Macromolecules Macromolecules form the living organisms have a

Macromolecules

Macromolecules • form the living organisms • have: – a carbon core base – the core has attached groups of atoms called functional groups which confer specific chemical properties • very large • assembled from many small components, called monomers; the assembled chain of monomers is known as a polymer • polymers/monomers are dynamic structures depending on the needs of the cells by two reversible processes

• There are four types of macromolecules: 1. Carbohydrates 2. Lipids 3. Proteins 4. Nucleic acids

Carbohydrates • a carbohydrate is any molecule that contains the elements C, H, and O in a 1: 2: 1 ratio • Important role in: 1. making up the structural framework of cells 2. energy storage • the sizes of carbohydrates varies § § simple carbohydrates – made up of one or two monomers complex carbohydrates – made up of polymers

• Simple carbohydrates are small molecules made up of one or two monomers 1. monosaccharides consist of only one monomer • an example is the sugar glucose (C 6 H 12 O 6) 2. disaccharides consist of two monosaccharides • • an example is the sugar sucrose, which is formed by joining together two monosaccharides, glucose and fructose the lactose is made up of two glucose molecules

• Complex carbohydrates are long polymer chains and called polysaccharides • Plants and animals store energy in polysaccharide chains formed from glucose • plants form starch • animals form glycogen

• Some polysaccharides are structural and resistant to digestion by enzymes § plants form cellulose cell walls § some animals form chitin for exoskeletons

Lipids § molecules are not soluble in water § lipids are non-polar molecules § lipids have many different types • • fats oils Steroids cholesterol rubber waxes pigments

Oleic acid: olive oil

Fats are converted from glucose for longterm energy storage § have two subunits 1. fatty acids 2. glycerol § fatty acids are chains of C and H atoms, known as hydrocarbons

Because there are 3 fatty acids attached to a glycerol, another name for a fat is triglyceride

• Fatty acids have different chemical properties due to the number of hydrogens attached § maximum number of hydrogens are attached, fat is saturated (bad fat for your body), they are solid at room temperature § there are fewer than the maximum attached, fat is unsaturated (the less number of hydrogens the better for your body), they are liquid at room temperature

Saturated and un-saturated fats

• cell membranes contain lipids § phospholipids make up the two layers of the membrane § cholesterol is embedded within the membrane

Fats are divided into three groups — § monounsaturated, § polyunsaturated § saturated. Monounsaturated Fats: • in foods that come from plants. • liquid at room temperature • can reduce blood cholesterol levels, but less than polyunsaturated fats do. • can raise HDL cholesterol (the "good" kind of cholesterol) levels. Polyunsaturated Fats: • mainly from plants. • liquid at room temperature. • can reduce blood cholesterol levels.

Saturated Fats: • animal origin food and some vegetables • in processed bakery goods, nondairy milk, cream substitutes. – Coconut Oil – Cocoa Butter (Chocolate) – Palm Kernel Oil, Palm Oil • As a rule of thumb when shopping, saturated fats are solid at room temperature. • When you have a lot of saturated fat in your diet, your liver responds by making more cholesterol. This raises your blood cholesterol level. It is the most harmful type of fat you can eat.

Hydrogenation / Trans Fats § hydrogen is bubbled through polyunsaturated and monounsaturated fats and oils to change from liquid to solid form § make vegetable margarines have a butter-like texture, and prolong the shelf life of packaged foods. § The effects: cause blood cholesterol levels to increase. § limit your use § manufacturers are not required to list how much trans fats are included in a product: Read the list of ingredients carefully

Saturated • Beef • Brazil Nuts, Macadamia Nuts • Butter • Cheese • Chocolate • Coconut, Coconut Oil • Lard • Milk • Palm Oil • Pistachios • Poultry Monounsaturated • Avocado • OIL: Canola Oil, olive oil, sesame oil • Cashews • Olives • Peanuts, Peanut Butter, Peanut Oil Polyunsaturated • Almonds, pecans, Walnuts • Corn Oil, Cottonseed Oil, Soybean Oil • Fish • Margarine • Mayonnaise • Sesame Seeds, Sesame Oil • Sunflower Oil, Sunflower Seeds

