biochemistry of cells
DESCRIPTION
Biochemistry of Cells. Americans consume an average of 140 pounds of sugar per person per year. Uses of Organic Molecules. Cellulose, found in plant cell walls, is the most abundant organic compound on Earth. Uses of Organic Molecules. A typical cell in your body has about 2 meters of DNA. - PowerPoint PPT PresentationTRANSCRIPT
2
Uses of Organic MoleculesAmericans consume an average of 140 pounds of sugar per person per yearCellulose, found in plant cell walls, is the most abundant organic compound on Earth
3
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
4
WaterAbout 60-90 percent of an organism is water
Water is used in most reactions in the bodyWater is called the universal solvent
6
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
7
Carbon is a Versatile Atom
It has four electrons in an outer shell that holds eight
Carbon can share its electrons with other atoms to form up to four covalent bonds
9
Carbon can use its bonds to::
Attach to other carbons
Form an endless diversity of carbon skeletons
10
Large Hydrocarbons:
Are the main molecules in the gasoline we burn in our cars
The hydrocarbons of
fat molecules provide energy for our bodies
11
Shape of Organic Molecules
Each type of organic molecule has a unique
three-dimensional shape
The shape determines its function in an
organism
12
Functional Groups are:
Groups of atoms that give properties to the compounds to which they attach
Gained Electrons Lost Electrons
14
Giant Molecules - PolymersLarge molecules are called polymers
Polymers are built from smaller molecules called monomersBiologists call them macromolecules
16
Most Macromolecules are Polymers
Polymers are made by stringing together many smaller molecules called monomers
Nucleic Acid
Monomer
17
Linking Monomers
Cells link monomers by a process called dehydration
synthesis (removing a molecule of water)
This process joins two sugar monomers to make a double
sugar
Remove H
Remove OH
H2O Forms
18
Breaking Down PolymersCells break
down macromolecules by a process called hydrolysis (adding a molecule of water)
Water added to split a double sugar
19
Macromolecules in Organisms
There are four categories of large molecules in cells:
Carbohydrates
Lipids
Proteins
Nucleic Acids
20
Carbohydrates
Carbohydrates include: Small sugar molecules
in soft drinksLong starch molecules in pasta and potatoes
21
CarbohydratesCarbohydratesSmall sugar moleculesSmall sugar molecules to large large
sugar moleculessugar molecules.
Examples:Examples:A.A. monosaccharidemonosaccharideB.B. disaccharidedisaccharideC.C. polysaccharidepolysaccharide
22
CarbohydratesCarbohydrates
Monosaccharide: one sugar unitMonosaccharide: one sugar unit
Examples:Examples: glucose (glucose (C6H12O6)
deoxyribosedeoxyribose
riboseribose
FructoseFructose
GalactoseGalactose
glucoseglucose
23
Monosaccharides:
Called simple sugars
Include glucose, fructose, & galactoseHave the same chemical, but different structural formulas
C6H12O6
24
Monosaccharides
Glucose is found in sports drinks
Fructose is found in fruitsHoney contains both glucose & fructoseGalactose is called “milk sugar”
25
Isomers
Glucose & fructose are isomers because they’re structures are different, but their chemical formulas are the same
28
Disaccharides
A disaccharide is a double sugar
They’re made by joining two monosaccharides
Involves removing a water molecule (dehydration)
29
Disaccharides
Common disaccharides include:
Sucrose (table sugar)
Lactose (Milk Sugar)
Maltose (Grain sugar)
30
Disaccharides
Sucrose is composed of glucose + fructose
Maltose is composed of 2 glucose moleculesLactose is made of galactose + glucose
GLUCOSE
31
CarbohydratesCarbohydrates
Disaccharide: two sugar unitDisaccharide: two sugar unit
Examples: Examples: Sucrose (glucose+fructose)Sucrose (glucose+fructose)
Lactose (glucose+galactose)Lactose (glucose+galactose)
Maltose (glucose+glucose)Maltose (glucose+glucose)
glucoseglucoseglucoseglucose
32
Polysaccharides
Complex carbohydrates
Composed of many sugar monomers linked togetherPolymers of monosaccharide chains
34
Starch
Starch is an example of a polysaccharide in plants
Plant cells store starch for energy
Potatoes and grains are major sources of starch in the human diet
35
Glycogen
Glycogen is an example of a polysaccharide in animals
Animals store excess sugar in the form of glycogen
(in muscles and liver)Glycogen is similar in structure to starch
36
Cellulose
Cellulose 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 wood
It is also known as dietary fiber
38
Dietary Cellulose
Most animals cannot derive nutrition from fiber
They have bacteria in their digestive tracts that can break down cellulose
39
CarbohydratesCarbohydratesPolysaccharide: many sugar unitsPolysaccharide: many sugar units
Examples:Examples: starch (bread, starch (bread, potatoes)potatoes)
glycogen (beef glycogen (beef muscle)muscle)
cellulose (lettuce, cellulose (lettuce, corn)corn)
glucoseglucoseglucoseglucose
glucoseglucoseglucoseglucose
glucoseglucoseglucoseglucose
glucoseglucoseglucoseglucose
cellulosecellulose
40
Sugars in Water
Simple sugars and double sugars dissolve readily in water
They are hydrophilic, or “water-loving”
WATER MOLECULE
SUGAR MOLECULE
41
Lipids
Lipids are hydrophobic –”water fearing”
Includes fats, waxes, steroids, & oils
Do NOT mix with water
FAT MOLECULE
43
Types of Fatty Acids
Unsaturated fatty acids have less than the maximum number of hydrogens bonded to the carbons (a double bond between carbons)
