Introduction to anatomy & physiology: Chemical level of body organisation

Question 1

Element

Answer 1

A pure substance that is distinguished from all other matter by the fact that it cannot be created or broken down by ordinary chemical means, that is, while your body can assemble many of the chemical compounds needed for life from the constitute elements it cannot make elements they must come from the environment.

Question 2

Compound

Answer 2

A substance composed of two or more elements joined by chemical bonds, that is always composed of the same three elements: carbon, hydrogen, and oxygen, in which the elements that make up any given compound always occur in the same relative amounts.

Question 3

Atom

Answer 3

The smallest quantity of an element that retains the unique properties of that element, that is an atom of hydrogen is a unit of hydrogen, the smallest amount of hydrogen that can exist.

Question 4

Subatomic particles

Answer 4

Atoms are made up of even smaller subatomic particles with there being three types: proton, neutron, and electron with the number of positively charged protons and non-charge (“neutral”) neutrons giving mass to the atom and the number of protons determines the elements.

Question 5

Electrons

Answer 5

The number of negatively charged electrons that “spin” around the nucleus at close to the speed of light equals the number of protons.

Question 6

Atomic number

Answer 6

The number of protons in the nucleus of the atom that is used to identify an element, including the number of electrons as an atom usually has the same number of electrons and protons.

Question 7

Mass number

Answer 7

The sum of the number of protons and neutrons in a nucleus excluding electrons as they have so little mass that they do not contribute to the mass of an atom.

Question 8

Isotope

Answer 8

One of the different forms of an element distinguished from one another by the different numbers of neutrons. The different isotopes of an element can also be indicated with the mass number hyphenated.

Question 9

Heavy isotope

Answer 9

A heavy isotope is one that contains more than the usual number of neutrons. Heavy isotopes are radioactive.

Question 10

Radioactive isotope

Answer 10

Radioactive isotopes having a nucleus that readily decay’s giving up subatomic particles and electromagnetic energy. Different radioactive isotopes differ in their half-life.

Question 11

Half life

Answer 11

The time it takes for half of any size sample of an isotope to decay.

Question 12

Electron shells

Answer 12

A layer of electrons that encircle the nucleus at a distinct energy level. The atoms of the elements found in the human body have from one to five electron shells and all electrons shells hold 8 electrons except the first shell which can only hold 2. The configuration for all electron shells is the same for all atoms however the precise number of shells depends on the number of electrons in the atom.

Question 13

Valence shell

Answer 13

An atom’s most electron shell.

Question 14

Describe what happens when an atom attains a full valence shell

Answer 14

If full the atom is stable meaning its electrons are unlikely to be pulled away from the nucleus by the electrical charge of other atoms.

Question 15

Describe what happens when an atom does not attain a full valence shell

Answer 15

If the valence shell is not full, the atom is reactive meaning it will tend to react with other atoms in ways that make the valence shell full.

Question 16

Inorganic and organic compounds

Answer 16

A substance that does not contain both carbon and hydrogen while an organic compound is a substance that contains both carbon and hydrogen.

Question 17

Heat sink

Answer 17

A substance or object that absorbs and dissipates heat but does not experience a corresponding increase in temperature.

Question 18

Mixture

Answer 18

A combination of two or more substances, each of which maintains its own chemical identity, that is the substances are not chemically bonded into a new, larger chemical compound.

Question 19

Solution

Answer 19

Consists of a solvent that dissolves a substance called a solute. Solutions are homogenous, that is, the solute molecules are distributed evenly throughout the solution.

Question 20

Hydrophobic

Answer 20

Nonpolar molecules which do not readily dissolve in water.

Question 21

Hydrophilic

Answer 21

Molecules that are polar, with regions of positive and negative electrical charge, able to dissolve ionic and polar covalent compounds, are referred to as hydrophilic (water-loving).

Question 22

Monomers

Answer 22

Atoms or small molecules that bond together to form more complex structures.

Question 23

Hydroxyl group (OH)

Answer 23

A group composed of one oxygen atom covalently bonded to one hydrogen atom.

Question 24

Covalent bond

Answer 24

A chemical bond that involves the sharing of electrons to for electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs.

Question 25

Polar covalent bond

Answer 25

Exists when two atoms share a pair of electrons unequally because of the differences in their electro negatives.

Question 26

Water as a lubricant and cushion

Answer 26

Water is a component of many of the bodies lubricating fluids: synovial and pleural fluids. Synovial fluids lubricate the actions of the body joints just as pleural fluid helps the lungs expand and recoil when breathing. Additionally, water protects cells and organs from physical trauma, cushioning the brain within the skull, and protecting the delicate nerves tissue of the eyes.

Question 27

Water as a heat sink

Answer 27

In the body water absorbs the heat generated by chemical reactions without greatly increasing in temperature. Additionally, when the environmental temperature soars, the water stored in the body helps keep the body cool.

Question 28

Water as a component of liquid mixtures

Answer 28

All of the body’s chemical reactions occur among compounds dissolved in water. As water molecules are polar, with regions of positive and negative electrical charge, water readily dissolves ionic compounds and polar covalent compounds, or those referred to as hydrophilic (water-loving). Nonpolar molecules which do not readily dissolve in water are called hydrophobic (water-fearing).

Question 29

Water in chemical reactions

Answer 29

Two types of chemical reactions involve the creation or consumption of water: dehydration synthesis and hydrolysis.

Question 30

Dehydration synthesis or condensation creation

Answer 30

Dehydration synthesis or a condensation creation involves one reactant giving up an atom of hydrogen and another reactant gives up a hydroxyl group (OH) in the synthesis of a new product. In the formation of their covalent bold, a molecule of water is released.