Proteins • are complex macromolecules/polymers made up by subunits called amino acids • the assembled polymer is called a polypeptide

Amino acids • are small molecules • 20 different types of amino acids

• the covalent bond linking two amino acids together is called a peptide bond

Protein structure is complex 1. order or sequence of the amino acids affects how the protein folds together, § example the insulin molecule 2. the way that a polypeptide folds to form the protein determines the protein’s function – some proteins are comprised of more than one polypeptide

• There are four general levels to protein structure 1. Primary 2. Secondary 3. Tertiary 4. Quaternary

• Primary structure – § is the sequence of the amino acids in the polypeptide chain § This affects all other levels of protein structure

• Secondary structure § • forms because regions of the polypeptide that are non-polar are forced together The folded structure may resemble 1. Coils 2. Helices 3. sheets

• Tertiary structure – • final 3 -D shape of the protein • The final twists and folds that lead to this shape are the result of polarity differences in regions of the polypeptide

• Quaternary structure – • the spatial arrangement of proteins • comprised of more than one polypeptide chain

The shape of a protein affects its function: • changes to the environment of the protein may cause it to unfold or denature: • increased temperature or lower p. H affects hydrogen bonding, which is involved in the folding process • a denatured protein is inactive

Enzymes • are globular proteins that have a special 3 D shape that fits precisely with another chemical • they cause the chemical that they fit with to undergo a reaction • this process of enhancing a chemical reaction is called catalysis

Nucleic Acids • are very long polymers that store information • There are two types of nucleic acids § § Deoxyribonucleic acid (DNA) Ribonucleic acid (RNA)

Nucleid acids are comprised of monomers called nucleotides (A, T, U, G, C) • each nucleotide has 3 parts 1. a five-carbon sugar 2. a phosphate group 3. a nitrogen-containing base • there are five different types of nucleotides whose sequence encodes genetic information

RNA is similar to DNA except that § it uses uracil instead of thymine § it is comprised of just one strand § it has a ribose sugar

DNA is a double helix with • two base pairs – Adenosine (A) pairs with thymine (T) – Cytosine (C) pairs with Guanine (G) • A hydrogen bond between the base pairs • a sugar-phosphate backbone comprised of phosphodiester bonds gives support

The DNA double helix

The structure of DNA helps it to function § the hydrogen bonds of the base pairs can be easily broken to unzip the DNA so that information can be copied • each strand of DNA is a mirror image so the DNA contains two copies of the information § having two copies means that the information can be accurately copied and passed to the next generation

Review questions 1. The four kinds of organic macromolecules are: A)hydroxyls, carboxyls, aminos, and phosphates. B)proteins, carbohydrates, lipids, and nucleic acids. C)ATP, ADP, DNA, and RNA. D)carbon, hydrogen, oxygen, and nitrogen. 2. Organic molecules are made up of monomers. Which of the following is not considered a monomer of organic molecules? A)amino acids B. simple sugars B)Polypeptides D. Nucleotides

3. Your body is filled with many types of proteins. Each type has a distinctive sequence of amino acids which determines both its specialized ______ and its unique ______. • number, weight B) length, mass C) structure, function D) charge, p. H 4. Nucleic acids: A) are the energy source for our bodies. B) act on other molecules, breaking them apart or building new ones, to help us function. C) are only found in a few, specialized locations within the body. D) are information storage devices found in every cell in the body.

5. The two strands of a DNA molecule are held together through hydrogen bonds between nucleotide bases. Which of the following best describes this base pairing? A)Adenine forms hydrogen bonds with thymine. B)Adenine forms hydrogen bonds with uracil. C)Cytosine forms hydrogen bonds with thymine. D)Guanine forms hydrogen bonds with adenine. 6. Carbohydrates are used for: A)structure and for energy. B) information storage. C) fat storage and for hair. D) hormones and enzymes.

7. Which carbohydrate is not found in plants? _____ 8. A characteristic common to all lipids is: A)that they contain long chains of C-H bonds. B)that they are insoluble in water. C)that they have a glycerol backbone. D)All of these are characteristics of all lipids. 9. Lipids are used for: A)motion and defense. B)information storage. C)energy storage and for some hormones. D)enzymes and for some hormones.