Introductory Science Introduction to Biology

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Introductory Science Introduction to Biology

• Biochemistry

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Biochemistry

• In this tutorial you will
• Describe the Features of Organic Compounds
• Describe the Features of Carbohydrates
• Describe the Features of Lipids
• Describe the Features of Proteins
• Describe the Features of Nucleic Acids
• Explain Protein Synthesis

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Describe the Features of Organic Compounds
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Home

• Biology is the study of living things.

• Before we can study living things we need to
  study the substances that compose living things.
• We began that process when we studied chemistry
  in the previous unit.
• You learned all substances are composed of atoms
  and molecules.
• We will continue that process in this section as
  we learn about biomolecules.
• Biomolecules are molecules that are specific to
  living things.

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• Most compounds that compose living things are
  called organic compounds.

Organic Compounds

• A characteristic property of organic compounds is
  that they contain carbon. All organic compounds
  contain carbon atoms.
• Lets take a closer look at carbon.

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Describe the Features of Organic Compounds

• Look up Carbon on your Periodic Table and answer
  the following questions.

• Carbon is in what group?

Group 4

• How many electrons are in the outer energy level?

4 electrons in the outer energy level

• What does carbon want to do when it reacts?

Carbon wants to get 4 more electrons. A Carbon
atom will form 4 covalent bonds with other carbon
atoms or with other nonmetals.
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• Carbon has 4 electrons in its outer energy level.

• It wants to get 4 more to fill its outer level.
• So, carbon tends to form 4 covalent bonds.

C

• Carbon will form these bonds with other nonmetals
  like oxygen, nitrogen, hydrogen, and especially
  other carbon atoms.

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• How do Hydrogen, Oxygen, and Nitrogen react?

Hydrogen
Oxygen
Nitrogen
1 e- in outer level
6 e- in outer level
5 e- in outer level
Wants 1 more e-
Wants 2 more e-
Wants 3 more e-
Forms 1 Covalent Bond
Forms 2 Covalent Bonds
Forms 3 Covalent Bonds
O
H
N
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Describe the Features of Organic Compounds

• Organic compounds are made from carbon atoms
  covalently bonded to other carbon atoms.

This substance is Propane Gas. Its formula
isC3H8.

• There are 3 carbon atoms in this molecule. But
  remember each carbon needs 4 bonds.
• The remaining bonds could be made with other
  atoms like hydrogen.

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Describe the Features of Organic Compounds

• Chains of carbon atoms make the backbone of
  organic compounds.

• We can make an unlimited number of different
  organic molecules starting with these carbon
  chains.
• The next few slides will show you how this can
  happen.

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Describe the Features of Organic Compounds

• The 2 molecules below were each made from 4
  carbon atoms and 10 hydrogen atoms. C4H10
  (The
  hydrogen atoms arent drawn in.)

Simply changing the arrangement of atoms in a
molecule is enough to create a different compound
with different properties.

• Although both of these molecules have the same
  chemical formula they are different compounds
  because they have a different structure.

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Describe the Features of Organic Compounds

• The three molecules below were each made from a
  two carbon atom chain and hydrogen.

(The hydrogen atoms arent drawn in.)
C2H6
C2H4
C2H2

• You can see these molecules are different because
  they each have different chemical formula.

• The difference between these 3 molecules is the
  way the carbons are bonded to each other.

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Describe the Features of Organic Compounds

• The bonding between the carbon atoms is the
  difference between these three molecules.

C2H4
C2H6
C2H2
Double Bond
Triple Bond
Single Bond
Remember, carbon has 4 electrons in its outer
level. It wants to get 4 more. So, carbon
always forms 4 covalent bonds
In the first molecule C2H6, the carbons are
sharing one pair of electrons. This is called a
single bond
Because there is a single bond holding the
carbons together in the first molecule, each
carbon can bond to three hydrogens.
In the second molecule C2H4, the carbons are
sharing two pairs of electrons. This is called
a double bond.
Because there is a double bond holding the
carbons together in the second molecule, each
carbon can bond to only 2 hydrogens.
In the third molecule C2H2, the carbons are
sharing three pairs of electrons. This is
called a triple bond.
Because there is a triple bond holding the
carbons together in the third molecule, each
carbon can bond to only 1 hydrogen.
Notice each carbon still has 4 bonds. But by
making more carbon carbon bonds there is less
room for bonds with hydrogen.
Each of these molecules is made from hydrogen and
a 2-carbon chain.But, the formulas are different.
This is because of the different bonding between
the carbon atoms. These are three different
substances.
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Describe the Features of Organic Compounds

