Post on 04-Jan-2016
description
Smallest unit of all living things
Composed of organelles
Each organelle performs specific jobs so the cell can do it’s job
The Cell
Cell membrane Nucleus Chromatin Nuclear envelope Microvilli Cytoplasm
Mitochondria Golgi body Rough ER Smooth ER Ribosome Centrioles
Organelles Know location of and function of the following sructures
The barrier surrounding each cell Separates the cells contents from the
surrounding environment Is selectively permeable This is the cells way of maintaining
boundaries
Plasma Membrane
Phospholipid bi-layer Meaning two layers Each layer consists
of a lipid tail connected to a surface protein
The tails face each other, away from the external or internal environments
Structure of plasma membrane
Hydrophobic◦ The lipid tails are
water insoluble◦ They are “water
fearing”◦ They are non-polar
Hydrophilic◦ The protein heads of
each Phospholipid is water soluble
◦ They are “water loving”
◦ They are polar and interact well with other polar objects
Phospholipid bi-layer
1. Proteins◦ a. Peripheral proteins act as binding sites or
receptors◦ b. Integral proteins- proteins that span the
membrane act as transport protein◦ c. Glycoprotein- act as markers, which allow your
cells to be recognized as “self” cells 2. cholesterol
◦ Help to stabilize the plasma membrane
Throughout the membrane you will find
Channel Proteins◦ Passive movement
of material through pores
Carrier proteins◦ Material binds to
carrier proteins and is moved by the protein through the membrane
Types of transport proteins
Use passive transport◦ Do NOT require energy◦ 1. diffusion- molecules move across membrane
through pores along a concentration gradient (high to low)
◦ 2. filtration-movement of water and other solutes from high to low concentration Based on a hydrostatic pressure, water gradient
which creates a pressure Occurs in the kidneys
Channel proteins
Facilitated diffusion- ◦ concentration gradient still needed◦ Protein carrier is used because molecules are too
large to enter pores◦ Still passive transport, just needs help◦ No energy because it is using a gradient
Solute Pump (page 70, figure 3.10)◦ Moves molecules or ions too large to enter on own◦ Moves materials AGAINST a concentration
gradient (usually)◦ REQUIRES ENERGY (active transport)
Carrier proteins
Several junctions are present in order for the cells to continue doing their jobs, while communicating with adjacent cells all the while staying anchored to each other!
Cells join to form tissue
Membrane junctions:◦ Tight junctions◦ Desmosomes◦ Gag junctions
Define the following terms and provide an example of where it occurs page 59