Biology A: Preparing for Test Unit 2

An atom that has gained or lost electrons is called an ion. True or False

True

The symbol Na+ represents a sodium atom that has lost an electron. True or False

True

An atom with six electrons in its n = 2 shell will become an ion with a charge of: + 6 - 6 + 2 - 2

- 2

The largest molecules in organisms are: carbohydrates proteins lipids nucleic acids

nucleic acids

The largest organic molecules are _________________.

nucleic acids

Many gases exist as ________________ molecules of an element.

diatomic

If the outer energy level of the atom is full, it ________ react readily with other atoms. does does not

does not

Atoms are electrically _________________ because they have the same number of protons and electrons.

neutral

The _____ carries no electrical charge in the atom. electron proton gluon neutron

neutron

The three subatomic particles are protons, electrons, and ______________________.

neutrons

Which organic compound serves this function? enzymes carbohydrates lipids nucleic acids proteins

proteins

The _____ carries a positive charge in the atom. electron proton gluon neutron

proton

Atomic mass is determined by the number of neutrons plus ____________________.

protons

When an atom loses an electron, it becomes ____________________ charged

positively

nucleic acids

"blueprint" molecules

From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion. (Remember the 2, 8, 18 level distribution.) Hydrogen (1) 0 -1 +1 -2 +2

+1

An ion which has lost two electrons has a charge of: 0 -2 +2 -6

+2

From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion. (Remember the 2, 8, 18 level distribution.) Magnesium (12) 0 -1 +1 -2 +2

+2

A strong acid has a pH approaching: 0 8 5 14

0

How many electrons does carbon lack in its outer shell? 1 2 3 4

4

In a protein molecule, the number of amino acid molecules may be as many as: 5 500 50 5,000

5,000

_________________ are compounds that produce H+ ions in solution.

Acids

double-stranded

DNA

A plant must supply energy through photosynthesis in order for its complex starch molecules to turn to simple sugar. True or False

False

(Select all that apply.) The four classes of organic molecules are _____. carbon carbohydrates polymers lipids nucleic acids amino acids proteins fatty acids

carbohydrates lipids nucleic acids proteins

All organic molecules contain the element _____. hydrogen oxygen nitrogen carbon

carbon

The n = 2 shell of an atom contains a maximum of: two electrons seven electrons eight electrons eleven electrons

eight electrons

The _____ carries a negative charge in the atom. electron proton gluon neutron

electron

ionic bonding

electron exchange

covalent bonding

electron sharing

The reactivity of an atom is due to the number and arrangement of _________________ in the outer energy level.

electrons

most highly concentrated energy source

fats

The atomic mass of an atom with six electrons, eight neutrons, and six protons is: six fourteen eight twenty

fourteen

The bonds that link many water molecules together to form a water drop are: ionic nuclear hydrogen covalent

hydrogen

The weak type of bonding which attracts molecules to molecules is: ionic hydrogen covalent nuclear

hydrogen

decomposition

hydrolysis

If an atom loses or gains an electron, it is called a(n)______________ .

ion

Atoms which transfer electrons can combine to form a(n) ____________________ bond.

ionic

transfer of electrons

ionic

Which organic compound has this component? steroids carbohydrates lipids nucleic acids proteins

lipids

Which organic compound serves this function? insulation against cold carbohydrates lipids nucleic acids proteins

lipids

Which organic compound serves this function? lamp oil carbohydrates lipids nucleic acids proteins

lipids

Which organic compound serves this function? most highly concentrated energy carbohydrates lipids nucleic acids proteins

lipids

Amino acids are the building blocks of _________________.

proteins

Enzyme, antibody, hormone, and muscle are roles played by: carbohydrates proteins lipids nucleic acids

proteins

Which organic compound serves this function? antibodies carbohydrates lipids nucleic acids proteins

proteins

The total number of elements that have been identified is: 20 92 52 118

118

Which is not a compound? H2 H2O 6CaO 5HCl

H2

A substance that releases hydrogen ions in water is a base. True or False

False

All proteins carry the genetic codes which determine the structure and function of an organism. True or False

