*Which one of the following is NOT a trace element in the human body?
*The four most common elements in living organisms are
Contains two or more elements in a fixed ratio
The nucleus of an atom contains
Protons and neutrons
The atom sodium contains 11 electrons, 11 protons, and 12 neutrons. What is the mass number of sodium?
The atomic number of an atom is
The number of protons in the atom
*Typically, nitrogen atoms are composed of seven electrons, seven protons, and seven neutrons. An isotope of nitrogen could
Have more than seven neutrons
Can be used with PET scans to diagnose a patient
*When full, the first electron shell of an atom contains __________ electrons, and the outermost shell contains __________ electrons.
What is the difference between covalent and ionic bonding?
In a covalent bond, the partners share a pair of electrons; in an ionic bond, one partner transfers electrons to the other.
________ are weak bonds that bridges between molecules.
The ability of water molecules to form hydrogen bonds with other water molecules is critical to
The movement of water from the roots of a tree to its leaves; the abliity of certain insects to walk on the surface of water; evaporative cooling of skin surfaces; (all these factors)
*Water molecules stick to other water molecules because
Hydrogen bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules.
*As ice melts,
Hydrogen bonds are broken
A solution with a pH of 7 is
A solution with a pH of 1 is
donates H+ ions when conditionsbecome too basic and accepts H+ ions when conditions become too acidic
In the equation 2 H2+O2 -> 2 H2O, the molecules are ________ and the H2O molecules are _________.
Characteristics of carbon that contribute to its ability to form an immense diversity of organic molecules include its
Ability to bond with up o four other atoms; tendency to form covalent bonds; ability to bond together to form extensive, branched, or unbranched "carbon skeletons"; (all choices are correct)
Contain only carbon and hydrogen atoms
always contain carbon and hydrogen and are syntehsized by cells
*Which one of the following is an amino group?
Monosaccharides can be joined together by a process called dehydration synthesis. Which of the following statements is/are true of this process?
Covalent bonds are formed between the monomers; one monomer loses a hydrogen atom, and the other loses a hydroxyl group; H2O is formed as the monomers are joined; (all the choices are correct)
*The molecular formula of most monosaccharides represents a multiple of
A molecule with the formula C55H110O55 is probably a(n)
Sucrose is formed
From two monosaccharides by dehydration synthesis
Which one of the following lists contains only polysaccharides?
Cellulose, starch, and glycogen
Cellulose differs from starch in that
Most animals cannot break down cellulose, whereas starch is easily digested
Foods that are high in fiber are most likely derived from
The starage from carbohydrates in animals is _________ and in plants is _________
Fatty acids with double bonds between some of their carbons are said to be
*If you were to add olive oil to your food as part of a diet to lower your risk of atherosclerotic disease, you would use olive oil that
Was liquid at room temperature
A major type of liquid found in cell membranes is
A scientist suspects that the food in an ecosystem may have been cantaminated with radioactive nitrogen over a period of months. Which af the followin substances could be examined for radioactivity to test the hypothesis?
The hair produced by humans living in the ecosystem
Proteins differ from one another because
The sequence of amino acids in the polypeptide chain differs from protien to protein
Glucose molecules are to starch as ________ are to protiens
Link amino acids together
The _______ structure of a protein consists of a chain of amino acids assembeled in a specific order
*The tertiary structure of a polypeptide refers to
The overall three-dimensional structure
DNA differs from RNA because DNA
Contains thymine in place of uracil
Genetic information is encoded in the
Sequence of nucleotides in DNA
*A new "wonder food" is being distributed by a rival company. The researchers in your company determine that hte new "wonder food" contains only carbon, oxygen, and hydrogen. At this point, your researchers can say with certainty that the food
Does not include protiens or nucleic acids
The glucose produced by a plant is used to make the carbohydrate, proteins, fats, and other nucleic acids of the plant. Which statemenr os true about the process of convertong sugars into other molecules?
Glucose contains all of the elements needed to produce the carbohydrates and fats, but other elements must come from the soil if the plant is to produce proteins and nucleic acids.
Many names for sugars end in the suffix
Which one of the following statements about anabolic steroids is FALSE? Anabolic steroids
Promote bone growth
Can be broken down into sub units that are exactly identical to each other
Contains nitrogen; macromolecule is found to have a gloular shape