Which of the following is necessary for proper conduction of nervous impulses?
D) Na
A phospholipid is usually ________.
A) partially polar and partially nonpolar
In general, the category of lipids that we refer to as oils have ________.
A) a high degree of unsaturated bonds
The genetic information is coded in DNA by ________.
A) the sequence of the nucleotides
Which of the following is not true of proteins?
B) They appear to be the molecular carriers of the coded hereditary information.
The single most abundant protein in the body is ________.
B) collagen
Carbohydrates are stored in the liver and muscles in the form of ________.
B) glycogen
Coenzymes are ________.
C) organic molecules derived from vitamins
The speed or rate of a chemical reaction is influenced by all of the following except ________.
D) the presence or absence of carbon
A chemical reaction in which bonds are broken is usually associated with ________.
C) the release of energy
Salts are always ________.
B) ionic compounds
The numbers listed represent the first, second, and third energy levels, respectively. On this basis, which of the following is an unstable or reactive atom?
C) 2, 8, 1
A solution that has a pH of 2 could best be described as being ________.
D) acidic
Which of the following is the major positive ion outside cells?
B) sodium
Which of the following would be regarded as an organic molecule?
D) CH4
A chain of 25 amino acids would be called a ________.
D) polypeptide
A long chain of simple sugars would be a ________.
A) polysaccharide
The coiling of the protein chain backbone into an alpha helix is referred to as the ________.
A) secondary structure
Carbohydrates and proteins are built up from their basic building blocks by the ________.
A) removal of a water molecule between each two units
Which statement about enzymes is false?
D) Enzymes raise the activation energy needed to start a reaction.
Many plasma proteins may function as _________.
B) buffers
Which of the following is true regarding the concentration of solutions?
A) Molarity is one mole of solute per 1000 ml of solution.
Select the statement about mixtures that is correct.
D) A solution contains solvent in large amounts and solute in smaller quantities.
HCO3- is _________.
B) a bicarbonate ion
Select which reactions will usually be irreversible regarding chemical equilibrium in living systems.
D) glucose to CO2 & H2O
In redox reactions ________.
A) both decomposition and electron exchange occur
Fibrous proteins ________.
A) are very stable and insoluble in water
The ATP molecule is not used in ___________.
C) pigments
Select the most correct statement regarding nucleic acids.
D) DNA is a long, double-stranded molecule made up of A, T, G, and C bases.
________ is a suspension.
D) Blood
Select the correct statement about isotopes.
C) Isotopes of the same element have the same atomic number but differ in their atomic mass.
The four elements that make up about 96% of body matter are ________.
B) carbon, oxygen, hydrogen, nitrogen
An example of a coenzyme is ________.
D) riboflavin (vitamin B2)
________ is fat-soluble, produced in the skin on exposure to UV radiation, and necessary for normal bone growth and function.
D) Vitamin D
In liquid XYZ, you notice that light is scattered as it passes through. There is no precipitant in the bottom of the beaker, though it has been sitting for several days. This liquid must be a ________.
D) colloid
Atom X has seventeen protons. How many electrons are in its valence shell?
B) 7
If an atom were to have two protons, then it would ________.
B) be very stable
If atom X has an atomic number of 74 it would have ________.
B) 74 protons and roughly the same number of neutrons
The formula C6H12O6 means ________.
B) there are 12 hydrogen, 6 carbon, and 6 oxygen atoms
Two good examples of a colloid would be Jell-O® or ________.
A) cytosol
An atom with a valance of 3 may have a total of ________ electrons.
A) 13
An atom with ________ electrons could be an anion when ionically bonded.
A) 9
The chemical symbol O=O means ________.
C) the atoms are double bonded
Dipole is ________.
C) a polar molecule
CH4 means ________.
A) there is one carbon and four hydrogen atoms
Amino acids joining together to make a peptide is a good example of a ________ reaction.
A) synthesis
________ is not considered to be a factor in influencing a reaction.
A) Time
Which of the following is not an electrolyte?
D) H2O
Human blood has a pH of ________.
A) 7.35-7.45
__________ is a heavy metal normally found in the body.
A) Iron
Sucrose is a ________.
B) disaccharide
Neutral fats have a ________ ratio of fatty acids to glycerol.
A) 3:1
In a DNA molecule, the phosphate serves ________.
C) to hold the molecular backbone together
Most fibrous proteins in the body contain all of these except:
C) eledin
Heat shock proteins (hsp) are a type of protein called ________.
A) chaperonins
_________ bonds often bind different parts of a molecule into a specific 3-dimensional shape.
C) Hydrogen
Choose the statement that is false or incorrect.
D) A key feature of the body's metabolism is the almost exclusive use of exergonic reactions by the body.
Which of the following is not a role of molecular chaperonins?
B) act as a biological catalyst
Which of the following statements is false?
A) Larger particles move faster than smaller ones and thus collide more frequently and more forcefully.
Which protein types are vitally important to cell function in all types of stressful circumstances?
D) molecular chaperones
Which property of water is demonstrated when we sweat?
E) high heat of vaporization
The atomic number is equal to the number of ________.
protons (and electrons)
Molecules such as methane that are made of atoms that share electrons have ________ bonds.
covalent
An atom with three electrons would have a valence of ________.
one
AB → A + B is an example of a(n) ________ reaction.
decomposition
________ have a bitter taste, feel slippery, and are proton acceptors.
Bases
A holoenzyme is composed of an apoenzyme and a(n) ________.
cofactor
In a DNA molecule, guanine would connect to ________.
cytosine
The ________ molecule directly provides energy for cellular work.
ATP
Hydrogen bonds are more like a type of weak ________ than true bonds.
attraction
Weak acids and bases make good ________.
buffers
Starch is the stored carbohydrate in plants, while ________ is the stored carbohydrate in animals.
glycogen
How many phosphates would AMP have attached to it?
one
Which metals have a toxic effect on the body?
heavy
The atomic weight is only an average of relative weights of an atom and its isotopes, and it may vary from the weight of a specific isotope. True or False
True
Emulsions and colloids are the same thing. True or False
True
Chemical properties are determined primarily by neutrons. True or False
False
A charged particle is generally called an ion. True or False
True
Isotopes differ from each other only in the number of electrons contained. True or False
False
About 60 to 80% of the volume of most living cells consists of organic compounds. True or False
False
Lipids are a poor source of stored energy. True or False
False
Current information theorizes that Omega-3 fatty acids decrease the risk of heart disease. True or False
True
Glucose is an example of a monosaccharide. True or False
True
A molecule consisting of one carbon atom and two oxygen atoms is correctly written as CO2. True or False
True
The lower the pH, the higher the hydrogen ion concentration. True or False
True
Covalent bonds are generally less stable than ionic bonds. True or False
False; more
Hydrogen bonds are comparatively strong bonds. True or False
False; weak
The fact that no chemical bonding occurs between the components of a mixture is the chief difference between mixtures and compounds. True or False
True
Alpha particles, although relatively weak energy particles, are second only to smoking as a cause of lung cancer. True or False
True
No chemical bonding occurs between the components of a mixture. True or False
True
All organic compounds contain carbon. True or False
True
A dipeptide can be broken into two amino acids by dehydration synthesis. True or False
