Chapter 2 - Chemistry of Life
Methyl group
CH3
Ketone group
CO
Carboxyl group
COOH
Group on the carboxyl-terminal end of proteins
COOH
Group that is very acidic
COOH
Forms quaternary protein structure by linking two sulfur atoms
disulfide
A protein inside cells that speeds up the rate of a chemical reaction is a(n) ____. - hydrocarbon - inorganic compound - enzyme - buffer - functional group
enzyme
Each carbon atom can share pairs of electrons with as many as ____ other atoms. - two - three - four - five - six
four
Donates H+
acid
Which statement is true of water? - Water molecules attract hydrophobic substances. - Water evaporates after absorbing small amounts of heat energy. - Water's hydrogen atom is slightly negative. - Water molecules are polar. - Water's oxygen atom is slightly positive.
Water molecules are polar
Unequal sharing of electrons
nonpolar covalent
A lipid is a(n) ____. - polar hydrocarbon - polar peptide - nonpolar peptide - ionic polar hydrocarbon - nonpolar hydrocarbon
nonpolar hydrocarbon
Basic unit of genetic material
nucleotides
A dissolved substance in water is a(n) _____. - solvent - solute - antioxidant - free radical - acid
solute
The interaction of many separate polypeptide chains determines the _____________ structure of a protein molecule.
quaternary
What is the maximum # of electrons in a shell? - 0 - 2 - 6 - 8 - 12
8
Phospholipids contain ____________________ tails that are repelled by water.
hydrophobic
Property of phospholipid tails
hydrophobic
A peptide bond is found between the amino group of one amino acid and the ___________ group of a second amino acid.
carboxyl
The sterol ____________________ is a vital component of all cell membranes and is used to synthesize steroid hormones.
cholesterol
A pure substance that cannot be broken down into another substance is known as: - proton - electron - compound - element - isotope
element
Atoms or clusters of atoms that are covalently bonded to carbon and influence the behavior of organic compounds are known as ____. - ions - anhydrides - antioxidants - acids - functional groups
functional groups
Which element is not one of the four most common elements found in organisms? - hydrogen - oxygen - carbon - helium - nitrogen
helium
Weak bonds between water molecules
hydrogen
An acid is a substance that donates a(n) ____. - neutron - antioxidant - hydroxide ion - electron - proton
proton
The atomic number denotes the number of _______ in an atom of a particular element. - electrons - neutrons - energy levels - protons - isotopes
protons
In saturated fats, the fatty acid backbones have only ____________ covalent bonds.
single
Positron emission tomography (PET) utilizes ____ to yield results of a scan. - x-rays - tracers - glucose - ion - photons
tracers
The most abundant lipids in the body are ____. - triglycerides - oils - waxes - fatty acids - phospholipids
triglycerides
A substance that gives up an electron to a free radical is a(n) ____. - oxidizer - antioxidant - antibiotic - antibody - antiviral
antioxidant
Fats that stay liquid at room temperature are ____. - animal fats - unsaturated - transfatty acids - phospholipids - cholesterol
unsaturated
A tracer is a substance with what attached to it? - a radioisotope - water - glucose - ion - antibodies
a radioisotope
A buildup of H+ in the blood will lead to ____. - alkalosis - acidosis - excess calcium - excess carbon dioxide - a higher than normal pH
acidosis
The structural building blocks for proteins are ____. - enzymes - amino acids - cholesterol - polysaccharides - vitamins
amino acids
A free radical takes what particle from a stable molecule? - a proton - an electron - a neutron - an atom - a hydrogen ion
an electron
Binds H+
base
During an hydrolysis reaction, ____. - covalent bonds are formed - a water molecule is formed - bonds are broken - polymers are formed - condensation occurs
bonds are broken
A system that compensates for pH fluctuations by donating or accepting H+ is known as a(n) ____. - acid - base - salt - buffer - antioxidant
buffer
Resists pH changes by binding and releasing H+
buffer
Which of the following is composed of a 1:2:1 ratio of carbon to hydrogen to oxygen? - carbohydrate - protein - lipid - nucleic acid - steroid
carbohydrate
Which carbohydrate, found only in plants, is indigestible by humans? - glycogen - starch - glucose - sucrose - cellulose
cellulose
Nucleotide-containing molecules that move hydrogen atoms and electrons from one reaction site to another are known as ___________.