• The molecule below is ethane gas (C2H6). It is
  a component of natural gas.

ethanol (C2H6O).
Do you notice a problem with theethanol molecule
above?(Hint Look at the oxygen.)
Oxygen has 6 e- in its outer level. It wants to
get 2 more electrons. So, oxygen always forms 2
bonds.
Oxygen will form its other bond with an atom of
hydrogen. Now, all atoms have the correct
number of bonds.
Ethane gas C2H6 and ethanol C2H6O only differ by
one oxygen atom. Yet, that is enough to create
two different compounds with different properties.
Ethane gas is made from 2 single-bonded carbon
atoms and 6 hydrogen atoms.
If we replace one of the hydrogen atoms with an
oxygen atom, we will create a different
substance.
This molecule is no longer ethane gas. It is
called ethanol or ethyl alcohol. This is the
alcohol that is in beer, wine, liquor, etc.
Changing a single atom in an organic compound is
enough to change the entire substance.
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Describe the Features of Organic Compounds

• Different organic compounds can be made by...

• Changing the arrangement of carbon atoms in a
  molecule.
• Changing the number of bonds between carbon
  atoms.
• Adding or Replacing atoms on the carbon chain.
• All of these changes were made by making changes
  an atom at a time.
• Another way to make organic compounds is through
  polymerization.

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Describe the Features of Organic Compounds

• First lets define the terms Monomer and Polymer

• Monomer Mono means one Mer means unit
• A monomer is a single unit
• Polymer Poly means many Mer means unit
• A polymer is many units bonded together
• Polymerization is the process of bonding small
  molecules (monomers) together to make larger
  molecules (polymers) with different properties.

Monomer
Polymer
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Describe the Features of Organic Compounds

• Polymerization is an important commercial process.

• Many synthetic materials that you use daily are
  made through polymerization.

Monomer Polymer Use
Ethylene Polyethylene Plastic BagsSqueeze Bottles
Vinyl Chloride Polyvinyl Chloride (PVC) Pipes Raincoats
Styrene Polystyrene Styrofoam CupsInsulation
Tetrafluoroethylene Teflon Non-stick Coating
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Describe the Features of Organic Compounds

• Polymerization is also an important biological
  process.

• Many biomolecules (organic compounds made by
  living things) are made by polymerization.

Monomer Polymer / Biomolecule
Sugar Carbohydrate
Amino Acid Protein
Nucleotide Nucleic Acid (DNA RNA)
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Describe the Features of Organic Compounds

• In the remainder of this tutorial, we will
  discuss four types of Biomolecules (organic
  compounds).

• Carbohydrates
• Lipids
• Proteins
• Nucleic Acids
• Most of the substances that compose living things
  can be classified as one of these biomolecules.
• Lets take a closer look at each type of
  biomolecule.

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Describe the Features of Organic Compounds

• Functions and Examples of Biomolecules

Biomolecule Function Example
Carbohydrate
Lipid
Protein
Nucleic Acid
Primary Energy Source
Sugar, Starch, Cellulose
Secondary Energy Source
Fats Oils
Muscle Tissue, Enzymes
Structural Components
Genetic Information
DNA RNA
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Describe the Features of Organic Compounds

• Review

• Living things are composed primarily of organic
  compounds.
• Organic compounds contain carbon atoms.
• Carbon atoms have 4 electrons in their outer
  level so they tend to from 4 covalent bonds.
• Carbons atoms bond readily to other carbon atoms
  forming chains.
• Because of carbon atoms ability to bond with
  each other and with other nonmetals there is an
  infinite number of different organic compounds.

