Ch1 lecture bio.pdf

1. What does a pH scale measure? Measure of hydrogen ion concentration in solution; indicate alkalinity(basic) and acidity in solution What is an acid? More H+ than OH- pH 7 a neutral solution? Same amount H+ and OH- ; pH:7 What is the pH of pure water? pH7 What is a buffer and how does it work? Buf...

1. What does a pH scale measure? Measure of hydrogen ion concentration in solution; indicate alkalinity(basic) and acidity in solution What is an acid? More H+ than OH- pH 7 a neutral solution? Same amount H+ and OH- ; pH:7 What is the pH of pure water? pH7 What is a buffer and how does it work? Buffers resist change in pH due to combining with or releasing hydrogen ions. Ex. bicarbonate/carbonic acid system maintain a blood pH 7.4 5. What are the 4 classes of the “molecules of life”? Carbohydrates-energy source to cells Subunits: (carbon hydrogen oxygen) Lipids- energy source/ storage, structure Subunits: (carbon hydrogen oxygen) Proteins-aid in structure and function of body (carbon, hydrogen, oxygen nitrogen) Major types: Structural protein-provide support Storage protein-provide amino acids for growth Contractile protein-help movement Transport protein-help transport substances Enzymes-help chemical reactions Nucleic acids- carry genetic info; direct cell function by control protein synthesis; ATP-transfer energy within cell DNA structure-nucleotide->phosphate group, nitrogen base, and deoxyribose sugar (A-T,C-G) RNA nucleotide->phosphate group, nitrogen base, and ribose sugar (A-U, C-G) 6. What is a monomer and polymer? Monomer: small group of atoms or molecule Polymer: many monomers Explain how dehydration and hydrolysis reactions occur. Dehydration: “Remove water to bond together” when the molecules gives up Hydrogen atom then bind with hydroxl (OH) given up by second molecule to form water Hydrolysis: break of water when hydrogen atom is added (opposite to dehydration) Water attacks a chemical bond betw. 2 molecules causing a break. The resulting molecules have extra molecules that bind to water molecule and split it, with H binding to one and OH- binding to other 7. For carbohydrates, classify these as monosaccharides, disaccharides, or polysaccharides: Monosaccharide: glucose, fructose, ribose, deoxyribose Disaccharides: sucrose, lactose, maltose Polysaccharides: starch, glycogen 8. Trace the pathway by which consumed food becomes energy for cellular work. Spaghetti has starch and digestion occurs. Glucose supplies your body and cellular respiration requires oxygen stored energy to high energy ATP (trigger ATP and Pi) -> chemical bond breaks to ADP to Pi ->release energy->use for cellular work. cycle repeats 9. What is the major characteristic of lipids? Lipids are hydrophobic-this means that fats are nonpolar and do not mix with water 10. List the 3 types of lipids. What are the subunits for a fat/triglyceride? What is the energy efficiency of a fat compared to a carbohydrate? Lipids: Phospholipids-forms membranes, steroids-some hormones, fats or triglycerides-store energy efficiently, compose glycerol and 3 fatty acids fats/triglycerides subunits-Carbon hydrogen oxygen -Fat supplies more energy than supplied by carbohydrates. Meaning fat has most energy efficient since takes longer for energy to take into your body 11. What is the general structure of an amino acid. How do 2 amino acids bond together? Hydrogen bond with 2 components: amine group (-NH2) and acid group (-COOH) And the only differentiate group is R group which creates different amino acid This is joined with Peptide bond 12. How is a protein’s shape related to its function? What is denaturation? What are the 2 overall structures of proteins? Shape determines function Denaturation refers to the process where a protein or nucleic acid loses its natural structure due to external factors, like changes in temperature, pH, or chemical exposure. For proteins, denaturation usually means the loss of the three-dimensional structure that is crucial for their function, which often leads to loss of biological activity. For nucleic acids like DNA, denaturation typically involves the separation of the double-stranded structure into single strands. For example, when you cook an egg, the heat causes the proteins in the egg white to denature, changing from a clear, liquid state to a white, solid state. In molecular biology, denaturation of DNA is an essential step in processes like PCR (Polymerase Chain Reaction), where the double-stranded DNA is heated to separate into single strands before being replicated. (question about this) Primary structure: sequence amino acids formed w peptide bond Secondary-amino acids form hydrogen bonds between polar parts of polypeptide causing various areas of molecules to twist (helix) or fold (pleated sheet) 13. Describe what enzymes are and what they do. Why are they necessary for life? Enzymes are globular proteins speed up (catalyze) reactions Make reaction and metabolism happen faster. This specificity ensures that enzymes catalyze only the intended reactions, which helps maintain proper metabolic pathways and prevents unwanted side reactions. 