Biology Notes PDF

Ch2 : cells as the basic unit of life Inorganic ① Water medium for chemical...

Ch2 : cells as the basic unit of life Inorganic ① Water medium for chemical : reactant photosynthesis in : reactions medium of transport cooling agent Turgid cells · => provides support/stay upright component of lubricant (pleural fluid) ② Nitrate (NO3] :· source of nitrogen turns into protein in plants ③ Magnesium : · Component ofchlorophyll : activates enzymes ④ Iron of component haemoglobin activates : enzymes ⑤ Calcium component of bones & teeth blood contraction clotting muscle : sending system · in nervous messages · strengthens cell wall ⑥ Phosphate : component of bones & teeth · components of phospholipids => cell membrane & nucleic acids Organic (all contain carbon) biomolecule ① Carbohydrates : · Glucose : energy source for cells (directly broken downin respiration) Starch : for energy reserve plants Glycogen : energy reserve for animals Cellulose : component of cell wall · ② Lipids Triglyceride adipose tissues protect internal : · reduce heat loss , : energy reserve , organs · Phospholipids component : of cell membrane ③ Proteins : · body tissues · enzymes (regulate chemical reactions) hormones (regulate body processes) antibodies transport of substances Chaemoglobin oxygen) · carries ④ Nucleic acids : · DNA : genetic informationE> control activities & determine features ( V. RNA : synthesis of proteins deoxyribonucleicd> ribonucleic acid Cell theory (Schwann) 1 All made of cells organisms are up 2 Cell => basic unit of life 3 Cells come from pre-existing cells  Microscopes I I I Light microscope Electron microscope Source Light Electron beam Images Coloured Black and white Advantage of light microscope : live specimen , prepared easily Transmission EM : 2-D images showing internal structures Scanning EM : 3-Dimages showing external structures Advantage of EM : higher magnification & resolution (clearer with more details) Eyepiece magnifying lens which : the eye looks through Body tube holds eyepiece and : nose piece Nosepiece rotate => switch objective : Objective magnifying : less pointing at specimen Condenser : focuses light Diaphragm adjusting : amount of light Arm : hold the microscope Course/Fine adjustment Knob : raise / lower stage > - rough/sharp focus Stage : clip slide Base : support the microscope Magnification Low-power Larger : area , Less details , Brighter image High-power : Smaller More Dimmer Total Magnification Eyepiece = X Objective  Cells Plant cells than that of a n animal cell are generally larger and have a more regular shape ① Nucleus : · Vnuclear membrane · /DNA => control cell activities ~water and reactions ② Cytoplasm protein jelly-like fluid Vorganelles site for chemical · :. of phospholipids of substances ③ Cell proteins differentially permeable membrane : · made and control movement up ① Cell wall Thick& : Rigid made up of cellulose fully permeable protects supports gives shape to the cell · , , ⑤ ER network of : interconnected membrane-bounded # Rough ER attatch to nucleus # sacs Rough V ribosomes=> proteins endoplasmic reficulum : Smooth X ribosomes : make lipids , ⑥ Ribosome : X membrane , lie free/rough ER => protein , ② Mitochondrion : double membrane respiration powerhouse (energy &4) · highly-folded ⑧ Chloroplast double membrane green plant cells Vchlorophyll Starch grains · · · : · ⑦ Vacuole food large in plant cells cell sap provide support · Eukaryotic cells : / true nucleus Prokaryotic cells : smaller , X true nucleus · Cell wall X cellulose Cytoplasm X membrane-bounded organelles · · free DNA & ribosome unicellular Levels of organization Cells - Tissues > - Organs > Systems - > - Organisms Ch3 : Cell membrane Fluid Mosaic model flid Phospholipid molecules : bilayer , more laterally I Protein molecules : · attached to the surface embedded half-way spanthe entire bilayer , , interspersed among the phospholipid molecules in a mosaic pattern Phospholipids Glycerol