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Describe the Features of Organic Compounds
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• Review

• Different organic compounds can be made by simply
  changing the number, type, arrangement, or
  bonding of atoms.
• Organic compounds are also formed through
  polymerization.
• Bonding small molecules (monomers) together to
  form large molecules (polymers).
• There are four classes of organic compounds
  (Biomolecules) that are essential for living
  things Carbohydrates, Lipids, Proteins, Nucleic
  Acids

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Describe the Featuresof Carbohydrates
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• Structure of Carbohydrates

• Carbohydrate is a broad term for those molecules
  that are made from sugar molecules.
• The chart below will help you make sense of some
  terms associated with carbohydrates.

Carbohydrate
Broadest term for molecules composed of sugar
molecules
Mono means OneSaccharide means SugarA
monosaccharide is a single sugar molecule
(monomer)Glucose is a monosaccharide
Di means TwoSaccharide means SugarA
disaccharide is two sugar molecules bonded
together.Sucrose (table sugar) is a disaccharide
Poly means ManySaccharide means SugarA
polysaccharide is 3 or more bonded sugar
molecules.Starch (like in a potato)is a
polysaccharide
Monosaccharides, Disaccharides, and
Polysaccharides are all carbohydrates.They are
all composed of one or more sugar molecules.
Monosaccharide
Disaccharide
Polysaccharide
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Describe the Featuresof Carbohydrates

• All carbohydrates are polysaccharides. (
  True or False )

• All polysaccharides are carbohydrates but
  carbohydrates also include monosaccharides and
  disaccharides as well.

polymer

• A polysaccharide is a ___________ composed
  ofthree or more monomers called __________.

sugars
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Describe the Featuresof Carbohydrates

• Carbohydrate is a broad term for those molecules
  that are made from sugar molecules.

• Two carbohydrates that are somewhat familiar to
  you are starch and cellulose.
• Starch and Cellulose are both polysaccharides
  composed of glucose sugar monomers.
• Starch is a primary food source in foods like
  pasta, bread, potatoes, etc.
• Cellulose is the material plants use for
  structural support. Cellulose is wood.

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Describe the Featuresof Carbohydrates

• Obviously, starch and cellulose are very
  different compounds with very different
  properties.

• Yet both compounds are glucose polysaccharides.
• The only difference between the two compounds is
  the way the glucose monomers are bonded.

Starch
Even when starting with the same building
materials, living things create different
substances simply by changing the arrangement of
the monomers.
Cellulose
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Describe the Featuresof Carbohydrates

• The following table shows some examples of common
  carbohydrates.

Monosaccharide
Disaccharide
Polysaccharide
GlucoseFructose
Found in Fruit, Blood, Living CellsFound in
Fruit
SucroseMaltoseLactose
Table Sugar (Glucose and Fructose)Malt Sugar (2
Glucose monomers)Milk Sugar (Glucose and
Galactose)
Starch Cellulose Glycogen
Plant material to store sugar (Glucose
monomers)Plant structural material (wood)
(Glucose monomers)Animal material to store sugar
(Glucose monomers)
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Describe the Featuresof Carbohydrates

• Functions of Carbohydrates

• The primary function of carbohydrates in an
  animal is to provide energy.
• Carbohydrates are broken down into simple sugars
  and burned for energy.

Starch
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Describe the Featuresof Carbohydrates

• Functions of Carbohydrates

• The carbohydrates you eat are first broken into
  simple sugars (monosaccharides)
• If you eat too many carbohydrates, your body
  stores the excess sugar first as glycogen
  (glucose polysaccharide) in the liver.
• Any additional carbohydrates are converted to fat
  and stored.

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Describe the Featuresof Carbohydrates

• Review

• Carbohydrates are molecules composed of one or
  more sugar molecules.
• Monosaccharide Single Sugar Molecule
• Disaccharide Two Sugar Molecules
• Polysaccharide 3 or more Sugar Molecules
• Some common carbohydrates are..
• Monosaccharides Glucose, Fructose
• Disaccharides Sucrose, Lactose, Maltose
• Polysaccharide Starch, Cellulose, Glycogen

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Describe the Featuresof Carbohydrates
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• Review

• Carbohydrates are the primary energy source for
  animals.
• Carbohydrates are broken down into simple sugars
  (monosaccharides)
• The simple sugars are then burned in the cells to
  produce energy.
• Excess sugars are stored temporarily as glycogen
  in the liver.
• They can also be converted to fat for long term
  storage.

