Chapter 2
Which bases below are purines? 1. adenine 2. cytosine 3. guanine 4. thymine 5. uracil
1 and 3
Lemon juice has a pH of about 2.0, compared to a pH of about 1.0 for stomach acid. Therefore, the concentration of H+ in stomach juice is ________ than that of lemon juice.
10 times higher
What is a substance that can moderate the change in pH of a solution?
A buffer
Which of the following situations BEST demonstrates solubility?
A teaspoon of salt disappears when stirred into a glass of water.
Which compound is hydrophobic?
Butter
Match the symbol with the correct element: A. P B. Na C. Ca D. C E. K F. Pb carbon
C
Match the symbol with the correct element: A. P B. Na C. Ca D. C E. K F. Pb calcium
Ca
Which of the following are examples of cations?
Ca2+
All of these statements about carbohydrates are true except one. Identify the exception.
Glycogen is important both for energy storage and to provide structure for cells
A component of an important buffer in the human body is
HCO3-.
Which of the following is a way to recognize a carbohydrate by looking at its name only?
It ends in -ose
Match the symbol with the correct element: A. P B. Na C. Ca D. C E. K F. Pb potassium
K
Which group of elements makes up more than 90% of the body's mass?
O, C, H
Match the symbol with the correct element: A. P B. Na C. Ca D. C E. K F. Pb phosphorus
P
Match the symbol with the correct element: A. P B. Na C. Ca D. C E. K F. Pb lead
Pb
What would cause a protein response rate to be maximal?
The protein binding sites are saturated.
Which of the following is an important characteristic of lipids?
They are nonpolar.
Cholesterol is
a precursor to steroid hormones and a structural component of cell membranes.
If a substance has a pH that is less than 7, it is considered
acidic.
The most important energy-transferring compound in cells is a nucleotide known as
adenosine triphosphate.
Stanley Miller set out to demonstrate an explanation for the origins of organic molecules using a combination of simple organic molecules, heat and periodic burst of electricity through the mixture, ultimately producing what kind of molecules?
amino acids
**What pieces of information do you need to know in order to calculate the molecular weight of a substance?
atomic mass of each element the number of atoms of each element
The organic molecules known as phospholipids are key components of cell membranes and composed of what monomeric units?
both glycerol and fatty acids
Essential amino acids that are used to build proteins
can be derived from the foods we eat and digest.
Atoms in a covalent molecule
can share electrons in single pairs, double pairs, or triple pairs.
Glycosylated molecules are those formed with which group of organic compounds?
carbohydrates
A positively charged ion is called a(n)
cation.
Each amino acid differs from others in the
chemical structure of the R group.
Identify each of the following as an element (A) or a compound (B). CO2
compound
Identify each of the following as an element (A) or a compound (B). O2
compound
A protein that no longer functions because its shape has changed (e.g., as a result of heating) has been ________.
denatured
Match the correct subatomic particle with the statement about it. A. proton(s) B. neutron(s) C. electron(s) This particle has a charge of -1 and a negligible mass.
electron(s)
Identify each of the following as an element (A) or a compound (B). C
element
**For ions in solution, the measurement unit that considers the number of electrical charges carried by each ion is the _____.
equivalent
Match the descriptions to the correct protein category. A. fibrous B. globular keratin
fibrous
A nucleotide consists of a
five-carbon sugar, a nitrogenous base, and a phosphate group.
anions _ electrons and are _ charged
gain, negatively
Match the descriptions to the correct protein category. A. fibrous B. globular soluble in water
globular
According to the rules of complementary base pairing, a nucleotide containing the base cytosine would only pair with a nucleotide containing the base
guanine.
Match each bond type with its description. A. van der Waals B. ionic C. hydrogen D. covalent These are weak attractive forces between hydrogen and certain other atoms.
hydrogen
The weak interactions between atoms that keep atoms near each other but don't tightly bind them together are called
hydrogen bonds and van der Waals forces.
Cells regulate their level of activity by regulating the amount of proteins present in the cell at any given time, so an up regulation of enzymes would be expected to
increase the level of productivity of chemical reactions that rely on them.
**Hydrophobic solutes are generally soluble/insoluble (choose one) in water, due to the presence of _____ covalent bonds between the atoms in each solute molecule.
insoluble; nonpolar
Match each bond type with its description. A. van der Waals B. ionic C. hydrogen D. covalent This results when an atom has such a strong attraction for electrons that it pulls one or more electrons completely away from another atom.
ionic
Which of the following is NOT considered an essential element for a living organism?
mercury
A free radical is a
molecule with an unpaired electron.
Match the correct subatomic particle with the statement about it. A. proton(s) B. neutron(s) C. electron(s) This particle has a neutral charge and a mass of 1.
neutron(s)
Match the correct subatomic particle with the statement about it. A. proton(s) B. neutron(s) C. electron(s) Isotopes of the same element differ by having different numbers of ________.
neutron(s)
Nucleic acids are polymers of units called
nucleotides
Polymers are a typical formation of ________ molecules.
organic
**Water readily dissolves ions because the atoms in water molecules are bonded by _____ bonds.
polar covalent
Match each level of protein structure with its description. A. primary B. secondary C. tertiary D. quaternary the sequence and number of amino acids in the chain
primary
Match the correct subatomic particle with the statement about it. A. proton(s) B. neutron(s) C. electron(s) The identity of an element can be determined by the number of ________.
proton(s)
Match the correct subatomic particle with the statement about it. A. proton(s) B. neutron(s) C. electron(s) This particle has a charge of +1 and a mass of 1.
proton(s)
Interactions between different globular or fibrous polypeptide chains result in which type of structure?
quaternary
Match each level of protein structure with its description. A. primary B. secondary C. tertiary D. quaternary applies to proteins containing more than one peptide chain
quaternary
Proteins that bind signal molecules and initiate cellular responses are called ________
receptors
Match each level of protein structure with its description. A. primary B. secondary C. tertiary D. quaternary the spatial arrangement of amino acids; can be a helix or a pleated sheet
secondary
The alpha-helix and pleated sheet are examples of the ________ structure of a protein.
secondary
The concentration of a solution expresses the amount of
solute per volume of solution
**You take salt and add it to a beaker containing water. You have just created which of the following?
solution
The largest carbohydrate molecules are called polysaccharides because they are composed of ________ molecules bonded together with one another.
sugar
MAYBE: Function of protiens (4)
support and structure, catalyst, carrying of messages, transport
Match each level of protein structure with its description. A. primary B. secondary C. tertiary D. quaternary the three-dimensional shape of an amino acid chain; can be fibrous or globular
tertiary
The chemical bonding behavior of an atom is directly determined by
the number and arrangement of electrons.
In regard to lipids, the term unsaturated refers to
the presence of double bonds between adjacent carbon atoms in a fatty acid.
Which of the following substances is most alkaline?
urine, pH = 6
A molecule referred to as highly soluble is
very likely to dissolve in water and is called aqueous
The most important polar molecule is ________ because it is practically a universal solvent
water