Chemistry of Life (157 – 163) 6.3 Cell Processes Active and Passive Transport, Osmosis, Diffusion, Exocytosis, and Endocytosis pp. 155 – 156; , 8.1 Hickox: Baker High School Biology

Objective 2.0: Describe cell processes necessary for achieving homeostasis, including active and passive transport, osmosis, diffusion, exocytosis, and endocytosis Identifying functions of carbohydrates, lipids, proteins, and nucleic acids in cellular activities Comparing the reaction of plant and animal cells in isotonic, hypotonic, and hypertonic solutions Explaining how surface area, cell size, temperature, light, and pH affect cellular activities Applying the concept of fluid pressure to biological systems Examples: blood pressure, turgor pressure, bends, strokes Core concept: Most cell functions involve chemical reactions. Food molecules taken into cells react to provide the chemical constituents needed to synthesize other molecules. There are four main biochemicals: Carbohydrates, Proteins, Lipids and Nucleic acids. Cells use carbohydrates to provide energy. Cells use proteins for cellular construction and repair, cellular chemical activities, and as a back-up energy source if carbohydrates are not available. Both breakdown and synthesis are made possible by a large set of protein catalysts, called enzymes. Cells use lipids for cell membrane construction. Cells use nucleic acids to store genetic information for protein synthesis. Vocabulary Carbohydrate Nucleic Acid Lipids Proteins Enzyme Core concep: Cell membranes are selectively permeable. This gives them the ability to maintain cell homeostasis by regulating what enters and leaves the cell. The direction of water movement across the cell membrane depends on the relative concentrations of free water molecules in the cytoplasm and in the fluid outside the cell. Different kinds of cells have evolved different ways of dealing with hypertonic, hypotonic, and isotonic solutions. The cells of plants have rigid cell walls that keep the cells from expanding too much. Animal cells can avoid swelling by moving dissolved particles from the cytoplasm. Cell membranes are selectively permeable. This gives them the ability to maintain cell homeostasis by regulating what enters and leaves the cell. The direction of water movement across the cell membrane depends on the relative concentrations of free water molecules in the cytoplasm and in the fluid outside the cell. Different kinds of cells have evolved different ways of dealing with hypertonic, hypotonic, and isotonic solutions. The cells of plants have rigid cell walls that keep the cells from expanding too much. Animal cells can avoid swelling by moving dissolved particles from the cytoplasm. Vocabulary Passive transport Active transport Endocytosis Isotonic Exocytosis Diffusion Hypotonic Hypertonic Homeostasis Osmosis

Core Concept: Small cells function more efficiently than large cells. Small cells can exchange substances more readily than large cells because small objects have a higher surface-area-to-volume ratio than larger objects. Most cells function best within a narrow range of light, temperature and pH. At very low temperatures, reaction rates are too slow. Extremes of light, temperature and pH can irreversibly change the structure of most protein molecules. Vocabulary: pH, surface area, volume Turgor pressure is the main pressure of the cell contents against the cell wall in plant cells and bacteria cells, determined by the water content. Blood pressure refers to the force exerted by circulating blood on the walls of blood vessels. High blood pressure can cause stroke.cellcell wall plant cellsbloodblood vessels BreathingBreathing gas under pressure can present a myriad of possible medical problems. One of these is decompression sickness or "the bends," caused by breathing nitrogen or other gases under pressure, which are not metabolized by the body.myriad nitrogen Vocabulary Bends Stroke Hickox: Baker High School Biology

Simple to Complex Life’s Levels of Organization Our journey begins here, atoms like Hydrogen (H) and Oxygen (O) Atoms come together to male up molecules like water, H 2 O. Hickox: Baker High School Biology

Chemical Reactions Chemical Reactions CO 2 + H 2 O C 6 H 12 O REACTANTS PRODUCT(S) CHEMICAL EQUILIBRIUM Sun

Acids and Bases Acids are substances that forms in water and release hydrogen ions (H + ). Bases are substances that either take up hydrogen ions (H + ) or release hydroxide ions (OH - ). pH measures how acidic or basic a solution is Hickox: Baker High School Biology

pH Scale A pH scale is used to indicate how acid and basic of a solution. A pH scale is used to indicate how acid and basic of a solution. – Ranges from = Neutral 7 = Neutral >7 = Base >7 = Base <7 = Acid <7 = Acid Hickox: Baker High School Biology

pH Matters pH is a measure of proton (hydrogen ion or H + ) concentration. In biology, keeping H + levels within a narrow range is critically important. Low pH = lots of H + s, high pH = few H + s. A strong acid is pH of 2 A strong base is pH of 12

