front 1 About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements makeup approximately 96% of living matter? A) carbon, sodium, chlorine, nitrogen B) carbon, sulphur, phosphorus, hydrogen C) carbon, hydrogen, nitrogen, oxygen D) carbon, oxygen, sulphur, calcium | back 1 C) Carbon, Hydrogen, Nitrogen and Oxygen |
front 2 Trace elements are those required by an organism in only minute quantities. Which of the following is a trace element that is required by humans and other vertebrates? A) Nitrogen B) Iodine C) Sodium D) Phosphorus | back 2 B) Iodine |
front 3 Atoms whose outer electron shells contain eight electrons tend to A) form ionic bonds in aqueous solutions. B) be stable and chemically nonreactive,or inert. C) be unstable and chemically very reactive. D) be isotopes and very radioactive. | back 3 B) Be stable and chemically nonreactive or inert. |
front 4 A covalent chemical bond is one in which A)electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. B) protons and neutrons are shared by two atoms so as to satisfy both atoms. C) Outer-shell electrons of two atoms are shared so as to fill the outer electron shells of both atoms. D) outer-shell electrons of one atom are transferred to the inner electron shells of another atom. | back 4 C) Outer-shell electrons of two atoms are shared so as to fill the outer electron shells of both atoms. |
front 5 The ionic bond of sodium chloride is formed when | back 5 A) chlorine gains an electron from sodium. |
front 6 Which of the following explains most specifically the attraction of
water molecules to one another? | back 6 D) hydrogen bond |
front 7 Van der Waals interactions result when | back 7 B) electrons are not symmetrically distributed in a molecule. |
front 8 Which two functional groups are always found in amino acids? | back 8 D) carboxyl and amino |
front 9 What is the chemical reaction mechanism by which cells make polymers
from monomers? | back 9 C) dehydration reactions |
front 10 All of the following statements concerning saturated fats are true,
except... | back 10 B) They have multiple double bonds in the carbon chains of their fatty acids. |
front 11 A strong covalent bond between cysteine amino acids that functions in maintaining a polypeptide's specific three-dimensional shape is a(an) A) ionic bond. B) hydrophobic interaction. C) disulphide bond. D) hydrogen bond. | back 11 C) disulphide bond. |
front 12 Which of the following statements about prokaryotic and eukaryotic cells is not correct? A) Prokaryotic cells contain small membrane-enclosed organelles. B) Eukaryotic cells contain amembrane-bound nucleus. C)DNA ,or deoxy ribonucleic acid, is present in both prokaryotic cells and eukaryotic cells. D)DNA or deoxy ribonucleic acid is present in the nucleus of eukaryotic cells | back 12 A) Prokaryotic cells contain small membrane-enclosed organelles. |
front 13 Prokaryotic and eukaryotic cells generally have which of the following features in common? A)a membrane-bounded nucleus B)ribosomes C) flagella or cilia that contain microtubules D) linear chromosomes made of DNA and protein | back 13 B) Ribosomes |
front 14 Which of the following best describes the flow of information in
eukaryotic cells? | back 14 A) DNA → RNA → proteins |
front 15 Which of the following are nitrogenous bases of the purine
type? | back 15 B) guanine and adenine |
front 16 The difference between the sugar in DNA and the sugar in RNA is that
the sugar in DNA | back 16 D) contains one less oxygen atom. |
front 17 Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules? A)lipids B)starches C)proteins D)steroids | back 17 C) Proteins |
front 18 Which structure is the site of the synthesis of proteins that may be exported from the cell? A) rough endoplasmic reticulum B) lysosomes C) plasmodesmata D) Golgi vesicles | back 18 A) rough endoplasmic reticulum |