14. How are enzymes affected by pH and temperature? What happens when an enzyme is at its optimal temperature and pH? How can enzymes be inhibited? pH: Enzymes have an optimal pH range and are sensitive to deviations from this range. Extreme pH values can lead to changes in the enzyme’s charge distribution, altering its structure and reducing its activity or causing denaturation. Temperature: Enzymes have an optimal temperature range. Low temperatures reduce activity by decreasing molecular movement, while high temperatures can increase activity up to a point but can cause denaturation if temperatures are too high. An enzyme inhibitor stops ("inhibits") this process, either by binding to the enzyme's active site (thus preventing the substrate itself from binding) or by binding to another site on the enzyme such that the enzyme's catalysis of the reaction is blocked. Enzyme inhibitors may bind reversibly or irreversibly 15. Give two examples of nucleic acids. DNA contain genetic info RNA carries coded instructions from dna to cellular machinery for protein synthesis 16. What are the 3 components of a nucleotide? Which part carries the genetic information? 5 carbon sugar, phosphate group, and nitrogenous base (carries genetic info) 17. What are 4 different DNA nitrogen bases and which ones bond together? Adenine (A) pairs w Thymine (T) & Cytosine (c) pairs w guanine (G) vice versa 18. What type of bond holds the 2 strands of DNA together? Hydrogen bond 19 What is chromosome and gene? Chromosomes-coiled structures consist of DNA and proteins(consist of many genes) Genes-section of DNA that codes for protein in chromosomes 20 Compare and contrast structure of DNA to RNA Single strand of nucleotides nucleotides are same except for uracil replaces thymine Double stranded sugar phosphate than single stranded sugar phosphate 21 cell structures and functions Nucleus control center Mitochondria sites of aerobic respiration that form ATP breakdown nutrients smooth ER/rough ER-support cytoplasm channels for material transport; protein and lipid synthesis Golgi-packs and sorts substances in vesicles for export from cell or use within cell; forms lysosomes Lysosome-digest foreign substances Ribosomes sites of protein synthesis Vesicles-transport and store substances Peroxisome-their enzymes break down fatty acids and amino acids. (think of hydrogen peroxide) Nucleolus-consist of RNA and protein site of ribosomal production Cytoskeleton-proteins that function in support, cell shaping and movement of substances in cell Microvilli-increase surface area Flagellum-enable movement of sperm Cilia-move materials along free surface of cell ​ What is the cell membrane composed of? Phospholipid bilayer, proteins, and cholesterol Describe the structure of a phospholipid. There is hydrophilic head, hydrophobic tails (make up 2 fatty acids, saturated and unsaturated)  Which substances does the cell membrane allow to pass through? What type of substances are blocked by the cell membrane? Pass thru: Small Nonpolar molecules O2, Co2, and N2 Blocked: Ions (Na+, K+, Cl-), large uncharged polar molecules (glucose and sucrose), small uncharged polar molecules (H2O, NH3, glycerol) Distinguish between passive transport and active transport. Passive transport high to low conc. with no energy req but active move against conc gradient low to high so needs energy  Explain how simple diffusion, facilitated diffusion, osmosis, and filtration occurs. Simple diffusion movement of molecules from high to low concentration Facilitated diffusion movement of substance down its concentration gradient through protein transport Osmosis- diffusion of water across semi permeable membrane Filtration small substances moved across membrane by physical force Ex. blood pressure forces substances to move into kidney tubules Define: hypertonic, hypotonic, and isotonic. Under what conditions does the cell lose or gain water? Hypertonic-the high concentration is outside the cell and water in cell moves out so cell lose water therefore cell shrinks Ex. drink seawater cell is surrounded w too much salt Na+ Cl- cannot diffuse into cell bc charges are unequal -water has to diffuse out cell to reach equilibrium Hypotonic - high concentration of molecules inside cell so water is going to move into the cell And cell gain water therefore cell will be grow big that it could pop Isotonic neutralizes solution so there is water move out and come into cell Explain how the sodium/potassium (Na+/K+) works. Why does it require energy? Binding on intracellular part of cell has binding room for 3 Na+ In ATP transfer phosphate to the protein pump this changes shape of protein and protein opens from extracellular so 3 Na+ ions moves out (due to break in ATP the energy release as ADP) and then 2 binding room for 2 K+ and once 2K+ bind the phosphate group detaches. Reverts back to its original position and opens into the intracellular site and 2K+ dropped off inside the cell. Once again there is space for 3 Na+ ions. The cycle repeats Binding of ATP to pump 3 Na+ goes in then then 2 K+ goes out And phosphate leaves ATP needed to bring these substances against concentration gradient  Describe endocytosis and exocytosis. Endocytosis eating so membrane is going to fold droplets enter and pinch that becomes vesicles Phagocytosis wbc lysosome digest Exocytosis is vesicle is going to exit fold membrane and vesicle disappear and with droplets particles released