coenzymes
A nucleotide is composed of at least one sugar, one phosphate group, and ____. - one nitrogen-containing base - one amino acid - multiple cholesterol molecules - fatty acid chains - ATP
one nitrogen-containing base
Which type of bond is responsible for the linking together of atoms within a water molecule? - hydrogen - ionic - polar covalent - nonpolar covalent - isotropic
polar covalent
Glycogen, starch and cellulose are examples of _____________ or complex carbohydrates.
polysaccharides
Which type of bond is responsible for the linking together of two water molecules? - hydrogen - ionic - polar covalent - nonpolar covalent - isotropic
hydrogen
Group that occurs repeatedly in alcohol and sugars
OH
Three of these groups found in ATP
PO4
Hydroxyl group
OH
Glucose is an example
organic compound
Amine group
NH2
Group on the amino-terminal end of proteins
NH2
What fat is the building block for cell membranes? -trans fatty acids -sterols - phospholipids - triglycerides - cholesterol
sterols
Which class of fats is used to synthesize various vitamins and hormones? -fatty acids -triglycerides -phospholipids - sterols - waxes
sterols
Basic units of proteins
amino acids
Determines special properties of molecules
functional group
Basic units of glycogen
glucose
The building block of large carbohydrates is ____. - amino acids - glycerol - polysaccharide - glucose - glycogen
glucose
Forms the backbone of phospholipids
glycerol
Animals store carbohydrates in the form of ____. - glycogen - starch - glucose - sucrose - lipids
glycogen
When an atom's outer electron shell is filled, the atom is _____. - unstable - positively charged - polarized - most stable - isotope
most stable
Which nucleotide is associated with energy transfer? - DNA - ATP - RNA - cAMP - UBP
ATP
Which pesticide can trigger rashes, hives, headaches and asthma? - atrazine - growth hormone - anthocyanin - DDT - sterols
DDT
____________________ determines the order in which amino acids form the primary structure of a protein.
DNA
Isotopes of an element are different from the most common standard form due to differences in the _____. - atomic # -position of the element in the periodic table - # of neutrons in the nucleus - # of protons in the nucleus - size of the electron cloud
# of neutrons in the nucleus
Carbohydrates consist of carbon, hydrogen and oxygen in a ratio of ____________.
1:2:1
There are how many different types of amino acids? - 5 - 10 - 15 - 20 - 50
20
What makes water a good solvent? - It dissolves ions and polar molecules. - It dissolves fats. - It mixes well with alcohol. - It heats up very quickly. - It is very acidic.
It dissolves ions and polar molecules
The protein enzymes in the stomach work best in a very acidic environment. As the material from the stomach moves into the small intestines, the pancreas must secrete alkaline buffers into the small intestines. Based on what you know about pH and protein structure explain why this function of the pancreas is important to digestive function.
Protein molecules have a specific three dimensional shape that determines its function. Factors such as temperature and pH can affect this shape and thus influence protein function. The enzymes that function in the stomach work best in an acidic environment but those in the small intestines work best at a more basic pH. So the pancreas must secrete alkaline buffers into the small intestines to neutralize the acidity to allow the small intestine enzymes to function properly.
Which part of the amino acid helps to determine its chemical properties? - amino group - carboxyl group - covalent bond - peptide bond - R-group
R-group
DNA carries the genetic material while ________ processes the genetic information to build proteins in cells.
RNA
Which nucleotide contains the sugar ribose? - DNA - ATP - RNA - cAMP - UBP
RNA
Which statement is true of electron shells? - The innermost shell can hold up to two electrons. - The innermost shell is at the highest energy level. - A shell can hold up 20 electrons. - Larger atoms have less electron shells. - A second shell with six electrons is completely filled.
