Chapter 2 The molecules of Cells

Question 1

What is essential to the normal functioning of cells and part of a cells outer membrane, and serves as a precursor to hormones such as testosterone and estrogen (sex hormones)?

Answer 1

Cholesterol

Question 2

Cholesterol on its way from the tissues to the liver for recycling is called?

Answer 2

HDL- high density lipoproteins

Question 3

“Good” cholesterol

Answer 3

HDL- high density lipoproteins- reduces the likelihood of the formation of plaque in the arteries

Question 4

Cholesterol on its way to the tissues is called?

Answer 4

LDL- low density lipoproteins

Question 5

“Bad” cholesterol

Answer 5

LDL- low density lipoproteins-contributes to the development of plaque which can result in heart disease

Question 6

Anything that takes up space and has mass refers to?

Answer 6

Matter

Question 7

Four distinct states of matter?

Answer 7

Solid
Liquid
gas
plasma

Question 8

All matter, non living and living is composed of?

Answer 8

elements

Question 9

Elements

Answer 9

substances that cannot be broken down into substances with different properties; composed of only one type of atom

Question 10

Each element has its own unique properties such as

Answer 10

density, solubility, melting point and chemical reactivity

Question 11

__ naturally occurring elements serve as the building blocks of all __.

Answer 11

92; matter

Question 12

Which six elements are essential to cells and are basic to life and make up about 95% of the body weight of organisms?

Answer 12

Carbon
Hydrogen
Nitrogen
Oxygen
Phosphorus 
Sulfur

Question 13

What other elements are important to all organisms?

Answer 13

Sodium
Potassium
Calcium
Iron
Magnesium

Question 14

Earth crust primarily contains the elements?

Answer 14

Silicon
Aluminum
Oxygen

Question 15

Elements consist of tint particles called

Answer 15

atoms

Question 16

John Dalton in 1800s said that elements consist of tiny particles called __ which was the __ theory?

Answer 16

atoms; atomic theory

Question 17

An __ and its atom share the same name.

Answer 17

element

Question 18

Elements are identified by an __ that is composed of one or two letters.

Answer 18

atomic symbol

Ex: H means hydrogen atom

Question 19

Three subatomic particles that make up atoms are called?

Answer 19

Protons: + charged
Neutrons: x uncharged
Electrons: - negatively charged

Question 20

Protons and Neutrons are located within the ___ of an atom and electrons move __ the nucleus.

Answer 20

nucleus; around

Question 21

electron shell or orbital

Answer 21

the average location, or energy level, of an electron in an atom. often drawn as a circle around the nucleus.

Question 22

atomic number

Answer 22

number of protons in the nucleus. 
EX:
29- atomic number
    CU
copper

Question 23

mass number

Answer 23

number of protons plus the number of neutrons within the nucleus.

Question 24

Atomic mass unit

Answer 24

AMU protons and neutrons are assigned one atomic mass unit each. electrons are so small that their amu is considered zero.

Question 25

Isotopes

Answer 25

"equal"; same atomic number but a different mass number due to a variation in the number of neutrons. Ex: carbon12, carbon13 carbon 14

Question 26

atomic mass

Answer 26

refer to the average mass for all teh isotopes of the atom.

