Chapter 2: The Chemistry of Life Flashcards
What is an element?
The simplest form of matter to have unique chemical properties. Cannot be broken down by ordinary chemical means. There are 91 naturally occuring elements (atoms are building blocks)
What are the elements that make up 98.5% of human body weight?
- Oxygen (O)
- Carbon (C)
- Hydrogen (H)
- Nitrogen (N)
- Calcium (Ca)
- Phosphorus (P)
What are the lesser and trace elements and minerals that make up the human body?
Lesser elements (.0.8%): Na, K, Cl, S, Fe
Trace Elements (less than 0.7%): required in minute amounts, found as part of enzymes (I, Fe, metals)
Minerals (about 4%): usually salts, inorganic elements extracted from soil by plants and passed to humans (Ca, P mostly, also Cl, Mg, K, Na, and S)
What determines the atomic number v. the atomic mass? What is an isotope (in relation)?
Atomic number: number of protons (Hydrogen has 1, Carbon has 6, Oxygen has 8), unique to each element
Atomic mass / weight: number of neutrons + number of protons
Isotope: element with can have atoms with a different number of neutrons (but the same number of protons)(some isotopes of Hydrogen are Hydrogen-0 neutron, Deutirium-1 neutron, and Tritium-2 neutron)
What is atomic weight?
The average of mass numbers for an element.
What is the overall structure of an atom?
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Define the following: ions, ionization
Ion: charged particle with unequal number of protons and electrons
Ionization: transfer of electrons from one atom to another
What are electrolytes and why are they important?
Electrolytes: substances that ionize in water (acids, bases, or salts) form solutions capable of coducting electric currents
They are important in chemical reactivity, osmotic effects, electrical excitability of nerve and muscle. Imbalance can lead to coma or cardiac arrest.
What are free radicals?
Short lived particles with an unusual number of electrons. Produced by metabolic reactions, radiation, and certain chemicals. Trigger reactions that destroy molecules (can cause cancer, death of heart tissue, and aging…)
Fought by antioxidants, which neutralize free radicals (some are in the body, some can be obtained through diet).
What is a molecule?
A chemical particle composed of two or more atoms united by a chemical bond.
What is a compound?
Molecule composed of two or more elements.
What is the octet rule?
Bonds are formed using electrons in the valence shell (outermost layer). Atoms interact in order to have 8 electrons in their valence shell.
Examples: Inert element won’t react (full shell). Hydrogen has 1 (will give it up), Carbon has 4 (wants 4 more), Oxygen has 6 (wants 2 more), Sodium has 1 (gets rid of it, next layer has 8)
What is distinction between intra and inter?
Intra: inside/within
Inter: between
What is a mixture and how does it apply to the human body?
Mixtures are physically blended but not chemically combinded. Body fluids are complex mixtures. The human body is 50 to 75% water (babies have more water–cartilage, men have more water, women have less-more adipose)
What are the properties of water?
- solvency (ability to dissolve other chemicals)
- cohesion (surface tension!)
- adhesion
- chemical reactivity
- thermal stability (water absorbs heat)