A&P Chapter 2: Chemistry of Living Things

Matter

anything that has mass/takes up space (ex: air, water, people, trees)

Elements

simplest form of pure substance made of one atom type (ex: oxygen, carbon, gold)

Compounds

pure substance made of two or more atom types (ex: water, salt, carbon dioxide)

Organization of matter (hierarchy)

Subatomic particles —> combine to form atoms —> bond together to make molecules —> make up living things

Characteristics of subatomic particles

1. Protons: +1 charge, found in nucleus, 1 amu

2. Neutrons: 0 charge, found in nucleus, 1 amu

3. Electrons: -1 charge, orbits around nucleus, much smaller

Atomic number

number of protons in an element (Z)

in a neutral element, the number of protons = electrons

Mass number

number of protons + neutrons in an atom (A)

Isotopes

atoms of an element that have the same atomic number, but different mass numbers (same protons, different neutrons)

1. How they’re used in biology/medicine: radioactive isotopes are used in biology to date geological fossils and in medicine to treat cancer, diagnose disease, find biochemical reaction/location, and DNA structure.

How do the location of electrons determine the chemical properties of an atom?

The number of electrons in the outer/valence shell determines how reactive an atom is (full valence shell = stable/non-reactive, incomplete valence shell = reactive/unstable) and the kinds of bonds it has. Basically how it interacts with other atoms.

[Different kinds of chemical bonds]

Ionic bond

forms when one atom gives an electron to another. the atom that loses the electron becomes positive, the one that gains it becomes negative.

1. ion: when an atom gains/loses electrons

2. cation: positive charge - atom loses electrons

3. anion: negative charge - atom gains electrons

[Different kinds of chemical bonds]

Covalent bonds

formed by sharing a pair of valence electrons = full outer shell

1. non-polar: equal sharing of electrons (balanced)

2. polar: unequal sharing of electrons (unbalanced)

[Different kinds of chemical bonds]

Hydrogen bonds

a weak bond between a partially positive hydrogen atom (already bonded) and a nearby electronegative atom

[Forms of energy in matter]

Kinetic energy

energy particles have from moving

ex: thermal (heat), electrical (electrons), radiant (x-rays)

[Forms of energy in matter]

Potential energy

stored energy based on position/arrangement of particles

ex: chemical (stores in bonds), nuclear (in the nucleus), elastic

[Forms of energy in matter]

Mechanical energy

sum of kinetic and potential energy

Energy interactions in the human body

energy from food/nutrients is converted into ATP through metabolism, which powers muscle movement, nerve signaling, and repair

[Chemical Reactions]

Metabolism

all chemical reactions in the body that sustain life (anabolism and catabolism make up metabolism)

[Chemical Reactions]

Anabolism

uses energy/ATP to build and repair body structures (consumes)

[Chemical Reactions]

Catabolism

breaks down molecules to release energy/ATP (releases)

[Chemical Reactions]

Activation Energy

the initial energy required to break bonds/start reaction

[Chemical Reactions]

Catalysts (enzymes)

increase the speed of a reaction (can be used in multiple reactions)

Structure of water and why it’s shape makes it a polar molecule

water is made of one oxygen atom covalently bonded to two hydrogen atoms in a V-shape. it’s polar because of uneven electron density/charge since the oxygen has a stronger attraction.

Chemical formula for creation of water from hydrogen and oxygen

2 H2(g) + O2(g) → 2 H2O(g)

the reactants are the hydrogen and oxygen gas

The Four Life-Supporting Properties of Water (and how they affect human life)

1. Cohesion of water: water molecules stick together via hydrogen bonds (cohesion) and stick to other surfaces = high surface tension (impact on humans: cohesion allows blood to travel against gravity + high surface tension helps lung function)

2. Resistance to change in temperature: takes more energy/heat to increase temperature. water can also moderate temperature. (impact on humans: prevents us from overheating during exercise)

3. Frozen Water Floats (Density): water is less dense when frozen = floats. (impact on humans: the surface of lakes freeze to allow aquatic life underneath to survive, we rely on those)

4. Solvent for Life: water’s polarity allows it to dissolve most substances (impact on humans: water is the solvent for blood, which transports nutrients and minerals)

Chemical properties of acids, bases, and neutral solutions + buffers

1. Acids: compound that releases H+ to solution (pH<7)

2. Bases: compound that accepts H+/releases OH-, removes H+ from a solution (pH>7)

3. Neutral solutions: have equal amounts of H+ and OH- ions (pH=7)

4. Buffers: help resist changes in pH by counteracting and making it neutral (ex: accepts H+ ions when they’re in excess and donates H+ ions when they’re depleted)

Special bonding properties of carbon (allows it to form an endless variety of organic molecules)

carbon has four covalent bonds (tetravalency), bonds with itself (catenation), can make multiple kinds of bonds (single, double, triple), and bonds with many elements.

The 4 types of macromolecules

carbohydrates, proteins, nucleic acids, and lipds

Carbohydrates

formed from building blocks/monomers of glucose. used as fuel/building material.

[Carbohydrates]

Monosaccharides

single sugars (monomers) that offer immediate energy, also used as building blocks. Ex: glucose, ribose, glyceraldehyde.

[Carbohydrates]

Disaccharides

double sugar made of two monosaccharides covalently bonded (condensation), used for energy source and energy transport. Ex: maltose, lactose, sucrose.

