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Transcript of An atom is the basic unit of matter The three subatomic particles are: 1. Neutrons – no charge 2....
The Chemistry of Life
An atom is the basic unit of matter
The three subatomic particles are:1. Neutrons – no charge2. Protons – + charge3. Electrons – - charge
The nucleus is the center of an atom and is made up of protons + neutrons
Electrons are located outside of the nucleus in the electron cloud. Electrons are in constant motion.
Atoms
An element is a pure substance that consists entirely of one type of atom Isotopes are atoms of the same element that differ
in the number of neutronsEx. carbon-12, carbon-13, carbon-14
Mass Number = Protons + NeutronsAtomic Number = Protons
Pure Substance
A compound is a substance that is formed from 2 or more elements.Chemical & Physical properties of compounds
are usually different from the elements that make them up. Ex. 2H2(g) + O2(g) 2H2O(l)
Chemical Bond – is the energy that holds atoms in a compound together. They are formed from electrons.
Pure Substances
2 main types of chemical bondsIonic Bonds – electrons are
gained or lost by each atom
2Na + Cl2 2NaCl
Covalent Bonds – electrons are sharing between atoms
C + O2 CO2
Pure Substances
A polar molecule is a molecule that has an uneven distribution of charges due to the hydrogen bonding between hydrogen and oxygen.
Because water molecules have slightly + and – ends they can attract each other as well as other polar substances
Water
A mixture is a material composed of 2 or more compounds or elements that are physically (Not Chemically) combined together.
Types of Mixtures:Homogeneous – even distribution of
components.Ex. Solution – shampoo, powdered drinks,
lotion, etc2 parts of a solution:
1. Solute – the substance that is dissolved2. Solvent – the substance doing the
dissolving Heterogeneous – components are easily
distinguishable, and easily separatedEx. Oil + water, salads, pizza
Mixtures
Suspension – materials that do not dissolve when placed in water but break up into smaller pieces and do not settle out.Ex. Italian dressing, dust particles in air, muddy
water, etc.
Mixtures
pH scale – indicates the concentration of H+ ions in a solutionRange is from 0 – 14
0 – 6 Acids7 Neutral usually water8 – 14 Bases
Acids – form hydrogen ions [H+] in a solutionBases – form hydroxide ions [-OH] in a
solution
Acids, Bases, and pH
Buffers are weak acids or bases that are added to help neutralizing a solution without any sudden changes in pH
Acids, Bases, and pH
An organic compound is a compound that usually contains carbonCarbon has 4 electrons in outer shell.Carbon can form 4 strong covalent bonds
usually with C, H, O, or N
Organic compounds in the body are often found as macromolecules which are made from thousands of smaller moleculesThe process of forming macromolecules is
called polymerization (small units called monomers join together to form polymers)
Organic Compounds
Examples:1. Carbohydrates2. Lipids3. Proteins4. Nucleic acids (DNA and
RNA)
Macromolecules
Energy is stored in the bonds that link these units together. The amount of energy stored in these bonds
varies with the type of molecule formed. As a result, not all organic molecules have the
same amount of energy available for use by the organism.
The energy stored in organic molecules determines its caloric value.
Proteins, carbohydrates, and fats/lipids are three organic molecules with different structures and different caloric values based on those structures.
Macromolecules
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Carbohydrates
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Carbohydrates
Small sugar molecules to large sugar molecules.
Examples:A. monosaccharideB. disaccharideC. polysaccharide
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Carbohydrates
Monosaccharide: one sugar unit
Examples: glucose (C6H12O6)
deoxyriboseriboseFructoseGalactose
glucose
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Carbohydrates
Disaccharide: two sugar unit
Examples: Sucrose (glucose+fructose)Lactose (glucose+galactose)Maltose (glucose+glucose)
glucoseglucose
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Carbohydrates
Polysaccharide: many sugar units
Examples: starch (bread, potatoes)
glycogen (beef muscle)
cellulose (lettuce, corn)
glucoseglucose
glucoseglucose
glucoseglucose
glucoseglucose
cellulose
Carbohydrates are important because they the main source of energy for the cell.When carbohydrates are synthesized (made) during
the process of photosynthesis, the plants or other photosynthetic organisms use them as a source of energy or they are stored in the cells.
When complex carbohydrates are consumed, the process of digestion breaks the bonds between the larger carbohydrate molecules so that individual simple sugars can be absorbed into the bloodstream through the walls of the intestines.The bloodstream carries the simple sugars to cells throughout
the body where they cross into the cells through the cell membrane.
Once inside the cells, simple sugars are used as fuel in the process of cellular respiration, releasing energy which is stored as ATP.
Carbohydrates
The caloric value of carbohydrates is dependent on the number of carbon-hydrogen bonds. If an organism has a greater supply of carbohydrates than needed for its energy requirements, the extra energy is converted to fats and stored by the body.
Carbohydrates
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Lipids
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LipidsGeneral term for compounds which are not
soluble in water.
Lipids are soluble in hydrophobic solvents.
