– All need energy for metabolism. Metabolism: All of the chemical processes in an organism that build up or break down materials. An organism is any individual living thing. Living things share some common characteristics: –All are made of one or more cells. –All respond to their environment. –Stimuli, or physical factors, include light, temperature, and touch. –All have genetic material (DNA) that they pass on to offspring.
O HH _ ++ Life depends on hydrogen bonds in water. Water is a polar molecule. – Polar molecules have slightly charged regions. – Nonpolar molecules do not have charged regions. 1.Hydrogen bonds form between slightly positive hydrogen atoms and slightly negative atoms. (oxygen) Atom: Oxygen Charge: Slightly negative Atom: Hydrogen Charge: Slightly positive
Hydrogen bonds are responsible for important properties of water. –High Specific Heat: water resists changes in temp. –Provides stability of temperature for land masses surrounded by water & for the temperature of the human body, & makes it an effective cooling agent. –Cohesion: water molecules stick to each other. –Adhesion: water molecules stick to other things. –Ice floats on water: one of the only solids to float on its liquid form – due to arrangement of water molecules due to charged regions.
Many compounds dissolve in water. A solution is formed when one substance dissolves in another. A solution is a homogeneous mixture. – Solvents dissolve other substances. – Solutes dissolve in a solvent. solution
“ Like dissolves like. ” –Polar solvents dissolve polar solutes. –Nonpolar solvents dissolve nonpolar solutes. –Polar substances and nonpolar substances generally remain separate. –Example: Oil (non-polar) and water (polar)
Maintaining homeostasis *Buffer: Helps to maintain pH. pH <7=Acid (more H + ) 7=Neutral >7=Base (less H + )
Speaking of homeostasis… Homeostasis refers to your body maintaining stable, constant internal conditions. This may include: – Regulation of temperature (thermoregulation) – Regulation of pH – Regulation of oxygen delivery (for cellular respiration!)
Carbon atoms have unique bonding properties. 1. Carbon forms covalent bonds (strong bonds) with up to four other atoms, including other carbon atoms 2. They can form large, complex molecules
3. Carbon can form single, double, or triple bonds 4. Carbon forms isomers – Isomers are compounds that have the same chemical formula, but different structural formulas Example: C 4 H 10 Only carbon has these 4 characteristics Carbon atoms have unique bonding properties – Slide 2
Many carbon-based molecules are made of many small subunits bonded together. Monomers are the individual subunits. Polymers are made of many monomers.
Carbohydrates Monomer monosaccharide Polymerdisaccharide (dimer), polysaccharide ExamplesMonosaccharide: glucose, fructose Disaccharide: sucrose (table sugar) Polysaccharide: starch & cellulose (cell wall in plants), glycogen (in animals) Unique-Provide a quick source of energy
Lipids Monomer glycerol & fatty acids; polar heads & fatty acid tails Polymer triglycerides; phospholipids ExamplesFats, oils, cholesterol, steroids, waxes, phospholipids Unique-Nonpolar -Broken down to provide energy -Used to make steroid hormones (control stress, estrogen, testosterone) -Phospholipids make up all cell membranes -Fats and oils contain fatty acids bonded to glycerol LIPIDS
Proteins Molecule Proteins MonomerAmino acid PolymerPolypeptide (protein) ExamplesEnzymes, hemoglobin (in blood), muscle movement, collagen Unique-3D structure makes them active -Peptide bonds hold amino acids together -Have a side group (R) that makes each amino acid (and therefore protein) different -Sometimes may contain sulfur
Nucleic acids Molecule Nucleic acids Monomer Nucleotide (5-carbon sugar, phosphate group, & base) PolymerNucleic acid ExamplesDNA & RNA Unique - Order of the bases makes every living thing unique -DNA stores genetic information -RNA builds proteins
Chemical reactions release or absorb energy. Activation energy is the amount of energy that needs to be absorbed to start a chemical reaction
A catalyst lowers activation energy. Catalysts are substances that speed up chemical reactions – Decrease activation energy – Increase reaction rate
Enzymes allow chemical reactions to occur under tightly controlled conditions. Enzymes are catalysts in living things. – Enzymes are needed for almost all processes. – Most enzymes are proteins.
Disruptions in homeostasis can prevent enzymes from functioning. Enzymes function best in a small range of conditions. – Changes in temperature or pH can break hydrogen bonds. An enzyme’s function depends on its structure.
An enzyme’s structure allows only certain reactants to bind to the enzyme. Substrates: reactants that bind to an enzyme Active site: area on the enzyme where substrates bind
Exothermic reactions release more energy than they absorb. Excess energy is released by the reaction. – Energy “exits” the reaction. (Exo = exit)
Endothermic reactions absorb more energy than they release. Energy is absorbed by the reaction to make up the difference. – Energy goes into the reaction. (Endo = “into”)
The Cell Theory: – All organisms are made of cells. – All cells come from other cells. – The cell is the basic unit of structure & function in living things.
All cells share certain characteristics. Cells tend to be microscopic. All cells are enclosed by a membrane. All cells are filled with cytoplasm. All cells have ribosomes.
There are two cell types: Eukaryotic cells – Have a nucleus – Have membrane- bound organelles Prokaryotic cells – Do not have a nucleus (still have DNA) – Do not have membrane-bound organelles
Review Eukaryotes Have nucleus (DNA) Have membrane-bound organelles Larger size because of organelles More complex Unicellular or multicellular Prokaryotes No nucleus (still have DNA) No membrane-bound organelles Smaller size because of lack of organelles Less complex Unicellular
Organelles and Functions See attached list!!! How does the rough ER work with the Golgi? Rough ER packages the proteins its ribosomes synthesize (including membrane and secretory proteins) in vesicles to ship to the Golgi Apparatus/Body for further processing, sorting and packaging.
