Macromolecules. Large molecules made up of smaller building blocks or subunits. Chapter

Transcription

1 Macromolecules Large molecules made up of smaller building blocks or subunits Chapter

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3 Types of macromolecules Carbohydrates Lipids Proteins Nucleic acids

4 Carbohydrates Primary fuel source for cellular work Mostly made up of C, H, & O atoms same # of C atoms as H 2 O units glucose is C 6 H 12 O 6 (6 carbons & 6 H 2 O units) the C-H bonds store a great deal of energy & are easily broken by organisms Two kinds; based on size monosaccharides polysaccharides

5 Monosaccharides Monosaccharides = simple sugars 3 7 carbon atoms ex. glucose; in sap & fruit of many plants & fructose; primary sugar of fruits, veggies & honey When broken down, products are not sugars Glucose is the most important sugar in humans, most forms of carbohydrates converted to glucose in digestive tract then circulates in our blood; called blood sugar

6 Fate of glucose (blood sugar) Energy for cellular activity energy is released when bonds b/w atoms of glucose molecule are broken Short term storage stored in muscle & liver tissue as glycogen (a polysaccharide made up of lots of glucose molecules bound together) when energy needed, glycogen easily broken down into glucose molecules again Long term storage converted to fat

7 Polysaccharides Polysaccharides = complex carbohydrates Contain more than one sugar unit can be as many as 10,000 sugar molecules linked together Two functions storage glycogen in animals starchin plants structural support cellulose in plants chitinin insects, crustaceans, & fungi

8 Polysaccharides

9 In our diet... Simple sugars (like in fruit or candy) provide quick & short energy bursts Complex carbs (like in oatmeal or pasta) provide slow & steady energy release

10 Not all carbs are digestible Structural polysaccharides cannot be digested chitin cellulose in huge variety of plant structures single most prevalent molecule on earth! passes through our digestive tract as fiber termites have microorganisms in their gut that break down the cellulose & extract useable energy from it

11 Types of macromolecules Carbohydrates Lipids Proteins Nucleic acids

12 Lipids Diverse group of compounds with one common trait: they are all hydrophobic Many more C-H bonds than carbs & contain significantly more stored energy Types of lipids fat (triglycerides) sterols phospholipids waxes

13 Fats (triglycerides) The fat in most foods we eat solid at room temp = fat liquid at room temp = oil 3 fatty acid chains linked to a glycerol molecule Main function: energy storage also protection & insulation Two kinds of fat saturated unsaturated (in reality, there is a range)

14 Saturated fats fat molecule with the maximum # of H atoms most animal fats not essential to health Unsaturated fats missing H atoms; results in double bond between C atoms causes kinks in the fatty acid chain mono-unsaturated has 1 C=C bond polyunsaturated has > 1 C=C bond most plant fats

15 Partially hydrogenated vegetable oil Vegetable oil with artificially added H atoms to saturate the C atoms Why do it? food has better texture & longer shelf life BUT is more likely to accumulate in our bodies Creates trans-fats difficult for body to break down & accumulate in blood vessels

16 Sterols Lipids made of 4 fused carbon rings Function is not energy storage, but to help regulate growth & development cholesterol essential component in most cell membranes steroid hormones estrogen & testosterone regulate sexual development, maturation, & sperm & egg production Steroids can increase muscularity, but with serious health consequences; extreme aggression, high cholesterol, cancer

17 1 glycerol, 2 fatty acids, and a phosphate group Hydrophilic end and hydrophobic end on same molecule Major component of cell membranes; controls the flow of chemicals into & out of cell Phospholipids

18 Waxes Resemble fats but only one fatty acid chain natural coating on surface of many plants & many insects to prevent water loss on many birds feathers to prevent becoming waterlogged when wet

19 Types of macromolecules Carbohydrates Lipids Proteins Nucleic acids

20 Proteins Chief building blocks of all life 1000s of different proteins enzymes (speed up chemical reactions) structural (connective tissue, hair, feathers, webs) contractile (muscle) defensive (antibodies) signal (hormones) receptor (in cell membrane) transport (delivers O 2 to muscles) storage (ovalbumin (egg white)) Can be used to fuel living processes All proteins are made of amino acids

21 Amino acids The building blocks of proteins Unique combinations of amino acids result in proteins with unique structure & function Made of a central C atom with a carboxyl group, amino group & a side chain the side chain determines the characteristics of each amino acid = side chain

22 Expanded amino acid structures

23 Making proteins Proteins formed by linking individual amino acids together with a peptide bond amino group of one amino acid binds to the carboxyl group of another 2 linked amino acids = dipeptide Several linked together = polypeptide chain

24 Protein structure and function Most enzymes and other proteins are globular in shape (like popcorn) Structural proteins typically are fibrous (like string) Shape is very specific to job If proteins lose their shape they cannot function properly, called denaturation caused by changes in ph or excessive heat ex. cooking eggs; heat breaks H-bonds, proteins unfold & lose shape

25 Four levels of protein structure Primary the unique sequence of amino acids Secondary the twists & folds formed by H-bonding between carboxyl and amine groups the peptide chain

26 Four levels of protein structure Tertiary the complex folding in the polypeptide chain resulting from interactions between side chains Quaternary formed when 2 or more polypeptide chains bind together

27 Enzymes Proteins that initiate & speed up chemical reactions in living organisms Can be used over & over do not get consumed by reaction Shape is critical, just like all other proteins substrate-specific even slightly altered enzymes can become non-functioning non-functioning enzymes are responsible for a large # of diseases & physiological problems

28 How enzymes work The making of a product

29 Enzymes can be used for building or breaking molecules

30 Regulation of enzymatic activity Competitive inhibitors Non-competitive inhibitors Feedback inhibition

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32 Feedback inhibition

33 Types of macromolecules Carbohydrates Lipids Proteins Nucleic acids

34 Nucleic acids Macromolecules that store information Two types DNA & RNA both play central roles the production of proteins & determining the inherited traits of individuals Made up of nucleotides a sugar a phosphate group a nitrogenous base

35 Nucleic acids continued Both DNA & RNA have a sugar-phosphate backbone attached to each sugar is the nitrogenous base cytosine guanine adenine thymine (DNA only) uracil (RNA only) different sequences of bases makes different proteins

36 DNA = Deoxyribonucleic acid Holds genetic information to build a whole organism (!!!) 2 strands, each wrapping around each other, forming a double helix sugar-phosphate backbone on the outsides and nitrogenous bases facing inward base bind together with hydrogen bonding bases pair up with each other in 2 combinations A with T C with G

37 RNA = ribonucleic acid The universal translator Directs protein production Differs from DNA sugar of backbone has an extra O atom single stranded; bases don t bind with anything else uracil instead of thymine (U instead of T)

38 Macromolecules summary Carbohydrates: energy & structure monosaccharides polysaccharides Lipids: hydrophobic triglycerides sterols phospholipids waxes Proteins: building blocks of life structure & function intimately related Nucleic acids: store information DNA RNA