Human BiologyJanuary 4th lectureLipids: SteroidsStructure:Composed of four joined carbon ringsExamples:CholesterolHormonesEstrogenTestosteroneWhich of the following molecules is most useful in building a cell membrane?PhospholipidProteinsProteins are macromolecules made of long chains of subunits called Amino AcidsAmino Acids:20 different typesAmino end, carboxyl end, R (variable) groupAmino acids are joined by peptide bonds (a type of covalent bond), which are produced by dehydration synthesis reactionsTherefore a simple chain of Amino Acids is called a “Polypeptide”R= variable chemical groupMost of these are nonpolar.Highlighted section are non polar.Carbon and carbon is non polar.Carbon and oxygen or nitrogen are polar.Protein Function Depends on StructurePrimary structureBasic Amino Acid sequence, straight chainStabilized by peptide bondsSecondary structureAlpha helix, Beta pleated sheet or random coilStabilized by hydrogen bondsTertiary structureThree-dimensional shapeStabilized by disulfide and hydrogen bondsCreates polar and nonpolar areas in moleculeQuaternary structureTwo or more polypeptide chains are associatedProteins are made of amino acids.Tertiary structures are 3 dimensional.DenaturationPermanent disruption of protein structureCan be damaged by temperature or changes in pHBoiling temperature, for example, will cause protein structure to unfoldLeads to loss of biological functionDenaturation happens when you crack an egg, and the clear yoke becomes white.Protein FunctionsThousands of types of Proteins in your cells, thousands of different functionsEnzymesFunction as biological catalystsSpeed up chemical reactionsAre not altered or consumed by the reactionWithout enzymes, many biochemical reactions would not proceed quickly enough to sustain lifeHormonesSome of our hormones, such as ADH, are proteinsThey are polar, unlike nonpolar steroid hormonesreactants approach reactants bind to enzyme changes Products releasedenzymes enzymes shapeNucleic AcidsNucleic Acids are long chains containing subunits calledNucleotidesTwo types:DNA: Deoxyribonucleic AcidRNA: Ribonucleic AcidFunctions:Store genetic informationProvide information used in making proteinsEach Nucleotide subunit contains:5 carbon SugarDNA Nucleotides: DeoxyriboseRNA Nucleotides: RiboseNitrogenous Base (A, T, C, or G)Phosphate groupStructure of DNA:Double HelixTwo chains (or “Double–Stranded”) of Nucleotides held together in the middle by Hydrogen Bonds, twisted in a helical shapeSpecific Base pairingAdenine – ThymineGuanine – CytosineStructure of RNA:Single–stranded chain of NucleotidesNucleic Acid Function(GENETIC INFORMATION)Nucleic Acid function:DNA: instructions for making RNARNA: instructions for making proteinsProteins: direct most of life’s processesDNA → RNA → ProteinsOn first exam, lots of questions about molecules. (chart)Structure of ATP (Adenosine Triphosphate):Made of an Adenosine (contains an Adenine Base + Ribose Sugar) with 3 Phosphate groups attachedSOURCES OF ENERGY: Carbohydrates, lipids.A – P – P – P^ stored energy, how to get energy out of the ATP molecule, you have to break the molecule. Chop off a phosphate.A – P – P + P (burst of energy) (does cellular work)^^ ADP (Adenosine di phosphate)Your body constantly breaks up ATP’s and then reconnects them to create energy, cycle happens over & over.Function of ATP:Cellular energy sourceBonds between phosphate groups contain potential energyBreaking the bonds releases energyATP → ADP + P + energyADD ATP to chart, source of energy.Cell DoctrineAll living things are composed of cellsA single cell is the smallest unit that exhibits all of the characteristics of lifeAll cells come only from preexisting cellsTwo Basic Cell Types: Prokaryotic & EukaryoticProkaryotic CellsNo nucleusNo membrane bound organellesCell membrane + cell wallSmallerEukaryoticNucleus: compartment containing DNAOrganelles: structures with specialized functionsCell Membrane (only plants have Cell Wall)Larger (10-100mm)All human cells are EukaryoticCell structure reflects cell functionAll Eukaryotic Cells share many features, but can specialize to perform specific functionsMuscle cellsContain more Mitochondria, the organelle that provides energy needed for muscle contractionNerve cellsLong and thin to carry nerve signals over distanceAll are microscopically smallSmall size is most efficientSmall Cell Size is Most EfficientCells need to:Import nutrients and oxygenExport products made in the cellDispose of wastes such as carbon dioxideAll cell traffic must move across the membraneSmall cells have a higher surface area:volume ratioHigh surface area:volume ratio is more efficient for bringing in/out enough materialsSurface Area:(1 X 1) x 6 = 6Volume1x1x1=1SA/VOL6/1 =6Human Biology Lecture 4 Outline of Last Lecture I. Bondsa. Hydrogen bonds, polar molecules, covalent bonds, ionic bondII. Carbohydratesa. Starch, glycogen, celluloseIII. Lipidsa. Triglycerides, phospholipidsOutline of Current Lecture I. Proteins, steroids, and structures, Prokaryotic & Eukaryotic cells a. Cell structures, functionsb. DNA, RNAII. Genetic informationa. DNA, RNA, nucleus These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. Human Biology January 4th lecture  Lipids: Steroids  Structure: Composed of four joined carbon rings Examples: Cholesterol Hormones Estrogen Testosterone Which of the following molecules is most useful in building a cell membrane? Phospholipid  Proteins Proteins are macromolecules made of long chains of subunits called Amino Acids Amino Acids: 20 different types Amino end, carboxyl end, R (variable) group Amino acids are joined by peptide bonds (a type of covalent bond), which are produced by dehydration synthesis reactions Therefore a simple chain of Amino Acids is called a “Polypeptide” R= variable chemical group - Most of these are nonpolar.- Highlighted section are non polar.- Carbon and carbon is non polar.- Carbon and oxygen or nitrogen are polar. Protein Function Depends on Structure  Primary structure- Basic Amino Acid sequence, straight chain- Stabilized by peptide bonds Secondary structure- Alpha helix, Beta pleated sheet or random coil- Stabilized by hydrogen bonds Tertiary structure-