1 biochemistry of cells copyright cmassengale. 2 carbon-based molecules although a cell is mostly...
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3 Carbon is a Versatile Atom It has four electrons in an outer shell that holds eight Copyright CmassengaleTRANSCRIPT
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Biochemistry of Cells
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Carbon-based MoleculesAlthough a cell is mostly water, the rest of the cell consists mostly of carbon-based molecules
Organic chemistry is the study of carbon compounds
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Carbon is a Versatile Atom
It has four electrons in an outer shell that holds eight
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Carbon can use its bonds to::
Attach to other carbons
Form an endless diversity of carbon skeletons
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HydrocarbonsThe simplest carbon compounds …
Contain only carbon & hydrogen atoms
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Large Hydrocarbons:Are the main
molecules in the gasoline we burn in our cars
The hydrocarbons of
fat molecules provide energy for our bodies
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Shape of Organic Molecules
Each type of organic molecule has a unique
three-dimensional shape
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Uses of Organic MoleculesAmericans consume an average of 140 pounds of sugar per person per year
Cellulose, found in plant cell walls, is the most abundant organic compound on Earth
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Uses of Organic MoleculesA typical cell in
your body has about 2 meters of DNA
A typical cow produces over 200 pounds of methane gas each year
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Functional Groups are:Groups of atoms that give properties to
the compounds to which they attach
Gained Electrons Lost ElectronsCopyright Cmassengale
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Common Functional Groups
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Giant Molecules - PolymersLarge molecules are called polymers
Polymers are built from smaller molecules called monomersBiologists call them macromolecules
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Examples of PolymersProteins
Lipids
CarbohydratesNucleic
Acids
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Most Macromolecules are Polymers
Polymers are made by stringing together many smaller molecules called monomers
Nucleic Acid
Monomer
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Linking MonomersCells link monomers by a process
called
Remove H
Remove OH
H2O Forms
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Breaking Down PolymersCells break
down macromolecules by a process called hydrolysis (adding a molecule of water)
Water added to split a double sugar
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Macromolecules in OrganismsThere are four categories of large
molecules in cells:
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CarbohydratesCarbohydrates include: Small sugar molecules
in soft drinksLong starch molecules in pasta and potatoes
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Monosaccharides:Called simple sugars
Include glucose, fructose, & galactoseHave the same chemical, but different structural formulas
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MonosaccharidesGlucose is found in sports drinksFructose is found in fruitsHoney contains both glucose & fructoseGalactose is called “milk sugar”
-OSE ending means SUGARCopyright Cmassengale
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IsomersGlucose & fructose are isomers because they’re structures are different, but their chemical formulas are the same
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RingsIn aqueous (watery) solutions,
monosaccharides form ring structures
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Cellular Fuel
Monosaccharides are the main fuel that cells use for cellular work
ATPCopyright Cmassengale
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DisaccharidesA disaccharide is a double sugarThey’re made by joining two monosaccharidesInvolves removing a water molecule (condensation)Bond called a GLYCOSIDIC bond
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Disaccharides
Common disaccharides include:
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DisaccharidesSucrose is composed of glucose + fructose
Maltose is composed of 2 glucose moleculesLactose is made of galactose + glucose GLUCOSE
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PolysaccharidesComplex carbohydrates
Composed of many sugar monomers linked together
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Examples of Polysaccharides
Starch
Glycogen
Cellulose
Glucose Monomer
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StarchStarch is an example of a
polysaccharide in plants
Potatoes and grains are major sources of starch in the human diet
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GlycogenGlycogen is an example
of a polysaccharide in animals
Animals store excess sugar in the form of glycogen
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CelluloseCellulose is the most abundant
organic compound on Earth
It forms cable-like fibrils in the tough walls that enclose plants
It is a major component of woodIt is also known as dietary fiber
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Cellulose
SUGARSCopyright Cmassengale
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Dietary CelluloseMost animals cannot derive
nutrition from fiberThey have bacteria in their digestive tracts that can break down cellulose
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Sugars in WaterSimple sugars and double sugars
dissolve readily in water
They are hydrophilic, or “water-loving”
WATER MOLECULE
SUGAR MOLECULE
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LipidsLipids are hydrophobic –”water
fearing”
Includes fats, waxes, steroids, & oils
Do NOT mix with water
FAT MOLECULE
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Function of LipidsFats store energy, help to insulate
the body, and cushion and cushion and protect organs protect organs
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Triglyceride
Monomer of lipids
Composed of Glycerol & 3 fatty acid chainsGlycerol forms the “backbone” of the fat Organic
Alcohol (-OL ending)
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Types of Fatty Acids
