Biology Midterm Friday PDF

Biology Midterm Friday 6:30-7:30 Monday, October 7, 2024 8:10 PM The Molecules of Life Water Solvent of life Dissolves more molecules than any other solvent Polar molecule Dissolves other polar molecules and charged molecules Macromolecules Carbohydrates -Polymers of sugars (glucose Li...

Biology Midterm Friday 6:30-7:30 Monday, October 7, 2024 8:10 PM The Molecules of Life Water Solvent of life Dissolves more molecules than any other solvent Polar molecule Dissolves other polar molecules and charged molecules Macromolecules Carbohydrates -Polymers of sugars (glucose Lipids -Not polymers but hydrophobic molecules (Fats, Oils) Proteins -Polymers of amino acids (structure determined by sequence and properties of amino acids) Nucleic acids -Polymers of nucleotides (DNA, RNA) Polymerization: Dehydration Synthesis- The process of linking monomers together by removing Depolymerization: Hydrolysis- The process of breaking apart polymer to form monomers by add (Enzymes catalyze the synthesis/Hydrolysis) Depolymerization: Hydrolysis- The process of breaking apart polymer to form monomers by add (Enzymes catalyze the synthesis/Hydrolysis) Protein Structure Primary Linear amino acid chain Secondary a-helix b-sheet through hydrogen bonding Tertiary Folding of the polypeptide into a 3D structure determined by chemistry of amino acid sidechain Quaternary Assembling with other proteins to into a complex Amino acids- Nitrogen, mildly acidic R= Sidechain Sidechain properties define the chemistry of proteins Protein Structure- Amino acids are linked by covalent bonds called peptide bonds Proteins aka polypeptides Cell Theory Core principles: All organisms composed of one or more cells The cell is the basic structural unit of life Cells arise only from the division of preexisting cells Why Cells are so small: Surface area must be sufficient to allow exchange of stuff between the cell and its surro Larger volumes require more surface area to achieve this Larger volumes need more structural support If the cell requires a large surface area they will devolved convoluted/Branchy surface m If the cell requires larger volume the use cell walls Miscopy Resolution- the ability of a microscope to distinguish two objects as being separate Magnification - Increases resolution Contrast- gives more detail but cant increase resolution Light Microscopy Reflected light Stereo microscope (dissecting) Lighting from top Can see bigger cells Transmitted light Stereoscopes ( some can also use light from bottom Compound microscopes Brightfield- Darkfield, Phase contrast, Differential Interference Contrast(DIC) - (Contrast-enhancing methods. They exploit the light scattering properties of specimens. Vari how light passes through it. ) Brightfield- ones in lab, staining often required to see more detail Darkfield- illuminates sample at an angle so that light does not hit the objective lenses direct sample reaches the objective lenses Phase contrast- This method creates slight phase shifts in the illumining light, which manifest DIC- Similar concept to phase contrast and gives a psuedo-3D appearance Fluorescence -Utilizes fluorophores to visualize specific structures by emitting light whe of live specimens and specific cellular components 1. Electron absorbs a photon and gets excited to a higher energy state (valance) 2. Excited electron returns to its ground state releasing a photon of longer wavelength (lo Electron Microscopy(EM) -provides a high resolution due to the shorter wavelengths of elect stained w heavy metals that electrons cant pass through Transmission Electron Microscopy Thin sections of specimens are imaged creating 2D images with high detail Scanning Electron Miscopy Visualizes 3D surface contours of specimens usually at lower magnifications Electron Microscopy(EM) -provides a high resolution due to the shorter wavelengths of elect stained w heavy metals that electrons cant pass through Transmission Electron Microscopy Thin sections of specimens are imaged creating 2D images with high detail Scanning Electron Miscopy Visualizes 3D surface contours of specimens usually at lower magnifications Prokaryotes Vs Eukaryotes Type Prokaryotes Eukaryotes Examples Bacteria, Archaea Animals, Plants Fun DNA DNA found in Nucleoid DNA housed in n Organization Single, circular chromosome and often several One or more line circular plasmids Basic Usually unicellular some multi Usually multicellu differences Small (1-3 micrometres) Small to very larg No membrane bound organelles Membrane boun Nucleoid Nucleus Single circular chromosome and plasmids Linear DNA chrom Similarities Plasma membrane cytoplasm ribosomes and cytoskeleton. Elements common to all living things Genetic information paradigm: DNA-RNA-Protein  Plasma membrane Structure- Phospholipid bilayer + thousands pf proteins embedded within Regulates the entry and exit of substances. Cytoplasm Consists of cytosol and organelles. Cytosol is the aqueous liquid- mostly water, full of macromolecules and smaller molecules lik Ribosomes Highly organized machined consisting of proteins and rRNA. Its actually more like an enzyme Reads the sequence or mRNAs to coordinate their translation into proteins Prokaryotic ribosomes are a bit smaller but do the same thing Translation of mRNA into protein by ribosomes takes place in the cytoplasm