The structure and function of life CELLS The structure and function of life

The Cell Theory Every organism is made of one or more cells The cell is the basic unit of structure and function in all living things All cells come from preexisting cells

Development of the Cell Theory Anton van Leeuwenhoek (1632-1723) Developed the 1st simple microscope Robert Hooke (1635-1702) Made crude compound microscope, studied cork, named the cell Robert Brown (1831) Named the NUCLEUS Matthias Schleiden (1838) “Plants are made of Cells” Theodor Schwann (1839) “ Animals are made of cells” Rudolf Virchow(1855) New cells come from preexisting ones

Every Good Rule Has Exceptions… Mitochondria and Chloroplasts have their own DNA and reproduce at will, but are much smaller than cells Viruses are not living, but contain DNA or RNA, and a protein coat. Inside a host, these reproduce like CRAZY. Outside, they show no signs of life If all cells come from preexisting cells, where did the first cell come from?

The Animal Cell

The Plant Cell

The Cell Membrane (Plasma Membrane) Semipermeable (selectively permeable) Fluid Mosaic Model: Large transport proteins float in a lipid bilayer. The lipids can actually flow back and forth (hence the fluid part of the theory) Regulates the cell makeup by regulating the passage of materials Some Proteins act as RECEPTORS on cell surface. These bind to hormones and other chemical messengers

Simplified Membrane: Fluid Mosaic Model LIPID BILAYER PROTEIN

More Plasma Membrane

Diffusion and Active Transport Diffusion and active transport move things in and out of cells Which do you think requires energy? Diffusion: The movement of materials from an area of HIGH concentration to an area of LOW concentration. This is also called passive transport Active Transport: materials move from LOW to HIGH concentration, requiring energy (ATP).

The NUCLEUS Information storage in the form of DNA Surrounded by a nuclear membrane Contains chromosomes (coiled DNA) and the nucleolus

The Nucleolus In the nucleus Makes ribosome parts (RNA)

The Mitochondria Involved in AEROBIC cellular respiration “The Powerhouse of the Cell” Release ATP

ENDOPLASMIC RETICULUM Transports materials throughout cell System of channels or canals Chemical reactions take place on the surface, which can be rough or smooth Rough E.R. contains ribosomes

Endoplasmic Reticulum

RIBOSOMES Make proteins from amino acids (Look Ma, SYNTHESIS!!!!) May be attached to the ER or free in the cytoplasm Look like little dots Made of RNA

Chromosomes Long, threadlike structures in the nucleus Made of DNA, organized into hereditary units called GENES Control cell activities mostly by coding for enzymes Passed on to the next generation

Chromosomes

Vacuoles Sac-Like structures in the cytoplasm Stores food, water, or wastes A food vacuole stores________ A contractile vacuole collects, contracts, pumps out excess ______

Vacuoles

Golgi Complex A stack of membranous sacs Used for packaging, transport, synthesis, secretion of cell products

Lysosomes Membrane bounded sacs containing digestive enzymes Involved in digestion and destruction of damaged/old cell parts or cells “Suicide sacs”

Centrioles CENTRIOLES Found in animal cells, look like cylinders, involved in cell division

Chloroplasts Contain Chlorophyll Found in green plants and algae Sites of photosynthesis

The Cell Wall Found in Bacteria, Fungi and Plants In Plants, made of Cellulose In Fungi, made of Chitin In bacteria, made of glycoproteins

CILIA and Flagella Responsible for cell motility (movement) Cilia (pl): many hair-like structures on membrane, beat in coordinated waves. Cilium (sing.) Flagella (pl): Fewer in number than cilia, wave in a whip-like motion Flagellum (sing.)

Flagella and Cilia