“stores the most energy” fats contain more energy (ATP) per gram than carbohydrates or proteins, which explains why fats have a greater caloric value
Examples: 1. Fats2. Phospholipids3. Oils4. Waxes5. Steroid hormones6. Triglycerides
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LipidsFats (lipids) are important to organisms for energy
when carbohydrates are scarce since they are the primary way to store energy.
Six functions of lipids:1. Long term energy storage2. Protection against heat loss (insulation)3. Protection against physical shock (cushioning of vital organs)4. Protection against water loss5. Chemical messengers (hormones)6. Major component of membranes
(phospholipids)
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Lipids
Triglycerides:composed of 1 glycerol and 3
fatty acids. H
H-C----O
H-C----O
H-C----O
H
glycerol
O
C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
=
fatty acids
O
C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
=
O
C-CH2-CH2-CH2-CH =CH-CH2 -CH
2 -CH2 -CH
2 -CH3
=
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Fatty AcidsThere are two kinds of fatty acids you may see these on
food labels:
1. Saturated fatty acids: no double bonds (bad)
2. Unsaturated fatty acids: double bonds (good)
O
C-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH2-CH3
=
saturated
O
C-CH2-CH2-CH2-CH=CH-CH2 -CH
2-CH2 -CH
2 -CH3
=
unsaturated
When fats are consumed, the molecules are broken down during the process of digestion so that individual glycerol and fatty acid molecules are absorbed into the bloodstream through the walls of the intestines.
The blood stream carries the glycerol and fatty acid molecules to cells throughout the body where the molecules cross into the cells through the cell membrane.
Once inside the cell, glycerols and fatty acids are stored for later use or used as fuel for cellular respiration if there are no carbohydrates available.
The process of cellular respiration releases the energy that is held in the chemical bonds of the glycerol and fatty acid molecules
Lipids
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Proteins
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Proteins (Polypeptides)
Made up of Amino AcidsAmino acids (20 different kinds of aa) bonded
together by peptide bonds (polypeptides).
Twelve of these amino acids are made in the body; others must be consumed from foods such as nuts, beans, or meat.
Although proteins are more important as a source of building blocks, amino acids may be used by the body as a source of energy (through the process of cellular respiration), but first they must be converted by the body to carbohydrates. This process does not happen as long as there is a carbohydrate or lipid available.
As a source of energy, proteins have the same caloric value per gram as carbohydrates.
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Proteins (Polypeptides)
Six functions of proteins:1. Storage: albumin (egg white)2. Transport: hemoglobin3. Regulatory: hormones (ie insulin)4. Movement: muscles5. Structural: membranes, hair, nails6. Enzymes: cellular reactions
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Nucleic Acids
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Nucleic acidsTwo types:
a. Deoxyribonucleic acid (DNA- double helix)
b. Ribonucleic acid (RNA-single strand)
c. odd ball Adenosine Triphosphate (ATP)
Nucleic acids are composed of long chains of nucleotides.
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Nucleic acidsNucleotides include:
phosphate grouppentose sugar (5-carbon)nitrogenous bases:
adenine (A)thymine (T) DNA onlyuracil (U) RNA onlycytosine (C)guanine (G)
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Nucleotide
OO=P O O
Phosphate Group
NNitrogenous base (A, G, C, or T)
CH2
O
C1C4
C3 C2
5
Sugar(deoxyribose)
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DNA - 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
Chemical Reactions and
Enzymes
A chemical reaction is a process that changes one set of chemicals into another set of chemicals.Two Components of a Chemical Reaction:
1. Reactants – enter into the chemical reaction (on the left side of the yield)
2. Products – are produced/made by the chemical reaction (on the right side of the yield)
Example: H3PO4 + Mg(OH)2 => Mg3(PO4)2 + H2O
Chemical Reactions
biochemical reactions allow organisms to grow, develop, reproduce, and adapt. Sometimes a chemical reaction must absorb
energy for the reaction to start; often, but not always, this energy is in the form of heat.
Energy, as heat or light, can also be given off as a result of biochemical reactions, such as with cellular respiration or bioluminescence.
Chemical Reactions
Video Clip
Energy is released or absorbed whenever chemical bonds form or are broken.Example: heat
Exothermic Reaction – heat is releasedEndothermic Reaction – heat is absorbed
Most reactions need energy to get started. The amount of energy needed for a reaction to take place is called its activation energy.
Chemical Reactions
Catalyst – speed up the rate of a chemical reaction. (NOTE: Only time is affected amount and type of chemicals is not changed)Catalysts are able to speed up
the rate of a chemical reaction by lowering a chemical reaction’s activation energy.
Enzymes are proteins that act as biological catalystsCells use enzymes to speed up
chemical reactions that take place inside of them.
Chemical Reactions
Enzymes are very specific. Each particular enzyme can catalyze only one chemical reaction by working on one particular reactant (substrate).
Enzymes are involved in many of the chemical reactions necessary for organisms to live, reproduce, and grow, such as digestion, respiration, reproduction, movement and cell regulation.
The structure of enzymes can be altered by temperature and pH; therefore, each catalyst works best at a specific temperature and pH.
Chemical Reactions
Enzyme