The Chemistry of Life ch. 2

Flashcards covering key vocabulary from the Chemistry of Life chapter, focusing on atoms, molecules, chemical bonds, water, acids, bases, organic compounds, and energy.

Biochemistry

The study of the molecules that compose living organisms. Carbohydrates, fats, proteins and nucleic acids. Useful for understanding cellular structures, basic physiology, nutrition and health.

Chemical element

Simplest form of matter to have unique chemical properties. Each identifies by an atomic number.

Atomic number

Number of protons in the nucleus. Periodic table arranges elements (1-2 letter symbols) by atomic number.

How many naturally occurring elements are there

91

How many naturally occurring elements play roles in humans?

24

Which 6 naturally occurring elements are most abundant in humans? (98.5% body weight)

Carbon, calcium, hydrogen, nitrogen, oxygen, phosphorus. (CCHNOP)

Minerals

Inorganic elements extracted from soil by plant, passed up food chain to humans

What percentage of body weight do humans have in our body weight, and which elements are the most?

4%, calcium and phosphorus

What body structures do minerals make up in the human body

Bones, teeth, enzyme function, nerve and muscle cell functions

Atom

Smallest unit of matter

Nucleus

Center of atom, composed of protons and neutrons

Proposed planetary model of atomic structure in 1913, useful as schematic but not an accurate structure.

Neils Bohr

Protons

Single (+) charge. Mass = 1 atomic mass unit (amu)

Neutrons

No charge. Mass = 1 amu

Atomic mass is…

Approximately equal to total number of protons and neutrons

Electrons

In concentric clouds surrounding nucleus. Have a single (-) charge, very low mass

An atom is electronically _____, as number of electrons equals number of ____.

Neutral, protons

Valence electrons

In the outermost shell and determine chemical bonding properties of an atom.

Isotopes

Varieties of an element that differ only in the number of neutrons and therefore in atomic mass. Extra neutrons increase atomic weight. Isotopes of an element are chemically similar because they have the same number of valence electrons.

Atomic weight (relative atomic mass)

Accounts for the fact that an element is a mixture of isotopes.

Radioisotopes

Unstable isotopes that decay and give off radiation in a process called radioactivity

The difference between an atom and an ion

Atom has an equal amount of protons and electrons so it is neutral

Ion has gained or lost electrons so it’s either pos or neg

Every element has at least one…

Radioisotope.

Ionizing radiation

Ejects electrons, destroys molecules, creates free radicals—and can cause genetic mutations and cancer

Examples of ionizing radiation

UV radiation, x-rays, alpha particles, beta particles, gamma rays

Physical half-life of radioisotopes

Time required for 50% to decay to a stable state

Biological half-life of radioisotopes

Time required for 50% to disappear from the body

Standard acceptable exposure of radiation per year

50 mSv

Fatal amount of Sv

5 Sv or more

The feature that contrasts a lipid from a carb is that a lipid

Has a lower ratio of oxygen to hydrogen

Amphipathic lipids of cell membranes are called

Phospholipids

Chemical that is derived from ATP and is a second messenger

CAM (cyclic adenosine monophosphate)

When oxygen is limited to meet ATP demand a cell employs

Anaerobic fermentation

All the synthesis reactions in the body form a division of metabolism called

Anabolism

Suffix that denotes sugar and suffix that denotes an enzyme

-ose and -ase

Any substance that increases the rate of a reaction is _______. In the body _____ serve this function

Catalyst, enzymes

Background radiation

Natural sources such as radon gas and cosmic rays

What function of carbs is more likely to be than proteins

Energy storage

Average background radiation Per year

2.4 mSv

Artificial sources of radiation

X-rays, color tvs

Average mSV of artificial sources of radiation per year

0.6

What was madame Curie known for

-first woman to receive Nobel prize

-first woman in the world to receive a PhD

-discovered and coined the term radioactivity

-trained the physicians on use of X-rays and pioneered radiation therapy as cancer treatment

Ion

Charged particle (atom or molecule) with unequal number of protons and electrons

Ionization

Transfer of electrons from one atom to another

Anion

Particle that has a net negative charge due to gain of electrons

Cation

Particle that has a net positive charge due to loss of electrons

Ions with opposite charges are

Attracted to each other

Electrically neutral compounds of cations and anions, dissociate in water ions and act as electrolytes

Salts

Sodium chloride, calcium chloride

Examples of salts

Electrolytes

Substances that ionize in water and form solutions capable of conducting electric current

Functions of electrolytes

Chemical reactivity, osmotic effects, electrical excitability of nerve and muscle

Electrolyte balance is one of the most important considerations in patient care because…

Imbalances can lead to coma or cardiac arrest

Free radicals

Unstable, highly reactive particles with an unusual number of electrons

What type of ions are produced by normal metabolic reactions, radiations and certain chemicals?

