A&P I Week 2 Chapter 2 PDF

# A&P I Week 2 Chapter 2 ## 1) Matter - Matter has mass and occupies space (although can be invisible). Atoms make up matter and the human body so we need to understand the basics. ## 2) Atomic Structure - There are 92 naturally occurring elements (atom types) in the universe that can be unbonde...

# A&P I Week 2 Chapter 2 ## 1) Matter - Matter has mass and occupies space (although can be invisible). Atoms make up matter and the human body so we need to understand the basics. ## 2) Atomic Structure - There are 92 naturally occurring elements (atom types) in the universe that can be unbonded (pure elements) or bonded to form compounds. Let’s look at the atoms. - Atoms are made up of mostly empty space. - Protons - in nucleus and have a + charge and a weight of 1 - Neutrons - in nucleus and have no charge and are the same weight as protons. - Electrons - Circle around the nucleus, have -ve charge and essentially no weight ## 3) Composition of Matter - Number of proton = No of electrons. - Atomic Number = No of protons & element has, Change to proton no, changed, element. - Atomic Mass = wt of d atom = wt of protons (don’t forget protons and neutrons weigh the same) - Number of Neutrons = Atomic mass minus atomic no. - Here is an example of a table: | Element | Protons | Electrons | Neutrons | | -------- | -------- | -------- | -------- | | C | 6 | 6 | 6 | | Na | 11 | 11 | 12 | ## 4) Electron Shells - Many atoms are unhappy with their lot in life. They will only be happy (stable) if they fill up their electron spaces and this involves bonding with other atoms to do this. Since only the electrons are involved in bonding all atoms with similar electron structures will act the same. - Electrons can be found in distinct “cloud” areas which we simplify into Bohr Models. - You add electrons in a shell until it is filled up and then you add to the next shell. You can see how many electrons are in a shell by looking at the rows of the periodic table (good for basic shells) ## 5) Chemical Bonding - Many atoms are unhappy with their lot in life. They will only be happy (stable) if they fill up their electron spaces and this involves bonding with other atoms to do this. Since only the electrons are involved in bonding all atoms with similar electron structures will act the same. - The valance shell is the outer most shell which contains the valence electrons. - Only d, valence electrons are involved in bonding. - The key to bonding is filling up the valence shell – Stable Octet rule. - Covalent (sharing electrons) vs Ionic (stealing electrons) should be read in your text. - Example of covalent bonding to form water. ## 6) Chemicals in the Body - Human body is composed of 4 major elements: Carbon, Hydrogen, Nitrogen and Oxygen - 96.1% of body mass. - Iron, Calcium, Sodium, Sulphur, Chlorine and potassium make up 3.9%, with some trace elements accounting for the remainder. - Carbon creates the backbone of most of our structure. It makes multiple (4) bonds. ## 7) Attractions between molecules (Not chemical Bonding) - Because atoms contain many + and – charges they can have some attractive forces. - Opposite attract and like Charges repel. ### a) Polarity - Some elements attract electrons very strongly and share unequally. This creates negative parts of the molecule to where they are drawn and positive parts to from where they leave and makes the molecule polar. - Can cause molecules to stick together. - Some molecules have elements that attract the electrons equally so they are evenly spread out. This creates no negative or positive areas, only neutral areas and is called non polar. ## I. Hydrogen Bonding - a special result of polarity - Hydrogen’s have their electrons taken (or shared very unevenly) and therefore have a + charge. They get attracted to very – charges. - Attractions are between oxygen and hydrogen. - Hydrogen bonding creates surface tension of water. ## 8) Special properties of Water - Polar molecule - Does hydrogen bonding (as diagramed above). - Has strong surface tension (due to hydrogen bonding) and a high specific heat (carries heat well). - Very unique - expands when it freezes. - Dissolves other polar molecules (like dissolves like). - Polar vs non-polar. ## 9) pH - scale of acids and bases - On a scale of 1-14. - 0 is acidic. - 7 is neutral. - 14 is basic. - Both extremes will kill you. - Changes in pH can denature (deactivate) proteins therefor you have buffering systems to maintain constant levels (Homeostasis). - CO2 in the blood aids in maintaining the pH (helps create the buffering system) and also helps control breathing. ## 10) Organic vs Inorganic - Inorganic - Lack Carbon, small simple molecules eg, CO2. - Organic - Carbon based compound eg, CH (major types are listed below). ### i. Carbohydrates - The Gobs are sugars (generally from plants). - **Monosaccharide** = One sugar eg, Glucose and Fructose. - **Disaccharide** = Two sugars eg, Glu + Fru = Sucrose. - **Polysaccharides** = Long chains of sugars eg, Starch, Glycogen and Allulose. - **Starch** - Plant food storage is how plants store sugars. - **Cellulose** - Plant structure. Humans don’t have the enzymes to break it down. Commonly known as fiber. It is the most abundant organic material on earth. - **Glycogen** - Animal storage of sugars in long chains. - **Glycogen** - Insect exoskeleton. ### ii. Lipids - **Triglycerides** - Involved in energy storage, insulation and cushioning, especially subcutaneous (under skin). - Women generally store more than men (12% body fat vs 8%). - Glycerol head group with 3 fatty acid tails. - **Saturated - usually solid**. Saturated fats are filled up with H and can’t take anymore. They tend to be solid in general. - **Unsaturated - usually liquid (oil)**. Kinks at d, double bond. ### 2. Phospholipids - **Amphipathic (amphi = both, patheia = feeling) molecule**. Have very polar head group (hydrophilic) & non-polar tail group (hydrophobic). - This creates a cell membrane. - Creates cell membrane (will discuss in detail then). ### 3. Steroids - Key steroid is cholesterol - used in cell membrane fluidity and to make steroid hormones. ### 4. Waxes - Waxes eg, ear waxes. ### iii. Nucleic Acids - Library of hereditary information that can be used to make certain proteins and passed on to offspring. - Both Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA) consist of 3 parts: - **Adenine (A)** - 2 ring base called a purine. - **Guanine (G)** - 2 ring base called a purine. - **Thymine (T)** - 1 ring base called a pyrimidine. - **Cytosine (C)** - 1 ring base called a pyrimidine. - A = T - 2 hydrogen bonds and are complementary base pairs. - C = G - 3 hydrogen bonds and are complementary base pairs. - Since they are H+ bonds holding the DNA ladder together they can easily be unzipped to gain access to a gene or to copy the DNA (in Synthesis phase of the cell cycle). - A base, a sugar and a phosphate together form a nucleotide. - RNA is single stranded and Uracil replaces Thymine. ### iv. Proteins - Create chains of amino acids. - Some amino acids are small, some are large, some are positive, some are negative. The result is they fold the chain to give a 3-D shape that has a specific function. - Therefore if you make a chain 10 amino acids long and there are 20 different types you have a possibility of 10,240,000,000,000 different proteins in the end. - A typical protein is usually made from between 50-2000 amino acids long and the longest we know of is 30,000. ## V. How macromolecules Bind - **Dehydration/condensation vs Hydrolysis** # Lecture 2: Read the Chapter. The notes and the following are fair game on tests: - General protein structure (section in 2.7). - 2.8 Protein structure.