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Anatomy and PhysiologyChapter #2
- Chemistry is the branch of science that considers the composition of matter and how this composition changes.
- Chemistry is essential for understanding anatomy and physiology because body structures and functions result from chemical changes within cells.
2.2 Structure of Matter
- Matter is anything that has mass (weight) and takes up space. Matter is found in various forms, gases, liquids, and solids
- Elements make up all matter.
- Elements are composed of tiny particles called atoms.
- The smallest complete units of elements are atoms.
- Nucleus is the central portion of the atom which contains neutrons (neutral) and protons (positive).
- Electrons, which are extremely small, found outside the nucleus in energy shells or levels or rings have a negative charge.
- What are the components of an atom that determine its electrical charge?
- Protons and electrons
- Atomic number is the number of protons in an element.
- The number of protons in the nucleus of an atom equal the number of electrons in its shells.
- Energy levels or shells:
- 1st shell can hold a max of 2 electrons
- 2nd – 6th shells can hold a max of 8 electrons
Drawing atoms continued…
- Atomic weight is the number of protons plus neutrons.
- SO…. Atomic weight – atomic number = the number of neutrons.
- Draw Lithium?
- The defining characteristic of stable elements is the maximum number of electrons in its outer shell. Noble gases.
- Unstable elements achieve stable structures by gaining, losing, or sharing electrons in their energy levels or shells.
Bond Types 3 Main Types
- Ionic bond between a metal and nonmetal they transfer electrons forming ions.
- Ion atoms that gain or lose electrons (-) become electrically charged.
- Covalent bond between two nonmetals they share electrons.
- When atoms combine with other atoms, they can share an electron with another atom, lose an electron or gain an electron.
- Hydrogen Bonds
Molecules and Compounds
- A molecule is formed when two or more atoms combine.
- If atoms of different elements combine, the resulting structure can also be called a compound. Examples: Baking soda, sugar
- Molecular formula represents the numbers and types of atoms in a molecule. Examples… H2O & C6H12O6
- Structural formulas show what molecules look like.
You do Not need in your notes
Chemical Reactions 4 Types
- Synthesis when two or more atoms or reactants bond to form a new, more complex structure. Synthesis requires energy and is important to the growth of body parts.
- Decomposition the opposite of synthesis
- Single Replacement
- Double Replacement
- Catalysts affect the speed of a reaction but is not consumed by the reaction.
- Electrolytes contains electrically charged particles (ions), it will conduct an electric current. When electrically charged ions disassociate in water, the solution will conduct electricity. Example: Salt water
Acids and Bases
- pH scale ranges from 0 to 14. It indicates how acidic something is.
- Acids have pH less than 7
- Neutral pH equal to 7
- Bases have pH greater than 7
2.3 Chemical Constituents of Cells
- 2 types of chemicals
- Organic must contain carbon and hydrogen but may contain other elements as well. (C6H12O6) Living things or once living things.
- Inorganic all the other compounds (H20) do NOT contain C.
- Carbon Dioxide
- In the human body, water plays an important role in dissolving solid substances, moving chemicals around the body, and absorbing and moving heat
- Is the most abundant compound in cells and is a solvent in which chemical reactions occur.
- Transports chemicals and heat.
- Releases energy from glucose and other nutrients.
- This energy drives metabolism.
- Is an inorganic substances that is a metabolic waste product, exhaled from the lungs.
- Provide a variety of ions that metabolic processes require.
- Nucleic acids
- Supply most of the energy needed by cells
- Composed of what 3 elements? C,H,O
- Monosaccharides (simple sugars)
- Disaccharides are two sugars joined together
- Polysaccharides, such as starch, are built of many sugars.
- Humans synthesize the complex carbohydrate called glycogen.
Lipids made of C,H,O but in different amounts
- Lipids include fats (most common), steroids, and phospholipids.
- A fat that has all of its carbon atoms joined by single carbon to carbon bonds is said to be saturated. (solid at room temp, bad for you)
- Unsaturated fats (liquid at room temp, good for you, double bonds)
- Cholesterol, estrogens, and testosterone are all steroids.
- A phospholipid typically has two fatty acid chains and a phosphate group.
- Proteins have a great variety of functions in the body---as structural materials, as energy sources, as certain hormones, as receptors on cell membranes, as antibodies, and as enzymes to catalyze metabolic reactions.
- Proteins contain what 4 elements? C,H,O,N Sometimes S
- Building blocks of proteins are the amino acids (20)
- Proteins have complex shapes held together by hydrogen bonds. (their many shapes changes their functions)
- Protein shapes, which determine how proteins function, can be altered by pH, temperature, radiation, or chemicals. H bonds break this is called denatured.
13. Aspartic acid
(NOTE: the 8 essential amino acids are in red. These cannot be synthesized by the human body and must be obtained from food. Arginine and histidine are essential only for children.)
You do NOT need in your notes
- Nucleic acids form genes and take part in protein synthesis.
- They contain the elements C,H,O,N,P
- The building blocks are called nucleotides.
- Nucleic acids are of two major types: DNA (with deoxyribose) and RNA (with ribose).
DNA & RNA
Deoxyribonucleic acid: DNA (deoxyribonucleic acid) stores the molecular code in genes.
- Prion protein can assume up to 12 different shapes before prion was discovered it was believed protein shape was always 3-D
- Some prions are infectious “mad cow disease”
- Some prions are not infectious “Alzheimer disease” which cause gummy plaques in the brain and disrupt functioning.
- Some forms of Alzheimer disease may be caused by protein misfolding
- Chemistry Image. www.aperfectworld.org/healthcare_medicine.html
- DNA image. www.pbs.org/wgbh/nova/origins/knoll.html
- Structural formula image.