Day 3

Cell Transport: Passive Transport

Passive Transport Cell uses no energy Random movement of particles along a concentration gradient from high to low concentration. (High  Low)

1. Diffusion Diffusion: -random movement of particles from high to low concentration. – continues until molecules at equilibrium (equal) Simple Diffusion AnimationSimple Diffusion Animation

Facilitated diffusion: diffusion of specific particles from High  Low conc. with help of proteins in membrane. a.Carrier Proteins -bind to specific molecules, carry across membrane. a.Transport large particles that can’t pass through on own. Ex. Glucose b.Ion Channels Protein - transports ions (charged particles) a.Ex. Na +, K +, Cl - Facilitated diffusion (Channel Protein) Diffusion (Lipid Bilayer) : 2. Facilitated Diffusion Carrier Protein AB

High Concentration Low Concentration Cell Membrane Glucose molecules Protein channel Facilitated Diffusion Go to Section: Transport Protein Through a  Cellular Transport From a- High Low Channel Proteins animationsChannel Proteins

Osmosis: diffusion of water – Moves from a high concentration to low concentration of water Cell cannot control movement of water through cell membrane Osmosis Osmosis animation 3. Osmosis

Effects of Osmosis on Life Water moves freely through pores. Substances dissolve well in water. – Solute: what is being dissolved – Solvent: what dissolves the solute In salt water, the solute is the salt and the solvent is the water Cells can be placed in 3 kinds of water solutions that affect their homeostasis.

1. Hypotonic Solution Hypotonic: Solution has lower concentration of solutes and higher concentration of water than inside the cell. (Low solute; High water) Result: Water moves from the solution to inside the cell: Cell Swells and bursts open ( called lyse)! Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis

2. Hypertonic Solution Hypertonic: Solution has higher concentration of solutes and lower concentration of water than inside the cell. (High solute; Low water) Result: Water moves out of the cell into the solution: Cell shrivels or shrinks! Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis shrinks

Isotonic Solution Isotonic: Concentration of solutes in solution is equal to concentration of solutes inside cell. Result: Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium) Osmosis Animations for isotonic, hypertonic, and hypotonic solutionsOsmosis

In what type of solution are these cells? A CB HypertonicIsotonicHypotonic

Real Life Examples If you are stranded in the ocean, should you drink the water to stay alive?

Why do we wrinkle when we are in the tube too long?

Why does it help to gargle salt water when we have a sore throat?

What happens to a snail when you put salt water on it?

Cell Transport: Active Transport

Active Transport Requires the cell to use energy Actively moves molecules to where they are needed Molecules move against the concentration gradient - from area of low concentration to area of high concentration (Low  High)

Types of Active Transport 1. Protein Pumps -transport proteins that require energy to do work Example: Sodium / Potassium (Na+/K+) Pumps important in nerve responses. Sodium Potassium Pumps Sodium Potassium Pumps (Active Transport using proteins) Protein changes shape to move molecules: this requires energy!

Types of Active Transport 2. Endocytosis: takes bulky materials into a cell by forming a vesicle. Uses energy Cell membrane in-folds around particles “cell eating” Forms vacuole & digests the particle This is how white blood cells eat bacteria!

Types of Active Transport 3. Exocytosis: Forces material out of cell in bulk Membrane surrounds material then fuses with cell membrane Cell changes shape – requires energy Ex: Hormones or wastes released from cell Endocytosis & Exocytosis Endocytosis & Exocytosis animations

Comparison

Photosynthesis

How Do Plants Make Their Own Food? Photosynthesis - process by which light energy is converted to chemical energy. – Plants, algae, and some bacteria use this process. Called Autotrophs or Producers – “Food” plants make is a sugar called glucose (C 6 H 12 O 6 ). Can be stored as sugar or made into starch or cellulose. – Plants use carbon dioxide (CO 2 ), water (H 2 O), and sun’s energy to make food. 6CO 2 carbon dioxide 6H 2 O water C 6 H 12 O 6 glucose (sugar) 6O 2 oxygen + + Sun (light energy) Reactants - InProducts - Out

3 Stages of Photosynthesis Stage 1 -Absorption of Light Energy – energy is captured from sunlight. – Occurs in chloroplasts found in leaves. – Pigments – found in cholorplasts absorb light. Different pigments absorb certain wavelengths and reflect others. Chlorophyll – (a &b) primary pigment. Absorbs mostly blue and red light; reflects green and yellow light. Carotenoids- (carotene, xanthrophyll) pigments that reflect yellow and orange colors. – Clusters of pigments found in Thylakoids in chloroplast. Stack of Thylakoids called a grana or granum

How is light captured? Stage 1 cont. – Light strikes thylakoids in chloroplast. Electrons get excited and jump around. – Electrons jump out of chlorophyll into other nearby molecules in thylakoid and go to 2 nd stage. Electrons (H) lost replaced by stealing them from water molecules forming O 2.