Cell membranes are composed of two phospholipid layers. The cell membrane has two major functions 1.Forms a boundary between inside and outside of the cell 2.Controls passage of materials in & out of cell
Phospholipid Bilayer Forms a double layer surrounding a cell Head is polar (attracted to water) and forms hydrogen bonds with water Tails are nonpolar (repelled by water)
Passive transport does not require energy (ATP) input from a cell. Molecules can move across the cell membrane through passive transport. Two types of passive transport: – Diffusion: movement of molecules from high to low concentration – Osmosis: diffusion of water
Diffusion and osmosis are types of passive transport (NO ENERGY) Molecules diffuse down a concentration gradient. – High to low concentration
Cell Membrane Dialysis Tubing – Diffusion Lab WHY? Starch stays in bag – too big. Iodine goes through bag - small
How do different solutions affect cells? There are 3 types of solutions: 1.Isotonic: solution has the same concentration of solutes as the cell. Water moves in and out evenly Cell size stays constant
How do different solutions affect cells? There are 3 types of solutions: 2.Hypertonic: solution has more solutes than a cell More water exits the cell than enters Cell shrivels or dies
How do different solutions affect cells? There are 3 types of solutions: 3.Hypotonic: solution has fewer solutes than a cell More water enters the cell than exits Cell expands or bursts
Some molecules can only diffuse through transport proteins Some molecules cannot easily diffuse across the membrane – Ex: glucose (needed by cell to make energy) Facilitated diffusion is diffusion through transport proteins DOES NOT USE ENERGY Video
3.5 Active Transport, Endocytosis, & Exocytosis Key Concept: – Cells use energy (ATP) to transport materials that cannot diffuse across a membrane.
Active Transport Drives molecules across a membrane from lower to higher concentration – Goes against the concentration gradient
TYPES OF ACTIVE TRANSPORT Endocytosis: Brings materials into cell (Endo=into) Exocytosis: Releases materials out of cell (Exo=Exit)
Sodium-Potassium Pump Uses a membrane protein to pump three Na + (sodium ions) across the membrane in exchange for two K + (potassium ions) – ATP (energy) is needed to make the protein change its shape so that Na + and K + can move through it and cross the membrane Helps the heart contract, helps regulate blood pressure, allows neurons to respond to stimuli and send signals
4.1 How do living things get ATP? ATP is the energy carrier in living things – it is usable energy for the cell. ATP stands for Adenosine triphosphate. Living things get ATP from breaking down carbon based molecules. (carbohydrates & lipids) Starch molecule Glucose molecule
4.2 & 4.3 Photosynthesis The process of photosynthesis captures energy from sunlight and converts it into sugar (glucose). This process happens in organisms called autotrophs or producers. (Need to make their own food) This process takes place in and organelle called the chloroplast. The chloroplast has a green pigment in it called chlorophyll that is responsible for capturing the light energy.
So how does photosynthesis work? The first stage of photosynthesis is called the Light Dependent Stage. Light is captured by the chlorophyll in the thylakoid.
So how does photosynthesis work? The second stage of photosynthesis is called the Light Independent Stage/ Calvin Cycle/ Dark Cycle. This process takes place in the stroma.
The chemical formula for photosynthesis 6CO 2 + 6H 2 O + light C 6 H 12 O 6 + 6O 2 (reactants) (products ) Carbon dioxide plus water plus light yieldsGlucose and oxygen
Purpose of Cellular Respiration To make ATP from the energy stored in glucose – Glucose comes from an organism doing photosynthesis themselves or from eating foods containing glucose – Remember: the purpose of photosynthesis was just to get glucose
Glycolysis Takes place in cytoplasm (eukaryotes and prokaryotes do this step since all cells have cytoplasm) Splits one glucose molecule into two pyruvate molecules – Costs the cell 2 ATP molecules to do this 4 ATP molecules are produced (only gain 2 ATP) This portion of CR does NOT require oxygen (anaerobic)
Kreb’s Cycle (Citric Acid Cycle) Takes place in matrix of mitochondria (only in eukaryotes) 2 pyruvate (made during glycolysis) enter the mitochondrion Each pyruvate is broken down to create 1 ATP Total products of Kreb’s cycle (because of 2 pyruvates): – 2 ATP
Electron Transport Chain (ETC) Takes place in inner membrane of mitochondria (cristae) – Folded to create more surface area for reactions to produce more ATP in a small space Oxygen and hydrogen ions combine to form water (released as a waste product) 32 ATP are made
ATP from Cellular Respiration 4 from Glycolysis (uses up 2, so really only gain 2 ATP) 2 ATP from Kreb’s cycle 32 ATP from ETC GAIN 36 ATP from one glucose molecule
Equation for Cellular Respiration C 6 H 12 O 6 + 6O 2 6CO 2 + 6H 2 O + 36ATP Like the reverse of photosynthesis Energy transfers: Photo: Light CPE CR: CPE CPE
What happens when there’s no/not enough oxygen or there are no mitochondria? Answer: Fermentation – Two Kinds: Lactic Acid Fermentation Alcoholic Fermentation Allows glycolysis to continue making ATP without oxygen