Assignment

1. Even if we knew the sequence of all the genes of a single-celled organism and could cause those genes to be expressed in a test tube, it would still be incredibly difficult to create a functioning organism. Why? Considering this, what do you think of the statement that the genome contains all of the information for a species?

2. Compare a covalent bond between two hydrogen atoms with a hydrogen bond between a hydrogen and an oxygen atoms, with regard to the electrons involved, the role of polarity, and the strength of the bond.

3. Human hair is composed of a protein, keratin. Considering protein structures, why do you think heat is frequently used when styling hair?

4. Why was the evolution of a self-contained cell essential for life as we know it?

5. The drug vincristine is used to treat many cancers. It apparently works by causing microtubules to depolymerize. Vincristine use has many side effects, including loss of dividing cells and nerve problems. Explain why this might be so.

Multiple Choice

1. Studying the impacts of energy drinks on academic performance in college students would be focusing at which organization level?
a. biosphere b. community
c. population d. organism

2. Which of the following best demonstrates the unity among all organisms?
a. emergent properties b. descent with modification
c. the structure and function of DNA d. natural selection

3. A researcher subjects frogs to various levels of UV-B radiation while keeping all other variables constant. Following the scientific method, what came directly before this step?
a. making a prediction b. asking a question
c. making an observation d. analyzing results/drawing conclusions

4. In presenting results from the previous question, the amount of radiation would be placed on the __ because it is the ___ variable.
a. x-axis; independent b. y-axis; independent
c. x-axis; dependent d. y-axis; dependent

5. An element is to a/an ___ as a tissue is to a/an ___.
a. compound; organelle b. atom; organ
c. compound; organ d. molecule; cell

6. Which of the following statements about the isotopes of an element is NOT true?
a. they have the same atomic number b. they have the same number of protons
c. they have the same number of neutrons d. they have identical chemical properties

7. The atomic number of sulfur is 16. When combined with hydrogen by covalent bonds it forms a compound, hydrogen sulfide. Based on this information, which would you predict is the correct chemical formula?
a. HS b. HS2
c. H2S d. H3S2

8. The ability of atoms to combine with other atoms is determined by
a. the atom's atomic weight b. the number and distribution of electrons
c. the atom's ability to form isomers d. the atom's nucleus

9. The reaction HCL -> H+ + Cl- in the human stomach is an example of:
a. formation of a hydrogen bond b. formation of ions by dissolving an acid
c. cleavage of a hydrophobic bond d. formation of polar covalent bonds

10. When table salt (NaCl) is added to water:
a. a covalent bond is broken b. an acidic solution is formed
c. the Na+ and Cl- ions are separated d. the Na+ ions are attracted to the hydrogen atoms of water

11. The most abundant molecule in the cell is:
a. a carbohydrate b. a nucleic acid
c. a protein d. water

12. All lipids are:
a. triglycerides b. polar
c. hydrophilic d. more soluble in nonpolar solvents than water

13. Which of the following statements about the primary structure of a protein is not true?
a. it may be branched b. it is held together by covalent bonds
c. it is unique to that protein d. it determines the tertiary structure

14. The amphipathic nature of phospholipids is:
a. determined by the fatty acid composition b. important to membrane structure
c. important to energy storage d. only visible in a nonpolar solvent

15. Nucleotides in RNA are connected to one another in the polynucleotide chain by:
a. covalent bonds between bases
b. covalent bonds between sugars
c. covalent bonds between sugar and phosphate
d. hydrogen bonds between purines

16. If all the lysosomes within a cell suddenly ruptured, what would be the most likely result?
a. more proteins would be made
b. the DNA within mitochondria would break down
c. the macromolecules in the cytosol would break down
d. there would be no change in cell function

17. You are studying how the protein transferrin enters cells. When you examine cells that have taken up transferrin, you find it inside clathrin-coated vesicles. Given this, the most likely mechanism for uptake of transferring is:
a. facilitated diffusion b. receptor-mediated endocytosis
c. an antiporter d. ion channels

18. Which statement about osmosis is NOT true?
a. it obeys the laws of diffusion
b. in animal tissues, water moves into cells if they are hypertonic to their environment
c. solute concentration is the principle factor in osmosis
d. red blood cells must be kept in a plasma that is hypotonic to the cells

19. Cyanide is a poison that binds to a protein used in the production of ATP. If a cell were exposed to cyanide, where would you expect the highest concentrations?
a. nucleus b. mitochondria
c. rough endoplasmic reticulum d. ribosomes.