Saturated fatty acids have the maximum number of hydrogens bonded to the carbons (all single bonds between carbons)
45
Triglyceride
Monomer of lipids
Composed of Glycerol & 3 fatty acid chainsGlycerol forms the “backbone” of the fat Organic
Alcohol
48
Fats in Organisms
Most animal fats have a high proportion of saturated fatty acids & exist as solids at room temperature (butter, margarine, shortening)
49
Fats in Organisms
Most plant oils tend to be low in saturated fatty acids & exist as liquids at room temperature (oils)
50
Fats
Dietary fat consists largely of the molecule triglyceride composed of glycerol and three fatty acid chains
Glycerol
Fatty Acid Chain
Dehydration links the fatty acids to Glycerol
54
SteroidsThe carbon skeleton of steroids is bent to form 4 fused ringsCholesterol is the “base steroid” from which your body produces other steroids
Estrogen & testosterone are also steroids
Cholesterol
TestosteroneEstrogen
55
Synthetic Anabolic SteroidsThey are variants of testosteroneSome athletes use them to build up their muscles quicklyThey can pose serious health risks
56
LipidsLipidsGeneral term for compounds which are not not
soluble in watersoluble in water.Lipids are soluble in hydrophobic solventsare soluble in hydrophobic solvents.Remember:Remember: “stores the most energy”“stores the most energy”Examples:Examples: 1. Fats1. Fats
2. Phospholipids2. Phospholipids3. Oils3. Oils4. Waxes4. Waxes5. Steroid hormones5. Steroid hormones6. Triglycerides6. Triglycerides
57
Proteins
Proteins are polymers made of monomers called amino acids
All proteins are made of 20 different amino acids linked in different orders
Proteins are used to build cells, act as hormones & enzymes, and do much of the work in a cell
59
Proteins (Polypeptides)Proteins (Polypeptides)Amino acids (20 different kinds of aa) bonded
together by peptide bondspeptide bonds (polypeptidespolypeptides).
Six functions of proteins:Six functions of proteins:1.1. Storage:Storage: albumin (egg white)albumin (egg white)2.2. Transport: Transport: hemoglobinhemoglobin3.3. Regulatory:Regulatory: hormoneshormones4.4. Movement:Movement: musclesmuscles5.5. Structural:Structural: membranes, hair, nailsmembranes, hair, nails6.6. Enzymes:Enzymes: cellular reactionscellular reactions
61
Structure of Amino Acids
Amino acids have a central carbon with 4 things boded to it:Amino group -NH3Carboxyl group -
COOHHydrogen -H
Side group -R
Amino
group
Carboxylgroup
R group
Side groups
Leucine -hydrophobic
Serine-hydrophillic
62
Linking Amino Acids
Cells link amino acids together to make proteinsThe process is called dehydration synthesisPeptide bonds form to hold the amino acids together
Carboxyl
Amino Side
Group
Dehydration Synthesis
Peptide Bond
64
Proteins (Polypeptides)Proteins (Polypeptides)
Four levels of protein structure:Four levels of protein structure:
A.A. Primary StructurePrimary Structure
B.B. Secondary Structure Secondary Structure
C.C. Tertiary Structure Tertiary Structure
D.D. Quaternary Structure Quaternary Structure
66
Primary Protein Structure
The primary structure is the specific sequence of amino acids in a protein
Amino Acid
67
Protein Structures
Secondary protein structures occur when protein chains coil or fold
When protein chains called polypeptides join together, the tertiary structure forms
In the watery environment of a cell, proteins become globular in their quaternary structure
71
Protein Structures
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
72
Denaturating Proteins
Changes 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
74
Changing Amino Acid Sequence
Substitution of one amino acid for another in hemoglobin causes
sickle-cell disease
(a) Normal red blood cell Normal hemoglobin
12 3
4 56
7. . . 146
(b) Sickled red blood cell Sickle-cell hemoglobin
2 314 5
67. . . 146
75
Proteins as Enzymes
Many proteins act as biological catalysts or enzymes
Thousands of different enzymes exist in the body
Enzymes control the rate of chemical reactions by weakening bonds, thus lowering the amount of activation energy needed for the reaction
76
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.
79
EnzymesEnzymes
FreeEnergy
Progress of the reaction
Reactants
Products
Free energy of activationFree energy of activation
Without Enzyme
With Enzyme
81
Nucleic Acids
Store hereditary information
Contain information for making all the body’s proteinsTwo types exist --- DNA & RNA
85
Nucleic AcidsNitrogenous base
(A,G,C, or T)
Phosphategroup
Thymine (T)
Sugar(deoxyribose)
Phosphate
BaseSugar
Nucleic acids are polymers of nucleotides
Nucleotide
86
Bases
Each DNA nucleotide has one of the following bases:
Thymine (T) Cytosine (C)
Adenine (A) Guanine (G)
–Adenine (A)
–Guanine (G)
–Thymine (T)
–Cytosine (C)
87
Nucleotide Monomers
Form long chains called DNA
Backbone
Nucleotide
Bases
DNA strand
Nucleotides are joined by sugars & phosphates on the side
89
DNA - double helixDNA - double helix
P
P
P
O
O
O
1
23
4
5
5
3
3
5
P
P
PO
O
O
1
2 3
4
5
5
3
5
3
G C
T A
90
RNA – Ribonucleic Acid
Ribose 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
92
Websites to Explore
http://www2.nl.edu/jste/biochem.htmMacromolecules of Life (animations)
http://faculty.ccbcmd.edu/biotutorials/energy/adpan.htmlHydrolysis of ATP molecule
http://www.okc.cc.ok.us/biologylabs/index.htmOKC Biology Labs Online: Organic Molecules
97
End
http://www.bbc.co.uk/education/asguru/biology/02biologicalmolecules/index.shtml