Ch 4 Chemicals Of Life PDF

CH 4 THE CHEMICALS OF LIFE  WATER- WHY IS IT IMPORTANT TO ORGANISMS? WATER IS A GOOD SOLVENT (NEED TO KNOW THE FOLLOWING EXAMPLES FOR EXAM) - PROVIDES A MEDIUM FOR METABOLIC REACTIONS TO OCCUR (THE REACTANTS NEED TO BE DISSOLVED IN WATER FOR REACTIONS TO OCCUR) - SUBSTANCES LIKE GLUCOSE ARE D...

CH 4 THE CHEMICALS OF LIFE  WATER- WHY IS IT IMPORTANT TO ORGANISMS? WATER IS A GOOD SOLVENT (NEED TO KNOW THE FOLLOWING EXAMPLES FOR EXAM) - PROVIDES A MEDIUM FOR METABOLIC REACTIONS TO OCCUR (THE REACTANTS NEED TO BE DISSOLVED IN WATER FOR REACTIONS TO OCCUR) - SUBSTANCES LIKE GLUCOSE ARE DISSOLVED IN WATER OF THE BLOOD PLASMA SO THEY CAN BE TRANSPORTED AROUND THE BODY. - WATER IS NEEDED TO DISSOLVE NUTRIENTS AND ENZYMES IN THE ALIMENTARY CANAL FOR DIGESTION - WASTE PRODUCTS FILTERED BY THE KIDNEYS SUCH AS UREA ARE DISSOLVED IN WATER TO FORM URINE AND EXCRETED FROM THE BODY. IMPORTANT FOR EXCRETION.  ADDITIONAL IMPORTANT PROPERTIES OF WATER ? Property Importance Good solvent -Substances dissolve in water and are carried around the organism via transport systems - Provides a medium for chemical reactions (metabolic reactions) to take place Reactivity -Takes part in many chemical reactions e.g. photosynthesis, hydrolysis High latent heat of vapourisation -Lot of heat energy is absorbed as water evaporates from the body surface - Acts as a cooling agent e.g. cooling from evaporation of sweat High specific heat capacity - Requires lot of energy to change the temp. of water - Hence thermally stable. Thermal stability is important for enzymatic reactions Incompressible -Provides turgor pressure in plant cells for support High density - Provides buoyancy for aquatic organisms  BIOLOGICAL MOLECULES CARBOHYDRATES LIPIDS PROTEINS  CARBOHYDRATES MADE OF 3 TYPES OF ATOMS - CARBON (C) - HYDROGEN (H) - OXYGEN (O) THE RATIO OF HYDROGEN ATOMS TO OXYGEN IS 2:1 NAMES GENERALLY END IN (OSE)  TYPES OF CARBOHYDRATES CARBOHYDRATES CAN BE CLASSIFIED INTO 3 TYPES DEPENDING ON THEIR LEVEL OF COMPLEXITY - MONOSACCHARIDES Increasing - DISACCHARIDES complexity - POLYSACCHARIDES  MONOSACCHARIDES (SIMPLE SUGARS) - MOST BASIC TYPE OF CARBOHYDRATE (SMALL) EXAMPLES: GLUCOSE, FRUCTOSE, GALACTOSE - SOLUBLE IN WATER - TASTE SWEET  GLUCOSE 2 Hydrogen atoms for every 1 oxygen atom GLUCOSE MOLECULAR FORMULA: C6H12O6 MOLECULAR FORMULA SHOWS NUMBER OF ATOMS OF EACH ELEMENT IN ONE MOLECULE (CARBON X 6, HYDROGEN X 12, OXYGEN X 6) CARBON ATOMS ARRANGED IN RING WITH ATTACHED HYDROGEN AND OXYGEN ATOMS STICKING OUT * Extra info not in exam *Ethylene glycol 6’ 5’ Hydrogen *Hydroxide Carbon 4’ 1’ *Oxhydride 3’ 2’  DISACCHARIDES TWO MONOSACCHARIDES (SIMPLE SUGARS) JOINED