cellular system
TRANSCRIPT
Red Blood Cells
The adult human body contains 100 trillion cells
Cellular Structure
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What tool do we use to observe cells?
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Observing a Cell
Microscope History
Robert Hooke – English scientist; first to use the term “cell”; came from monk’s quarters
Anton von Leeuwenhook - Dutch scientist first to observe and describe microorganisms
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Microscope Characteristics Magnification - making image larger than it really is
Resolution - measure of clarity of an image
Good = clear crisp image
Poor = fuzzy image
Micrograph – the image produced by a microscope
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Types of Microscopes
Compound Light – uses two lenses; magnify up to 1,000 times, can view live specimens
Electron Microscope – magnify up to 200,000 times
-Used to look at cell structure or cell surfaces
Scanning Tunneling Microscope – able to view atoms, can view live specimens
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Transmission Electron Microscope
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Smallest unit of life is the cell
Cell Theory
- developed by 3 German scientists: Schleiden, Schwenn, and Virchow
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Cell Features
3 parts of Cell Theory
1) all living things are made of one or more cells
2) cells are the basic unit of structure and function in organisms
3) all cells arise from existing cells
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Why are cells so small?
Smaller = more efficient
Small cells can exchange substances more readily
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Surface area and cell size
Cell size is limited by the cell surface area
Cell size increases = surface-area-to-volume ratio decreases
When the volume of a cell increases, the surface area increase at a slower rate.
Surface area is important to cell growth because the cell may become too big to take in enough food and to remove enough wastes.
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Two types of cells
Prokaryotic & Eukaryotic
Only eukaryotic cells have membrane-bound organelles
Orgnaelles: structures that perform a specific function
All cells have the following:
Cell membrane, cytoplasm, cytoskeleton, ribosomes
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Chromosomes
Cilia or
Flagella
Cell Membrane
Ribosomeso
Cytoplasm
Cytoskeleton
Cell Wall(NO NUCLEUS)
Centrioles
Endoplasmic Reticulum
Golgi Complex
Lysosomes
Mitochondria
Nucleus
Peroxisomes
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Comparing Cells
small single celled organism that lacks a nucleus and other internal compartments (lacks membrane-bound organelles)
DNA is single, circular molecule
cell wall determines shape due to no internal skeleton
many use flagella for locomotion
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Prokaryotes (bacterium)
Examples of Prokaryotic Cells
Blue Green BacteriumE.Coli Bacterium
Salmonella Bacterium
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(plants, animals, fungi, protists)
Cell Membrane
* encloses the contents of a cell
* allows materials to enter and leave
cell
* selective permeability – allows
certain substances to pass thru
cell membrane
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Eukaryotes
Cell Membrane as a Barrier
phospholipid – phosphate group and two fatty acids Forms a lipid bilayer within a cell membrane phosphate group – polar heads that interacts with H20 fatty acids – non-polar tails
lipid bilayer non-polar tails form interior of membrane polar head form exterior
membrane proteins proteins and enzymes embedded in membrane polar and non-polar amino acids, which allow them to remain in membrane
different roles played:
cell-surface marker
receptor proteins
transport proteins
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Diagram of Lipid Bilayer
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Membrane Proteins
Lipid Bilayer
Outside of cell
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Diagram of Eukaryotic Cell
Cell Organelles: Structure that performs a specific function Found only in Eukaryotes
A. The Nucleus
controls most functions of the cell
nuclear membrane/ nuclear envelope: double membrane around the nucleus that has nuclear pores
heredity info coded as DNA in nucleus as strands called chromosomes
Identifies cell as Eukaryotic
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Ribosome and Endoplasmic Reticulum (ER)
B. ribosomes – where proteins are made
-attached to ER and others are free floating
C. ER – move proteins and other substances
thru the cell, maintains homeostasis
rough ER – ribosomes attached
smooth ER – lack ribosomes; make lipids
and breakdown toxic substances
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D. Golgi Apparatus – flatten, membrane-bound sacs that serve as packaging and distributing center of cell(warehouse of cell)
Produces vesicles filled with proteins
E. Lysosomes – contain cell’s digestive enzymes (Fig. 3.15 in book)
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Packing and Distributing Proteins
harvests energy from organic compounds to make ATP
outer and inner membrane
have specific mitochondrial DNA; different from nuclear DNA
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Mitochondria
Other Organelles
Cilia: short, hairlike structures that protrude from the surface of a cell
Packed in tight rows
Help in movement
Flagella: used for movement
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1. Cell Wall – support and maintain cell shape (cellulose)
2. Chloroplasts – use light energy to make carbs from CO2 and H20, photosynthesis
-have own DNA
3. Central Vacuole – stores water & nutrients; maintains rigidity of plant.
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Unique Features of Plant Cells
Anatomy of Animal Cell
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