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Describe theFeatures of Lipids
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• You are very familiar with lipids although you
  may not be familiar with the term lipid.

• Lipid is the generic term for fats and oils
• Fats are solid like lard and butter
• Oils are liquid like corn oil or vegetable oil

Lipids
Fat
Oil
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Describe theFeatures of Lipids

• Unlike carbohydrates, lipids are not formed from
  monomers through polymerization.

• Lipids are long chains of carbons and hydrogen.

O
C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C-C
OH

• This lipid is called a fatty acid because it has
  a long chain of carbons and an acid group at the
  end.

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Describe theFeatures of Lipids

• Lets take a closer look at the fatty acid from
  the previous slide.

H H H H H H H H H H H H H H H H
H H H H H H H H H H H H H H H
H H H H

• Notice the carbons are all held with single bonds
• Except for the carbon on the right, these carbon
  atoms need to form some additional bonds (4
  total)
• These bonds are formed with hydrogen atoms.

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Describe theFeatures of Lipids

• This fatty acid is said to be Saturated.

• All the carbons are single bonded to each other.
  So
• We have the maximum number of hydrogen atoms
  possible for a carbon chain of this size.
• The fatty acid is saturated with hydrogen atoms.

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Describe theFeatures of Lipids

• Lets see what happens when 2 of the carbons are
  double bonded to each other.

C-C

• If the carbon atoms in red form a double bond

• Then they each need one less hydrogen.
  (Remember carbon can only have 4 bonds.)

• This fatty acid is now said to be Monounsaturated
  because it has one double bond which caused it to
  lose hydrogen

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Describe theFeatures of Lipids

• Lets add another double bond to the fatty acid.

C-C

• If the carbon atoms in green form a double bond

• Then they each need one less hydrogen.
  (Remember carbon can only have 4 bonds.)

• This fatty acid is now said to be Polyunsaturated
  because it has at least two double bonds which
  caused it to lose hydrogen

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Describe theFeatures of Lipids

• Saturated fatty acids (all single bonds) are
  usually found in solid or semisolid fats.

• Unsaturated fatty acids (1 or more double bonds)
  are usually found in oils.

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Describe theFeatures of Lipids

• The polyunsaturated fatty acid we just created is
  called Linoleic Acid

• Linoleic Acid is an Essential fatty acid.
• An essential nutrient is one that must be a part
  our diet because our bodies cant manufacture it.

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Describe theFeatures of Lipids

• The majority of lipids in our diet come from
  compounds called Triglycerides

• A Tryglyceride is composed of a glycerol molecule

• Bonded to 3 fatty acid molecules

Tryglyceride
Glycerol
Fatty Acids
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Describe theFeatures of Lipids

• Another group of lipids are the Phospholipids.

• Phospholipids are similar to Triglycerides. They
  have two fatty acids attached to a glycerol

• There is a Phosphate group attached to the third
  glycerol carbon.

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Describe theFeatures of Lipids

• Phospholipids are interesting because they have
  two parts.

• There is the nonpolar fatty acid part and the
  polar phosphate part.

Nonpolar
Polar
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Describe theFeatures of Lipids

• Phospholipids behave like soaps.

• The fatty acid end can interact with other
  nonpolar compounds like fat.
• The phosphate end can interact with other polar
  compounds like water.
• Phospholipids are the main component of cell
  membranes.
• The polar / nonpolar structure allows a membrane
  to control the movement of both polar and
  nonpolar substances.

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Describe theFeatures of Lipids

• There are a few other types of lipids that have
  important biological functions.

Type Function



A major component of the fatty covering of nerve
cells (myelin sheath)
Sphingolipids
Includes compounds with hormonal functions like
cholesterol, progesterone, testosterone, etc.
Steroids
Solid insoluble compounds that form protective
waterproof covering like lanolin, beeswax, etc.
Waxes
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Describe theFeatures of Lipids

• There are a number of uses for lipids in the
  body.