[Carbohydrates]

Polysaccharides

long polymers made of monosaccharides that are used for energy storage (starch and glycogen) and structural support (cellulose and chitin).

Lipids

hydrophobic compounds that are insoluble in water but dissolve in non-polar solvents. Consist of triglycerides (glycerol + fatty acids), phospholipids, steroids, and waxes.

Structure/properties of Saturated VS Unsaturated Fatty Acids

1. Saturated: have only a single C-C bond in their fatty acid tails. solid at room temperature

2. Unsaturated: have one or more double bonds between carbons = “kinks” in tails. Liquids (oils) at room temperature

Steroids VS Anabolic Steroids

1. Steroids: treat inflammation and conditions like asthma/allergies

2. Anabolic steroids: synthetic drugs that mimic testosterone to treat hormone problems or muscle loss (can be dangerous because it’s incorrectly used to increase muscle mass = liver/kidney/cardiovascular damage, hormone imbalance)

Proteins

the molecular tools of cells composed of monomers of amino acids

Structure of Proteins

1. Primary Structure: unique sequence of amino acids in proteins - determined by genes

2. Secondary Structure: regular repeated coiling/folding of polypeptides. Contributes to conformation.

3. Tertiary Structure: 3-D shape of a single polypeptide, formed by interactions between R groups/side chains.

4. Quaternary Structure: multiple folded polypeptides formed into one unit.

5. Primary VS Final: primary is the linear sequence with the genetic code that determines future folding. The final shape is 3-D, functional, and determines the protein's purpose.

DNA (type of nucleic acid)

stable, double-stranded, long helix that has deoxyribose sugar and thymine, used for storing genetic information.

RNA (type of nucleic acid)

temporary, single-stranded, short molecule that has ribose sugar and uracil, used for protein synthesis/regulation.

Why Lactose Intolerance Evolved Differently Throughout the World

evolved differently due to convergent evolution, where independent mutations arose in distinct human populations to enable adult milk consumption (different diet/evolutionary pressures)

[Roots]

Aqua

water (aqueous: a type of solution where water is the solvent)

[Roots]

Valent

strength (covalent bond: an attraction between atoms that share one or more pairs of outer-shell electrons)

[Roots]

Iso

equal (isotope: an element having the same number of protons and electrons but a different number of neutrons)

[Roots]

Neutr

neither (neutron: a subatomic particle with a neutral electrical charge)

[Roots]

Sacchar

sugar (disaccharide: two monosaccharides joined together)

[Roots]

Glyco

sweet

[Roots]

Gen

producing (glycogen: a polysaccharide sugar used to store energy)

[Roots]

Hydro

water

[Roots]

Lyse

break (hydrolysis: breaking chemical bonds by adding water)

[Roots]

Philic

loving (hydrophilic: water-loving property of a molecule)

[Roots]

Phobos

fearing (hydrophobic: water-repelling property of a molecule)

[Roots]

Sclero

hard (atherosclerosis: hardening of the arteries)

[Quiz Question]

Match the compounds with the type of chemical bonding (hydrogen bond, polar covalent bond, ionic bond, and non-polar covalent bond)

1. Sodium chloride: ______

2. Carbon to carbon bond in glucose molecule: _______

3. Bond between hydrogen and oxygen in water molecule: ______

4. Bonds between two strands of DNA: ________

1. Sodium chloride: ionic bond

2. Carbon to carbon bond in glucose molecule: non polar covalent bond

3. Bond between hydrogen and oxygen in water molecule: polar covalent bond

4. Bonds between two strands of DNA: hydrogen bond

[Quiz Question]

The Group 8A (noble elements) are inert/unreactive because _____

1. They are heavy

2. Do not interact with other elements

3. Have maximum number electrons in their outermost shells

4. Have eight protons and neutrons

3. Have maximum number electrons in their outermost shells

[Quiz Question]

The life sustaining properties of water is due to _______

1. Molecule is made up of hydrogen and oxygen

2. Asymmetric charge distribution of the molecule

3. It is liquid

4. It can exist in liquid, solid, and gaseous form

2. Asymmetric charge distribution of the moleucle

[Quiz Question]

1. The number of water molecules: ______

2. Oxygen and hydrogen within each molecule are bonded by: _____

3. Different water molecules are bonded by: ______

4. The partial charge on the oxygen atom is: ________

5. The partial charge on the hydrogen atom is: _______

1. The number of water molecules: five

2. Oxygen and hydrogen within each molecule are bonded by: polar covalent bond

3. Different water molecules are bonded by: hydrogen bonds

4. The partial charge on the oxygen atom is: delta negative

5. The partial charge on the hydrogen atom is: delta positive

[Quiz Question]

pH is the measurement of ________

1. Hydrogen ions in a solution

2. Hydroxyl ions in a solution

3. Carbonate in solution

4. Chloride in a solution

1. Hydrogen ions in a solution

[Quiz Question]

pH is important in living organisms because __________ (multiple answers)

1. It maintains cell structures

2. Living cells can survive under certain range of pH

3. Enzymes function within a narrow range of pH

4. Blood plasma and body fluids have fluids have pH of 6.8-7

1, 2, and 3 are correct answers.

[Quiz Question]

Identify the molecule in the photo:

1. phospholipid

2. hexose

3. glycerol

4. amino acid

4. amino acid

Concept Map