Basic Structure of a Cell copyright cmassengale 1
Basic Structure of a Cell copyright cmassengale 1
What Are the Main Characteristics of organisms? 1. Made of CELLS 2. Require ENERGY (food) 3. REPRODUCE (species) 4. Maintain HOMEOSTASIS 5. ORGANIZED 6. RESPOND to environment 7. GROW and DEVELOP 8. EXCHANGE materials with surroundings (water, wastes, gases) copyright cmassengale 2
LEVELS OF ORGANIZATION Nonliving Levels: 1. ATOM (element) 2. MOLECULE (compounds like carbohydrates & proteins) 3. ORGANELLES (nucleus, ER, Golgi …) copyright cmassengale 3
LEVELS OF ORGANIZATION Living Levels: 1. CELL (makes up ALL organisms) 2. TISSUE (cells working together) 3. ORGAN (heart, brain, stomach …) 4. ORGAN SYSTEMS (respiratory, circulatory …) 5. ORGANISM copyright cmassengale 4
History of Cells & the Cell Theory copyright cmassengale 5
First to View Cells • In 1665, Robert Hooke used a microscope to examine a thin slice of cork (dead plant cell walls) • What he saw looked like small boxes copyright cmassengale 6
First to View Cells • Hooke is responsible for naming cells • Hooke called them “CELLS” because they looked like the small rooms that monks lived in called Cells copyright cmassengale 7
Anton van Leeuwenhoek • In 1673, Leeuwenhoek (a Dutch microscope maker), was first to view an organism (living thing) • Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth copyright cmassengale 8
Beginning of the Cell Theory • In 1838, a German botanist named Matthias Schleiden concluded that all plants were made of cells • Schleiden is a cofounder of the cell theory copyright cmassengale 9
Beginning of the Cell Theory • In 1839, a German zoologist named Theodore Schwann concluded that all animals were made of cells • Schwann also cofounded the cell theory copyright cmassengale 10
Beginning of the Cell Theory • In 1855, a German medical doctor named Rudolph Virchow observed, under the microscope, cells dividing • He reasoned that all cells come from other preexisting cells by cell division copyright cmassengale 11
CELL THEORY • All living things are made of cells • Cells are the basic unit of structure and function in an organism (basic unit of life) • Cells come from the reproduction of existing cells (cell division) copyright cmassengale 12
Cell Size and Types • Cells, the basic units of organisms, can only be observed under microscope • Three Basic types of cells include: Animal Cell Plant Cell copyright cmassengale Bacterial Cell 13
Number of Cells Although ALL living things are made of cells, organisms may be: • Unicellular – composed of one cell • Multicellular- composed of many cells that may organize into tissues, etc. copyright cmassengale 14
Which Cell Type is Larger? Plant cell > _______ Animal cell > ______ bacteria _____ copyright cmassengale 15
How Big is a Micron ( µ ) ? 1 cm = 10, 000 microns 1” = 25, 000 microns copyright cmassengale 16
CELL ORGANELLES
Let’s Review! v. Two cell types n. Prokaryotes (Prokaryotic Cells) n. Eukaryotes (Eukaryotic Cells)
Prokaryotes - Bacteria • No Nucleus • No Membrane bound organelles.
Eukaryotes • Have a nucleus • Have membrane bound organelles Nucleus
Two Types of Eukaryotic Cells Animal Cell 2. Plant Cell 1. v Both cells function similarly
Cell Organelles • Organelle = “little organs” • Specialized structures that perform specific jobs in the cell • Found only in eukaryotic cells • Many are “membrane-bound” (a membrane surrounds the organelle) • Cytosol: watery matrix that organelles float in • Cytoplasm: Everything in a cell except the nucleus
Cell Membrane • Surrounds the cell and decides what comes in and out • Semi-permeable: allows nutrients in and waste products out • Made of a phospholipid bilayer • Also called Plasma Membrane
Factory Part: n Gates or Doors Found in: n Plant cells n Animal cells n Prokaryotic cells
Nucleus Control center of the cell Stores DNA (chromosomes) Surrounded by the nuclear membrane n. Pores let material in and out Also contains the Nucleolus, which makes ribosomes
• Factory Part: • • Manager’s Office Found in: Plant cells • Animal cells •
Ribosome Smallest organelle NOT surrounded by a membrane Makes proteins according to DNA instructions. Two Types: n. Free ribosomes: float free in cytosol n. Bound ribosomes: attached to rough ER That looks familiar…what is a polypeptide?
• Factory Part: • • Machines Found in: Plant cells • Animal cells • Prokaryotic cells •
Endoplasmic Reticulum Transport system for materials in cell Two Types: Rough ER: covered with ribosomes; site of protein synthesis Smooth ER: NO ribosomes; it makes hormones & lipids
• Factory Part: • • Conveyor Belts Found in: Plant cells • Animal cells •
Golgi Apparatus Delivery system of the cell Collects, modifies, and packages molecules in the cell Distributes and transports molecules in vesicles
• Factory Part: • • Post office or Mail Room Found in: Plant cells • Animal cells •
Lysosomes • Trash Disposal of the cell • Contain digestive enzymes that break down waste
• Factory Part: • • Custodians Found in: Plant cells • Animal cells •
Mitochondria • “Powerhouse” of the cell • Site of cellular respiration • Converts energy stored in food into energy the cell needs – ATP Sugar + Oxygen Carbon dioxide + Water + ATP = Adenosine triphosphate
• Factory Part: • • Power Plant / Electrical Room Found in: Plant cells • Animal cells •
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