• Lipids are used for structures like membranes,
  coverings, and to cushion and protect organs.
• Lipids have hormonal functions in the case of
  steroids.
• The main use for lipids is as a secondary energy
  source.
• Remember, carbohydrates (sugars) are your bodys
  primary energy source.

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Describe theFeatures of Lipids
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• When you eat a meal the first nutrients your body
  uses for energy are the carbohydrates.

• Next your body uses the lipids from the meal

• Any extra carbohydrates and lipids are stored as
  triglycerides in fat cells for later use.

Carbohydrates

Lipids
Triglycerides
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Describe theFeatures of Proteins
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• The food you eat has one of two functions

• The first function is as an energy source. In
  other words some of the food you eat is burned up
  to produce energy.
• That energy is used to keep your body at 98.6 F,
  to move your muscles, and to make new substances,
  etc.
• Carbohydrates and Lipids are the your bodys main
  energy sources.
• You studied them in the previous sections.

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Describe theFeatures of Proteins

• The second function of your food is to provide
  the raw materials for making new structures.

• In other words, some of your food is broken down
  into small molecules that can then be reassembled
  to make structures your body needs.
• Most of your bodys structural components are
  made from the biomolecules in your food called
  proteins.

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Describe theFeatures of Proteins

• Proteins are similar to carbohydrates in that
  they are polymers.

• The monomers from which proteins are made are
  called amino acids.

Monomer
Protein
Polymer
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Describe theFeatures of Proteins

• There are approximately 22 different amino acids.
  

• All amino acids have the general structure below.

R

• Amino acids get their name because they have an
  Amine Group and an Acid Group.

• The difference between amino acids is determined
  by the group that is attached to the central
  carbon.
• This varying group is represented by an R .

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Describe theFeatures of Proteins

• Proteins perform a variety of functions in the
  body. The table highlights many of these
  functions.

Protein Function




Respond to foreign substances in the body to help
fight infection.
Antibodies
Act as hormones (ex insulin), as receptor cites
on cells, and as a means of transport in the body.
Regulators
Act as catalysts to build or break down
substances. Make chemical reactions occur that
couldnt proceed otherwise.
Enzymes
Compose structures in the body like muscles
(actin myosin), tendons, ligaments (collagen),
hair (keratin), etc
Structures
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Describe theFeatures of Proteins

• Like all substances, a proteins function is
  dependent on its structure.

• There are 4 aspects of a proteins structure that
  help to determine its function.
• The first is called the Primary Structure.
• The Primary Structure refers to the type and
  sequence of amino acids in the protein.
• The following slide has a further explanation of
  Primary Structure.

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Describe theFeatures of Proteins

• The protein below is composed of 6 amino acids.

• The primary structure is determined by the amino
  acids that are present and the order they are in.

• Replacing one of the amino acids, would change
  the primary structure produce a different
  protein.

• Likewise, changing the sequence of the amino
  acids, changes the primary structure and the
  protein.

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Describe theFeatures of Proteins

• Once they are assembled, some protein strands
  will take on a particular shape by folding or
  coiling.

• This shape is called the Secondary Structure.
• There are 2 common Secondary Structures

Helix
Pleated Sheet
A helix is a coiled shape like telephone cord or
a spring.
A pleated sheet is a folded shape like a paper
fan.
Many structural proteins are in the shape of a
helix.
Collagen in tendons, Keratin in hair are 2
examples
The protein that composes silk is a pleated sheet.
The helix is strong and resilient.
It can be stretched and spring back.
The pleated sheet is very strong but not very
elastic.
Silk, for example, resists tearing but it doesnt
stretch.
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Describe theFeatures of Proteins

• A single protein strand may have portions that
  are helical and other portions that are pleated
  sheet.

• The 3-dimensional shape of the entire strand is
  called the Tertiary Structure.

• The tertiary structure is critical to enzymes.
  They must have a precise shape so they can
  interact with the substances they are to
  catalyze.
• The substance and enzyme fit together like a lock
  and a key.

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Describe theFeatures of Proteins

• Many proteins are made from more than one protein
  strand.

• The 3-dimensional shape of all the strands is
  called the Quarternary Structure.

• Collagen consists of 3 strands that are coiled
  around each other forming a quaternary structure
  called a triple helix.
• This structure makes collagen extremely strong
  and elastic as well.

