Written Exam One Q1 - Q30

Question 1

1. Nuclear pores:
   A. Regulate entry and exit from the nucleus
   B. Provide passage through only the outer nuclear membrane
   C. Are covered over by the nuclear lamina
   D. Are covered over by heterochromatin

Answer 1

A. Regulate entry and exit from the nucleus

Question 2

2. Heterochromatin:
   A. Is composed of densely packed RNA and protein
   B. Contains most of the actively transcribed genes
   C. Can be very prominent in cells that secrete a lot of protein
   D. Is absent from the nuclei of the majority of cells

Answer 2

A. Is composed of densely packed RNA and protein

Question 3

3. Which of the following pairs is MISMATCHED?
   A. rER – vectorial translation of proteins into the cisterna
   B. golgi – further modifications of carbohydrate portion of glycoproteins
   C. rER – initial addition of carbohydrate onto a glycoprotein
   D. sER – accumulation of Ca+2 from the cytosol
   E. lysosomes – bud off directly from the rER

Answer 3

E. lysosomes – bud off directly from the rER

Question 4

4. Which of the following pairs is MISMATCHED?
   A. microfilaments – tubulin
   B. intermediate filaments – desmin
   C. microtubules – 24 nm diameter
   D. microfilaments – 5-7 nm diameter
   E. intermediate filaments – 10 nm diameter

Answer 4

A. microfilaments – tubulin

Question 5

5. Which method of viewing would be most appropriate to visualize the
   membranes of the golgi apparatus?
   A. light microscopy of an H&E stained paraffin section
   B. TEM
   C. SEM
   D. none of the above since these membranes cannot be visualized

Answer 5

B. TEM

Question 6

6. In which cell type would one expect to find mitochondria with tubular or
   vesicular cristae?
   A. a cell that secretes steroid hormones
   B. a cell that secretes digestive enzymes
   C. a stratified squamous epithelial cell
   D. an osteoblast
   E. a goblet cell

Answer 6

A. a cell that secretes steroid hormones

Question 7

7. Freeze fracture of membranes has provided information on the
intramembranous distribution of
A. phospholipids
B. glycogen
C. carbohydrates
D. proteins
E. ribosomes

Answer 7

D. proteins

Question 8

8. Which of the following is/are located within the cytosol?
A. ribosomes
B. microtubules
C. IFs
D. microfilaments
E. all of the above

Answer 8

E. all of the above

Question 9

9. Polymerization of actin filaments from actin monomers requires:
A. ADP
B. ATP
C. GDP
D. GTP
E. No energy

Answer 9

B. ATP

Question 10

10. Most mitochondrial proteins are synthesized:
    A. In the intermembranous space of the mitochondria
    B. In the mitochondrial matrix
    C. In the nucleus
    D. On free polysomes in the cytoplasm
    E. On the rough endoplasmic reticulum (RER)

Answer 10

D. On free polysomes in the cytoplasm

Question 11

11. Before a protein can be secreted from a cell via a regulated secretory
    pathway, which of the following must occur:
    A. The fully synthesized protein is released from the rough endoplasmic
    reticulum into the cytosol
    B. Mannose-6-phosphate is added to the carbohydrate side chains of the
    protein
    C. The cell receives an extracellular signal that initiates secretion of the
    protein
    D. The fully synthesized protein undergoes covalent modification in the
    nucleus
    E. The protein is transported in clathrin-coated vesicles from the rough
    endoplasmic reticulum to the Golgi

Answer 11

C. The cell receives an extracellular signal that initiates secretion of the
protein

Question 12

12. Which of the following conclusions would you most be justified in
    making about a cell if you observed that it had a large amount of
    heterochromatin?
    A. The cell is about to extrude its nucleus
    B. The cell is dying
    C. The cell is making large amounts of protein for its own internal use rather
    than for secretion
    D. The cell is metabolically very inactive
    E. The cell is using a small percentage of its genome

Answer 12

E. The cell is using a small percentage of its genome

Question 13

13. The structure of biologic membranes can best be described as:
    A. a phospholipid bilayer interspersed with membrane proteins and all held
    together by covalent bonds
    B. a fluid-mosaic of proteins interspersed in a phospholipid bilayer
    C. a phospholipid bilayer with the hydrocarbon tails of the phospholipids
    oriented toward the cytoplasm
    D. an internal layer of protein covered on either side by a layer of
    phospholipid

Answer 13

B. a fluid-mosaic of proteins interspersed in a phospholipid bilayer

Question 14

14. Which of the following statements regarding primary lysosomes is
    correct?
    A. They reproduce by division
    B. They contain lysosomal DNA
    C. They are identifiable only after specific histochemical staining
    D. They contain enzymes synthesized on free ribosomes
    E. They are the site of β-oxidation of fatty acids

Answer 14

C. They are identifiable only after specific histochemical staining

Question 15

15. Which of the following statements correctly describes the nucleolus?
    A. It is a membrane-bounded intranuclear organelle
    B. It is the site of synthesis of ribosomal proteins
    C. It is not visible in the interphase nucleus
    D. It is the site of assembly of ribosomal subunits

Answer 15

D. It is the site of assembly of ribosomal subunits

Question 16

16. Glycoproteins are asymmetrically distributed in the plasma membrane
    with their carbohydrate moiety oriented toward the extracellular
    environment. In what organelle is this asymmetry established?
    A. Plasma membrane
    B. Trans-Golgi network
    C. Rough endoplasmic reticulum (rER)
    D. Smooth endoplasmic reticulum (sER)