What is done with energy that is captured? Stage Two: Electron transport chain-light energy is converted to chemical. – Electrons enter Electron transport chain in thylakoid membrane (series of rxns where ATP is made through transfer of electrons). Produces ATP (energy) and NADPH (electron carrier) Stage 1 and 2 are called Light-dependent reactions.

Electrons Jumping

What is energy? In cells, energy is stored as ATP (adenosine triphosphate) – delivers energy to other cells When the energy released, ATP becomes ADP – loses a phosphate atom. – Therefore, the energy is stored in the phosphate bond! ATP ADP + P + energy

Copyright Cmassengale Electrons lose energy as go through protein in membrane. Energy lost from electrons used to pump Hydrogens into thylakoid through Active transport. This creates concentration gradient of H which then starts to pass through an ion channel that is also an enzyme (ATP Synthase). As H passes through channel, the protein catalyzes a reaction that adds a phosphate group to ADP to form ATP. A second electron transport chain makes NADPH by adding a H to an electron acceptor called NADP +. Produces ATP (energy) and NADPH (electron carrier) All this from the light hitting the chlorophyll to making ATP is called the Light- dependent reaction Electron Transport Chain- how does it work?

Stage Three: Calvin Cycle – Through carbon fixation, CO 2 is used to make glucose. Carbon fixation – transfer of CO2 to organic compounds (sugars) Calvin Cycle – series of enzyme-assisted chemical reaction that produces a 3-carbon sugar. – Enzyme Rubisco converts inorganic carbon dioxide molecules into organic molecules that can be used by the cell. Stage 3 is called a Light-independent reaction or Dark reactions.

Factors affecting Photosynthesis Amount of Light. Amount of CO 2 & H 2 O. Amount of temperature.

Electron Transport Chain Animation Copyright Cmassengale

Cellular Respiration

How Do Organisms Get Energy From Food? BOTH plants and animals must break down (digest) food in order to get energy from it (so they can live, grow, & develop) – Cellular Respiration - process that makes energy (ATP) from organic compounds like glucose; done in mitochondria 2 types: Aerobic and Anaerobic Food (glucose) is broken down into CO 2 and H 2 O and energy is released C 6 H 12 O O 2  6 CO H 2 O + energy (ATP) This energy can be used for: – Keeping constant body temperature (Homeostatsis) – Storage (ATP) - to be used later for things like growth

What Do You Notice?

Check It Out! Did you notice that cellular respiration is just the opposite of photosynthesis?

Aerobic Respiration Requires oxygen Carried out by plants, animals, and some bacteria 3 stages – 1. Glycolysis - Breakdown of Glucose – Occurs in cytoplasm – Enzymes break down glucose into 2 sugars called pyruvate, 2 ATP also made. – 2. Krebs Cycle – Occurs in mitochondria – Pyruvate made in stage 1 enters mitochondria and is converted to a 2 C compoound. – Produces CO 2, 2 ATP, NADH, Acetyl-CoA, and FADH 2 (electron carrier) – Electrons carried by NADH and FADH to stage 3

– 3.Electron Transport Chain – Occurs in mitochondria membrane – Electrons move down electron transport chain – Electrons combine with oxygen to make water. – 32 ATP made 2 ATP 32 ATP

Anaerobic Respiration No Oxygen required. Organisms such as yeast and bacteria use it and organisms that normally require oxygen can do it if their cells can’t get enough oxygen. Also called Fermentation. 2 types: alcoholic and lactic acid – Both start with glycolysis Pyruvate and 2 ATP produced – No Krebs or electron transport chain.

Lactic Acid Pyruvate lactic acid – Carried out by your muscles when you’re exercising hard and can’t get enough oxygen fast enough (can’t do aerobic respiration) – Causes muscle cramps and soreness Alcoholic Pyruvate ethyl alcohol – Carried out by yeast and some bacteria. – Used in brewing beer, making wine, and baking bread and cakes