False

An organism can live without enzymes. True or False

False

Because enzymes have high specificity, fewer than fifteen are required by any organism. True or False

False

Chemical reactions in cells are faster than the same reactions outside cells. True or False

False

Water is an example of a compound. True or False

True

a new substance formed by the combination of two or more different atoms

compound

The principal elements found in living things are carbon, hydrogen, oxygen, and ____________________.

nitrogen

How many atoms are in the following molecules of ammonia: 3(NH3) three four 8 12

12

The atomic mass of an element whose atoms consist of eight protons, nine neutrons, and eight electrons is: 8 16 17 25

17

The number of hydrogen atoms in 6NH3 is _________________.

18

Lipids are water soluble True or False

False

Carbon forms _________________ bonds.

covalent

a substance consisting of only one type of atom

element

When a salt dissolves in water, it produces either a hydrogen ion or a hydroxyl ion. True or False

False

DNA "rung"

Paired set

The number of protons in an atom determines the __________________.

element

From your knowledge about the distribution of electrons in the levels and from the atomic number (in parentheses), indicate the most likely charge on the ion when this atom forms an ion. (Remember the 2, 8, 18 level distribution.) Oxygen (8) 0 -1 +1 -2 +2

-2

According to the text, how many elements have been identified? 20 92 112 118

118

If an atom has twelve electrons, how many electrons are in the n=1 energy level? How many electrons are in the n=2 energy level? How many electrons are in the n=3 energy level? n=1 shell n=2 shell n=3 shell

2 8 2

Enzyme molecules react with reactants to produce substrate molecules. True or False

False

Many elements bond to carbon by exchanging electrons. True or False

False

Of the known elements only about ten are needed by living things. True or False

False

Organic catalysts are called polysaccharides. True or False

False

Polysaccharides are simple sugars, True or False

False

Sodium and chlorine atoms combine readily because they both tend to lose electrons. True or False

False

The number of protons within an atom of an element is equal to its atomic mass. True or False

False

Water can dissolve only inorganic compounds. True or False

False

Carbohydrates are converted to energy by the process of hydrolysis. True or False

True

Lipids are composed of the same basic elements as carbohydrates. True or False

True

Of the three lipid types, phospholipids are more similar to fats. True or False

True

The DNA bases are attached to the phosphate part of the structure. True or False

True

The effect of a catalyst is the reduction of activation energy required to initiate a chemical reaction. True or False

True

Two bases of DNA connects the double chain of DNA like a step on a ladder. True or False

True

A substance which yields an anion plus a proton is a(n): salt acid base

acid

The energy required to start a chemical reaction is called: a catalyst covalence activation energy reversibility

activation energy

The heat needed for chemical reaction to take place is called _____. heat of reaction activation energy friction

activation energy

Large organic molecules which are synthesized from multiple identical subunits are: carbohydrates polymers proteins nucleic acids all of the above

all of the above

When compounds which are formed from ionic bonds decompose, the products: are usually atoms of the original reactants are usually simple molecules are usually ions of the original elements are usually of no further chemical value

are usually ions of the original elements

Substances which maintain a body's pH within narrow limits are called __________________.

buffers

Lipids are chemically most similar to: carbohydrates nucleic acids proteins amino acids

carbohydrates

Which organic compound has this component? saccharides carbohydrates lipids nucleic acids proteins

carbohydrates

Which organic compound has this component? starches carbohydrates lipids nucleic acids proteins

carbohydrates

Which organic compound has this component? sugars carbohydrates lipids nucleic acids proteins

carbohydrates

Which organic compound serves this function? most readily available energy carbohydrates lipids nucleic acids proteins

carbohydrates

(Select all that apply.) The elements most often found in organic molecules are _____. carbon sodium potassium hydrogen nitrogen magnesium oxygen

carbon hydrogen nitrogen oxygen

Four elements which comprise over 95% of the human body are: carbon, phosphorus, oxygen, hydrogen calcium, phosphorus, hydrogen, nitrogen carbon, hydrogen, oxygen, nitrogen calcium, hydrogen, oxygen, nitrogen

carbon, hydrogen, oxygen, nitrogen

A substance that helps a reaction to take place, but does not participate in the reaction is called a(n) _____. catalyst reactant product activation energy

catalyst

Nonprotein substances (such as vitamins and some metal ions) which need to be present for enzymes to function are called __________________.

