BI 171 - Third Exam - 2003

Answer Key

Multiple Choice.

Place the letter of the choice that best answers the question on the line to the left.
Two Points Each. NOTE: "e" answers are never the correct answer.

___B___ 1. The 9 + 2 pattern involves

                    a. Cell connections in multicelled systems                     b. Microtubules
                        c. Particle exchange through a membrane                      d. Chromosomes
                                                                    e. Ummmm, eleven-?

                        ...it's the arrangement in cilia and flagella.

___C___ 2. Which are the reactions in coupled reactions?

                    a. Hydrolysis & dehydration synthesis
                        b. Oxygen-producing & oxygen-using
                        c. Endergonic & exergonic
                    d. Enzyme-catalyzed & non-enzyme-catalyzed
                        e. That’s really no one’s business but their’s

                        ...the endergonic reactions pick up their energy from the
                            exergonic ones.

___D___ 3. A ligand can also be called a

                    a. Chaperonin                     b. Domain                     c. Channel
                    d. Substrate                                 e. Suitably nasty name

                        ...it's a molecule that binds to some protein region, like a substrate
                            binds to an enzyme's active site.

___A___ 4. The plant cells in the lab exercise, in fresh water, are surrounded by which 
                                type of solution?
                    a. Hypotonic                     b. Hypertonic                     c. Isotonic
                        d. Cytotonic                                     e. Toonytonic

                        ...fresh water, with almost no dissolved materials, had much more
                            water and less "stuff."

___C___5. A protein other than enzymes that follows Michaelis-Menten patterns:

                     a. Microtubules                     b. Histones                    c. Carriers 
                    d. Centromeres                                        e. Annoying ones

                        ...they follow that "worker" curve - give them more to carry, and they
                            carry more (the movement rate goes up), until the molecules are active
                            100% of the time and can't (the movement rate stops increasing).

___D___6. Introns are

                    a. Materials released from a cell
                        b. Parts of an enzyme that are not functional
                        c. Byproducts of an enzyme-catalyzed reaction
                        d. Parts of a gene sequence that are not used in the coded protein
                        e. Some sort of big honkin’ corporate monster

                        ...from beginning to end of a gene, not all of the sequence is used as
                            code - the used sequence is the exon.

___C___7. A cell membrane’s fluidity is affected by

                        a. Phosphate groups                 b. Carriers                 c. Cholesterol
                   d. Flux                                                 e. How drunk it is

                        ...these little molecules in the hydrophobic layer act like lubricants.

___A___8. Which is a critical protein in microfilaments?

                    a. Actin     b. Dynein      c. Thylakoid      d. Kinesin     e. Filamentin

                        ...it is the most common microfilament component.

___B___9. Which are, on a molecular level, most analogous to spools?

                    a. Plasmids                     b. Histones                     c. Microtubules
                    d. Microfilaments                         e. Twirlyloopidies

                        ...they are proteins that DNA wraps around.

___D___10. Which process has its first steps occur in the cytoplasm?

                     a. Photosynthesis                         b. DNA transcription  
                    c. RNA production                       d. Aerobic respiration
                                                    e. Training camp

                        ...a happens all in chloroplasts, b and c in the nucleus, while d
                            ends in mitochondria.

___B___11. Which are most likely to be covered by microvilli?

                    a. Breathing tube cells moving mucus
                        b. Kidney tube cells moving wastes into urine
                        c. Protective skin cells
                        d. Cells inside a mitochondrion
                        e. The typical cafeteria lunch

                        ...it has to be an example where materials move through a    
                            surface, which microvilli add to.

___D___12. If the products of a reaction are continually removed, the reaction will 
                                reach equilibrium

                    a. Faster                 b. Slower                 c. At the same rate
                        d. Never                             e. Next Tuesday

                        ...as long as the products are removed, there's nothing to change in
                            reverse, which is necessary for equilibrium.

___C___13. Which is counteracted by gravity?

                    a. Turgor pressure             b. Telomerase             c. Root pressure
                    d. Optimum pH                             e. Spandex

                        ...it pushes water up a plant until gravity stops it.

___C___14. An enzyme with a low Michaelis constant has high affinity, which means it

                    a. Works with multiple substrates                 b. Is limited in substrate choice
                    c. Works more slowly                                 d. Works more quickly
                                                                e. A fin’ lookin’ enzyme

                        ...affinity is strength of binding - high affinity means the enzyme grabs
                            the substrate quickly but holds it tighter, is slower to release the products
                            - a low constant occurs on a very steep curve that tops out quickly.

___C___15. Waterproof body coverings probably first evolved as an adaptation to

                        a. Land environments                        b. Salty marsh environments
                    c. Fresh water environments             d. Deep ocean environments
                                                                e. Matching boots

                        ...the barriers were to prevent osmosis from the dilute surroundings into the
                            tissues.

___A___16. Which would most likely involve glycocalyx?

                    a. Recognition between cells in multicelled systems
                        b. Movement of a cell across a surface
                        c. Movement of a cell by swimming
                        d. Connections between cells in multicelled systems
                        e. An alphabet chart and a handful of darts

                        ...this is commonly used as markers on cells.

___C___17. A Q₁₀ compares a reaction’s rate with the reaction under what changed condition?

                        a. Ten times more reactant                         b. Ten times less reactant
                   c. 10^o C rise in temperature                        d. 10^o C drop in temperature
                                    e. Ten times more colorful gay guys criticizing it

                        ...connect the symbol to the concept.

___B___18. Group translocation involves what two processes?

                    a. Transport in and transport out
                        b. Transport and chemical change
                        c. Removal of one organic group and replacement by another
                        d. Movement of genetic materials between two cells
                        e. Confusion and induction of anger

                        ...match term and definition.

Short Answer. 

Pick NINE questions to answer in the spaces provided.
NOTE: if you answer MORE than nine, only the first nine will be corrected.
Four Points each. Partial credit is possible.

Long Answer. 

Select and answer completely any four of the following questions.
Note: if you answer more than four, only the first four will be corrected.
Seven Points Each. Partial credit is possible.

NO KEY FOR  BONUS QUESTIONS. 

Answer as many or as few as you wish. You can't lose points on the rest of the exam by getting these wrong. Partial credit is possible.

Name the general terms given to the various proteins that contribute to DNA translation. Three Points each.

Briefly explain how one codon can stand for two different things. Four Points.

Enzyme-catalyzed reactions are not reversible through the enzymes. Why? Four Points.

What is the typical limitation of the term vitamin? Three Points.

Some enzymes have a broad, low curve for their temperature - activity graph. Why? Four Points.

Cancer cells develop two capabilities that most normal cells, including the original cells that became cancerous, do not have. For Three Points each, what are they?

Which Kingdom of organisms do not have cell walls? Three Points.

Where do steroid hormones usually connect on / in a cell? Four Points.