TOGETHER FORM A DISACCHARIDE EXAMPLES: SUCROSE (TABLE SUGAR) =(GLUCOSE + FRUCTOSE) MALTOSE= (GLUCOSE + GLUCOSE) LACTOSE= (GLUCOSE + GALACTOSE) SOLUBLE IN WATER & TASTE SWEET  SUCROSE (C12H22O11) Glucose Fructose  POLYSACCHARIDES (COMPLEX SUGARS) MANY SIMPLE SUGARS (MONOSACCHARIDES) JOINED TOGETHER TO FORM A POLYSACCHARIDE EXAMPLES: CELLULOSE Many Glucose molecules joined STARCH together GLYCOGEN - INSOLUBLE - DO NOT TASTE SWEET CELLULOSE  FUNCTION OF CARBOHYDRATES REQUIRED FOR ENERGY 1GRAM OF CARBOHYDRATE CAN RELEASE 17KJ OF ENERGY ENERGY IS RELEASED BY RESPIRATION GLUCOSE IS THE CARBOHYDRATE USED FOR RESPIRATION  FUNCTION OF CARBOHYDRATES IN ANIMALS GLUCOSE IS CONTAINED IN BLOOD PLASMA WHICH IS DELIVERED TO ALL CELLS PLANTS TRANSPORT SUCROSE AROUND THEMSELVES INSTEAD OF GLUCOSE. THEIR CELLS CHANGE THE SUCROSE TO GLUCOSE WHEN THEY NEED TO USE IT PLANTS STORE CARBOHYDRATES AS STARCH. THE STARCH CAN BE EASILY CONVERTED TO GLUCOSE WHEN NEEDED AND VICE VERSA. ANIMALS DO NOT STORE CARBOHYDRATES AS STARCH BUT AS GLYCOGEN (A POLYSACCHARIDE) Starch can be stored in large quantities in plant seeds or tubers Tuber Seeds  TEST FOR CARBOHYDRATES: BENEDICT'S SOLUTION BENEDICT'S SOLUTION TO TEST FOR REDUCING SUGARS (TYPE OF SUGAR) EXAMPLES: ALL MONOSACCHARIDES (E.G. GLUCOSE) SOME DISACCHARIDES (E.G. MALTOSE) WHEN HEATED WITH A REDUCING SUGAR, BENEDICT’S SOLUTION GRADUALLY TURNS FROM BLUE TO BRICK RED ORDER OF COLOUR CHANGE: BLUE🡪 GREEN🡪 YELLOW🡪 ORANGE🡪 BRICK RED BENEDICT'S SOLUTION COLOUR CHANGE  TESTING FOOD FOR REDUCING SUGARS 1. CUT/GRIND THE FOOD BEING TESTED INTO SMALL PIECES AND PUT IT INTO A TEST TUBE 2. ADD WATER TO THE TEST TUBE AND MIX THEM TOGETHER SO THE FOOD DISSOLVES INTO THE WATER 3. ADD AN EQUAL AMOUNT OF BENEDICT’S SOLUTION TO THE MIX 4. PLACE THE TEST TUBE INTO A WATER BATH AT 80 DEGREES CELSIUS 5. WAIT FOR 5 MINUTES THEN RECORD THE COLOUR OF THE SOLUTION AND INDICATE IF THERE IS A PRESENCE OF REDUCING SUGAR  REDUCING & *NON-REDUCING SUGARS EXAMPLES REDUCING SUGARS NON-REDUCING SUGARS (CAN USE BENEDICT’S TEST) (CANNOT USE BENEDICT’S TEST) MALTOSE SUCROSE LACTOSE ALL POLYSACCHARIDES ALL MONOSACCHARIDES -GLUCOSE - CELLULOSE -FRUCTOSE - GLYCOGEN -GALACTOSE - STARCH  TEST FOR CARBOHYDRATES: IODINE SOLUTION IODINE SOLUTION IS USED TO TEST FOR STARCH IF STARCH IS PRESENT, IODINE SOLUTION TURNS FROM BROWN TO BLUE/BLUE BLACK No starch Starch present present  FATS (LIPIDS) FATS ARE ALSO KNOWN AS LIPIDS CONTAIN 3 TYPES OF ATOMS: - CARBON - HYDROGEN - OXYGEN LIPIDS ARE INSOLUBLE IN WATER LIPIDS THAT ARE LIQUID AT ROOM TEMP. ARE CALLED OILS  FATS (LIPIDS) A LIPID MOLECULE IS MADE UP OF 4 SMALLER MOLECULES: THREE FATTY ACIDS ATTACHED TO ONE