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Review
polymers

• Proteins are ______________ that are composed of
  monomers called _______________.

amino acids

• Catalysts help chemical reactions happen. In the
  body, these protein catalysts are called
  _________.

enzymes

• Collagen, Keratin, Actin and Myosin in muscle are
  examples of ______________ proteins.

structural

• Proteins that help fight infection are called
  ______________.

antibodies
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Describe theFeatures of Proteins
Home
Review

• Proteins are used by the body as an energy
  source. True or False.

Proteins are the structural components of our
bodies.
Matching
Primary Structure Secondary Structure Tertiary
Structure Quaternary Structure
3-D Shape of the Entire Protein Strand Type
Sequence of Amino Acids 3-D Arrangement of All
the Protein Strands Folding or Coiling of the
Amino Acid Chain
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Describe the Features of Nucleic Acids
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• Nucleic Acids are the final biomolecule we will
  study.

• The term nucleic acid may be unfamiliar but you
  are familiar with the two examples.
• DNA and RNA are the two types of nucleic acids we
  will study in this section.

• DNA stands for Deoxyribonucleic Acid
• RNA stands for Ribonucleic Acid

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Describe the Features of Nucleic Acids

• Unlike Carbohydrates, Lipids, and Proteins,
  Nucleic Acids are neither an energy source nor a
  structural component.

• DNA RNA carry your genetic information.
• Nucleic Acids are the instructions for making all
  the substances and controlling all the processes
  in the body.

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Describe the Features of Nucleic Acids

• How can Nucleic Acids (DNA RNA) control how
  your body works?

• Nucleic acids carrying the instructions for
  creating proteins.
• Proteins make up the structures of your body.
• Enzymes that control chemical reactions and
  Hormones that regulate metabolic processes are
  also proteins.
• By carrying the instructions for making proteins,
  DNA and RNA control the body structures and
  functions.

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Describe the Features of Nucleic Acids

• Like carbohydrates and proteins, nucleic acids
  are polymers built from many monomers.

• The monomers in a nucleic acid are called
  nucleotides.
• Nucleotides have three parts

Phosphate
Sugar
Base
Nucleotide
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Describe the Features of Nucleic Acids

• A nucleotide will have one of 4 possible bases

Four Possible Bases
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Describe the Features of Nucleic Acids

• Nucleotides (monomers) attach to form the Nucleic
  Acid polymer.

• Notice that the Phosphate and the Sugar are the
  backbone of the nucleic acid molecule.

• The bases protrude from the Phosphate Sugar
  chain.
• All nucleic acids have this fundamental
  structure.
• So, what is the difference between nucleic acids
  like DNA and RNA?

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Describe the Features of Nucleic Acids

• DNA and RNA are structurally different in a few
  subtle yet important ways.

• The sugar in DNA is slightly different from the
  sugar in RNA. (Ribose is the sugar part of the
  nucleotide.)

• The D in DNA stands for Deoxyribose.
• The R in RNA stands for Ribose.

DNA Sugar
RNA Sugar
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Describe the Features of Nucleic Acids

• There are 4 possible bases for both DNA and RNA.

• DNA has Cytosine, Guanine, Adenine, Thymine

• RNA has Cytosine, Guanine, Adenine

• In RNA Thymine is replaced with a slightly
  different base called Uracil

DNA Bases
RNA Bases
CytosineC
GuanineG
CytosineC
GuanineG
AdenineA
ThymineT
AdenineA
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Describe the Features of Nucleic Acids

• The final structural difference is that RNA is
  single stranded and DNA is double stranded.

• The structure of RNA is similar to generic
  nucleic acid you saw on a previous slide.

RNA
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Describe the Features of Nucleic Acids

• DNA is double stranded.

DNA
Notice1.) The two strands run in opposite
directions.
Notice2.) The two strands are held together
with hydrogen bonding between the bases
Notice3.) The bases always pair up the same
way. Adenine ?? Thymine Cytosine ?? Guanine
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Describe the Features of Nucleic Acids

• The DNA molecule looks like a ladder.
• The Phosphate - Sugar chain makes the rails.
• The Bases make the rungs.

