Chp. 2 Chemical Basis of Life

The atomic weight of an element whose atoms contain 8 protons, 8 electrons, and 8 neutrons is 24. 8. 16. 32. 64.

16.

The first electron shell of an atom can hold a maximum of 8 electrons. 1 electron. 4 electrons. 16 electrons. 2 electrons.

2 electrons.

Carbon can form ___ covalent bonds. 1 16 8 4 2

4

Which of these is not a monosaccharide? 5-carbon sugar Ribose 6-carbon sugar Glycogen

Glycogen

Which of the following substances is an element? Glucose Fat Iron Water Salt

Iron

Which of the following compounds is not hydrophilic? Carbohydrates Nucleic Acids Lipids Proteins Water

Lipids

The four most abundant elements in the human body are Ca, C, O, and Na. H2O and CH4. N, H, Mg, and K. O, C, H, and N. Na, Mg, P, and K.

O, C, H, and N.

Which of the following is not organic? Oxygen Nucleic acids Lipids Enzymes Cholesterol

Oxygen

Which of the following is characteristic of carbohydrates? They contain C, H, O, with twice as many hydrogen as oxygen atoms. They include sugars and starches. They provide much of the energy that the cell requires. They often are stored as reserve energy supplies. all of the above

all of the above

Which of the following molecules does not have a polar region? Triglycerides Glucose Kryptonite Water Tryptophan

Triglycerides

Proteins are chemical messengers. can function as enzymes. contain C, H, O, and N, and sometimes sulfur. all of the above are structural materials

all of the above

A biomarker test for cancer should ideally be easy to perform. specific. inexpensive all of the above. sensitive.

all of the above.

Biochemistry is the study of chemical reactions in organisms. the origin of life. energy transfer in non-living matter. how organisms relate to their environment. how drugs affect the body.

chemical reactions in organisms.

Exposure to ionizing radiation may cause a urinary tract infection. cause diabetes. cause a woman to conceive twins. cloud the lens of the eye. none of the above.

cloud the lens of the eye.

Synthesis reactions are particularly important in the body for growth of body parts. digestion of food products. neutralization of acids by buffers. release of energy. clearance of toxins.

growth of body parts.

Saturated fats _______ than unsaturated fats. have fewer hydrogen atoms bonded to carbon atoms taste better are heavier have more single carbon-carbon bonds are more soluble in water

have fewer hydrogen atoms bonded to carbon atoms

The unique, three-dimensional structure of a protein molecule is determined largely by hydrogen bonds. covalent bonds. stocks and bonds. oxygen bonds. ionic bonds.

hydrogen bonds.

The isotope most likely to be used to study the thyroid gland is iodine-141. iron-59. thallium-201. cobalt-60. carbon-14.

iodine-141.

The difference in hydrogen ion concentration between solutions with pH 4 and pH 5 is twofold. twentyfold. fivefold. a hundredfold tenfold.

tenfold.

The informational content of DNA and RNA is in the nitrogenous bases because the bases are also parts of amino acids. the sugars and phosphates vary too much. they contain nitrogen. nitrogen comes in several different forms. the bases are of several types and therefore can form a sequence.

the bases are of several types and therefore can form a sequence.

A decomposition reaction can be symbolized by A + B → AB. none of the above. C + D → AB. A + B → C + D. AB → A + B.

AB → A + B.

Which of the following substances account for more than 95% of the human body? Carbon, hydrogen, oxygen, nitrogen Calcium, hydrogen, oxygen, nitrogen Carbon, calcium, nitrogen, hydrogen Calcium, phosphorus, hydrogen, nitrogen Carbon, phosphorus, oxygen, hydrogen

Carbon, hydrogen, oxygen, nitrogen

Which of the following is not a source of ionizing radiation? Smoke detectors Atomic and nuclear weapons TV components Cosmic rays from outer space Cholesterol and triglycerides

Cholesterol and triglycerides

DNA and RNA differ in that DNA is found in males and RNA is found in females. RNA is double-stranded and DNA is single-stranded. RNA holds genetic information and DNA uses that information to synthesize protein RNA has deoxyribose and DNA has ribose. DNA holds genetic information and RNA uses that information to synthesize protein

DNA holds genetic information and RNA uses that information to synthesize protein

Nucleic acids include enzymes and RNA. vitamins and minerals. RNA and DNA. steroids and triglycerides. proteins and DNA

RNA and DNA.

Which of the following isotopes has the longest half-life? Radium-226. Phosphorus-32. Fahrenheit-451. Iron-59. Iodine-131.

Radium-226.