GLYCEROL MOLECULE  FATS(LIPIDS) & OILS USES FATS & OILS CAN BE USED IN CELLS TO RELEASE ENERGY 1 GRAM OF FAT GIVES 39KJ (KILOJOULES) OF ENERGY (MORE THAN TWICE AMOUNT OF CARBOHYDRATES) CELLS WILL GENERALLY USE CARBOHYDRATES FIRST BEFORE RELEASING ENERGY FROM FATS & OILS  FATS(LIPIDS) & OILS USES DUE TO THE LARGE AMOUNT OF ENERGY STORED IN FATS, THEY ARE OFTEN USED AS A ENERGY STORAGE IN MAMMALS CELLS UNDERNEATH THE SKIN CAN BE FILLED WITH FATS AND OILS AS AN ENERGY STORAGE. THIS LAYER OF CELLS (ADIPOCYTES) IS KNOWN AS ADIPOSE TISSUE  ADIPOSE TISSUE Adipocytes/lipocytes epidermis dermis Adipose tissue  ADIPOSE TISSUE AND OILS ADIPOSE TISSUE CAN ALSO BE USED TO KEEP THE BODY WARM (ACT AS INSULATION) ANIMALS LIVING IN COLD ENVIRONMENTS HAVE A THICK LAYER OF ADIPOSE TISSUE CALLED BLUBBER (E.G. WALRUSES, WHALES) PLANTS ALSO STORE OILS IN THEIR SEEDS TO PROVIDE THEM ENERGY FOR GERMINATION (E.G. PEANUT, COCONUT OIL)  TEST FOR FATS(LIPIDS): ETHANOL EMULSION TEST WE USE AN ETHANOL EMULSION TEST TO TEST FOR LIPIDS STEPS: 1- CUT UP THE FOOD TO BE TESTED INTO SMALL PIECES 2- MIX THE FOOD PIECES WITH ETHANOL IN A TEST TUBE (FAT WILL DISSOLVE IN ETHANOL BUT NOT WATER) 3- ADD WATER TO THE SOLUTION 4- THE WATER WILL BREAK-UP THE FAT/ETHANOL SOLUTION INTO SMALL TINY DROPLETS TURNING THE SOLUTION A MILKY WHITE COLOUR. THIS WATER-ETHANOL MIXTURE IS CALLED AN EMULSION  ETHANOL EMULSION TEST If lipids are present, a white cloudy emulsion is formed when water is added to the mix If lipids are absent, the mix remains clear. Positive test results: Presence of lipids  TEXTBOOK QUESTIONS PAGE 45 4.7 WHICH THREE ELEMENTS ARE FOUND IN ALL FATS AND OIL? 4.8 STATE TWO USES OF FATS AND OILS TO LIVING ORGANISMS 4.9 WE GET COOKING OIL MOSTLY FROM SEEDS OF PLANTS. WHY DO PLANT SEEDS CONTAIN OIL?  PROTEINS MADE UP OF: CARBON (C) OXYGEN (O) Main components of protein HYDROGEN (H) NITROGEN (N) *SULPHUR (S) (*SMALL AMOUNTS)  PROTEINS PROTEINS ARE MADE UP OF LONG CHAINS OF SMALLER MOLECULES CALLED AMINO ACIDS JOINED END TO END AMINO ACIDS ARE HELD TOGETHER IN PROTEINS BY PEPTIDE BONDS  AMINO ACIDS THERE ARE AROUND 2O DIFFERENT AMINO ACIDS THESE AMINO ACIDS CAN BE ARRANGED IN ANY ORDER TO MAKE A PROTEIN EACH PROTEIN HAS A SPECIFIC ARRANGEMENT OF AMINO ACIDS A CHANGE IN ORDER WILL RESULT IN A DIFFERENT PROTEIN  FUNCTIONS OF PROTEINS SOME PROTEINS ARE SOLUBLE IN WATER (E.G. HEMOGLOBIN, FOUND IN RED BLOOD CELLS) AND SOME ARE INSOLUBLE (E.G. KERATIN, A PROTEIN FOUND IN HAIR & NAILS) PROTEINS ARE USED TO MAKE: -NEW CELLS -REPAIR CELLS -ANTIBODIES -ENZYMES Cell membrane contains a lot of proteins as well as the cytoplasm  FUNCTION OF PROTEINS: ANTIBODY ANTIBODIES ARE MADE OF PROTEIN THEY