Physiology

  • Chapter 3-Cellular Structure, Proteins and Metabolic Pathways

1. A major function of plasma membranes is to

a. Store calcium ions

b. Store organic chemicals for metabolism

c. Provide genetic information

d. Generate ATP

e. Regulate the passage of molecules into and out of the cell

2. In the fluid-mosaic model of membrane structure,

A. The proteins exist in a bilayer formation

B. The phospholipids are tightly bound in place

C. The term “mosaic” refers to the cholesterol component

D. Integral proteins are amphipathic

E. None of the choices are true

3. Cell membranes

A. Are components of the cytosol

B. Are passive barriers against the passage of molecules from one side to the other

C. Consist primarily of protein and carbohydrate

D. Consist primarily of phospholipids and protein

E. Both are passive barriers against the passage of molecules from one side to the other and consist primarily of protein and carbohydrate are correct

4. Cholesterol

A. Is slightly amphipathic

B. Is a prominent lipid component of all membranes in a cell

C. Allows the plasma membrane to form vesicles that deliver their contents to cell organelles

D. Both is slightly amphipathic and is a prominent lipid component of all membranes in a cell are correct

E.Both is slightly amphipathic and allows the plasma membrane to form vesicles that deliver their contents to cell organelles are correct

5. Phospholipids form effective barriers between the aqueous cytosol of cells and the aqueous extracellular fluid because they are

A. Polar

B. Nonpolar

C. Lipids

D. Rigid

E. Amphipathic

6. Tight junctions

A. Hold cells tightly together so that they cannot readily be pulled apart

B. Form barriers that regulate the passage of materials across epithelial membranes

C. Are commonly found in smooth muscle

D. Both hold cells tightly together so that they cannot readily be pulled apart and form barriers that . regulate the passage of materials across epithelial membranes are correct

E. Both form barriers that regulate the passage of materials across epithelial membranes and are commonly found in smooth muscle are correct

7. Which of the following is not true regarding cell membrane junctions?

A. Tight junctions anchor cells to basement membranes in tissues that are subjected to stretch

B. Desmosomes anchor adjacent cells together

C. Gap junctions seal spaces between cells and control permeability across epithelial membranes

D Both tight junctions anchor cells to basement membranes in tissues that are subjected to stretch and . desmosomes anchor adjacent cells together are correct

E. Both tight junctions anchor cells to basement membranes in tissues that are subjected to stretch and . gap junctions seal spaces between cells and control permeability across epithelial membranes are correct.

8. Desmosomes represent a type of cell to cell connection resembling a rivet

A. Well suited to locations in the body where considerable stresses due to stretching are likely to occur.

B. Which is enhanced by proteins that extend from the cell into the extracellular space

C. That can be strengthened by keratin filaments that extend to interior cell structures

D. Both well suited to locations in the body where considerable stresses due to stretching are likely to . occur and which is enhanced by proteins that extend from the cell into the extracellular space are correct

9. In contrast to “spot type” cell junctions,         junctions resemble tightly drawn belts, completely encircling the cell and leaving gaps above below them at the points of attachment with adjacent cells.

A. Cadherin

B. Tight

C. Gap

D. Connexin

E. Nexus

10. Since their discovery, vaults appear to be associated with pores in the nuclear membrane

A. And may have an ability to influence the effectiveness of anticancer drugs

B. And could be used as a treatment for viral infections

C. Consequently representing a point of potential vulnerability to cells infected by bacteria D. Clearly representing an organelle with functions that are similar if not identical to mitochondria

D. That participate in the process of mitotic cell division

11. Functions of agranular endoplasmic reticulum include

A. Synthesis of proteins for use in the cell

B. Synthesis of steroids

C. Storage of intracellular calcium ion

D. Synthesis of proteins for use in the cell and storage of intracellular calcium ion

E. Synthesis of steroids and storage of intracellular calcium ion

12. The organelles that digest engulfed bacteria and cell debris are the

A. Peroxisomes

B. Endosomes

C. Lysosomes

D. Ribosomes

E. Mitochondria

13. Which organelles would you expect to be especially numerous in cells that expend a great deal of energy in the form of ATP?

