Cellular Biology Cell Structure Cell Function History of

Cellular Biology • Cell Structure • Cell Function

History of the Cell Theory • 1600’s – Anton van Leeuwenhoek started using the microscope • • • to study nature. 1665 – Robert Hooke published Micrographia (contained drawings of cork sections observed using a microscope. He saw “cells”. ) 1674 – Leeuwenhoek sees tiny organisms swimming in pond water using a microscope. 1838 – Matthais Schleiden concludes all plants are made up of cells. 1839 – Theodor Schwann concludes all animals are made up of cells. 1855 - Rudolf Virchow – all cells come from existing cells Cork Video

“The Cell Theory” • All living things are composed of cells. • Cells are the basic units of structure • and function in living things. New cells are produced from existing cells.

Levels of Organization • Cell: Functional and structural unit of • living things Tissue: Composed of groups of cells alike in their structure and function. – – Nervous Epithelial (covers and lines the body and organs. Ex. Skin) Muscle Connective (bones, blood, cartilage, lymph) • Organ system • Organism

Nucleus Function Controls most cell processes. • Contains DNA that controls the building of proteins. • Contains chromatin – a granular material that is dispersed throughout the nucleoplasm. (Chromatin is made up of DNA and protein. ) – When a cell divides, the chromatin condense and coils up to form chromosomes • Nucleolus - Small dense area within the nucleus that contains RNA and DNA • Plays a role in making proteins…. produces ribosomes to be used in manufacturing proteins

Cell Membrane/Cytoplasm • Cell Membrane – thin flexible barrier around a cell…selectively permeable • Cytoplasm – Liquid material inside the cell membrane. Organelles are found in the cytoplasm – Cytoplasm Streaming/Brownian movement

Cell Wall • Cell wall*: Found in many plants, algae, fungi, and bacteria. – The cell wall lies outside the cell membrane – Function To provide support and protection for the cell. – Made mostly of a hard starch known as cellulose, with a jelly like substance known as pectin. – As cell walls become older, they become woody with a substance known as lignin.

Endoplasmic Reticulum & Ribosomes • An “intracellular highway” …transport a canals • Function: Area where cell membrane parts are assembled and some proteins are made. – Rough ER – Produces proteins to be transported “outside” the cell. – Smooth ER - Plays a role in building lipids, regulating enzymes in muscle cells, and breaking down toxic substances in the liver. • Ribosomes – Free Ribosomes: Float around in cytoplasm and make proteins used inside the cell – Bound Ribosomes: Attached to rough ER and make protein used outside the cell

Golgi Apparatus/Bodies • Function: The storage, packaging, and secreting organelle of the cell. – Shaped like stacks of flattened sacks. – Packages proteins made in the rough ER into small packages called vesicles.

Lysosome “Enzyme Sacs” • • Functions Made by Golgi bodies and contain digestive enzymes Break down food particles in the cell Digests worn out organelles in the cell Also digests ingested bacteria and other debris (work with White Blood Cells) • Common in animals, fungi, and algae cells. Not found in plants. Lysosome Animations

Mitochondria “power house” • Uses food to produce • • the high energy molecule ATP. The site of cellular respiration. Found in all eukaryotic cells.

Vacuoles* • Sometimes called the “waste dumps of the cell”. • Contain fluid filled sacs that store water, salts, and enzymes. • Vacuoles are commonly found in PLANT cells and some protozoans. • Vacuoles can be very large and take up as much as 90% of a cell’s volume.

Plant Cells versus Animal Cells Plant Cells Have – – cell walls chloroplasts large vacuoles No Lysosomes Animal Cells Have – – – No cell walls No chloroplasts No vacuoles (some animal cells may have very small vacuoles) – Contain Lysosomes

Cytoskeleton • Provides the cell support, structure and ability to • move Made up of protein filaments – Microtubules • • Hollow protein tubes that organelles slide along. Similar to “tracks” Form centrioles in animal cells during mitosis. Also form cilia and flagella on the outside of cells to enable cells to move. – Microfilaments • Smaller tubes that form a tough and flexible framework to support the cell.

Prokaryote vs Eukaryote • • • Prokaryotes (Pro = No) Smaller cells NO true nucleus NO membrane-bound organelles Evolved early…primitive DNA is in the cytoplasm and is a circular mass Eukaryotes (Eu = True) • Larger cells (by comparison) • Have a nucleus • Contain membrane-bound • • organelles Greater specialization DNA is in the nucleus

Endosymbiotic Theory - Mitochondria/chloroplast: Have their own DNA and RNA Produce their own energy and proteins Reproduce on their own Double membrane Biochemically similar to prokaryotes

• Domain Archae Kingdom Archaebacteria – – – Prokaryotic Unicellular Characteristics different from “more recognizable” bacteria • Domain Bacteria Kingdom Eubacteria – – – Prokaryotic Unicellular Recognizable…. such as e-coli, streptococcus, staph(MRSA) Domain Eukarya Kingdom Protista Kingdom Fungi Kingdom Plantae Kingdom Animalia