BIO 101 - chapter 2

Question 1

Element

Answer 1

A pure substance that cannot be broken down by chemical means into other substances. Examples: oxygen (O), carbon (C), Nitrogen (N), sodium (Na), hydrogen (H).

Question 2

Bulk Elements

Answer 2

Elements required in large amounts because they make up the vast majority of every living cell.

Question 3

4 most abundant bulk elements in life

Answer 3

Carbon, hydrogen, nitrogen, oxygen.

Question 4

Minerals

Answer 4

Essential elements other than C,H,O,N

Question 5

Trace elements

Answer 5

Required in small amounts

Question 6

Goiter

Answer 6

Enlarged thyroid gland due to iodine deficiency in diet.

Question 7

Anemia

Answer 7

Deficiency in ion(Fe) - required by blood carry oxygen to the body’s tissues.

Question 8

Atom

Answer 8

Smallest possible piece of an element that contains characteristics of that element.

Question 9

Composition of an atom

Answer 9

Protons (positively charged)
Neutrons (not charged)
Protons and neutrons form a nucleus
The nucleus is surrounded by negatively charged electrons.

Question 10

Atomic number

Answer 10

The number of protons in an element

Question 11

Uranium

Answer 11

Has 92 protons.

Question 12

Electrically neutral

Answer 12

When the number of protons equal the number of electrons (no net charge).

Question 13

Ion

Answer 13

Atom or group of atoms that has lost or gained electrons giving it an electrical charge.

Question 14

Common positively charged ions (cations)

Answer 14

Hydrogen (H+)
Sodium (Na+)
Potassium ( K+)

Question 15

Common negatively charged ions

Answer 15

Hydroxide (OH-)

Chloride (CI-)

Question 16

Some biological processes of ion

Answer 16

Message transmission to the nervous system.

Question 17

Atomic mass number

Answer 17

Total number of protons and neutrons in its nucleus.

Question 18

Isotope

Answer 18

Any of the forms of elements each having a different number of neutrons in the nucleus.

Many known isotopes are unstable and radioactive

Question 19

Atomic mass

Answer 19

Average weight of all isotopes

Question 20

Radio active isotopes

Answer 20

Emit energy as rays or particles when they are broken down into more stable form

Question 21

Half life

Answer 21

The time it takes for half of the atoms in a sample to emit radiation or decay to a more stable form.

Question 22

Compound

Answer 22

Molecules composed of two or more elements.

Ex: water (H20, nitric oxide)

Question 23

Energy cell

Answer 23

A group of electron orbitals that share the same energy level

Question 24

Orbital

Answer 24

The most likely position of an electron relative to its nucleus

Question 25

Valence shell

Answer 25

Outermost occupied energy cell of an atom | Atoms are more stable when full

Question 26

Chemical bond

Answer 26

Attracting force that holds atoms together - either by sharing, stealing, or donating electrons.

Question 27

Covalent bonds

Answer 27

2 atoms share electrons. Shared electrons travel around both nuclei, strongly connecting the atoms together Eg: water h20 and methane ch4

Question 28

Methane (CH4)

Answer 28

1 carbon and 4 hydrogen

Question 29

Electronegativity

Answer 29

The tendency of an atom to attract electrons

Question 30

Non-polar covalent bond

Answer 30

Both atoms exert approximately equal pull on their shared electrons

Question 31

Polar covalent bond

Answer 31

One nucleus exerts a much stronger pull on shared electrons

Question 32

Ionic bond

Answer 32

One atom transfers electrons to another atom

Question 33

Hydrogen bond

Answer 33

Weak chemical bond between opposit partial charges on two molecules or within one large molecule

Question 34

Cohesion

Answer 34

A property of water The tendency of water molecules to stick together.

Question 35

Adhesion

Answer 35

Another property of water - the tendency to form hydrogen bonds with other substances. Eg. water from roots to leaves.

Question 36

Why is water essential to life?

Answer 36

Cohesion Adhesion Many substances dissolve in water - eg. water molecules suuround each ion in salt individually, seperating them from one another. Hence, the apparent disapearance of salt in water. It regulates temperature It expands as it freezes

Question 37

Solvent

Answer 37

A chemical in which other substances dissolve, forming a solution

Question 38

Two categories of water

Answer 38

Hydrophilic - attracted to water (sugar, salt, ion) Hydrophobic - repelled by water (grease)

Question 39

Acid

Answer 39

A molecule that releases hydrogen ions into a solution, making the concentration of H+ ions exceed the concentration of OH- (i.e., hydrochloric acid: HCI)

Question 40

Base

Answer 40

a molecule that either releases hydroxide ions into a solution or removes hydrogen ions from it

Question 41

pH scale

Answer 41

a measurement of how acidic or basic a solution is

Question 42

How do the values of 0, 7, 14 relate to the pH scale

Answer 42

0 - strong acid 7 - neutral 14 - strong base

Question 43

Buffer Systems

Answer 43

Pairs of weak acids and bases that resist pH changes.

Question 44

Carbonic acid

Answer 44

One of several buffers that maintain the pH of blood at about 7.4

Question 45

Organic molecules

Answer 45

Chemical compounds that contain both carbon and hydrogen. Generates life's form and function

Question 46

Hydrocarbons

Answer 46

Organic molecules consisting almost entirely of carbon and hydrogen

Question 47

Four most abundant type of organic molecules in organisms

Answer 47

Carbohydrates, proteins, lipids, Nucleic acids

Question 48

Buffer Systems

Answer 48

Pairs of weak acids and bases that resist pH changes.

Question 49

Carbonic acid

Answer 49

One of several buffers that maintain the pH of blood at about 7.4

Question 50

Organic molecules

Answer 50

Chemical compounds that contain both carbon and hydrogen. Generates life's form and function

Question 51

Hydrocarbons

Answer 51

Organic molecules consisting almost entirely of carbon and hydrogen

Question 52

Four most abundant type of organic molecules in organisms

Answer 52

Carbohydrates, proteins, lipids, Nucleic acids