• DNA has a primary structure shown above.
• It also has a secondary structure. Each strand is
  a helix and the double strand is helical as well.
• Imagine twisting each end of the ladder until you
  get a coil that looks like a spiral staircase.

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Describe the Features of Nucleic Acids
Review

• Nucleic Acids are ( monomers / polymers ) that
  are made up of ( monomers / polymers ) called
  ____________.

Nucleotides

• Nucleotides are composed of three parts. What
  are they?

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Describe the Features of Nucleic Acids
Review

• How is DNA structurally different from RNA?

• They have different sugars. DNA has Deoxyribose
  RNA has Ribose.
• They have one different base.DNA has Thymine
  RNA has Uracil
• RNA is single stranded DNA is double stranded.
• DNA strands are held together by hydrogen bonding
  between the bases. Adenine ? ? Thymine
  Cytocine? ? Guanine

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Describe the Features of Nucleic Acids

• Nucleic Acids, specifically DNA, carries genetic
  information by coding for the creation of
  proteins.

• But how can a molecule carry information?
• Humans transfer information through language but
  a molecule cant talk
• So, how does DNA convey information?
• On the following slides, you will see DNA uses a
  system very similar to our language.

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Describe the Features of Nucleic Acids

• DNA carries the information necessary for making
  proteins.

• Two things are critical when making a protein.
• First, identify the proper amino acids.

• Second, the amino acids must be in the correct
  sequence.

• In other words, DNA carries the code for the
  primary structure of a protein.

Alanine
Serine
Serine
Alanine
Cysteine
Cysteine
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Describe the Features of Nucleic Acids

• Information is coded in DNA in much the same way
  as our language carries information.

• In our language, ideas and things are represented
  by words and words are made up of letters.
• We have a 26 letter alphabet from which we make
  our words.
• We create words by arranging letters.

D O G
G O D

• The two words above are composed of the same
  letters. But, when the letters are put in a
  different order the words have different meanings.

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Describe the Features of Nucleic Acids

• DNA has a 4 different bases that act as its
  alphabet.

• This 4-letter alphabet is organized into 3-letter
  words called codons.
• Codons code for a particular amino acid.

• The codon C G T codes for Alanine
• The codon G C T codes for Arginine
• A sequence of 3 bases creates a codon which codes
  for a particular amino acid.

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Describe the Features of Nucleic Acids

• To convey information in our language, we put
  words into sentences.

• The sequence of words determines the meaning of
  the sentence.

The Cat Ate The Rat.
The Rat Ate The Cat.

• Even if we use the same words, when they are
  rearranged, the sentence has a totally different
  meaning.

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Describe the Features of Nucleic Acids

• To make a functional protein, the DNA code must
  identify the appropriate amino acids and insure
  they are put in the correct order.

• Codons are specifically arranged on the DNA
  molecule, like the words in a sentence, to insure
  the amino acids are in the proper sequence.

T C G C G T A C G
Serine
Alanine
Cysteine
C G T A C G T C G
Alanine
Cysteine
Serine
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Describe the Features of Nucleic Acids
Home
Review

• Three Bases are called a Codon
• One Codon codes for one amino acid

• A sequence of Codons codes for a particular
  sequence of Amino Acids.
• A sequence Amino Acids is a Protein

3 Bases
Codon
Amino Acid
Sequence of Codons
Sequence of Amino Acids
Protein
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ExplainProtein Synthesis
Home

• In the previous section you learned how the DNA
  molecule is able to carry the information
  necessary to create proteins.

• In this section, we will explore the process of
  making proteins in more detail.
• Virtually every cell in your body makes proteins.
• The process of creating proteins from the DNA
  code is called Protein Synthesis.

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ExplainProtein Synthesis

• Protein Synthesis involves both types of nucleic
  acids DNA and RNA

• You already know that DNA is structurally
  different from RNA.
• DNA and RNA perform different functions as well.
• The next few slides will outline the functional
  differences between DNA and RNA then we will be
  ready to explore protein synthesis.

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ExplainProtein Synthesis

• DNA acts as the master plan for making all the
  proteins in your body.

• DNA is a collective term to represent all of an
  individuals genetic information.
• In the nucleus of every cell in your body you
  have a complete set of DNA that codes for every
  possible protein your body will produce.