A. Peroxisomes

B. Endosomes

C. Lysosomes

D. Ribosomes

E. Mitochondria

14. Functions of the Golgi apparatus include

A. Modifying proteins synthesized on free ribosomes

B. Modifying proteins synthesized on ribosomes associated with granular endoplasmic reticulum

C. Allowing the distribution of modified proteins throughout the cell in vesicles

D.Modifying proteins synthesized on free ribosomes and allowing the distribution of modified proteins throughout the cell in vesicles

E. Modifying proteins synthesized on ribosomes associated with granular endoplasmic reticulum and . allowing the distribution of modified proteins throughout the cell in vesicles

15. Which of the following is not true of the cytoskeleton?

A. It refers to the cellular components of bone

B. It refers to a network of cytoplasmic filaments

C. It is important for cellular movement

D. It helps to determine a cell’s shape

E. None of the choices are false

16. Cell A is a gland cell that makes and secretes proteins. Cell B is another type of cell that synthesizes and secretes steroids. If you were to look at electron micrographs of the two cells, what differences would you expect to see?

A. Cell A would have more granular endoplasmic reticulum than cell B

B. Cell A would have fewer secretion granules than cell B

C. Cell A would have more agranular endoplasmic reticulum than cell B

D. Both cell A would have more granular endoplasmic reticulum than cell B and cell A would have . fewer secretion granules than cell B are correct

E. Both cell A would have more granular endoplasmic reticulum than cell B and cell A would have . more agranular endoplasmic reticulum than cell B are correct

17. Neurons have a very prominent nucleolus which indicates that they are actively

A. Making ATP

B. Synthesizing lipids

C. Manufacturing ribosomes

D. Breaking down carbohydrates

E. Dividing by mitosis

18. In Tay Sach’s disease, lysosomes do not carry out their normal function. Predict which condition would be a symptom of Tay Sach’s disease.

A. There is excessive accumulation of damaged organelles in a cell

B. Cells are unable to synthesize proteins

C. Cells can only make ATP by glycolysis

D. Proteins cannot be secreted by exocytosis

E. Steroid hormones can’t be produced

19. Carbohydrate chains can be added to glycoproteins by the

A. Golgi apparatus

B. Smooth endoplasmic reticulum

C. Nucleus

D. Lysosomes

E. Mitochondria

20. A gene

A Contains information necessary for the synthesis of proteins

B. Is a sequence of nucleotides in DNA

C. Is composed of many molecules of DNA

D. Contains information necessary for the synthesis of proteins and is a sequence of nucleotides in DNA

E. All of the choices are correct

21. A genome is

A. cluster of genes that are all regulated in the same manner

B. A measure of the genetic variability in a population

C. A region of DNA that codes for a single protein

D. All of the DNA and RNA in a cell ata given point in time

E. The total genetic information in a typical cell of an organism

22. A codon is

A. triplet of deoxyribonucleotides

B. A triplet of ribonucleotides

C. A sequence of ribonucleotides on tRNA

D. A triplet of ribonucleotides and a sequence of ribonucleotides on tRNA

E. None of the choices are correct

23. The codon that corresponds to the DNA sequence G-T-A is

A. G-T-A

B. A-T-G

C. C-A-T

D. C-A-U

E. T-A-C

24. The genetic code

A. Consists of one code word for each amino acid

B. Is the same for all cells

C. Is the same for all organisms

D. Is the same for all cells and is the same for all organisms

E. All of the choices are correct

25. Which of the following statements about RNA transcription and translation is true?

A. All of the nucleotide sequences in a gene are transcribed into RNA

B. The entire transcribed message of a gene is translated into amino acid sequences

C. The mRNA that enters the cytosol is considerably shorter than that synthesized during transcription

D. Both all of the nucleotide sequences in a gene are transcribed into RNA and the mRNA that enters the cytosol is considerably shorter than that synthesized during transcription are correct

E. All of the choices are correct