AP Biology|Complete Questions with A+ Graded Answers
Elements
Elements are substances that cannot be broken down into simpler substances by chemical means.
Oxygen
Oxygen is an element with symbol O and atomic number 8. It is a highly reactive nonmetal and
oxidizing agent. In living organisms, oxygen is used in respiration and in a number of organic
molecules.
Carbon
Carbon is an non mental element with symbol O and atomic number 6. It is the second most
abundant element in living organisms and is present in all organic compounds.
Hydrogen
Hydrogen is an element with symbol H and atomic number 1. Hydrogen combines with non-metallic
elements to form water and other organic compounds.
Nitrogen
Nitrogen is an element with the symbol N and atomic number 7. In biology, nitrogen is important as it
is found in a number of organic compounds and is used in fertilizers and antibiotics.
Trace elements
Trace elements are elements required by an organism in very small quantities. Trace elements include
iron, iodine, and copper.
Atom
An atom is the smallest unit of an element that retains its characteristic properties; they are the
building blocks of the physical world.
Protons
Protons are positively charged subatomic particles that are found in an atom's nucleus.
Neutrons
Neutrons are uncharged subatomic particles found in an atom's nucleus.
Electrons
Electrons are negatively charged subatomic particles that spin around the nucleus.
Nucleus
The nucleus is the positively charged core in an atom made up of neutrons and protons.
Isotopes
Atoms that have the same number of protons but differ in the number of neutrons in the nucleus are
called isotopes.
,Compound
A chemical compound is formed when two or more different types of atoms are combined in a fixed
ration.
Chemical reaction
A chemical reaction describes a chemical change in which reactants react to form products chemically
different from the reactants.
Chemical bond
The atoms of a compound are held together by chemical bonds, which may be ionic bonds, covalent
bonds, or hydrogen bonds.
Ionic bond
An ionic bond is formed between two atoms when one or more electrons are transferred from one
atom to the other. In this case, one atom becomes negatively charged and one atom becomes
positively charged.
Ions
An ion is a charged form of an atom.
Covalent bond
A covalent bond is formed when electrons are shared between atoms and can be polar or non-polar.
Non-polar covalent
A non-polar covalent bond is a covalent bond in which the electrons are shared equally between the
atoms.
Polar covalent
A polar covalent bond is a covalent bond in which the electrons are shared unequally - one atom
attracts electrons more than the other.
Polar
A molecule is polar if it has partially positive and partially negative charged ends, such as water.
Hydrogen bonds
Hydrogen bonds are intermolecular attractions that form when a hydrogen bond that is covalently
bonded to one electronegative atom that it also attracted to another electronegative atom. Hydrogen
bonds are individually weak but are strong when present in large numbers.
Cohesion
Cohesion refers to the tendency of water molecules to stick together and allows water to have a high
surface tension.
Adhesion
,Adhesion refers to the tendency of water molecules to stick to other substances, which accounts for
the phenomenon of capillary action.
Capillary action
Capillary action is the ability of water, or other liquids, to travel against gravity in a thin vessel and
accounts for the ability of water to rise up the roots, trunks, and branches of trees.
Heat capacity
Heat capacity refers to the ability of a substance to store heat and is the quantity of heat required to
change the temperature of a substance by 1 degree. Water has a high heat capacity, allowing it to
keep a fairly stable temperature in our bodies and in the environment.
Surface tension
Surface tension is a property of water, due to the cohesiveness of its molecules, that allows things
(sometimes organisms) to float and stride on its surface without sinking.
Acidic
A solution is acidic if it contains excess hydrogen ions. It will have a pH less than 7.
Basic
A solution is basic if it releases hydroxide ions when added to water. These solutions are said to be
alkaline and are usually slippery.
Neutral
A solution is neutral, neither basic nor acidic, if it has a pH of 7.
pH scale
The pH scale is a logarithmic scale to measure acidity, with 1 being most acidic, 14 being most basic,
and 7 being neutral.
Organic compounds
Organic compounds are compounds that contain carbon and include carbohydrates, lipids, proteins,
and nucleic acids.
