Cells And Cellular Transport

Where does the name “cell” come from? “Cells” were named by Englishman Robert Hooke in He observed that cork wood looked like monk’s cells in a monastery.

The Cell Theory 1.The cell is the basic unit of structure and function. 2.All organisms are made of one or more cells. 3.All cells come from pre-existing cells.

This is the human Herpes Virus! Exceptions to the Cell Theory 1.Viruses!! They have DNA and/or RNA inside a protein shell. They are capable of reproduction inside another living cell, but not on their own. 2.Mitochondria and chloroplasts have their own DNA and can reproduce inside a cell. 3.Obviously….the first cell.

Levels of Organization Atoms Molecules **Cells** Organelles Tissue ?? Cells with a similar structure and function.

Levels of Organization…Continued Organs Organ Systems Organism

Types of Cells Prokaryotic Cells The first and most primitive cells Lack a nucleus and other membrane bound organelles (mitochondria, etc) Bacteria are the ONLY prokaryotes Eukaryotic Cells Most organisms have eukaryotic cells (ex: all plant and animal cells!) All genetic material is contained in a nucleus Have many membrane bound organelles

Lysosome

Cell Organelle Functions Cell Membrane: provides a barrier between the cell and the environment. Vacuole: stores water, minerals and sometimes food. Lysosome: a sac of digestive juices (acts like a stomach). Mitochondria: where cellular respiration takes place, our energy comes from here! Golgi Bodies: “packages” cell material, wraps a membrane around protiens and materials made in the cells.

Cell Organelle Functions Centrioles: (ONLY in animal cells) help the cell undergo cellular division, or mitosis. Cytoplasm: jelly like material that fills in the extra space in a cell, also where most of our chemical rxns occur. Ribosomes: site of protein production. Endoplasmic Reticulum (ER): Transports materials around the cell. Nuclear Membrane: separates the nucleus from the rest of the cell.

Cell Organelle Functions Nucleolus: dense part of a nucleus, where RNA is made. Nucleus: stores DNA, controls most cellular activities. Cell Wall: rigid structure around the outside of plant cells to give them structure and support. Chloroplast: site of photosynthesis, makes sugar molecules using sunlight, water and carbon dioxide.

The Cell Membrane Also called: The Lipid Bi-Layer, Fluid Mosaic Model, And The Plasma Membrane Cell membranes are “semi-permeable” because they allow some molecules to pass through, while others cannot. A barrier that separates a cell from its surroundings.

Components of the Cell Membrane MOVIE

Just the lipids!

The lipid bilayer consists of two (bi) layers of phospholipids. The ____________ heads point to the outside and the ____________ tails point to the inside of the membrane. Various _________ molecules are embedded in the membrane as well Membrane Facts! hydrophilic hydrophobic proteins

Cell Membrane Cross Section This is the Lipid Bilayer. Why does this name fit? This is one of many kinds on proteins embedded in the membrane.

Membrane Proteins Marker Proteins: They are like a “name tag” for the cell.

Membrane Proteins Continued… Channel Proteins: These proteins reach through the membrane to both sides. It allows specific molecules to pass from one side of the membrane to the other. YouTube - Cell membrane animation Transport Proteins: Proteins that physically move molecules across the membrane. There are a variety of types!

Cellular Transport

Passive Transport does NOT require cellular energy (ATP) Moves molecules from high to low concentration Active Transport DOES require ATP

Diffusion The movement of molecules from an area of HIGH concentration to an area of LOW concentration. The direction of diffusion is called the concentration gradient. This is a form of passive transport. _________ molecules CANNOT diffuse, regardless of concentration gradient! LARGE

What types of molecules can NOT diffuse?? Even though all molecules seem small to us, they do vary in size a lot! Large molecules can NOT cross the cell membrane! Large molecules must rely on active transport.

Cellular Transport Passive Transport does NOT require cellular energy (ATP) Moves molecules from high to low concentration Examples: Diffusion Active Transport DOES require ATP

Osmosis Osmosis is a special name for the diffusion of ________ across a semi-permeable membrane. Because this requires NO ATP, it is called _____________. WATER Passive transport Water always moves from low to high SOLUTE concentration. This is osmosis!

If a cell is placed in a solution with a LOWER concentration of solute, it will _________ (water will _________ the cell) If a cell is placed in a solution with a HIGHER concentration of solute, it will _________ (water will _________ the cell) swell enter shrivel leave

Cellular Transport Passive Transport does NOT require cellular engery (ATP) Moves molecules from high to low concentration Examples: Diffusion Osmosis Active Transport DOES require ATP

Phagocytosis This is “cell eating”. A cell engulfs (or wraps itself around) a food particle thus creating a food vacuole. This is a type of ACTIVE TRANSPORT! Clip

Cellular Transport Passive Transport does NOT require cellular engery (ATP) Moves molecules from high to low concentration Examples: Diffusion Osmosis Active Transport DOES require ATP Examples: Phagocytosis

Pinocytosis This is “cell drinking”. The cell membrane pinches inward (like a pin poking a hole) and creates a vacuole of dissolved particles. This is a type of ACTIVE TRANSPORT! Clip

Cellular Transport Passive Transport does NOT require cellular engery (ATP) Moves molecules from high to low concentration Examples: Diffusion Osmosis Active Transport DOES require ATP Examples: Phagocytosis Pinocytosis

Membrane Proteins Using Cellular Energy: The proteins we learned about in the membrane sometimes require energy!

Cellular Transport Passive Transport does NOT require cellular energy (ATP) Examples: Diffusion Facilitated Diffusion Osmosis Active Transport DOES require ATP Examples: Phagocytosis Pinocytosis Use of membrane proteins (ex: transport proteins)

Moving Molecules Against the Concentration Gradient The sodium ions are more highly concentrated on the inside of the cell. With the help of ATP, the sodium ions are still pumped back into the cell (against the concentration gradient).

Cellular Transport Passive Transport does NOT require cellular energy ATP) Examples: Diffusion Facilitated Diffusion Osmosis Active Transport DOES require ATP Examples: Phagocytosis Pinocytosis Use of membrane proteins (carrier proteins, etc) Moving molecules from low to high concentration