Human Bio Chpt 2
Each carbon atom can share pairs of electrons with as many as ____ other atoms. a. three b. two c. five d. six e. four
Four
What is the maximum number of electrons in a shell? a. 0 b. 12 c. 2 d. 6 e. 8
8
An ion is formed ____. a. during covalent bonding b. when atoms exchange electrons c. when water molecules are bound together d. when atoms share electrons equally e. when atoms share electrons unequally
When atoms exchange electrons
Positron emission tomography (PET) utilizes ____ to yield results of a scan. a. ions b. x-rays c. tracers d. glucose e. photons
tracers
The blending of two or more kinds of molecules is a(n)____. a. isotope b. mixture c. compound d. chemical bond e. reactant
Mixture
When an atom's outer electron shell is filled, the atom is ____. a. unstable b. positively charged c. polarized d. most stable e. an isotope
Most stable
Isotopes of an element are different from the most common standard form due to differences in the ____.
Number of neutrons in the nucleus
A compound that contains both carbon and hydrogen is ____. a. always an acid b. a salt c. organic d. non-biological e. inorganic
Organic
Animals store carbohydrates in the form of ____. a. glycogen b. starch c. lipids d. sucrose e. glucose
Glycogen
Which element is NOT one of the four most common elements found in organisms? a. oxygen b. nitrogen c. carbon d. helium e. hydrogen
Helium
Which type of bond is responsible for the linking together of atoms within a water molecule? a. isotropic b. hydrogen c. ionic d. nonpolar covalent e. polar covalent
Polar covalent
An acid is a substance that donates a(n) ____. a. electron b. proton c. neutron d. hydroxide ion e. antioxidant
Proton
The atomic number denotes the number of ____ in an atom of a particular element.
Proton
A tracer is a substance with what attached to it?
Radioisotope
A dissolved substance in water is a(n)____. a. free radical b. solvent c. solute d. acid e. antioxidant
Solute
Plants store large amounts of carbohydrates in the form of ____. a. glucose b. sucrose c. lipids d. starch e. glycogen
Starch
Which statement is true of electron shells? a. A second shell with six electrons is completely filled. b. Larger atoms have fewer electron shells. c. A shell can hold up 20 electrons. d. The innermost shell can hold up to two electrons.
The innermost shell can hold up to two electrons
The bonding of two or more atoms creates a(n) ____. a. isotope b. molecule c. ion d. solution e. mixture
molecule
A buildup of H+ in the blood will lead to ____. a. excess calcium b. excess carbon dioxide c. acidosis d. a higher-than-normal pH e. alkalosis
Acidosis
A free radical takes what particle from a stable molecule? a. a hydrogen ion b. an electron c. a proton d. a neutron e. an atom
An electron
A substance that gives up an electron to a free radical is a(n) ____. a. antioxidant b. antibiotic c. antiviral d. oxidizer e. antibody
Antioxidant
Covalent bonds ____. a. occur during oxidation reactions b. are extremely strong and stable c. occur when ions of opposite charge are attracted to each other d. are the weak link between two water molecules e. form bonds that hold Na and Cl together in NaCl (table salt)
Are extremely strong and stable
During a hydrolysis reaction, ____. a. a water molecule is formed b. covalent bonds are formed c. polymers are formed d. bonds are broken e. condensation occurs
Bonds are broken
Which of the following is composed of a 1:2:1 ratio of carbon to hydrogen to oxygen? a. protein b. steroid c. lipid d. carbohydrate e. nucleic acid
Carbohydrate
A protein inside cells that speeds up the rate of a chemical reaction is a(n) ____. a. buffer b. hydrocarbon c. functional group d. inorganic compound e. enzyme
Enzyme
The building block of large carbohydrates is ____. a. glycerol b. glucose c. amino acids d. glycogen e. polysaccharide
Glucose
Which type of bond is responsible for the linking together of two water molecules? a. ionic b. nonpolar covalent c. hydrogen d. isotropic e. polar covalent
Hydrogen
What makes water a good solvent? a. It dissolves ions and polar molecules. b. It is very acidic. c. It heats up very quickly. d. It mixes well with alcohol. e. It dissolves fats.
It dissolves ions and polar molecules
During a synthesis reaction, glucose and fructose combine to form ____. a. a monosaccharide b. starch c. glycogen d. sucrose e. a polysaccharide
Sucrose
How do hydrophilic molecules interact with water? a. They are repelled by water. b. They absorb heat from water. c. They are absorbed by water. d. They are attracted to water. e. They transfer heat to water.
They are attracted to water