Ap Biology Chapter 11 and 12

4. Consider the pathway : epinephrine ------> G protein-coupled receptor -----> G protein -----> adenylyl cyclase -------> cAMP. Identify the second messenger (a) cAMP (b) G protein (c) GTP (d) adenylyl cyclase

(A) cAMP

7. A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in (a) G1 (b) G2 (c) prophase (d) metaphase

(a) G1

19. The genetic material of the cell replicates to prepare for cell division.

(a) Synthesis (S-phase)

21. Failure of this stage to occur prior to mitosis would result in daughter cells without sufficient DNA.

(a) Synthesis (S-phase)

5. In the cells of some organisms, mitosis occurs without cytokinesis. This will result in (a) cells with more than one nucleus (b) cells that are unusually small (c) cell lacking nuclei (d) cell cycles lacking S phase

(a) cells with more than one nucleus

2. The activation of receptor tyrosine kinases is characterized by (a) dimerization and phosphorylation (b) dimerization and IP3 binding (c) a phosphorylation cascade (d) GTP hyrdolysis

(a) dimerization and phosphorylation

2. Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to (A) disruption of mitotic spindle formation (b) suppression of cyclin production (c) myosin denaturation and inhibition of cleavage furrow formation (d) inhibition of DNA synthesis

(a) disruption of mitotic spindle formation

2. If the S phase were eliminated from the cell cycle, the daughter cells would, (a) have half the genetic material found in the parent cell (b) be generally identical to each other (c) be genetically identical to the parent (d) synthesize the missing genetic material on their own

(a) have half the genetic material found in the parent cell

11. In cell signaling, how is the flow of specific ions regulated? (a) opening and closing of ligand-gated ion channels (b) transduction (c) cytoskeleton rearrangement (d) endocytosis

(a) opening and closing of ligand-gated ion channels

8. Which of the following component molecules of the plasma membrane is most important in the reception phase of cell signaling? (a) protein (b) phospholipids (c) cholesterol (d) carbohydrates

(a) protein

20. The cell is carrying out its typical functions, not engaged in producing molecules without sufficient DNA.

(b) Gap 1

1. Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. The cell is most likely (a) an animal cell in the process of cytokinesis (b) a plant cell in the process of cytokinesis (c) a bacteria cell dividing (d) a plant cell in metaphase

(b) a plant cell in the process of cytokinesis

13. What is a G protein? (a) a specific type of membrane receptor protein (b) a protein on the cytoplasmic side of a membrane that becomes activated by a receptor protein (c) a membrane-bound enzyme that converts ATP to cAMP (d) a guanine nucleotide that converts between GDP and GTP to activate and inactivate relay proteins

(b) a protein on the cytoplasmic side of a membrane that becomes activated by a receptor protein

16. If the melanin production were not sufficient to prevent UV damage to the DNA, which of the following would you expect? (a) decreased rate of melanin production (b) apoptosis and lysis of damaged cells (c) decreased cell divisions (d) peeling of the skin due to sebaceous glands shutting down

(b) apoptosis and lysis of damaged cells

3. lipid-soluble signaling molecules, such as aldestrone, cross the membranes of all cells but affect only target cells because (a) only target cells retain the appropriate DNA segments (b) intracellular receptors are present only in target cells (c) only target cells have enzymes that break down aldestrone (d) only in target cells in aldestrone able to initiate the phosphorylation cascade that turns genes on

(b) intracellular receptors are present only in target cells

6. Which of the following does not occur during mitosis? (a) condensation of the chromosomes (b) replication of the DNA (c) separation of sister chromatids (d) spindle formation

(b) replication of the DNA

17. If this did not occur, daughter cells would have tow complete sets of chromosomes.

(c) Cytokinesis

18. Division of the cytoplasm of the cell

(c) Cytokinesis

6. Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells? (a) Enzymatic activity was proportional to the amount of calcium added to a cell-free extract (b)Receptor studies indicated that epinephrine was a ligand (c) Glycogen breakdown was observed only when epinephrine was administered to intact cells (d) Glycogen breakdown was observed when epinephrine and glycogen phosphorylase were combined

(c) Glycogen breakdown was observed only when epinephrine was administered to intact cells

7. Earl Sutherland received the Nobel Prize for his discovery of cAMP as a second messenger. Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells? (a) Enzymatic activity was proportional to the amount of calcium added to a cell-free extract (b) Receptor studies indicated that epinephrine was a ligand (c) Glycogen breakdown was observed only when epinephrine was administered to intact cells (d) Glycogen breakdown was observed when epinephrine and glycogen phosphorylase were combined