Essential Question What are differences and similarities of Osmosis and Diffusion? Hickox: Baker High School Biology

Diffusion higher lower Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration. VIDEO FROM FILE Diffusion continues until there is no concentration gradient! What affects the speed of Diffusion? concentration: main factor, higher the more concentration: main factor, higher the more temperature: if temp. increase greater diffusion temperature: if temp. increase greater diffusion pressure: increasing pressure increases diffusion pressure: increasing pressure increases diffusion

no concentration gradient! Dynamic equilibrium

Osmosis Hickox: Baker High School13

Your turn: Compare Osmosis and Diffusion Osmosis Diffusion Hickox: Baker High School Biology

Osmosis Isotonic Solution - Solute and Solvent (water) concentrations both inside and outside the membrane are equal. Hypotonic Solution - Solution with a lower concentration of solute than the solution on the other side of the membrane. – Cells placed in a hypotonic solution will swell. Lysis Hickox: Baker High School15

Osmosis Hypertonic Solution - Solution with a higher concentration of solute than the solution on the other side of the membrane. – Cells placed in a hypertonic solution will shrink. Plasmolysis Hickox: Baker High School16

Summary Section 2 – pages The results of diffusion When a cell is in dynamic equilibrium with its environment, materials move into and out of the cell at equal rates. As a result, there is no net change in concentration inside or outside the cell. Material moving out of cell equals material moving into cell

What type of osmosis is this? (Isotonic, hypotonic, or hypertonic) Does cell shrink, expand, or stay the same?

Your Turn: OSMOSIS ______________ is the diffusion of particles through a semi- permeable membrane. __________________: movement of particles across cell membranes by diffusion or osmosis. The cell uses NO energy to move these particles __________________: the transport of materials against the gradient and this takes energy ___________________: the pushing out of water in a plant cell against the cell wall ___________________: shrinking of cell due to water moving out (dissolved solution outside cell high) _____________: swelling of a cell due to water moving in ____________: concentrations inside and outside cell is balanced. VIDEO FROM FILE

Diffusion in Living Systems: the way cells move substances in and out of the cell Osmosis is the diffusion of particles through a semi- permeable membrane. IsotonicHypotonicHypertonic

Essential Question Hickox: Baker High School Biology What are the essential molecules of Life?

Biomolecule: Structures vary amino acids lipids Three views of glucose, a common simple sugar. RINGS BUNCHED CHAINS LONG CHAINS

Molecules of Life Start with water, add lots of small carbon-containing molecules and ……. How do you build a cell? Use these four major classes of biological molecules: Carbohydrate, lipid, protein, nucleic acid.

Carbohydrates Carbon, Hydrogen, and Oxygen Carbohydrates are used for energy and to create structures. The building blocks for carbohydrates are simple sugars. Three views of glucose, a common simple sugar.

Lipids are large and are made mostly of carbon and hydrogen and small amounts of oxygen. Fat Phospholipid Lipids do not dissolve in water. Lipids are used by cells for energy storage, insulation, and protective coatings, such as in membranes.

Phospholipids Form Double-Layered Biological Membranes

Protein p. 66 Proteins are THE key elements of life. Proteins provide structure for tissue and organs and carry out cell metabolism. Provide the body with the ability to move muscles. They are needed to transport oxygen in the bloodstream. Proteins are large and complex; made of carbon, hydrogen, oxygen, nitrogen and sometimes sulfur. Enzymes, a type of protein that change the speed of chemicals reactions in the body.

An enzyme (p. 66) is a protein that enables other molecules to undergo chemical changes to form new products. Enzymes increase the speed of reactions that would otherwise proceed too slowly. Substrate Active site Section 3 Check

Strands of the Protein Keratin Create Hair

Nucleotides are Chains of Linked Amino Acids DNA and RNA The building blocks of proteins are amino acids! There are two kinds of nucleic acids, DNA and RNA. Both are involved in the storage and flow of information from gene to gene product.

Nucleotides Are the Monomers That Create Polymers of DNA and RNA The small subunits that make up nucleic acids are nucleotides.

Hickox: Baker High School BiologyDNA

Mader: Biology 8 th Ed. RNA