phosphat a " fatty and molecules by Polar Hydrophilic Hydrophobic Head : points outwards in contact with the aqueous solutions environment Tail : points inwards , protected from contacting the aqueous Proteins O Channel Proteins > provide channels Diffusion charged particles - Ions, ② carrier proteins > bind &transport - Active transport ③ Receptors > - bind to chemical messengers Chormones) furn on activities ④ Antigen > - Glycoprotein for cell recognition ⑤ Enzymes > biological catalysts for reactions speeding up - Differential Permentality Non-polar - Hydrophobic core of bilayer < impermeable to polar substances Channel/Carrier proteins Temperature KEX- > pack less closely > more across more easily (Boiling damage->fully) · : - · Organic solvents : Dissolve > - damage > permeability ↑ - Fluidity More laterally > fluidin nature - => change shape & fuse (cell division , pseudopodium in phagocytosis) Diffusion Particles more randomly in all directions > distribute evenly (equilibrium/no not movement) - · Concentration gradient V: High-con > - Low-con · Passive does not , require energy => cells exchange materials (O2, CO2, nutrients) => Absorption of untrients in small intestine , gas exchange in longs Osmosis Solute - => Water pot ↓ ·. => Water moves from high water pot. to low water pot. (low-con to high-con) Passive, does not require energy * Highest water pot. = O KPa Hypotonic cell support the - plants X water > flacciel> droop - - => Absorption of waterin small intestine/soil into plant roofs Active transport active , Carrier proteins particles against the concentration gradient (low-con to high-con) Venergy · more * Usually high respiration rate with lots of Mitochondria E Absorption of nutrients in small intestine/minerals from soil to plantroots Phagocytosis · Take inlarge particles by packaging the particles into racuoles formed by coll membrane Pseudopodium surrounds particle vacuole formed fuse with vacuoles with digestine > - - > enzymes ) absorbed into the ↳ cytoplasm = Unicellular engulf food particles => nutrition => White blood cells engulf harful microorganisms > body defence Macrophages - Ch 4. Enzymes and Metabolism Metabolism Catabolism : Complex breakindoa > Simple E.. g Respiration : Glucose > - CO2 + +20 Anabolism : buildinga bed Complex Simple E. g. Photosynthesis : CO2+ H20 > Glucose - Energy level N & Enzymes act as biological catalysts and Lower the activationeny a > Time Enzymes * The active site specific shape specific substrate molecules > -> only - O Substrate molecules bind to the active site > - enzyme-substrate complex > - ↓ activation energy catabolism anabolism ② ↳ split into products/joined together ③ & leave the atire site ① Enzyme released inits original form to be reused · Biological catalysts > - ↓ activation energy > - speed up reaction · Specific in action : Unique active site > - Specific shape - Enzymes only catalyse one type of reaction * Lock-and-key hypothesis Enzymes proteins affected by temperature : and pH-> denature · are Enzymes are reusable : remain unchanged after reactions > - bind again ↳) needed in small amounts relatively Enzyme activity O Temperature : Low : Inactive (KEX , more slowly + chance of collision ↓) activity ↑ (KEY a subst rapidly + chance of collision ↑ enzyme- TM > - , more around more > - Optimum : Maximum at optimal temperature -45-50 % (diff enzyme. > - diff. optimum) (change in shape High : Denaturation (T &* > - conformational change of active site > denatured) - => Substrate no longer fit into the activesite + loses catalytic ability permanently ② Maximum at pH Optimum : : optimal pH -7 Low/High denaturation (activity & : , no longer fit, lose catalytic ability) enzymein ③ Inhibitors : Cyanide respiration > Heavy metals (Hgt Hight ppt cut) affect , , , metabolism Advantages Limitations Shorters production time X high temperature/unsuitable pH · clean E contaminated with inhibitors Lowers cost of production · · Fewer unwanted producte ·