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Carbon-based molecules are the foundation of life.
Bonding Properties of Carbon
• Carbon forms covalent bonds with up to four other atoms, including other carbon atoms.
1
2 3, 4
Structure of carbon-based molecules…
• Three general types:
1. straight chain
H H Cl H H | | | | | H - C- C - C - C - C - H | | | | | H H H H H 3-chloropentane
Structure of carbon-based molecules…
• Three general types:
2. Branched chain
Structure of carbon-based molecules…
• Three general types:
3. Ring
• Many carbon-based molecules are made of many small subunits bonded together.
– Monomers are the individual subunits.
– Polymers are made of many monomers.
Four Types of Carbon-
Based Molecules
Carbohydrates
Lipids
Proteins
Nucleic Acids ALL four are found in LIVING things.
Carbohydrates
• Organic molecules made of the elements carbon, hydrogen, and oxygen (CHO)
• Includes sugars and starches
• Pasta, bread, and fruit are high in carbohydrates
Structure of Carbohydrates
• Monomer • Monosaccharides
– “saccharide” means sugar
– simple sugars
– Glucose, galactose, fructose
Structure of Carbohydrates
• Disaccharide
• Two monosaccharide molecules bonded together
• Sucrose, or table sugar, made of one glucose and one fructose molecule
Structure of Carbohydrates
• Polymer • Polysaccharides
– Chains of monosaccharides
– starches, cellulose, and glycogen
Function of Carbohydrates
• Can be broken down to provide energy for cells. – Glucose-main source of energy
for cells, product of photosynthesis
• Provide us with energy – Sugar rush then crash
• Some carbohydrates are part of cell structure. – Cellulose-makes up the cell wall
of plant cells
LIPIDS • Organic molecules made
of the elements carbon, hydrogen, and oxygen (CHO)
• Nonpolar molecules –Do not dissolve in water
• Include fats, oils, cholesterol, and wax
Structure of Lipids
• Fatty acids bonded to glycerol. – Glycerol-3 hydroxyl
groups – Fatty acids-long carbon
chains Two different types of
fatty acids found in fats and oils: oSaturated fatty acids oUnsaturated fatty
acids
Two Types of Fatty Acids
Functions of Lipids • Used for long term energy
storage
• Make up cell membranes – Phospholipid bilayer
• Used to make hormones – Testosterone (males) & estrogen
(females)
• Insulate and waterproof organisms – Cutin-waxy substance that
coats leaves of plants to help prevent water loss
Lipid Polymer-Phospholipid
• Consists of glycerol, two fatty acids (nonpolar tails) and a phosphate group (polar head of molecule)
• Makes up ALL cell membranes
Lipid Polymer-Triglycerides
• Consists of glycerol and three fatty acids
• Type of fat found in your blood.
– Your body uses them for energy.
• You need some triglycerides for good health.
– But high triglycerides can raise your risk of heart disease and may be a sign of metabolic syndrome
Nucleic Acids
• EXTREMELY long carbon-based molecules made of carbon, hydrogen, oxygen, nitrogen, and phosphorus (CHONP)
Structure of Nucleic Acids
• Monomer – Nucleotide
• made of a five-carbon sugar, phosphate group, and a nitrogen base.
• 5 kinds: Adenine, Thymine, Cytosine, Guanine, & Uracil
• Polymers – DNA-Deoxyribonuleic
Acid
– RNA-Ribonucleic Acid
A phosphate group
nitrogen-containing molecule, called a base
deoxyribose (sugar)
Function of Nucleic Acids
DNA
RNA
• DNA stores genetic information
• RNA builds proteins using information from DNA
Proteins
• Large organic molecules made of carbon, hydrogen, oxygen, and nitrogen (CHON)
• Essential to all life
• Foods high in proteins:
– Poultry, fish, eggs, beans, nuts, peanut butter, milk
Structure of Proteins
• Monomer
– Amino acid • Contain an amino group and
a carboxyl group
• Interact to give a protein its shape and function
• Peptide bonds form between amino acids to form chains
• Organisms use 20 different amino acids to build proteins
– Your body makes 12, others come from food you eat
Structure of Proteins • Polymer
– Protein
– Also called polypeptide
• Each protein has a different arrangement of amino acids
• Incorrect amino acid sequence and/or arrangement changes the protein’s structure and function
Function of Proteins
• Building and connecting materials of living things
– Collagen-forms bones, tendons, ligaments, and cartilage
• Take part in chemical reactions and transport materials
– Hormones, antibodies, and enzymes
Function of Proteins
• Longer-lasting energy source than carbohydrates because broken down more slowly
• Involved in eyesight, digestion, etc. as well
2.5: Enzymes Enzymes are catalysts for chemical reactions in
living things.
Chemical Reactions
• Substances are changed into different substances by breaking and forming chemical bonds – Reactants are changed to
form products
Reactants Products
Chemical Reactions in Organisms
Cell growth, reproduction, interaction with the environment, and response to stimuli are the
result of a chemical reaction
Catalysts
• Lowers activation energy
• Speeds up chemical reactions
Activation Energy
• Energy that needs to be absorbed for a chemical reaction to start
–Energy reactants need in order to react
• Break bonds and form new ones
Rate of Chemical Reactions
• Biochemical reactions must occur at certain speeds, or rates, in order to be useful.
• Rate of a reaction depends on:
– Temperature
– Concentration of the chemicals
– Surface area
Enzymes as Catalysts
• Enzymes are mostly proteins
• Make reactions that happen in cells possible – Lower activation energy and speed up reaction
rate
• Without enzymes, many reactions would not happen – Others would occur too slowly for the organism to
survive
• Enzyme will not be used up or changed during the reaction
Structure of Enzymes
• Gives reactants a site where they can come together to react
– Substrates-reactants affected by enzyme
• Substrates bind to the active site
• Shape of substrate and active site are complimentary, or opposite
– Fit together like a lock and key
substrates (reactants)
enzyme
Substrates bind to an enzyme at certain places called active sites.
Lock and Key Model Illustrates how enzymes function
Substrates bind to an enzyme at certain places called active sites.
The enzyme brings substrates together and weakens their bonds.
The catalyzed reaction forms a product that is released from the enzyme.
Structure of Enzymes
• Allows only certain reactants to bind to the enzyme
– An organism may have thousands of different enzymes
– Each is specific to one chemical reaction
• An enzyme’s function depends on its structure.
Functions of Enzymes
• Energy-releasing enzymes power cell functions
• Enzymes in nerve cells produce neurotransmitters to carry impulses from nerves to muscles
• Muscle cells have enzymes that are triggered in response to the neurotransmitters
Functions of Enzymes
• Blood contains enzyme carbonic anhydrase
– Catalyzes reaction in your blood where carbon dioxide combines with water to form carbonic acid
– Makes reaction one million times faster so that carbon dioxide does not build up in your blood, which could be fatal
• Enzyme lipase in the pancrease
– Speeds up digestion of lipids
Uses of Enzymes
• Biological washing powders for clothes
• Food – Alcohol
– Meat tenderizer
– Cheese
– Chocolate covered mints
• Industry – Textile and paper
production
– Photography
– Pharmaceuticals
– Crime Scene Investigating
Functions of Enzymes
• Disruptions in homeostasis can prevent enzymes from functioning. – Enzymes function best in a small range of
conditions.
– Changes in temperature and pH can break hydrogen bonds.
– Destroyed at temperatures above 50˚C
– Work best at pH of 7