Ch 5 Biomolecules Lifes 4 large molecules carbohydrates

Ch. 5 -Biomolecules. Life’s 4 large molecules carbohydrates lipids proteins nucleic acids

5. 1 Organic Molecules n Carbon: 4 e- in highest energy field n n n Carbon shares electrons with other atoms Carbon can form up to 4 bonds with other atoms Carbon based molecules – organic Non carbon based molecules- inorganic Biomolecules have a backbone of carbon atoms

3 carbon backbone shapes

Carbon can bond to other atoms: n n. Functional groups- groups of atoms that react a certain way in a molecule n. Affects properties of the molecule. n. OH- hydroxyl groups make water loving-hydrophilic molecules n. Water- fearing molecules are hydrophobic. n. Hydrocarbons- carbon bonded to hydrogen n. Fuels- CH 4 methane nfat storing molecules Other atoms- oxygen & nitrogen

Functional groups n -OH hydroxyl group- n n n COOH- carboxyl group n n Fatty acids & proteins NH 2 - amino group n n Attracts water- hydrophilic- water-loving Alcohols & carbohydrates Proteins & Nucleic acids C=O- carbonyl group n Aldehydes & ketones

4 categories of biomolecules n n Carbohydrates- sugars Lipids- fats & oils Proteins Nucleic Acids- DNA & RNA

Building Blocks n Monomer- literally “one part” n n Polymer- literally “many parts” n n n The smaller building blocks Composed of many monomers Example- starch is the polymer composed of thousands of ______ monomers Every cell has thousands of different polymers, each has a different function.

Building Polymers n When 2 monomers are added to form a polymer - water is lost n Dehydration reaction

Breaking down polymers n When a polymer is broken down into smaller monomers -water is added n Hydration reaction- hydrolysis

5. 2 - Carbohydrates n n n Provide energy. Sugars- simple to complex. Contains carbon, hydrogen, and oxygen. n n Ratio of 1 carbon: 2 hydrogen: 1 oxygen. General Formula- CH 2 O ; ex. Glucose C 6 H 12 O 6. Functional group=Hydroxyl group- OH. n n n Hydrophilic- water-loving. Simple Sugars dissolve in water. Absorbancy of cotton.

Functional Groups:

Monosaccharidesn n n n Simple sugars. Mono= One sugar unit. Ex. Glucose, fructose, and galactose. Suffix (ending)- ose. Ring-shaped form. Glucose- main fuel for cellular work. Unused glucose starch, glycogen, or fat molecules.

Figure 5 -6 The complete structural diagram of the monosaccharide glucose (left) shows all its atoms. The simplified representation (right) shows just the core ring formed by some of the carbon and oxygen atoms. Ring shapes are common in sugar molecules found in nature.

Disaccharides n n “Double”; two monosaccharides combined. Dehydration reaction - building. Ex. Sucrose- table sugar.

Polysaccharides n n Polymer chain ; many sugar monomers. Starch- plant cells. -potatoes, corn, rice n n n Glucose monomers. Digested by humans Cellulose- plant cells n n n Glucose monomers Building material- protects, support. Celluose=Fiber- necessary; not a nutrient. Not digested by humans Cows and termites digest cellulose.

n Glycogen- Animal Cells n n Glucose monomers Storage of excess sugar Liver and muscle cells Breakdown of glycogen releases glucose.

5. 3 Lipids- Fats & steroids n Lipid n n n Hydrophobic-”water fearing” Boundary in cell membrane Fat- n n n Glycerol- 3 C backbone 3 fatty acids- long hydrocarbon chains Functional group- carboxyl group

Saturated Fat vs. Unsaturated Fat n n Saturated- all 3 fatty acid chains are filled with hydrogen atoms. Ex, animal fats- lard and butter n n Solids at room temp Unsaturated Fats- not all places are filled with hydrogen atoms n n n Found in fruits, vegetables, & fish Corn, olive & vegetable oils Liquid at room temp.

Figure 5 -9 Certain vegetable oils contain unsaturated fat molecules, which have at least one double bond in at least one of the fatty acid chains. In this case, the double bond is located about halfway along the bottom chain.

Steroids & Cholesterol n Steroid- lipid with 4 fused carbon rings. n n Steroids differ in types and locations of functional groups. Cholesterol- essential for membrane function n Used to produce steroids in the body

Figure 5 -10 The only difference in these two steroid hormones is the location of their functional groups. Yet, these two molecules contribute to major differences in the appearance and behavior of male and female mammals.

5. 4 Proteins n n Perform most cell functions Polymer of amino acids Polypeptide=chain of amino acids Amino Acidn n n Proteins- made in the ribosomes n n Functional group-NH 2 Monomer Proteins have a specific shape in order to work correctly. Denaturation- unraveling- changes the shape of the protien- caused by changes in p. H and temperature. n n If the protein does not have the right shape it does not work properly. Lego activity.

Figure 5 -12 All amino acids consist of a central carbon bonded to an amino group, a carboxyl group, and a hydrogen atom. The fourth bond is with a unique side group. The differences in side groups convey different properties to each amino acid.

Figure 5 -13 The order of amino acids makes each polypeptide unique. There are 129 amino acids in this protein, called lysozyme. The three-letter symbols are abbreviations for the amino acid names.

5. 5 Enzymes n n n Speed up “catalyze” reactions in cells. Lower the energy needed for a reaction to occur. Activation Energy- start-up energy needed for a chemical reaction. Catalyst- speed up reactions Enzyme- special protein n n Suffix- ending- ase Ex. amylase, catalase Substrate-( what is being acted on) binds to the enzyme. Active site- substrate-enzyme binding region

Figure 5 -15 The activation energy barrier is like a wall between two parts of a pond. If an enzyme lowers the wall, more frogs have enough energy to reach the other side.

Figure 5 -16 A substrate binds to an enzyme at an active site. The enzyme-substrate interaction lowers the activation energy required for the reaction to proceed. In this example, water is added to the weakened bond in sucrose, breaking sucrose into glucose and fructose.