the structure and function of macromolecules

macromolecules lipids carbohydrates proteins nucleic acids

what is a polymer? poly = many, meris = part a chain-like molecule made up of repeating parts each link in the chain is called a monomer

polymers lipids carbohydrates proteins nucleic acids

Making and Breaking Polymers A dehydration reaction removes a water molecule, forming a new bond Condensation reaction (dehydration synthesis) Hydrolysis A hydrolysis reaction adds a water molecule, breaking a bond http://science.nhmccd.edu/biol/dehydrat/dehydrat.html

lipids are not polymers have little to no affinity for water three most biologically important kinds are: Fats Phospholipids Steroids

lipids: fats Energy storage Cushion for internal organs Insulation http://dsc.discovery.com/videos/wreckreation-nation-wipeout.html lipids: fats Energy storage Cushion for internal organs Insulation http://www.mtv.com/search/?searchterm=kevin+valot&searchtype=1 http://www.metacafe.com/watch/548781/worst_wipeout_ever_at_the_wedge/

lipids: fats 1 gram of fat can store twice as much energy as 1 gram of polysaccharide

lipids: fats composed of 1 glycerol and 3 fatty acids ester linkage composed of 1 glycerol and 3 fatty acids Ester linkage: 3 fatty acids to 1 glycerol (dehydration formation) also called triglycerides Fats are not polymers; they are much smaller and are grouped because of their hydrophobic behavior glycerol fatty acid chains http://bcs.whfreeman.com/thelifewire/content/chp03/0302002.html fat molecule http://www.tvdsb.on.ca/westmin/science/sbioac/biochem/triglyc.htm

Saturated vs. Unsaturated fats Saturated Unsaturated Liquid at room temperature Solid at room temperature Found mostly in plants Found mostly in animals Double bound in fatty acid chain No Double bond in fatty acid chain

lipids: fats

lipids: phospholipids Structure: Glycerol + 2 fatty acids + phosphate group. Function: Main structural component of membranes, where they arrange in bilayers. 12

Phospholipids in Water 13

lipids: steroids carbon skeleton consists of 4 rings Ex: cholesterol Found in cell membranes Precursor for other steroids (sex hormones)

lipids: steroids Examples: corticosteroids sex steroids anabolic steroids

carbohydrates Sugars Carbo = carbon, hydrate = water; carbohydrates have the molecular formula (CH2O)n used as cellular “fuel” used for structure and support monomer = monosaccharide polymer = polysaccharide

carbohydrates monosaccharides (simple sugars) fuel for cellular processes synthesis of amino acids and fatty acids glucose is the most common monosaccharide

carbohydrates disaccharides (two monosaccharides) monosaccharides are linked by glycosidic linkages.

what kind of reaction creates disaccharides from monosaccharides? hydrolysis reaction covalent reaction dehydration reaction

what kind of reaction creates disaccharides from monosaccharides? C) dehydration reaction

after you drink a class of milk, how does your body digest lactose (glucose + galactose)? hydrolysis reactions covalent reactions dehydration reactions

after you drink a class of milk, how does your body digest lactose (glucose + galactose)? hydrolysis reactions

carbohydrates polysaccharides energy storage building material for structure

Polysaccharides Storage : joined by a alpha 1-4 glycosidase linkage Starch: Plants amylose and amylopectin Glycogen: Animals Structural: joined by a Beta 1-4 glycosidase linkage Cellulose~ most abundant organic compound Found in the cell wall of plants Chitin~ exoskeletons of insects http://bcs.whfreeman.com/thelifewire/content/chp03/0302002.html

proteins amino acids polypeptide protein Account for more than 50% of dry cell weight. Polymers of amino acids make polypeptides. Proteins consist of one or more polypeptides. protein

Proteins Importance: Instrumental in nearly everything organisms do 50% dry weight of cells Most structurally sophisticated molecules known

Types of proteins: Structural functions in support Storage food source ex.: elastin, collagen, and keratin Storage food source ex.: ovalbumin (eggs) Transport moves other substances ex.: hemoglobin, myoglobin and cell membrane proteins Hormonal coordinates bodily activities ex.: insulin Contractile movement ex.: actin and myosin (muscle) Antibodies defense ex.: Ig.E, IgA, and Ig.G Enzymes aid in chemical reactions ex.: amylase and protease

amino acids: monomers of proteins Amino acids have an amino group, carboxyl group, a hydrogen atom and a variable R group/side chain.

Structure of Amino Acid Monomers Consist of an asymmetric carbon covalently bonded to: Hydrogen Amino group Carboxyl (acid) group Variable R group specific to each amino acid 29

polypeptides: amino acids connected by peptide bonds Cells don’t have to make each protein from scratch; they just link monomers (amino acids). http://www.tvdsb.on.ca/westmin/science/sbioac/biochem/amino.htm

proteins function depends on conformation (shape) (Example: enzyme substrate complex) Polypeptide=yarn, protein=sweater. Function depends on ability to recognize and bind to some other molecule. http://www.metacafe.com/watch/yt-lijQ3a8yUYQ/protein_structure/

Primary Structure Ex: lysozyme Amino acid substitution: Linear structure Ex: lysozyme Each type of protein has a unique primary structure of amino acids Amino acid substitution: hemoglobin; sickle-cell anemia amino acids = beads polypeptide = necklace

Secondary structure Coils & folds results from interactions between carboxyl and amino groups Alpha Helix: coiling (keratin) Beta (ß) Pleated Sheet: Folded (silk)

Tertiary structure Hydrophobic Interactions Disulfide bridges Conformation: irregular contortions results from interactions between side chains (R-groups) Hydrophobic Interactions Disulfide bridges Hydrogen bonds Ionic bonds (Salt Bridge)

Quaternary structure 2 or more polypeptide chains aggregated into 1 macromolecule Ex.: collagen (connective tissue) hemoglobin peptides = yarn protein = sweater http://bcs.whfreeman.com/thelifewire/content/chp03/0302002.html http://www.learner.org/courses/biology/units/proteo/images.html

Nucleic acids nucleotides nucleic acid/polynucleotide two kinds: DNA and RNA

Nucleic Acids Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA) DNA->RNA->protein Polymers of nucleotides Nucleotide consists of: nitrogenous base (variable part) pentose sugar phosphate group Nitrogenous bases: Pyrimidines ~ cytosine, thymine, uracil (RNA only) Purines ~ adenine, guanine Number of purines equals # of pyrimidines

Nucleic acids Polynucleotide: phosphodiester linkages (covalent) between the phosphate + sugar

Nucleic Acids Inheritance based on DNA replication Double helix (Watson & Crick - 1953) H bonds~ between paired bases Complementary pairing A to T C to G http://www.johnkyrk.com/DNAanatomy.html http://bcs.whfreeman.com/thelifewire/content/chp03/0302002.html

Check yourself… Which of the 4 macromolecules is not composed of polymers? What is the difference between a polypeptide and a protein? Which type of macromolecule conveys information to the cell?

Check yourself… Which of the 4 macromolecules is not composed of polymers? lipids

Check yourself… What is the difference between a polypeptide and a protein? A polypeptide is a string of amino acids while a protein consists of more than one polypeptide.

Check yourself… Which type of macromolecule conveys information to the cell? Nucleic acid/polynucleotide