HELP IDENTIFY FOREIGN INVADERS TO THE BODY (ANTIGENS) SO THAT THEY CAN BE DESTROYED Antigen binding site has to be specific shape to bind to the specific antigen  FUNCTION OF PROTEINS: ENZYMES PROTEINS ARE ALSO USED TO MAKE ENZYMES THEY ARE BIOLOGICAL CATALYSTS THAT HELP INCREASE THE RATE OF METABOLIC REACTIONS IN THE BODY Enzyme active site needs to be specific shape to fit the specific substrate  FUNCTION OF PROTEINS - AS PROTEINS ARE MADE OF LONG CHAINS OF AMINO ACIDS, THEY CAN CURL INTO 3-D DIFFERENT SHAPES - THE WAY A PROTEIN MOLECULE CURLS AND THE 3-D SHAPE IT FORMS IS DETERMINED BY THE SEQUENCE OF ITS AMINO ACIDS - THE SHAPE DIRECTLY AFFECTS THEIR FUNCTION E.G. SHAPE OF ENZYMES ALLOWS IT TO BIND TO DIFFERENT SUBSTRATES SHAPE OF ANTIBODY DEPENDS WHICH ANTIGENS IT CAN BIND TO PROTEIN 3D STRUCTURE 3D structure of protein (antibody)  TEST FOR PROTEINS: BIURET TEST WE USE THE BIURET TEST TO TEST FOR THE PRESENCE OF PROTEINS FOOD IS MIXED IN WATER AND COPPER SULFATE IS ADDED, FOLLOWED BY DILUTE POTASSIUM HYDROXIDE OR WE ADD A READY-MIXED REAGENT, BIURET REAGENT (COPPER SULFATE AND DILUTE POTASSIUM HYDROXIDE PRE-MIXED) TO THE FOOD-WATER MIX TEST FOR PROTEINS: BIURET TEST (RESULT) VIDEO: FOOD TESTS FOR CARBOHYDRATES, PROTEINS & LIPIDS HTTPS://WWW.YOUTUBE.COM/WATCH?V=SQWTJWOBWW4 TEXT BOOK QUESTIONS PAGE 46 , S* (trace amount only)  DNA DNA – DEOXYRIBONUCLEIC ACID DNA IS THE GENETIC MATERIAL INHERITED FROM OUR PARENTS DNA MAKES UP GENES AND CHROMOSOMES MANY OF OUR CHARACTERISTICS ARE DETERMINED BY OUR DNA  3-D Double helix shape DNA: STRUCTURE Bases - DNA is made of two long strands with a series of bases arranged along it. - These bases are held together by hydrogen bond cross links - The two strands twist together to form a 3-D double helix shape  DNA: BASES (A, T, G, C) DNA HAS 4 BASES * (ONLY NEED TO KNOW THE LETTER FOR EACH BASE) - ADENINE (A) A & T always pair up - THYMINE (T) - GUANINE (G) G & C always pair up - CYTOSINE (C) THE SEQUENCE OF BASES PROVIDES CODE TO DETERMINE WHICH PROTEINS ARE PRODUCED BY OUR CELLS. THIS DETERMINES HOW OUR CELLS & ORGANS DEVELOP. (I.E. THE KIND OF ORGANISM WE ARE, MANY CHARACTERISTICS SUCH AS HAIR, EYE COLOUR, BLOOD TYPE)  TEST FOR VITAMIN C: DCPIP TEST TO TEST FOR THE PRESENCE OF VITAMIN C IN FOOD, WE PERFORM THE DCPIP TEST DCPIP SOLUTION IS BLUE🡪 IN THE PRESENCE OF VITAMIN C IT BECOMES COLOURLESS ADD FEW DROPS OF THE SOLUTION YOU WISH TO TEST TO A TEST TUBE OF DCPIP SOLUTION, THE HIGHER CONCENTRATION OF VITAMIN C, THE FEWER DROPS IT TAKES TO DECOLOURISE THE DCPIP SOLUTION  VIDEO OF ALL FOOD TESTS HTTPS://WWW.YOUTUBE.COM/WATCH?V=SLP8DCNWNJG (3:55 FOR DCPIP TEST) END-OF-CHAPTER QUESTIONS (TEXTBOOK PAGE 48)