Answer 16

C. Rough endoplasmic reticulum (rER)

Question 17

17. A nucleosome is a unit of structure of which of the following nuclear
components?
A. Nuclear matrix
B. Nuclear lamina
C. Nuclear pore
D. Nuclear chromatin
E. Nuclear envelope

Answer 17

D. Nuclear chromatin

Question 18

18. An epidermal germinative cell has recently replicated its DNA in
    anticipation of mitosis but a mitotic spindle has not yet formed. In which of
    the following phases of the cell cycle is this cell?
    A. Go phase
    B. G1 phase
    C. S phase
    D. G2 phase
    E. M phase

Answer 18

D. G2 phase

Question 19

19. Which of the following events is required to stimulate secretion of stored
    proteins?
    A. Influx of Na+ into the cytoplasm
    B. Increase in cytoplasmic Ca+2 concentration
    C. Release of stored ATP from mitochondria
    D. Cleavage of a signal peptide from the stored protein
    E. Release of elementary particles stored in mitochondria

Answer 19

B. Increase in cytoplasmic Ca+2 concentration

Question 20

20. Colchicine inhibits cell division by which of the following processes?
    A. Inhibiting DNA synthesis in mitochondria
    B. Preventing assembly of the mitotic apparatus
    C. Stabilizing microtubules into a rigid structure
    D. Preventing cytokinesis by inhibiting membrane flow
    E. Inhibiting the ATPase activity of G-actin

Answer 20

B. Preventing assembly of the mitotic apparatus

Question 21

21. Tubulin polymerizes into microtubules that constitute which of the
following cellular elements?
A. Cores of microvilli
B. Spectrin filaments in erythrocytes
C. Mitotic spindles of dividing cells
D. Glial filaments in astrocytes
E. Neurofilaments of axons and dendrites

Answer 21

C. Mitotic spindles of dividing cells

Question 22

22. Release of proenzymes from the pancreatic acinar cell is accomplished
by which of the following processes?
A. Exocytosis
B. Transcytosis
C. Apoptosis
D. Endocytosis
E. Phagocytosis

Answer 22

A. Exocytosis

Question 23

23. The beating of cilia and flagella is dependent upon which of the
    following processes?
    A. Polymerization and depolymerization of microtubules at the tip of the
    cilium
    B. Attachment of actin microfilaments to the membrane of the cilium
    C. Attachment and release of dynein side arms between adjacent
    microtubules of each doublets
    D. Attachment and release of doublet microtubules from the central pair of
    singlet microtubules
    E. Attachment and release of microtubule-associated proteins (MAPs) by
    doublet microtubules

Answer 23

C. Attachment and release of dynein side arms between adjacent
microtubules of each doublets

Question 24

24. In meiosis, synapsis is characterized by which of the following
    activities?
    A. Exchange of neurotransmitters between daughter cells
    B. Pairing of homologous chromosomes during prophase I
    C. Formation of a narrow cleft between daughter cells
    D. Arrival of chromosomes at their respective poles

Answer 24

B. Pairing of homologous chromosomes during prophase I

Question 25

25. Nuclear lamins are intermediate filaments that
    A. bind to the nuclear envelope and prevent disassembly during mitosis
    B. form the channel of the nuclear pore complex
    C. form the membrane of the nucleolus
    D. line the inner aspect of the nuclear envelope

Answer 25

D. line the inner aspect of the nuclear envelope

Question 26

26. Which of the following statements regarding the cell cycle is correct?
    A. It takes place once during the life of a cell (i.e., from origin to death)
    B. It is an ordered sequence of events during which the cell duplicates its
    chromosomes and divides into two cells
    C. It is divided into four phases: prophase, metaphase, anaphase, and
    telophase
    D. It is divided into karyokinesis and cytokinesis, which produce two
    identical cells from a single parent cell
    E. Its divisions represent diurnal variations in the protein synthetic activity
    of a cell

Answer 26

B. It is an ordered sequence of events during which the cell duplicates its
chromosomes and divides into two cells

Question 27

27. Synthetic processes that occur in membrane-bounded cytoplasmic
    organelles include all of the following EXCEPT
    A. hydroxylation of proline and lysine in collagen synthesis
    B. glycosylation of proteins
    C. β-oxidation of fatty acids
    D. polymerization of G-actin to F-actin

Answer 27

D. polymerization of G-actin to F-actin

Question 28

28. Rough endoplasmic reticulum (rER) functions in the synthesis of all of
the following molecules EXCEPT
A. collagen triple helix
B. lysosomal enzymes
C. adenosine triphosphate (ATP)
D. trypsinogen and pepsinogen
E. N-linked glycoproteins

Answer 28

C. adenosine triphosphate (ATP)

Question 29

29. All of the following statements concerning protein secretion are correct
    EXCEPT
    A. zymogen granules contain stored proenzymes
    B. storage granules form at the cis face of the Golgi apparatus
    C. post-translational modification of proteins occurs in the rough
    endoplasmic reticulum (rER) and Golgi apparatus
    D. acid hydrolases are synthesized in the rER and targeted to lysosomes
    E. constitutive secretion is a continuous function of all cells

Answer 29

B. storage granules form at the cis face of the Golgi apparatus

Question 30

30. All of the following statements concerning the nuclear envelope are
    correct EXCEPT:
    A. it is continuous with the membranes of the rough endoplasmic reticulum
    (rER)
    B. it serves as the boundary between the cytoplasmic and nuclear
    compartments
    C. it contains pores that regulate passage of materials in both directions
    between nucleus and cytoplasm
    D. it is the site of synthesis of proteins that will form elements of the nuclear
    matrix
    E. it is stabilized on its inner aspect by filaments of the nuclear lamina

Answer 30

D. it is the site of synthesis of proteins that will form elements of the nuclear
matrix