Question 27

``` atomic number element symbol atomic mass (carbon) ```

Answer 27

6 carbon c 12.0112

Question 28

On the periodic table the vertical columns are

Answer 28

groups

Question 29

on the periodic table the horizontal rows are

Answer 29

periods

Question 30

group VIII of atoms are called the

Answer 30

noble gases | EX: helium and krypton

Question 31

Radioactive isotope

Answer 31

unstable; has a nucleus with excess neutrons that is often unstable and emits energy as it decays

Question 32

Carbon 14 changes over time into nitrogen 14. As carbon 14 decays it releases rays and subatomic particles. This is an example of a __ isotope.

Answer 32

radioactive.

Question 33

Instrument that is commonly used to detect radiation?

Answer 33

The Geiger

Question 34

Radioactive isotope in small samples are used as _ to detect molecular changes.

Answer 34

tracer or chemical tag

Question 35

__is a way to determine the comparative activity of tissues.

Answer 35

PET- positron emission tomography

Question 36

__is used to illustrate the structure of an atom.

Answer 36

Bohr model;

Question 37

Named after Niels Bohr, its useful in examining the number of __ in an atom.

Answer 37

electrons

Question 38

The first shell contains up to __ electrons. The shell after is most stable with __ electrons. In all atoms, the _ shells are filled with electrons before the next higher level contains any electrons.

Answer 38

2;8; lower

Question 39

The __ shell helps determine the atoms chemical properties and how many other elements it can interact with.

Answer 39

Valence; outermost

Question 40

Bohr diagrams the energy level of the electrons called __are drawn as __ about the __.

Answer 40

electron orbital; circle; nucleus

Question 41

The __ of the periodic table tells you how many _ an atom has. The __ tells you how many electrons an atom has in its __ shell.

Answer 41

Periods or horizontal rows ; electron shells or electron orbitals; groups; outer EX sulfur is in the third period and contains 3 shells and in group VI meaning 6 electrons

Question 42

Valence shell

Answer 42

the outer electron shell of an atom which determine the chemical reactivity of the atom.

Question 43

octet rule

Answer 43

an atom is more stable when its outer shell is complete with 8 electrons. except hydrogen which only requires 2 to be complete

Question 44

The number of electrons in an atoms valence shell determins whether an atom __

Answer 44

gives up, accepts or shares electrons to get to 8 in the outer shell

Question 45

When two or more atoms bond together they form a?

Answer 45

molecule

Question 46

Molecule

Answer 46

union of two or more atoms of the same element. smallest part of a compound that retains the properties of the compound. EX: O2

Question 47

When two or more different elements bond its called

Answer 47

compound Ex: H2O

Question 48

Compound

Answer 48

Substance having two or more different elements in a fixed ratio.

Question 49

Ions form when electrons are transferred from one atom to another. True or False.

Answer 49

True

Question 50

Ions

Answer 50

charged particle that carries a negative or positive charge.

Question 51

Ionic bond

Answer 51

chemical bond in which ions are attracted to one another by opposite charges

Question 52

covalent bond

Answer 52

chemical bond in which atoms share one pair of electrons. Results when two atoms share electrons that each atom has an octet of electrons in the outer shell.

Question 53

In a hydrogen atom the outer shell is complete when it contains two electrons. Hydrogen can share with another atom and thereby have a completed outer shell. Their two shells overlap and the electrons are shared between them. Each atom has a completed outer shell due to the sharing electrons. This is known as?

Answer 53

A covalent bond

Question 54

H-H is the ___explaining that atoms are sharing electrons

Answer 54

structural formula

Question 55

H2 in the __ is explaining that atoms are sharing electrons

Answer 55

molecular formula

Question 56

__ occurs when two atoms share two pairs of electrons and even triple covalent bonds like as in __ gas.

Answer 56

double covalent bond; nitrogen

Question 57

Molecules consisting of only two atoms are always

Answer 57

linear

Question 58

Molecules such as methane with five atoms have a __ shape.

Answer 58

tetrahedral: each bond is pointing to the corners of a tetrahedron

Question 59

The __ model of a molecules shape comes closest to the actual shape of the molecule.

Answer 59

space-filling

Question 60

"structure equals function" means

Answer 60

the shape of a molecule is important to the structural and functional roles it plays in an organism.

Question 61

Antibodies combine ith disease causing agents like a key fits a lock to protect us. This is an example of?

Answer 61

"structure equals function"

Question 62

When the sharing of electrons between two atoms is fairly equal the covalent bond is said to be a

Answer 62

nonpolar covalent bond

Question 63

Non polar covalent bond

Answer 63

Equal; bond in which the sharing of electrons between atoms is fairly equal.

Question 64

H2O, the sharing of electrons between oxygen and each hydrogen is not completely equal because one atom is able to attract electrons to a greater degree than the other atom. The atom that has a greater attraction for a shared pair of electrons has a greater ___.

Answer 64

Electronegativity.

Question 65

Electronegativity

Answer 65

the ability of an atom to attract electrons toward itself in a chemical bond

Question 66

polar covalent bond

Answer 66

bond in which the sharing of electrons between atoms in unequal