The innermost shell can hold up to two electrons
How do hydrophilic molecules interact with water? - They are attracted to water. - They are absorbed by water. - They are repelled by water. - They absorb heat from water. - They transfer heat to water.
They are attracted to water
If a chlorine atom has 7 electrons in its outer energy level, which of the following is true about chlorine? - It is stable as it is and will not react with other atoms. - It will lose an electron during a chemical reaction. - It has an electron structure similar to sodium atoms. - It will form a covalent bond with sodium. - When it fills its outer electron shell, it becomes a negatively charged ion.
When it fills its outer electron shell, it becomes a negatively charged ion
Covalent bonds ______. - occur when ions of opposite charge are attracted to each other - occur during oxidation reactions - are the weak link between two water molecules - are extremely strong and stable - form bonds that hold Na and Cl together in NaCl (table salt)
are extremely strong and stable
Radioisotopes ______ - are unstable and emit energy and particles to stabilize themselves - are different elements from the "standard" elements - are very stable and do not change over time - are so unstable that they rarely exist in nature - exist only for carbon and oxygen
are unstable and emit energy and particles to stabilize themselves
Three of these basic units found in triglycerides
fatty acids
Which protein binds and releases oxygen molecules? - collagen - insulin - keratin - hemoglobin - enzymes
hemoglobin
Water has a high heat capacity because it has ____. - covalent bonds - ionic bonds - low freezing point - high boiling point - hydrogen bonds
hydrogen bonds
Does not contain both C and H
inorganic compound
Formed when electrons are transferred between atoms
ion
Associated with the transfer of electrons between atoms
ionic
A phospholipid molecule contains a "head" portion that ____. - is hydrophilic - is derived from cholesterol - contains two fatty acid chains - is similar in structure to a triglyceride - forms a hydrophobic barrier
is hydrophilic
A solution with a pH of 7.4 ____. - is considered an acid - has more H+ than OH- - has equal numbers of H+ and OH- - has a pH similar to ammonia - is similar in acidity to normal body fluids
is similar in acidity to normal body fluids
A protein combined with cholesterol in the blood is an example of a(n) ____. - irregular protein - lipoprotein - glycoprotein - denatured protein - collagen
lipoprotein
The blending of two or more kinds of molecules is a(n) _____. - compound - isotope - reactant - mixture - chemical bond
mixture
The bonding of two or more atoms creates a(n) ______. - molecule - ion - isotope - mixture - solution
molecule
A compound that contains both carbon and hydrogen is ____. - a salt - always an acid - non-biological - organic - inorganic
organic
Binds amino acids within a protein
peptide
The type of bond that exists between amino acids in a protein is a(n) ____ bond. - peptide - hydrogen - ionic - glycosidic - primary
peptide
The sequence of amino acids in a protein represents its ____. - primary structure - secondary structure - three dimensional shape - tertiary folding pattern - biological function
primary structure
An atom carries no charge because it has as many electrons as ____. - protons - neutrons - orbitals - neutrinos - shells
protons
The process by which the movement of internal bonds converts one type of organic compound into another is ____. - condensation - cleavage - functional group transfer - electron transfer - rearrangement
rearrangement
Releases ions other than H+ and OH-
salt
Plants store large amounts of carbohydrates in the form of ____. - glycogen - starch - glucose - sucrose - lipids
starch
Proteins perform four of the following functions. They do NOT, however ____. - act as enzymes - store large amounts of energy - act as transport molecules - bind molecules to or inside cells - adjust cell activities
store large amounts of energy
During a synthesis reaction, glucose and fructose combine to form ____. - glycogen - sucrose - starch - a monosaccharide - a polysaccharide
sucrose
What level of protein structure is associated with the folding of coils and sheets to form a hollow region through which substances can move into and out of cells? - primary - secondary - tertiary - quaternary - binary
tertiary
An ion is formed _____. - during covalent bonds when water molecules are bound together - when atoms exchange electrons - when atoms share electrons equally - when atoms share electrons unequally
when atoms exchange electrons
Used to synthesize hormones and vitamins
cholesterol