SC-100
Review Questions with Answers for Quiz #4
SC-100 Unit 11
b 3. An electrically neutral atom will have the same number of electrons as it has protons; however, the electrons and protons differ greatly because
• a. electrons are more massive than protons.
• b. protons are more massive than electrons.
• c. the electrons determine the chemical identity of the atom.
• d. an electron is about as massive as a neutron.
• e. more protons can be added to an element's nucleus and it will retain its chemical identity.
d 5. How do two isotopes of the same element differ?
• a. Their nuclei have different protons.
• b. Their electrons have different orbits.
• c. They have different electrical charges.
• d. Their neutrons differ in number.
• e. They have a different atomic number.
d 7. The difference between nuclear fusion and nuclear fission is that
· a. you can get energy from the first, but not from the second.
· b. you can get energy from the second, but not from the first.
· c. the former splits apart a nucleus, the latter combines two nuclei into one.
· d. the former combines two nuclei into one, the latter splits apart a nucleus.
· e. fusion has been successfully accomplished in laboratory conditions.
d 8. A particular isotope has a half-life of 10 minutes. If we start with 2000 atoms now, in a half hour we will have how many atoms left?
• a. 2000 atoms
• b. 1000 atoms
• c. 500 atoms
• d. 250 atoms
• e. 125 atoms
b 10. Which force holds the nucleus together?
• a. gravity
• b. strong force
• c. weak force
• d. electromagnetic force
• e. centripetal force
e 16. If an atom emits two protons and two neutrons, the atom has
· a. created a daughter nucleus from the parent nucleus.
· b. emitted an alpha particle.
· c. changed the mass and chemical identity of the atom.
· d. produced a small amount of helium.
· e. all of the above
SC-100 Unit 12:
c 2. Which of the following exemplified the law of unintended consequences on Lake Victoria in Africa?
• a. clearcutting of old growth pine trees
• b. building jetties on the Lake Victoria shore
• c. introducing the Nile perch
• d. growing algae for a food supplement
• e. beginning an escargot aquaculture
c 3. Urban landfills
• a. increase the decay rate for most trash.
• b. accelerate the process by which aluminum is recycled.
• c. decrease the decomposition rate for newspapers.
• d. are being filled up with disposable diapers.
• e. are an excellent way to recycle some plastics.
d 5. Which term refers to the particular way an organism obtains energy?
• a. ecosystem
• b. environment
• c. ecology
• d. ecological niche
• e. habitat
b 13. What is ozone?
• a. two oxygen molecules combined with methane
• b. a molecule with three oxygen atoms
• c. molecular carbon dioxide and water
• d. an energy level
• e. a waste product from a landfill
a 15. What is the ozone hole?
• a. annual drop in ozone concentrations over Antarctica
• b. annual drop in ozone concentrations over Alaska
• c. the first indication of cleaner air
• d. decrease in ozone levels due to the greenhouse effect
• e. decrease in ozone levels due to acid rain
a 16. Which are products of burning hydrocarbons completely in pure oxygen?
• a. carbon dioxide and water
• b. nitrogen oxides and sulfur compounds
• c. hydrogen dioxide and sulfur compounds
• d. carbon dioxide and nitrogen oxides
• e. all of the above
b 17. How far above the Earth would we find the highest concentration of ozone?
• a. 10,000 feet
• b. 20 miles
• c. 50 miles
• d. sea level
• e. 10 miles
T 35. The atmosphere is transparent to the Sun’s incoming visible and ultraviolet radiation.
T 36. The atmosphere is opaque to infrared (heat) energy that radiates from Earth to space.
T 37. Scientists are unable to predict the consequences of the greenhouse effect with certainty.
SC-100 Unit 13:
d 10. Which of the following does not describe a way that living things acquire energy?
a. directly from the Sun
b. by consuming other organisms
c. by absorbing materials in their environment
d. by creating their own energy, without taking in any other molecules of energy
e. Each of the above describes a way that living things acquire energy.
e 18. Where on Earth are there no living things besides humans and pets?
a. in the middle of a large city
b. Antarctica
c. a dry desert
d. the deepest trenches in the ocean
e. none of the above
b 21. Which of the following is not true about all living things?
a. They are subject to the laws of thermodynamics.
b. They are made from more than one cell.
c. They respond to their environments.
d. They need energy to live.
e. They are dependent upon chemical reactions.
SC-100 Unit 14:
e 1. What do cow hide, silk, flowers, and eye lashes have in common?
• a. They all contain carbon, hydrogen, oxygen and nitrogen atoms.
• b. They all are composed of a modular molecular structure.
• c. They all are a result of a unique combination of molecule shapes.
• d. The dominant element in each item is carbon.
• e. All of the above are true.
c 2. How many essential amino acids are there?
• a. 20
• b. 12
• c. 8
• d. 30
• e. 22
a 3. Which of the following would you not find in all proteins?
• a. carbon and calcium
• b. an amino group
• c. a carboxyl group
• d. water
• e. a peptide bond
a 4. An organic molecule's chemical function is controlled by
• a. molecule shape
• b. molecule size
• c. molecule age
• d. a, b and c
• e. none of the above
d 5. Which element is not essential to all life?
• a. phosphorous
• b. nitrogen
• c. carbon
• d. iron
• e. oxygen
b 6. Which of the following is a protein molecule that facilitates chemical reactions between two other molecules?
• a. amino acid
• b. enzyme
• c. hydrogen bond
• d. lipid
• e. vitamin
d 7. Some amino acids called "essential" because they
• a. are synthesized by the body.
• b. can be stored by the body.
• c. are found in most of the foods we eat.
• d. should be taken into the body with every meal.
• e. are high-quality proteins.
a 8. One difference between carbohydrates and proteins is
• a. the carbohydrate molecule lacks nitrogen.
• b. the protein molecule contains more stored energy.
• c. the carbohydrate molecule is in butter.
• d. only the protein molecule contains iron.
• e. only the carbohydrate molecule can form long chains.
c 9. Why can cows digest grass and humans cannot?
• The human stomach contains a peptide that binds grass into an indigestible mass.
• Grass contains a lipid that is poisonous to humans.
• Humans lack the enzyme to separate the glucose molecule from the cellulose polymer in grass.
• Cows have several stomachs in their digestive system.
• Humans can digest grass but choose not to grow it for food.
F 10. Lipids link together to form carbohydrates.
T 11. Starch is an example of a polysaccharide.
T 12. Phospholipids repel and attract water.
T 13. All organic molecules are based on carbon.
F 15. Sugar molecules are the building blocks of cell membranes.
T 15. Amino acids link to form proteins.
F 16. Amino acids form the backbone of cellulose and hair.
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