Biology - Chapter 7
a phospholipid bilayer is two layers of
phospholipids arranged tail-to-tail
Section 1
Section 4
Section 3
History of the cell theory
a cell is the basic structural and functional unit of all living
things
In 1665, an Robert Hooke made a simple microscope to look at a piece of cork. He saw small, box-shaped structures in the cork which he called cellulae, but we now call them cells.
In 1838, Matthias Schleiden studied plants under microscopes, which led him to conclude that all plants are composed of cells. Theodor Schwann, declared that animal tissues were made up of cells.
The cell theory is a fundamental idea of modern biology. Its principles include: all living organisms are made up of one or more cells, the cell is the basic organizational unit in living organisms, and all cells come from living cells, as cells pass on genetic material copies on to their daughter cells.
A plasma membrane is a special boundary
that controls what substances enter and leave the cell.
Microscopes
Electron microscope
Compound light microscope
A modern compound light microscope uses glass lenses to magnify an object. When visible light passes through each lens, the image of the previous lens is magnified. Two lenses that each magnify an image 10x result in a microscope that magnifies the object 100x.
The transmission electron microscope uses magnets to aim a beam of electrons at the image to be magnified up to 500,000×. The scanning electron microscope produces a three-dimensional image of the cell. The scanning tunneling electron microscope can magnify living cells.
a prokaryotic cell is a simple cells that has no specialized structures.
Eukaryotic cells have a nucleus (contains genetic material) organelles (specialized structures that carry out specific functions).
phospholipids are composed of a phosphate head, glycerol backbone, and two fatty acids tails
Plasma membranes have selective permeability which allows some substances to pass through while keeping others out
cholesterol prevents fatty acids from sticking together, keeping the plasma membraine fluid
transport proteins create tunnels to move substances throughout the plasma membrane
receptor proteins transmit signals to the inside of the cell
the fluid mosaic model refers to the plasma membrane as a sea in which molecules float in
carbohydrates stick out the plasma membrane and identify chemical signals from the environment
the cytoplasm is a semifluid material in the plasma membrane
the cytoskeleton is a framework of protein fibers that provde a framework for the cell and is an anchor for organelles
cell wall is a rigid barrier that provides support and protection
chloroplast is the area where photosynthesis occurs
highly folded membrne
golgi apparatus is a flattened sack of membranes that packages proteins
the lysosome contains digestive enzymes to digest excess substances
mitochondria convert fuel energy into energy
ribosomes manufacture proteins
the vacuole stores food
facilitated diffusion is the use of transport proteins to move molecules across the plasma membrane
dynamic equilibrium is when molecules move, but concentration is the same
osmosis is the diffusion of water across a
selectively permeable membrane
diffusion is the movement of particles from an area of
high concentration to an area of lower concentration
an isotonic solution is a cell in a solution with equal concentrations of water and solute
a hypotonic solution is when a cell is in a solution with a lower concentration of solutes
In coupled transport sugars can pair with Na+ and enter the cell through a coupled channel
a hypertonic solution is when a cell is in a solution with a
higher concentration of solutes
active transport is the movement of particles across the cell membrane, against the concentration gradient
exocytosis is the excretion of materials at the plasma
membrane
endocytosis is process in which a cell surrounds an
object in the outside environment of the plasma membrane
Section 2