Free radicals

Which ion can trigger reactions that destroy molecules, cause cancer, death of heart tissue and aging?

Free radicals

Antioxidants

Chemicals that neutralize free radicals

Examples of antioxidants obtained through the diet

Selenium, vitamin E, vitamin C, carotenoids

Molecule

Particle composed of two or more atoms united by a chemical bond

Compound

Molecule composed of two or more different elements

What can be represented by a molecular formula which identifies constituent elements and how many atoms are present?

Compounds

Isomers

Molecules with identical molecular formulae but different arrangements of their atoms

Molecular weight (MW)

Sum of the atomic weights of its atoms

Ionic bonds

Attraction of a cation to an anion, relatively easily broken by something more attractive such as water

Chemical bonds

Hold atoms together within a molecule, or attract one molecule to another.

Covalent bonds

Atoms share one or more pairs of electrons

What is a single covalent bond

Nuclei share 1 pair of electrons

Double covalent bond

Nuclei shares 2 pairs of electrons

If electrons are shared equally it is a…

Nonpolar covalent bond ex. Carbon atoms bonding together

If electrons are shared unequally, its a…

Polar covalent bond. Ex. Hydrogen bonding with oxygen, electrons spend more time by oxygen

Nonpolar covalent bond

If electrons are shared equally

Polar covalent bond

If electrons shared unequally

What is this called

Nonpolar covalent

What is this called

Polar covalent bond

Hydrogen bond

Weak attraction between a slightly positive hydrogen atom in one molecule and a slightly negative oxygen or nitrogen atom in another atom

Why are hydrogen bonds important to physiology

Water molecules are attracted to eachother by hydrogen bonds. Large molecules (DNA and proteins) are shaped in part by the formation of hydrogen bonds within them

Van der Waals forces

Weak, brief attractions between neutral atoms, only 1% as strong as a covalent bond but are important in physiology (protein folding)

Mixtures

Consist of substances that are physically blended but not chemically combined, each substance retains its own chemical properties

What percentage of our body weight is water?

50-70%

The difference between a mixture and a compound

A mixture is a combo of substances that are physically blended and can be separated

A compound is a substance formed by a chemical bond and can’t be separated.

Properties that account for waters ability to support life

Adhesion, chemical reactivity, cohesion, solvency, thermal stability

Solvency (of water)

Ability to dissolve other chemicals. Water is the universal solvent because it dissolves more substances than any other solvent

Hydrophilic substances

Dissolve in water, are polarized or charged

Hydrophobic substances

Do not dissolve in water, are Nonpolar or neutral

Adhesion (of water)

Tendency of one substance to cling to another

Cohesion (of water)

Tendency of molecules of the same substance to cling to each other

Water is very cohesive due to its…

Hydrogen bonds

Surface film is due to

Molecules being held together by surface tension

Chemical reactivity

Ability to participate in chemical reactions

Thermal stability due to high Heat capacity

Amount of heat needed to raise the temperature of 1g of a substance by 1°C

Calorie (cal)

The base unit of heat, 1 cal is the amount of heat to raise the temperature of 1g of water by 1 degree C

Solution

Consists of particles called the solute mixed with a more abundant substance (usually water) called the solvent. Can be gas, solid or liquid

Action of buffers and function in the body

Help keep pH steady by soaking up extra acid or base

They keep things like blood from getting too acidic or too basic which helps the overall function of the body.

Solute particles are defined by

Are under 1 nm

Do not scatter light

Will pass through most membranes

Will not separate on standing

Water stabilizes

Internal temperature

Colloids

Often mixtures of protein and water and Can change from liquid to gel state within and between cells

Colloids are defined by

Range from 1-100 nm in size

Scatter light and usually cloudy

Too large to pass though semipermeable membrane

Remain permanently mixed with the solvent when mixture stands

Suspension (mixtures) are defined by

Particles exceed 100 nm, Too large to penetrate selectively permeable membranes, Cloudy or opaque in appearance, and Separates on standing

Ex. Blood cells in blood plasma

Emulsion

Suspension of one liquid in another. Ex. Oil and vinegar, fat in breast milk

Acid

Proton donor; releases H+ ions in water

Base

Proton acceptor; accepts H+ ions in water