Inorganic compounds
Inorganic compounds are compounds that do not contain carbon atoms (except for some simple
carbon compounds such as carbon oxides)
Carbohydrates
Carbohydrates are organic compounds that contain carbon, hydrogen, and oxygen, usually in a ratio
of 1:2:1.
Monosaccharides
Monosaccharides are the simplest sugars which serve as an energy source for cells. The two most
common monosaccharides are glucose and fructose.
, Disaccharides
Disaccharides are formed by two sugar molecules combining together through dehydration synthesis.
An example of a disaccharide is maltose, make by linking two glucose molecules.
Polysaccharides
Polysaccharides are made up of many repeated unites of monosaccharides, and is therefore a type of
polymer. The most common polysaccharides are starch, cellulose, and glycogen. Polysaccharides are
often storage forms of sugar.
Glucose
Glucose is the most abundant monosaccharide and is a six-carbon sugar with the chemical formula C-
6, H-12, O-6. Glucose comes in two forms: alpha glucose and beta glucose, which differ simply by a
reversal of the H and OH of the first carbon.
Fructose
Fructose is a monosaccharide that is a common sugar in fruits. It is a six-carbon sugar with the
chemical formula C-6, H-12, O-6.
Glycosidic bond
A glycosidic bond is a covalent bond in which a carbohydrate binds to another group, which could also
be a carbohydrate. A glycosidic bond is found between the two glucose molecules in maltose.
Dehydration synthesis
Dehydration synthesis, or condensation, is the process by which two molecules come together by the
loss of a water molecule, such as the forming of maltose from two glucose molecules.
Hydrolysis
Hydrolysis is the opposite process of dehydration synthesis by which molecules are broken up by the
addition of a water molecule, such as the formation of two glucose molecules from a maltose.
Polymer
A polymer is a molecule with repeating subunits of the same general type, such as polysaccharides.
Starch
Starch is a polysaccharide of alpha glucose molecules bound together and is produced by most green
plants as an energy store.
Cellulose
Cellulose is a polysaccharide of beta glucose molecules that is a major part of the cell wall in plants
and is used to lend structural support.
Glycogen
Glycogen is a multi-branch polysaccharide of glucose that is the main storage of glucose in the body.
Plastids
Elements
Elements are substances that cannot be broken down into simpler substances by chemical means.
Oxygen
Oxygen is an element with symbol O and atomic number 8. It is a highly reactive nonmetal and
oxidizing agent. In living organisms, oxygen is used in respiration and in a number of organic
molecules.
Carbon
Carbon is an non mental element with symbol O and atomic number 6. It is the second most
abundant element in living organisms and is present in all organic compounds.
Hydrogen
Hydrogen is an element with symbol H and atomic number 1. Hydrogen combines with non-metallic
elements to form water and other organic compounds.
Nitrogen
Nitrogen is an element with the symbol N and atomic number 7. In biology, nitrogen is important as it
is found in a number of organic compounds and is used in fertilizers and antibiotics.
Trace elements
Trace elements are elements required by an organism in very small quantities. Trace elements include
iron, iodine, and copper.
Atom
An atom is the smallest unit of an element that retains its characteristic properties; they are the
building blocks of the physical world.
Protons
Protons are positively charged subatomic particles that are found in an atom's nucleus.
Neutrons
Neutrons are uncharged subatomic particles found in an atom's nucleus.
Electrons
Electrons are negatively charged subatomic particles that spin around the nucleus.
Nucleus
The nucleus is the positively charged core in an atom made up of neutrons and protons.
Isotopes
Atoms that have the same number of protons but differ in the number of neutrons in the nucleus are
called isotopes.
,Compound
A chemical compound is formed when two or more different types of atoms are combined in a fixed
ration.
Chemical reaction
A chemical reaction describes a chemical change in which reactants react to form products chemically
different from the reactants.
Chemical bond
The atoms of a compound are held together by chemical bonds, which may be ionic bonds, covalent
bonds, or hydrogen bonds.
Ionic bond
An ionic bond is formed between two atoms when one or more electrons are transferred from one
atom to the other. In this case, one atom becomes negatively charged and one atom becomes
positively charged.
Ions
An ion is a charged form of an atom.
Covalent bond
A covalent bond is formed when electrons are shared between atoms and can be polar or non-polar.