Unsaturated fatty acids h
Saturated fatty acids
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Types of Fatty Acids
Single Bonds in Carbon chain
Double bond in carbon chain
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Triglyceride
Glycerol Fatty Acid Chains
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Fats in OrganismsMost animal fats have a high
proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening)
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Fats in OrganismsMost plant oils tend to be low in
saturated fatty acids & exist as liquids at room temperature (oils)
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FatsDietary fat consists largely of the
molecule triglyceride composed of glycerol and three fatty acid chains
Glycerol
Fatty Acid Chain
Condensation links the fatty acids to Glycerol
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Lipids & Cell Membranes
•Cell membranes are made of lipids called phospholipids
•Phospholipids have a head
•Phospholipids also have 2 tails
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SteroidsThe carbon skeleton of steroids is bent to form 4 fused ringsCholesterol is the “base steroid” from which your body produces other steroidsEstrogen & testosterone are also steroids
Cholesterol
TestosteroneEstrogen
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Synthetic Anabolic SteroidsThey are variants of testosteroneSome athletes use them to build up their muscles quicklyThey can pose serious health risks
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ProteinsProteins are polymers made of
monomers called amino acids
All proteins are made of 20 different amino acids linked in different orders
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Four Types of Proteins
Structural
Contractile
Storage
TransportCopyright Cmassengale
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Structure of Amino Acids
Amino acids have a central carbon with 4 things boded to it:Amino group –NH2
Carboxyl group -COOH
Hydrogen -HSide group -R
Amino
group
Carboxylgroup
R group
Side groups
Leucine -hydrophobic
Serine-hydrophillic
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Linking Amino AcidsCells link amino acids together to make proteinsThe process is called condensation or dehydration
Carboxyl
Amino Side
Group
Dehydration Synthesis
Peptide BondCopyright Cmassengale
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20 Amino Acid Monomers
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Primary Protein StructureThe primary structure is the specific sequence of amino acids in a proteinCalled polypeptide
Amino Acid
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Protein Structures
Secondary protein structures occur when protein chains coil or foldWhen protein chains called
polypeptides join together, the tertiary structure forms because R groups interact with each otherIn the watery environment of a cell, proteins become globular in their quaternary structure
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Protein Structures or CONFORMATIONS
Hydrogen bond
Pleated sheet
Amino acid
(a) Primary structure
Hydrogen bond
Alpha helix
(b) Secondary structure
Polypeptide(single subunit)
(c) Tertiary structure
(d) Quaternary structure
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Proteins as EnzymesMany proteins act as biological
catalysts or enzymes
Thousands of different enzymes exist in the body
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Enzymes
Their folded conformation creates an area known as the active site.
Enzymes are globular proteins.
The nature and arrangement of amino acids in the active site make it specific for only one type of substrate.
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Enzyme + Substrate = Product
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How the Enzyme Works
Enzymes are reusable!!!Active site changes SHAPECalled INDUCED FIT
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Denaturating ProteinsChanges in temperature & pH can denature (unfold) a protein so it
no longer worksCooking denatures protein in eggs
Milk protein separates into curds & whey when it denatures
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Changing Amino Acid Sequence
Substitution of one amino acid for another in hemoglobin causes
sickle-cell disease
(a) Normal red blood cell Normal hemoglobin
1 2 34 5
6 7. . . 146
(b) Sickled red blood cell Sickle-cell hemoglobin
2 314 5
6 7. . . 146
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Other Important Proteins
•Blood sugar level is controlled by a protein called insulin•Insulin causes the liver to uptake and store excess sugar as Glycogen
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INSULIN
Cell membrane with proteins & phospholipids
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Nucleic AcidsStore hereditary information
Contain information for making all the body’s proteinsTwo types exist --- DNA & RNA
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Nucleic AcidsNitrogenous base
(A,G,C, or T)
Phosphategroup
Thymine (T)
Sugar(deoxyribose)
Phosphate
BaseSugar
Nucleic acids are polymers of nucleotides
NucleotideCopyright Cmassengale
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Nucleotide – Nucleic acid monomer
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BasesEach DNA nucleotide has one of the following bases:
Thymine (T) Cytosine (C)
Adenine (A) Guanine (G)
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Nucleotide MonomersForm long chains called DNA
Backbone
Nucleotide
Bases
DNA string
Nucleotides are joined by sugars & phosphates on the side
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DNA
Basepair
Double helix
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RNA – Ribonucleic AcidRibose sugar has an extra –OH or hydroxyl groupIt has the base uracil (U) instead of thymine (T)
Nitrogenous base(A,G,C, or U)
Sugar (ribose)
Phosphategroup
Uracil
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ATP – Cellular Energy
•ATP is used by cells for energy
•Adenosine triphosphate•Made of a nucleotide with 3
phosphate groups
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Summary of Key Concepts
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Nucleic Acids
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Macromolecules
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Macromolecules
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End
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