Question 31

Hydrolysis

Answer 31

In hydrolysis, a molecule of water disrupts a compound breaking its bond with the water itself being split into H and Oh. One portion of the severed compound then bonds with the hydrogen atom and the other portion bonds with the hydroxyl group.

Question 32

Solvent

Answer 32

A substance that dissolves a solute, resulting in a solution.

Question 33

Anion and cations

Answer 33

Anions are negatively charged ions while cations are positively charged ions.

Question 34

Salts (NaCl)

Answer 34

Formed when ions for ionic bonds that typically dissociates in water. There is one sodium (Na+) for every chloride (Cl-).

Question 35

Describe how salts behave

Answer 35

A typical salt, NaCl, dissociates completely in water with the positive and negative regions on the water molecule attracting the negative chloride and positive sodium ions, pulling them away from each other. Nonpolar and polar covalently bonded compounds break apart into molecules in solution, salts dissociate into ions that are electrolytes that are capable of conducting an electrical current in solution critical to the function of ions in transmitting nerve impulses and prompting muscle contraction.

Question 36

Describe the process of salts forming ionic bonds

Answer 36

An atom gives up one or more electrons becoming positively charged whereas the other accepts one or more electrons and becomes negatively charged. This defines salt as a substance that when dissolved in water dissociates into ions other than H+ (hydrogen ions) or OH- (hydroxide).

Question 37

Acids

Answer 37

An acid is a substance that releases hydrogen ions (H+) in solution, as an atom of hydrogen is just one proton and electron, a positively charged hydrogen ion is simply a proton, with this solitary proton is highly likely to participate in chemical reactions.

Question 38

Strong and weak acids

Answer 38

Strong acids are compounds that release of their hydrogen ions (H+) in solution or ionize completely while weak acids do not ionize completely as some of their hydrogen ions remain bonded within a compound in solution.

Question 39

Base

Answer 39

A substance that releases hydroxyl ions (OH-) in solution or one that accepts H+ already present in solution.

Question 40

Strong and weak bases

Answer 40

Strong bases release most or all of their hydroxyl ions while weak bases release only some hydroxyl ions or absorb only a few H+.

Question 41

Define the meaning of pH (potential hydrogen)

Answer 41

A measure of the acidity or alkalinity of a solution equal to the common logarithm of the concentration of hydrogen ions in moles per cubic decimetre of solution. Acid solutions have a pH less than 7, and alkaline solutions a pH greater than 7.

Question 42

Describe the pH scale

Answer 42

The pH scale consists of a series of increments ranging from 0 to 14 with a solution with a pH of 7 being considered neutral, neither acidic nor basic, with a number lower than 7 increasing the acidity, that is the more acidic the concentration the greater the concentration of H+. The higher the number above 7, the more basic (alkaline) the solution, that is the lower the concentration of H+.

Question 43

List the five organic compounds

Answer 43

Carbohydrates, lipids, proteins, nucleic acids, and high energy compounds.

Question 44

Emulsion

Answer 44

The term for a mixture of solutions that do not mix well.

Question 45

Chains of nucleotides

Answer 45

All nucleotides have a nitrogen base, sugar group, and phosphate group. The nitrogen bases that make up DNA include: Adenine (A), guanine (G), cytosine (C), thymine (T). The nitrogen bases that make up RNA include: Adenine (A), guanine (G), cytosine (C), and uracil( U).

Question 46

Deoxyribonucleic acid (DNA)

Answer 46

Deoxyribonucleic acid (DNA) is nucleotide that stores genetic information. DNA contains deoxyribose (so-called because it has one less atom of oxygen than ribose) plus one phosphate group and one nitrogen-containing base.

Question 47

Ribonucleic acid (RNA)

Answer 47

Ribonucleic acid (RNA) is a ribose-containing nucleotide that helps manifest the genetic code as protein. RNA contains ribose, one phosphate group, and one nitrogen-containing base. RNA consists of a single strand of sugar-phosphate backbone studded with bases.

Question 48

Messenger RNA (mRNA)

Answer 48

Created during protein synthesis to carry the genetic instructions from the DNA to the cell’s protein manufacturing plants in the cytoplasm, the ribosomes.

Question 49

Purine

Answer 49

The nitrogen-containing bases adenine and guanine are classified as purines. A purine is a nitrogen-containing molecule with a double ring structure, which accommodates several nitrogen atoms.

Question 50

Pyramidines

Answer 50

The bases cytosine, thymine (found in DNA only) and uracil (found in RNA only) are pyramidines. A pyramidine is a nitrogen-containing base with a single ring structure.

Question 51

Backbone

Answer 51

Bonds formed by dehydration synthesis between the pentose sugar of one nucleic acid monomer and the phosphate group of another form a “backbone,” from which the components’ nitrogen-containing bases protrude. In DNA, two such backbones attach at their protruding bases via hydrogen bonds. These twist to form a shape known as a double helix.

Question 52

Genes

Answer 52

The sequence of nitrogen-containing bases within a strand of DNA forms the genes that act as a molecular code instructing cells in the assembly of amino acids into proteins. These genes carry the genetic code to build one’s body, and are unique for each individual except identical twins.

Question 53

Adenosine triphosphate (ATP)

Answer 53

Composed of a ribose sugar, an adenine base, and three phosphate groups it is classified as a high energy compound because the two covalent bonds linking its three phosphates store. In the body, the energy released from these high energy bonds helps fuel the body’s activities, from muscle contraction to the transport of substances in and out of cells to anabolic chemical reactions.