Lamellae connect the grana

Chloroplasts Like mitochondria, chloroplasts have a double membrane, their own DNA and ribosomes. Chloroplasts can reproduce themselves.

Ribosomes Granular organelles Site of protein synthesis Attached to rough ER or located in the cytoplasm Manufactured in the nucleolus Made of RNA and protein subunits

Ribosomes & Protein Synthesis

Endoplasmic Reticulum

ROUGH ENDOPLASMIC RETICULUM A complex network of membranes Bears the ribosomes during protein synthesis Processes and transports polypeptides to the Golgi complex Hollow interior is known as the “lumen”

SMOOTH ENDOPLASMIC RETICULUM Smooth ER is associated with the production and storage of lipids, especially steroids.

Smooth ER Releases calcium in cardiac and skeletal muscle cells so that contraction can occur Detoxifies alcohol and poisons in the liver and kidney cells

Golgi Apparatus Receives proteins from the rough ER Processes, packages, and delivers the proteins Packaging occurs via vesicles

GOLGI APPARATUS Responsible for packaging proteins for the cell Proteins produced by the rough E.R. pass into the G.A. cisternae These proteins are then squeezed off into vesicles (small vacuoles) for transport out of the cell.

Golgi Apparatus

Lysosomes Found in animal cells Contain hydrolytic enzymes to digest almost everything in the cell Manufactured by the Golgi apparatus

Lysosomes Autophagy-digestion of worn organelles Autolysis-digestion of damaged or extra cells

Peroxisomes Not from the Golgi apparatus Neutralize free radicals in the liver and kidneys Oxygen ions that damage cells Detoxify alcohol and drugs Break down fatty acids for the mitochondria to use for energy

Glyoxysomes Found in some seeds Break down stored fats to provide energy for the developing plant embryo

Vacuole Large fluid-filled vesicle surrounded by a membrane Can store water, nutrients, wastes, pigments Larger in plant cells Help plant cells create turgor, internal water pressure

CONTRACTILE VACUOLES Membrane-bound sac Plays roles in release of excess water from protists that live in watery environments

Other Vesicles Amyloplasts store starch in plant cells Chromoplasts store pigments other than chlorophyll; give color to petals and leaves

CYTOSKELETON For movement and stability Primary types of fibers comprising the cytoskeleton are microfilaments, microtubules, and intermediate filaments

CENTRIOLES In animal cells only Two cylinders at right angles to one another Close to the nucleus Help to form the spindle fibers for cell division

Flagella and Cilia Flagella are long and whiplike The cilia are short and hairlike Both are used for locomotion Cilia are also used internally to sweep cells or particles