Which of the following is the most abundant inorganic substance in cells? Carbohydrate Lipid Protein Bone Water

Water

The formula H2O means an atom contains two hydrogen molecules and one oxygen molecule. a molecule contains two hydrogen atoms and two oxygen atoms. a molecule contains two hydrogen atoms and one oxygen atom. an atom contains one hydrogen molecule and two oxygen molecules. a molecule contains one hydrogen atom and two oxygen atoms.

a molecule contains two hydrogen atoms and one oxygen atom.

Electrolytes that release hydrogen ions in water are bases. catalysts toxins. acids electrons.

acids

On the pH scale a tenfold difference in hydrogen ion concentration separates each whole number pH values below 7 are acidic. pH values above 7 are basic. all of the above. the lower the whole number on the scale, the greater the H+ concentration.

all of the above.

In a covalent bond all of the above. atoms share pairs of electrons. oppositely charged atoms repel. oppositely charged atoms attract. one atom shares and another atom gains electrons.

atoms share pairs of electrons.

Nucleic acids are sources of cellular energy. structural molecules that do not have a function other than support. very small, simple molecules. composed of building blocks called nucleotides. all of the above.

composed of building blocks called nucleotides.

The pH scale measures the number of water molecules in solution. concentration of hydrogen ions in solution. number of hydroxyl ions in water. strength of an electrical current that a solution carries. number of molecules of salts dissolved in water.

concentration of hydrogen ions in solution.

Organic molecules ____, whereas inorganic molecules ____. are small; are very large contain carbon; do not dissolve in water are sprinkled on organically-grown foods; are removed from foods contain carbon; do not contain carbon do not contain carbon; do contain carbon

contain carbon; do not contain carbon

The atoms of two types of elements are likely to have different colors. the same size and same weight. the same size but different weights. different sizes and different weights. different sizes but the same weight.

different sizes and different weights.

When cations and anions meet they form cells. form a 3-D structure. form covalent bonds. form electrolytes. repel.

form a 3-D structure.

An atom that has 3 electrons in its second shell and a filled first shell will lose all of the electrons from its first shell. lose 3 electrons from its second shell. gain 2 electrons in its second shell. gain 5 electrons in its second shell. lose all of the electrons from its first and second shells.

lose 3 electrons from its second shell.

A complete atom is electrically neutral because the number of electrons is greater than the number of protons and neutrons combined. negative electrons and positive protons are equal. none of the above positively charged protons and neutral neutrons are equal. negatively charged electrons and neutral neutrons are equal.

negative electrons and positive protons are equal.

A solution that contains equal numbers of hydrogen and hydroxyl ions is basic. neutral. toxic. alkaline. acidic.

neutral.

The type of organic molecule that can replicate is a lipid. nucleic acid. salt. carbohydrate. protein.

nucleic acid.

An enzyme is a ____. fat that speeds up chemical reactions without being changed or depleted protein that inhibits chemical reactions by being changed or depleted protein that functions as a hormone fibrous protein that is part of certain tissues in the body protein that speeds up chemical reactions without being changed or depleted

protein that speeds up chemical reactions without being changed or depleted

In phenylketonuria, an individual cannot break down the amino acid phenylalanine. Molecules that include phenylalanine build up in the blood, which causes mental retardation and other symptoms. This inherited disease can be controlled by following a diet that is very low in carbohydrates. lipids. nucleic acids. tomatoes. protein.

protein.

Atomic number equals the number of ______ and atomic weight equals the ____. none of the above. neutrons in the nucleus; number of protons plus electrons atoms in an element; weight of all the atoms protons in the nucleus; weight of all the electrons protons; number of protons plus neutrons

protons; number of protons plus neutrons

In the body, oxygen releases energy from glucose during cellular respiration exchanges with carbon dioxide. helps regulate body temperature. is used in various metabolic processes. reacts with water to form carbonic acid.

releases energy from glucose during cellular respiration

Bases reacting with acids form ________ and water. proteins buffers hydrochloric acid salts electrolytes

salts

DNA stores genetic information. is important in building carbohydrates. is important in building fats. provides cellular energy. helps synthesize nucleic acids.

stores genetic information.

Chemistry deals with energy sources. none of the above. the composition of organisms only. the composition of non-living matter only. the composition and changes of substances that make up living as well as non-living matter.

the composition and changes of substances that make up living as well as non-living matter.

The parts of a protein that change when it denatures are the primary and secondary structures. the secondary and tertiary structures. the tertiary and quaternary structures. the amino and carboxyl groups exchange locations. the amino acid sequence and the secondary structure.

the secondary and tertiary structures.

A CT scan differs from a conventional X-ray image because it is safer. two dimensional. three dimensional. not radioactive. four dimensional.

three dimensional.

The ______ uses the element iodide. spleen liver thymus spinal cord thyroid

thyroid