Biology I Cells

Why is it good that your house is made out of many smaller rooms rather than one big space?

What is a cell? A cell is a small specialized compartment It keeps what is inside separate from the rest of the organism

Why must living things be made of cells? To have enzyme/substrate concentrations high enough so that rates of reactions are reasonable to support life (Rates of Reaction) To have enzyme/substrate concentrations high enough so that rates of reactions are reasonable to support life (Rates of Reaction) Rates of Diffusion Rates of Diffusion Rates of Transport Rates of Transport Reactions can occur without interference (conflicting reactions can happen simultaneously) Reactions can occur without interference (conflicting reactions can happen simultaneously) Local environments can allow different reactions to happen Local environments can allow different reactions to happen

Why must living things be made of cells - continued Specialization (different cells can do different things) Specialization (different cells can do different things) Damage can be contained Damage can be contained

Cell Theory

Cell Theory Continued All Living Things are Made of Cells All Cells Come From Other Cells

Prokaryotic vs. Eukaryotic Cells

Cell Membrane Structure Phospholipid Bilayer

Cell Membrane Structure

Membrane Proteins Protein Channels – Control what moves in and out of membrane Protein Channels – Control what moves in and out of membrane –Passive Transport –Active Transport Receptors – Receives messages so the cell knows what to do Receptors – Receives messages so the cell knows what to do Marker or Signal Proteins – Identifies the cell so your immune system knows what belongs to you vs. foreign cells Marker or Signal Proteins – Identifies the cell so your immune system knows what belongs to you vs. foreign cells Attachment Proteins – attach cells to other cells and ECM Attachment Proteins – attach cells to other cells and ECM

Ways Things Move Through the Cell Membrane Diffusion – movement of molecules from a high to low concentration due to random motion of molecules Diffusion – movement of molecules from a high to low concentration due to random motion of molecules Osmosis – diffusion of water Osmosis – diffusion of water Simple diffusion – thru phospholipid bilayer – driven by kinetic energy of the molecules or atoms themselves Simple diffusion – thru phospholipid bilayer – driven by kinetic energy of the molecules or atoms themselves

Ways Things Move Through the Cell Membrane Facilitated diffusion – using the help of protein channels Facilitated diffusion – using the help of protein channels –Cell uses no energy, substances move from high to low concentration (still diffusion) –Used when molecules are polar, charged, or too big –Channels are still small – nothing bigger than a monomer goes through protein channels

Ways Things Move Through the Cell Membrane Active Transport Active Transport –Movement through protein channels from low to high concentration –Cell must use energy to pump things through Ocean Fish pump salt out of their cells Muscle cells pump Na+ out so they can reset to contract again

How can big things like cholesterol and fatty acids get into cells since protein channels can’t be big?

You will figure it out using the following materials: A grocery bag as the cell A grocery bag as the cell Candy as the large particles being taken in Candy as the large particles being taken in 2 pieces of string and scissors 2 pieces of string and scissors The Rules The inside of the bag (cell) cannot be open to the external environment at any time The inside of the bag (cell) cannot be open to the external environment at any time You can put your hands inside the bag to manipulate the cell membrane You can put your hands inside the bag to manipulate the cell membrane You cannot turn the bag inside out You cannot turn the bag inside out You cannot put the particles through the hole You cannot put the particles through the hole Food particles must remain together during the whole process including after they enter the cell Food particles must remain together during the whole process including after they enter the cell You cannot tie the food particles together with the string You cannot tie the food particles together with the string You must demonstrate the process to me and show me how you did it to win!

Ways Things Move Through the Cell Membrane Endocytosis – engulfing large particles with part of the cell membrane and bringing them into the cell in a vesicle Endocytosis – engulfing large particles with part of the cell membrane and bringing them into the cell in a vesicle Exocytosis – (secretion) – wrapping molecules in a membrane vesicle inside the cell – having it fuse with the cell membrane and dump the contents outside the cell (with or against conc. Gradient – big stuff like proteins Exocytosis – (secretion) – wrapping molecules in a membrane vesicle inside the cell – having it fuse with the cell membrane and dump the contents outside the cell (with or against conc. Gradient – big stuff like proteins

Onion Cells with and without stain

Elodea Cells and Salt Water cytoplasmic streaming in elodea adding salt to a red onion cell

Pond Water tailpage&v=cwgGJaNlGKM