• Although every cell doesnt need to make every
  protein, a complete plan is locked up the nucleus
  of every cell.

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ExplainProtein Synthesis

• RNA, on the other hand, acts as an intermediary
  between the DNA master plan and the protein
  making machinery in the cytoplasm of the cell.

• RNA gets a copy of a piece of DNA that codes for
  a single protein.
• RNA transports the message to the cytoplasm of
  the cell where the protein will be made.

• RNA allows a cell to produce only the proteins
  that are needed by that cell at that time.

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ExplainProtein Synthesis

• Functional differences between DNA and RNA

DNA

• DNA is the master plan
• Codes for the creation of all possible proteins
• DNA stays in the nucleus of the cell.

RNA

• RNA is copy of a part of the DNA
• Codes for the creation of a single protein
• RNA moves between the nucleus the cytoplasm

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ExplainProtein Synthesis

• Protein Synthesis can be divided into 2 major
  steps.

• The first step is called Transcription.
• Transcription happens in the nucleus of the cell
• The word transcribe means to copy.
• During transcription a part of the DNA that codes
  for a single protein is copied.
• This copy is in the form of RNA
• The RNA copy is called Messenger RNA (mRNA for
  short) because it carries the DNA message to the
  Cytoplasm where the protein will be made.

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ExplainProtein Synthesis
Transcription (in Nucleus)
mRNA
1.) A portion of the double stranded DNA
molecule that codes for a single protein unwinds
and unzips.
2.) A strand of RNA is built in opposition to
one of the DNA stands. A ??T C ??G Remember
Uracil replaces Thymine in RNA
3.) When it is complete the RNA will move out
of the nucleus and into the cytoplasm. This new
single strand of RNA is called Messenger RNA
(m-RNA for short).
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ExplainProtein Synthesis

• The second step is called Translation.

• Messenger RNA moves into the cytoplasm. It is a
  copy of the DNAs code for a single protein.
• m-RNA attaches to a Ribosome. The ribosome acts
  as a platform for the assembly of the protein.
• The mRNA codons are translated one at a time.
• Another RNA called Transfer RNA (t-RNA) attaches
  to amino acids and brings them to m-RNA.
• The amino acids are put in order by t-RNA because
  it has a complimentary set of bases called an
  anticodon that matches the codon of m-RNA.

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ExplainProtein Synthesis
Translation (in Cytoplasm)
1.) Messenger RNA moves into the cytoplasm and
attaches to a ribosome. The ribosome is like an
work bench that helps organize all the tools
needed to make the protein.
2.) A Transfer RNA (t-RNA) attaches to a
specific amino acid and brings it to the m-RNA.
3.) The correct amino acid is put in the correct
place because the codon on m-RNA must match the
anticodon on t-RNA.
4.) Once the appropriate amino acid is in
place,the next codon is translated. Another
t-RNA brings in the appropriate amino acid and
the two amino acids bond.
5.) This continues one codon at a timeuntil the
entire m-RNA strand has been translatedand the
correct protein has been created.
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ExplainProtein Synthesis

• DNA is often compared to a blueprint. This
  analogy is helpful in understanding DNA RNA

• Just like the original blueprint for a
  construction project, DNA is master plan for
  building you.
• Original blueprints stay locked up in the
  contractors office. DNA stays locked up in the
  nucleus.

• A contractor wouldnt give the original blueprint
  to the workers on the job site for two reasons.
• They dont want the original damaged
• A worker doesnt need all the information. Just a
  copy of the plans for todays work.

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ExplainProtein Synthesis
Home

• For similar reasons in the cell, a copy of a
  small part of the DNA is made in the form of
  m-RNA

• We dont want our DNA out in the cytoplasm where
  it could be damaged.
• We dont need to make all of our proteins, all
  the time, in every cell.
• The crew at the job site works from a copy of a
  part of the original blueprint.
• In the cell, proteins are made in the cytoplasm
  from the m-RNA copy while the originalDNA stays
  in the nucleus.

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Introductory Science Introduction to Biology

• You have Completed
• Biochemistry
• Created by John W. Pluemer