Macromolecules

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Macromolecules
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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

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• There are four types of macromolecules
• Carbohydrates
• Lipids
• Proteins
• Nucleic acids

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Carbohydrates

• a carbohydrate is any molecule that contains the
  elements C, H, and O in a 121 ratio
• Important role in
• making up the structural framework of cells
• energy storage
• the sizes of carbohydrates varies
• simple carbohydrates made up of one or two
  monomers
• complex carbohydrates made up of polymers

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• Simple carbohydrates are small molecules made up
  of one or two monomers
• monosaccharides consist of only one monomer
• an example is the sugar glucose (C6H12O6)
• 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

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• 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

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

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Lipids

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

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Oleic acid olive oil
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• Fats are converted from glucose for long-term
  energy storage
• have two subunits
• fatty acids
• glycerol
• fatty acids are chains of C and H atoms, known as
  hydrocarbons

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

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Saturated and un-saturated fats
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• cell membranes contain lipids
• phospholipids make up the two layers of the
  membrane
• cholesterol is embedded within the membrane

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• 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.

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• 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.

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• 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

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• 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

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Proteins

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

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

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the covalent bond linking two amino acids
together is called a peptide bond
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• Protein structure is complex
• order or sequence of the amino acids affects how
  the protein folds together,
• example the insulin molecule
• the way that a polypeptide folds to form the
  protein determines the proteins function
• some proteins are comprised of more than one
  polypeptide

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• There are four general levels to protein
  structure
• Primary
• Secondary
• Tertiary
• Quaternary

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

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

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• 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

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

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• 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 pH affects
  hydrogen bonding, which is involved in the
  folding process
• a denatured protein is inactive

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• 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

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Nucleic Acids

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

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

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• 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

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• 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

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The DNA double helix
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• 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

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Review questions

• 1. The four kinds of organic macromolecules are
• hydroxyls, carboxyls, aminos, and phosphates.
• proteins, carbohydrates, lipids, and nucleic
  acids.
• ATP, ADP, DNA, and RNA.
• 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?
• amino acids B. simple sugars
• Polypeptides D. Nucleotides

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• 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, pH
• 4. Nucleic acids
• are the energy source for our bodies.
• act on other molecules, breaking them apart or
  building new ones, to help us function.
• are only found in a few, specialized locations
  within the body.
• are information storage devices found in every
  cell in the body.

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• 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?
• Adenine forms hydrogen bonds with thymine.
• Adenine forms hydrogen bonds with uracil.
• Cytosine forms hydrogen bonds with thymine.
• Guanine forms hydrogen bonds with adenine.
• 6. Carbohydrates are used for
• structure and for energy.B) information storage.
• C) fat storage and for hair. D) hormones and
  enzymes.

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