Non-polar covalent
A non-polar covalent bond is a covalent bond in which the electrons are shared equally between the
atoms.
Polar covalent
A polar covalent bond is a covalent bond in which the electrons are shared unequally - one atom
attracts electrons more than the other.
Polar
A molecule is polar if it has partially positive and partially negative charged ends, such as water.
Hydrogen bonds
Hydrogen bonds are intermolecular attractions that form when a hydrogen bond that is covalently
bonded to one electronegative atom that it also attracted to another electronegative atom. Hydrogen
bonds are individually weak but are strong when present in large numbers.
Cohesion
Cohesion refers to the tendency of water molecules to stick together and allows water to have a high
surface tension.
Adhesion
,Adhesion refers to the tendency of water molecules to stick to other substances, which accounts for
the phenomenon of capillary action.
Capillary action
Capillary action is the ability of water, or other liquids, to travel against gravity in a thin vessel and
accounts for the ability of water to rise up the roots, trunks, and branches of trees.
Heat capacity
Heat capacity refers to the ability of a substance to store heat and is the quantity of heat required to
change the temperature of a substance by 1 degree. Water has a high heat capacity, allowing it to
keep a fairly stable temperature in our bodies and in the environment.
Surface tension
Surface tension is a property of water, due to the cohesiveness of its molecules, that allows things
(sometimes organisms) to float and stride on its surface without sinking.
Acidic
A solution is acidic if it contains excess hydrogen ions. It will have a pH less than 7.
Basic
A solution is basic if it releases hydroxide ions when added to water. These solutions are said to be
alkaline and are usually slippery.
Neutral
A solution is neutral, neither basic nor acidic, if it has a pH of 7.
pH scale
The pH scale is a logarithmic scale to measure acidity, with 1 being most acidic, 14 being most basic,
and 7 being neutral.
Organic compounds
Organic compounds are compounds that contain carbon and include carbohydrates, lipids, proteins,
and nucleic acids.
Inorganic compounds
Inorganic compounds are compounds that do not contain carbon atoms (except for some simple
carbon compounds such as carbon oxides)
Carbohydrates
Carbohydrates are organic compounds that contain carbon, hydrogen, and oxygen, usually in a ratio
of 1:2:1.
Monosaccharides
Monosaccharides are the simplest sugars which serve as an energy source for cells. The two most
common monosaccharides are glucose and fructose.
, Disaccharides
Disaccharides are formed by two sugar molecules combining together through dehydration synthesis.
An example of a disaccharide is maltose, make by linking two glucose molecules.
Polysaccharides
Polysaccharides are made up of many repeated unites of monosaccharides, and is therefore a type of
polymer. The most common polysaccharides are starch, cellulose, and glycogen. Polysaccharides are
often storage forms of sugar.
Glucose
Glucose is the most abundant monosaccharide and is a six-carbon sugar with the chemical formula C-
6, H-12, O-6. Glucose comes in two forms: alpha glucose and beta glucose, which differ simply by a
reversal of the H and OH of the first carbon.
Fructose
Fructose is a monosaccharide that is a common sugar in fruits. It is a six-carbon sugar with the
chemical formula C-6, H-12, O-6.
Glycosidic bond
A glycosidic bond is a covalent bond in which a carbohydrate binds to another group, which could also
be a carbohydrate. A glycosidic bond is found between the two glucose molecules in maltose.
Dehydration synthesis
Dehydration synthesis, or condensation, is the process by which two molecules come together by the
loss of a water molecule, such as the forming of maltose from two glucose molecules.
Hydrolysis
Hydrolysis is the opposite process of dehydration synthesis by which molecules are broken up by the
addition of a water molecule, such as the formation of two glucose molecules from a maltose.
Polymer
A polymer is a molecule with repeating subunits of the same general type, such as polysaccharides.
Starch
Starch is a polysaccharide of alpha glucose molecules bound together and is produced by most green
plants as an energy store.
Cellulose
Cellulose is a polysaccharide of beta glucose molecules that is a major part of the cell wall in plants
and is used to lend structural support.
Glycogen
Glycogen is a multi-branch polysaccharide of glucose that is the main storage of glucose in the body.
Plastids
