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Cell Basics. What IS a Cell?. The smallest unit of structure and function in all living things Cells work together to make up tissues Humans are made of BILLIONS of cells!. Discovery of Cells. 1600’s: Time of discovery in the area of cell biology Leeuwenhoek:
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What IS a Cell? • The smallest unit of structure and function in all living things • Cells work together to make up tissues • Humans are made of BILLIONS of cells!
Discovery of Cells • 1600’s: Time of discovery in the area of cell biology • Leeuwenhoek: • First to magnify nature with a lens (mid 1600’s) • Called the “father of microbiology”
Robert Hooke: • Monk who was the first to magnify plant material (cork) • Saw small divisions that he named “CELLS” • Made his discovery in 1665
Matthias Schleiden • Botanist • Made the discovery that all plants are made of cells • Made his discovery in 1838
Theodor Schwann • Physiologist • Made the discovery that all animals are made of cells • Made his discovery in 1839
Rudlof Virchow • Pathologist • In 1855, he made the discovery that all cells come from another pre-existing cell
Cell Theory • The summary of all cell biology research • Developed in the 1800’s • Explains how cells and life connect • All living things are made of cells • Cells are the smallest units of structure and function in living things • New cells come from existing cells
Types of Cells • Prokaryotic • Pro= before • Very simple cells • No true nucleus • No membrane bound organelles • Has cell membrane and cytoplasm • Has a single, circular DNA strand (genetic material) • Can respond to the environment (irritability) • Bacteria
Eukaryotic • Eu= true • More complex • Has a true nucleus that houses double-stranded DNA • Has membrane bound organelles • Mitochondria, vesicles, smooth/rough ER…etc. • Has cytoplasm and a cell membrane • Protists, Fungi, Plants, Animals are all made of eukaryotic cells
Cell Structures • Cytoplasm: • Jelly-like substance that all organelles float in • Contains organic molecules • In constant motion “Cytoplasmic Streaming” • http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter4/animation_-_cytoplasmic_streaming.html
Organelles • Small structures that perform a special function for the cell • “ Small Organs”
Types of Organelles • Mitochondria: • The “powerhouse” of the cell • Creates cellular energy in the form of a molecule called ATP (Adenosine Tri Phosphate) • Cellular energy created through a process called cellular respiration • Double layered which increases surface area
Endoplasmic Reticulum (ER) • A system of tubes which move molecules throughout the cell • “Intracellular Highway” • Can be covered with ribosomes- Rough ER • Ribosomes make proteins • Enzymes on the Rough ER change proteins into other forms • Can also be without ribosomes-Smooth ER • Function to create lipids
Ribosomes • “Protein Factories” • Can be imbedded on the rough ER or floating in the cytoplasm • Most abundant organelle in a cell • Made of RNA and proteins • Makes more proteins with plans given from DNA in the nucleus
Golgi Body/Golgi Apparatus • The “UPS” or “Fed-Ex” of the cell • Processes, packages and secretes proteins and other molecules both inside and outside of the cell • Secretes molecules in vesicles • Example: hormones
Lysosome • “Stomach” of the cell • Contain digestive enzymes • Break down proteins, carbohydrates and lipids that the cell can use • Breaks down organelles the cell no longer needs • Cleans up cellular clutter
Centrioles • Found only in Animal Cells • Rod-shaped bodies which guide the cell during cell division (mitosis)
Vacuoles • Storage organelle for water, wastes, enzymes, salt and organic molecules • Plant cells have large organelles • Up to 90% of the plant cell is the vacuole • Plants need a great deal of water because of photosynthesis • Animal cells have small organelles called vesicles
Plastids • Found only in plants • Chemical factories to create energy • Often contain pigment • Example: Chloroplast • Contains chlorophyll which traps solar energy for photosynthesis
Cytoskeleton • The framework of the cell • Made of protein filaments • Two types- Microfilaments and Microtubules
Cilia and Flagella • Aid in movement • Cilia: “Hair-like” • Flagella: “Whip-like”
The Nucleus • First Identified in 1831 • Is the “brain” of the cell • Houses DNA molecule Parts of the Nucleus • Nuclear Envelope/Membrane: • Double layer of phospholipids and proteins • Has pores to allow molecules to enter and leave
2. Nucleoplasm: Cytoplasm in the nucleus -protein rich fluid 3. Nucleolus: Makes ribosomes, made of RNA 4. Chromatin: DNA and protein coiled together -Genetic material -Chromosomes: Chromatin that coils together during mitosis
The Cell Membrane • Cell structure that is found in both plant and animal cells • Made of proteins and phospholipids • Moves like a liquid • “Fluid mosaic model” • Allows molecules in and out of the cell • Is considered “semi-permeable” or “selectively permeable”
Plant vs. Animal Cells • Both cells are eukaryotic • Plant Cells: • Cell Wall • Structure made of cellulose that surrounds the cell membrane • Plastids • Chloroplast (green), leucoplasts (white), chromoplast (orange, yellow) • Large vacuole • 90% of plant’s volume
The Endosymbiotic Theory • A theory stating that prokaryotic cells developed into organelles in larger eukaryotic cells • Mitochondria have their own DNA • Cyanobacteria (blue-green bacteria) are said to have developed into chloroplasts
Viruses • Are NOT cells • Are NOT living until they find a host • Cause diseases such as the common cold, the flu, polio, HIV • Have a protein capsid coating that “tricks” cells into accepting the virus • Virus then takes over the genetic machinery of the cell • http://highered.mcgraw-hill.com/sites/0072556781/student_view0/chapter18/animation_quiz_1.html