cofactors

Atoms that form compounds are held together by chemical bonds. The bond that includes sharing electrons with another atom is called ______________________.

covalent

When electrons are shared, the type of bonding is called: ionic nuclear hydrogen covalent

covalent

sharing of electrons

covalent

Identify the type of chemical reaction. H2CO3 H2O + CO2 decomposition exchange reversible synthesis

decomposition

When atoms combine, interactions occur between their: nuclei electrons protons neutrons

electrons

Lavoisier proposed that all matter is composed from the same _____. atoms elements molecules gases

elements

area that electrons are found around an atomic nucleus

energy level

What is expected when reactants break bonds? energy output energy input equilibrium exchange reaction

energy output

A catalyst for chemical reactions in biological systems is called a(n) ___________________.

enzyme

Protein catalysts which cause reactions to occur at temperatures and pH values which are common to living cells are called ____________________.

enzymes

A(n) __________________ reaction occurs when the bonds of the reacting compounds are broken and new combinations are formed.

exchange

Identify the type of chemical reaction. H2SO4 + 2KOHK2SO4 + 2H2O decomposition exchange reversible synthesis

exchange

Acid + base yields salt + water is an example of a(n): synthesis reaction exchange reaction decomposition reaction reversible reaction

exchange reaction

(Select all that apply.) Choose the three types of bonds introduced. ionic molecular compound covalent hydrogen oxygen

ionic covalent hydrogen

DNA has a structure similar to a: ladder wall wheel tree

ladder

Steroids are: complex carbohydrates lipids a subclass of fats a type of phospholipids

lipids

Which organic compound has this component? fats carbohydrates lipids nucleic acids proteins

lipids

Which organic compound has this component? fatty acids carbohydrates lipids nucleic acids proteins

lipids

The most abundant sources of proteins are derived from: vegetables and fruit bread and fish meat and cheese green vegetables and milk

meat and cheese

The simplest structured unit of a compound is a(n): electron atom proton molecule

molecule

the smallest complete unit of a compound or diatomic gas

molecule

simple sugars

monosaccharides

When an atom gains an electron, it becomes ___________________ charged.

negatively

A solution that contains equal numbers of hydrogen and hydroxide ions would be called: acidic basic alkaline neutral

neutral

Which organic compound has this component? DNA carbohydrates lipids nucleic acids proteins

nucleic acids

Which organic compound has this component? RNA carbohydrates lipids nucleic acids proteins

nucleic acids

Which organic compound serves this function? genetic code carbohydrates lipids nucleic acids proteins

nucleic acids

Most of the mass of an atom is contained in its _____. electrons protons nucleus neutrons

nucleus

Bonds between amino acids are what type bonds? covalent peptide hydrogen ionic

peptide

complex sugars

polysaccharides

The substance upon which an enzyme acts is called the _________________.

substrate

DNA "upright"

sugar and phosphate

A(n) _________________ reaction occurs when a molecule is formed from the bonding of atoms, ions or simpler molecules.

synthesis

Identify the type of chemical reaction. NH3 + H2ONH4OH decomposition exchange reversible synthesis

synthesis

polymerization

synthesis

Chemical reactions are the result of an atom attempting _____. to reduce the number of electrons to become electrically neutral to rearrange its configuration to result in a stable octet add sufficient electrons to complete its outer shell

to rearrange its configuration to result in a stable octet

The n = 1 shell of an atom contains a maximum of: two electrons seven electrons eight electrons eleven electrons

two electrons

The most abundant sources of carbohydrates are: vegetables butter beef fish

vegetables

Enzymes are produced only _________________________. outside the active cell in the DNA of the cell within an active cell in another cell and transported

within an active cell