Molecules of Life: Elements of Life and Death (Chapter 2)

What is fortification? Why is it important?

addition of iron to foods

it is important because the body needs iron for the function of the protein hemoglobin, which transports oxygen from the lungs to the body's tissues

Describe how hemoglobin transports oxygen from the lungs to the body's tissues.

Elemental Iron is consumed

Elemental iron is processed in the stomach, being converted to the iron ion Fe2+

The iron is used in a protein, hemoglobin, which transports oxygen in our blood stream via red blood cells

What are the four subunits of hemoglobin? What does this tell us about hemoglobin?

there are two alpha chains and two beta chains, each containing a heme group (a ring-shaped molecule that contains an iron ion at its center)

Because one oxygen molecule attaches to each iron ion, one hemoglobin protein can carry four oxygen molecules

What is iron deficiency anemia?

individuals who have low levels of iron, which inhibits hemoglobin's ability to transport oxygen and lowers the body's production of red blood cells

What is matter?

any substance that occupies space and has mass

What is mass?

the amount of matter than an object contains

What is weight?

force exerted on an object by gravity

What is a physical property? How can it be studied?

a characteristic that can be measured without changing the composition of the substance. It can be studied in isolation.

What is a chemical property? How can it be studied?

a characteristic of a substance that can (only) be observed during a chemical reaction

What is an extensive property?

A property that depends on the amount of material (ex: length, mass, volume)

What is an intensive property?

A property that remains the same regardless of the amount of material (ex: temperature, density, color)

What is volume?

The amount of space occupied by an amount of matter

What is temperature?

A measurement of how hot or cold a substance is, relative to a standard scale

What is density?

The amount of mass contained in a unit of volume (D = M / V)

What is a physical change?

a change in the physical properties of a substance that does not modify its composition

What is a chemical change?

the transformation of one substance to another via chemical reaction (ex: oxidation)

What is a mixture?

a physical combination of multiple substances that are not chemically bonded to one another (ex: coffee with milk and sugar)

What is a homogeneous mixture?

mixture in which the composition is the same throughout (ex: ocean)

What is a heterogenous mixture?

mixture in which the composition is different throughout (ex: cereal, blood)

What is a pure substance?

substance with a constant composition and characteristic chemical properties; it cannot be separated into components by physical methods (ex: distilled water)

What is a compound?

A pure substance formed from two or more different elements that are chemically joined in a fixed ratio (ex: water, H20)

How can a compound be decomposed?

by use of chemical methods that make use of reactions that break or form chemical bonds

(ex: water can be chemically decomposed by passing an electric current through liquid water to yield the gasses it is composed of)

What is an element?

substance composed of only one type of atom, which cannot be broken down into simpler substances using chemical methods(ex: oxygen, O)

How is the periodic table organized?

based on their physical and chemical properties (based on atomic structure)

What is a group on the periodic table?

a column that contains elements with similar chemical propertiesand the same number of valence electrons.

What is a period on the periodic table?

a row in the periodic table that indicates elements with the same number of electron shells

What is a noble gas?

an unreactive (or mostly unreactive) element in Group 8A of the periodic table

What is an atom?

the fundamental component of matter which contains protons, neutrons, and electrons

What is a Scanning Tunneling Microscope (STM)?

a microscope that uses a moving metal probe to monitor the landscape of atoms arranged on a surface. STM makes it possible to produce images of individual atoms.

What is a proton?

a positively charged subatomic particle located in the nucleus of an atom

What is a neutron?

an electrically neutral subatomic particle that surrounds the nucleus

What does the Atomic Number (Z) signify?

the number of protons in the nucleus of an atom

What does the Mass Number (A) signify?

the sum of the protons and neutrons in the nucleus of an atom

What are isotopes?

variants of an atom that have the same atomic number but different mass numbers

What is relative atomic mass?

a unitless number that compares the mass of one atom of the element to 1 amu

What is Atomic Mass Unit (amu)?

the unit used to measure the mass of subatomic particles

it is defined as 1/12 of the mass of a ¹²C atom

What is atomic mass?

the weighted average of all the naturally occurring isotopes of an element, based on their mass and relative abundance

What is an electron shell?

a quantized energy level where electrons are located

What is electron configuration?

the location of electrons within specific shells of an atom

What are valence shells?

the outer shell of an atom

What are valence electrons?

the electrons that are located in the outer shell; they determine the chemical properties of the atom

Why are noble gases unreactive?

they have filled electron shells

What is an ion?

an atom (or group of atoms) that has lost or gained one or more electrons and acquired an electrical charge

What is quantum mechanics?

a theory that describes electrons as waves

What are electron orbitals?

a quantum mechanical description of an electron’s probable location

What is electron density?

the probability of finding an electron at a specific location within an orbital

What are the non-metal building block elements of life? What makes them important?

Hydrogen (H), Carbon (C), Nitrogen (N), Oxygen (O), Phosphorus (P), and Sulfur (S)

“ON HCPS?” - my mnemonic device since HCPS was important for my education/life

they are important because they readily form chemical bonds to create molecules

Why do we need calcium?

it plays an essential role in forming the solid structures of bones and teeth.

It also serves a variety of other biological purposes, such as acting as a chemical signaling agent

What is osteoporosis? How can you mitigate your risk for it?

reduction of bone density that can occur when a person ages. Risk of developing the disease can be reduced by consuming enough calcium at a young age.

Why is arsenic a poison?

it has similar chemical properties as phosphorus, an essential element for life.

It acts as a poison by replacing phosphorus in ATP (adenosine triphosphate), which causes the molecule to become unstable and deprives the cell of a vital source of energy.