All living things
The Cell Theory
mid 1600s microscopes were used by Robert Hooke
Slices of cork
1693, Anton van Leeuwenhoek
1824, Henry Dutrochet living things made of cells
1831, Robert Brown noticed the nucleus
1838, Matthias Schleiden, theory all plants made of cells
1839, Theodor Schwann, proposed that all animals were made of cells
1839, Johannes Purkinje, used the term protoplasm
1855, Rudolf Virchow, all cells rise from pre-existing cells.
1861, Max Schultze, define protoplasm
1861, Felix Dujardin, recognized the existence of one-celled organisms
Ideas that make up the
Allorganisms are made of one or more cells and the products of those cells. An organism may be a single cell, such as a bacterium, or many cells organized to function together, as in an animal or plant. In many-celled organisms, there may be intercellular material made by the cells.
All cells carry on life activities. The life activities of a many-celled organism are the combined results of the activities of its individual cells.
New cells arise only from other living cells by the process of cell division.
The Two Basic Cell Types
Fundamentally alike, but
Prokaryotic cells without nucleus
Lacks any kind of organelle
Eukaryotic cells true nucleus
Does contain many membrane-bound organelles
Nucleus, very important part of cell.
Prokaryotic 1 and 10 micrometers
Eukaryotic 10 times larger than prokaryotic, 10 100 micrometers
Organelles specialized internal structures of the cell.
Some enclosed within own membrane, some are not.
Figure 5-5, p. 83
Cells are enclosed by a rigid wall
Lies just outside cell membrane
Shape and protection
Plants composed of cellulose
Many small openings
Animal cells do not have cell walls
The Cell Membrane
Also called plasma membrane
Separates cell from its environment
Controls material in and out of cell
Structure two layers composed of lipids, proteins, and carbohydrates
Behaves like a fluid mosaic
Transport, receptors, enzymes, binding the membrane to cytoplasm
Round control center for cells metabolism and reproduction
Removed cell will die
Nuclear envelope surrounds nucleus
Forming well define pores
Controls the substances that goes in and out
Nucleoplasma remains chemically different and mostly chromatin
Chromosomes contains hereditary material of cell
Nucleoli dense granular bodies, made up of DNA, RNA and protein. Site of ribosome production
Watery material between cell and cell membrane
Many chemical reactions o cell metabolism take place in cytoplasm
Location of a variety of organelles
Organelles in the cytoplasm
Cilia and Flagella
System of fluid-filled canals enclosed by membranes, fig 5-8
Serve as paths for transport of material through cell
Divide into different compartments for various reactions to occur
Rough or smooth
Rough have ribosome lining
Smooth no ribosomes
Cilia and Flagella
Origins of the Eukaryotic Cell
5.3 Maintaining a Constant Cell Environment
Disrupted cell dies
Special properties of cell membrane
Selective Permeability of the cell Membrane
Passing through cell membrane with ease
Neutral molecules vs charged ions
Permeability varies from one type of cell to another, or even the same cell
Spread from one region of high concentration to an area of lower concentration
Molecules are in constant motion
Oxygen and carbon dioxide
Some substances diffuse across cell membranes more rapidly than one might expect from the chemical properties of these substances.
Specialized proteins in the cell membrane
No chemical reactions from transport proteins
Works in the direction of the concentration gradient
Higher to lower concentration speeds up.
Glucose from your blood into cells of your body
Figure 5-16, p. 93
Osmosis The Diffusion of Water
The diffusion of water across a selectively permeable membrane from a region of high water concentration to a region of low water concentration
Figure 5.17, p. 93
Increased pressure resulting from osmosis is equal to the tendency of water to enter the solution.
Effects of Osmosis
Isotonic solution is one that has the same concentration of dissolved substances as the living cell placed in it.
Hypotonic solution contains a lower concentration of dissolved substances than the cell.
Hypertonic solution contains a higher concentration of dissolved substances than the cell.
Figure 5-18, p. 95
Plasmolysis shrinking of cytoplasm by ososis.
Passive and Active Transport
5.4 Organization of Cells in Living Things
A cell exists independently is regarded as a one-celled, or unicellular, organism
Unicellular and Colonial Organisms
Able to carry out life processes
Bacteria, protozoa, algae, some fungi
Simplest level colonial organisms or colony
Complex colonies show some specialization
Volvox ( algae ) fig. 5-20
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