(c) Glycogen breakdown was observed only when epinephrine was administered to intact cells

5. Apoptosis involves all but which of the following? (a) fragmentation of the DNA (b) cell-singaling pathways (c) lysis of the cell (d) digestion of cellular contents by scavenger cells

(c) Lysis of the cell

7. Protein phosphorylation is commonly involved with all of the following EXCEPT (a) activation of receptor tyrosine kinases (b) activation of protein kinase molecules (c) activation of G protein-coupled receptors (d) regulation of transcription by signaling molecules

(c) activation of G protein-coupled receptors

3. One difference between cancer cells and normal cells is that cancer cells (a) are unable to synthesize DNA (b) are arrested at the S phase of the cell cycle (c) continue to divide even when they are tightly packed together (d) cannot function properly because they are affected by density-dependent inhibition

(c) continue to divide even when they are tightly packed together

15. The skin is the body's largest organ, It's made up of many different types of cells. Oils, produced by the sebaceous glands, prevent the skin from drying and splitting. The protein melanin, produced by melanocytes in the epidermis, protects the skin from the harmful effects of ultraviolet radiation. Sweat, released through ducts to the skin surface, helps to cool the body. The types of cells that produce these compounds have different numbers of specific organelles, depending on their function. -Based on their function you would expect melanocytes in the skin to have a higher than usual number of (a) lysosomes (b) chloroplasts (c) Golgi bodies (d) microtubules

(c) golgi bodies

2. Prokaryotic and eukaryotic cells have all of the following structures in common EXCEPT (a) a plasma membrane (b) cytoplasm (c) linear chromosomes (d) ribosomes

(c) linear chromosomes

15. Many signal transduction pathway use second messengers to (a) transport a signal through the lipid bilayer portion of the plasma membrane (b) relay a signal from the outside to the inside of the cell (c) relay the message from the inside of the membrane throughout the cytoplasm (d) diffuse directly into the nucleus, turning on genes

(c) relay the message from the inside of the membrane throughout the cytoplasm

4. The decline of MPF activity at the end of mitosis is due to (a) the destruction of the protein kinase Cdk (b) decreased synthesis of Cdk (c) the degradation of cyclin (d) the accumulation of cyclin

(c) the degradation of cyclin

22. Sister chromatids begin to separate

(d) Anaphase

25. Which of the following statements regarding the cell-cycle control system is false? (a) The cell-cycle control system receives messages from outside the cell that influences cell division (b) The cell cycle control system triggers and controls major events in the cell cycle (c) The cell cycle control system includes fluctuating levels of cyclins and cyclin-dependent kinases (d) The cell cycle control system operates independently of the growth factors

(d) The cell cycle control system operates independently of the growth factors

8. The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by the cytochalasin B? (a) spindle formation (b) spindle attachment to kinetochores (c) cell elongation during anaphase (d) cleavage furrow formation and cytokinesis

(d) cleavage furrow formation and cytokinesis

1. Binding to a signal molecule to which type of receptor leads directly to a change in the distribution of ions on opposite sides of the brain? (a) intracellular receptor (b) G protein-coupled receptor (c) phosphorylated receptor tyrosine kinase dimer (d) ligand-gated ion channel

(d) ligand gated ion channel def: specific molecules cause the channels in a membrane to open or close, regulating the flow of specific ions

14. Which of the following can activate a protein by transferring a phosphate group to it? (a) cAMP (b) G protein (c) protein phosphatase (d) protein kinase

(d) protein kinase

16. Which of the following signal molecules pass through the plasma membrane and bind to intracellular receptors that move into the nucleus and function as transcription factors to regulate gene expression? (a) epinephrine (b) neurotransmitter released into synapse b/w nerve cells (c) yeast mating factors alpha and a (d) testosterone, a steroid hormone

(d) testosterone, a steroid hormone

What is a second messenger?

A small non-protein , water soluble molecule or ion, such as calcium (Ca 2+) or cyclic AMP, that relays a signal to a cell's interior in response to a signaling molecule bound by a signal receptor protein

What is dimerization and phosphorylation?

Dimerization: to form a dimer (a chemical compound with identical sub units) Phosphorylation:The process of generating ATP from ADP and phosphate by means of chemiosmosis, using a proton-motive force generated across the thylakoid membrane of the chloroplast or the membrane of certain prokaryotes during the light reactions of photosynthesis

What is a ligand?

Its basically a signal molecule that binds with a receptor protein , causing it to change shape

What are intracellular receptors?

They are found inside the plasma membrane in the cytoplasm or nucleus. The signal molecule must cross the plasma membrane and therefore must be hydrophobic, like the steroid hormone testosterone