Transcript Ch. 5-Biomolecules- Life`s 4 large molecules

Ch. 5-BiomoleculesLife’s 4 large molecules
carbohydrates
lipids
proteins
nucleic acids
5.1 Organic Molecules
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Carbon: 4 e- in highest energy field
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Carbon shares electrons with other atoms
Carbon can form up to 4 bonds with other
atoms
Carbon based molecules – organic
Non carbon based molecules- inorganic
Biomolecules have a backbone of carbon
atoms
3 carbon backbone shapes
Carbon can bond to other atoms:
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Functional
groups- groups of atoms that react a
certain way in a molecule
Affects
properties of the molecule.
OH- hydroxyl groups make water loving-hydrophilic
molecules
Water-
fearing molecules are hydrophobic.
Hydrocarbons-
carbon bonded to hydrogen
Fuels-
CH4 methane
fat storing molecules
Other atoms- oxygen & nitrogen
Functional groups
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-OH hydroxyl group
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COOH- carboxyl group
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Fatty acids & proteins
NH2- amino group
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Attracts water- hydrophilic- water-loving
Alcohols & carbohydrates
Proteins & Nucleic acids
C=O- carbonyl group
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Aldehydes & ketones
4 categories of biomolecules
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Carbohydrates- sugars
Lipids- fats & oils
Proteins
Nucleic Acids- DNA & RNA
Building Blocks
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Monomer- literally “one part”
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Polymer- literally “many parts”
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The smaller building blocks
Composed of many monomers
Example- starch is the polymer composed of
thousands of ___________ monomers
Every cell has thousands of different
polymers, each has a different function.
Building Polymers
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When 2 monomers are added to form a
polymer - water is lost
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Dehydration reaction
Breaking down polymers
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When a polymer is broken down into
smaller monomers -water is added
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Hydration reaction- hydrolysis
5.2- Carbohydrates
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Provide energy.
Sugars- simple to complex.
Contains carbon, hydrogen, and oxygen.
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Ratio of 1 carbon: 2 hydrogen: 1 oxygen.
General Formula- CH2O ;
ex. Glucose C6H12O6.
Functional group=Hydroxyl group- OH.
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Hydrophilic- water-loving.
Simple Sugars dissolve in water.
Absorbancy of cotton.
Functional Groups:
Monosaccharides
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Simple sugars.
Mono= One sugar unit.
Ex. Glucose, fructose, and galactose.
Suffix (ending)- ose.
Ring-shaped form.
Glucose- main fuel for cellular work.
Unused glucose
starch, glycogen, or fat
molecules.
Figure 5-6
The complete structural diagram of the monosaccharide
glucose (left) shows all its atoms. The simplified
representation (right) shows just the core ring formed by
some of the carbon and oxygen atoms. Ring shapes are
common in sugar molecules found in nature.
Disaccharides
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“Double”; two monosaccharides combined.
Dehydration reaction - building.
Ex. Sucrose- table sugar.
Polysaccharides
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Polymer chain ;many sugar monomers.
Starch- plant cells.-potatoes, corn, rice
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Glucose monomers.
Digested by humans
Cellulose- plant cells
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Glucose monomers
Building material- protects, support.
Celluose=Fiber- necessary; not a nutrient.
Not digested by humans
Cows and termites digest cellulose.
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Glycogen- Animal Cells
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Glucose monomers
Storage of excess sugar
Liver and muscle cells
Breakdown of glycogen releases glucose.
5.3 Lipids- Fats & steroids
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Lipid
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Hydrophobic-”water fearing”
Boundary in cell membrane
Fat
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Glycerol- 3C backbone
3 fatty acids- long hydrocarbon chains
Functional group- carboxyl group
Saturated Fat vs. Unsaturated Fat
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Saturated- all 3 fatty acid chains are filled
with hydrogen atoms.
Ex, animal fats- lard and butter
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Solids at room temp
Unsaturated Fats- not all places are filled
with hydrogen atoms
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Found in fruits, vegetables, & fish
Corn, olive & vegetable oils
Liquid at room temp.
Figure 5-9
Certain vegetable oils contain unsaturated fat molecules, which have at
least one double bond in at least one of the fatty acid chains.
In this case, the double bond is located about halfway along the bottom chain.
Steroids & Cholesterol
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Steroid- lipid with 4 fused carbon rings.
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Steroids differ in types and locations of
functional groups .
Cholesterol- essential for membrane
function
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Used to produce steroids in the body
Figure 5-10
The only difference in these two steroid hormones is the location of their
functional groups. Yet, these two molecules contribute to major
differences in the appearance and behavior of male and female mammals.
5.4 Proteins
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Perform most cell functions
Polymer of amino acids
Polypeptide=chain of amino acids
Amino Acid
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Proteins- made in the ribosomes
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Functional group-NH2
Monomer
Proteins have a specific shape in order to work correctly.
Denaturation- unraveling- changes the shape of the
protien- caused by changes in pH and temperature.
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If the protein does not have the right shape it does not work
properly.
Lego activity.
Figure 5-12
All amino acids consist of a central carbon bonded to an amino group, a carboxyl
group, and a hydrogen atom. The fourth bond is with a unique side group. The
differences in side groups convey different properties to each amino acid.
Figure 5-13
The order of amino acids makes each polypeptide unique. There are 129 amino
acids in this protein, called lysozyme. The three-letter symbols are abbreviations
for the amino acid names.
5.5 Enzymes
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Speed up “catalyze” reactions in cells.
Lower the energy needed for a reaction to
occur.
Activation Energy- start-up energy needed for
a chemical reaction.
Catalyst- speed up reactions
Enzyme- special protein
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Suffix- ending- ase
Ex. amylase, catalase
Substrate-( what is being acted on) binds to the
enzyme.
Active site- substrate-enzyme binding region
Figure 5-15
The activation energy barrier is like a wall between two parts of a pond. If an
enzyme lowers the wall, more frogs have enough energy to reach the other
side.
Figure 5-16
A substrate binds to an enzyme at an active site. The enzyme-substrate
interaction lowers the activation energy required for the reaction to proceed. In
this example, water is added to the weakened bond in sucrose, breaking sucrose
into glucose and fructose.