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| 1 | |
Which of the following statements is incorrect? |
| | A) | Multicellular organisms typically have larger genomes and therefore larger proteomes than unicellular organisms. |
| | B) | Plants, which lack a rigid skeleton, require an extracellular matrix; animals, which possess more defined shapes, do not require an extracellular matrix. |
| | C) | More proteins are devoted to cell-cell communication in multicellular organisms than in unicellular organisms. |
| | D) | Some material secreted outside of a cell allows that cell to attach to neighboring cells. |
| | E) | The extracellular matrix found in woody portions of plants can continue to support the plant after the cells within it have died. |
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| 2 | |
True or False: Gap junctions rely on the functioning of membrane proteins called cell adhesion molecules, or CAMs. |
| | A) | True |
| | B) | False |
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| 3 | |
Which of the following is not a major protein component of the ECM in animals? |
| | A) | Collagen |
| | B) | Elastin |
| | C) | Laminin |
| | D) | Fibronectin |
| | E) | Glycosaminoglycans |
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| 4 | |
Collagens are _______________ which form a ______________. |
| | A) | proteins : triple helix |
| | B) | nucleic acids : double helix |
| | C) | polysaccharides : branched structure |
| | D) | lipids : diglyceride |
| | E) | proteins : quaternary structure |
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| 5 | |
Which one of the following represents an important function of the extracellular matrix? |
| | A) | Cell signaling |
| | B) | Structural support |
| | C) | Organization |
| | D) | Strength |
| | E) | All of these choices are important functions of the extracellular matrix. |
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| 6 | |
Which one of the following molecules would most likely be found in the lumen of the endoplasmic reticulum? |
| | A) | Collagen fibers |
| | B) | Procollagen |
| | C) | Collagen fibrils |
| | D) | Collagen polypeptides with extension sequences |
| | E) | Collagen polypeptides without extension sequences |
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| 7 | |
Which one of the following statements about ECM polysaccharides is (ignore)incorrect(ignore)? |
| | A) | The carbohydrate portion of a proteoglycan is composed of repeating disaccharide units. |
| | B) | GAGs carry a net negative charge, and are attracted to the positively charged ions and water. |
| | C) | Chitin is an example of a glycosaminoglycan found mainly in joints. |
| | D) | The maximum length of a GAG is approximately 25,000 carbohydrate units. |
| | E) | A GAG linked to a core protein is referred to as a proteoglycans. |
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| 8 | |
Which of the following statements regarding plant cell walls is correct? |
| | A) | Primary cell walls are composed primarily of a phospholipid bilayer. |
| | B) | Cellulose is composed of repeating glucose molecules |
| | C) | The secondary cell walls in plants are relatively similar in all species. |
| | D) | Glycans contribute to the flexibility of the primary cell wall |
| | E) | Pectins are positively charged polysaccharides that attract water. |
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| 9 | |
Which of the following cellular junctions are found in plants? |
| | A) | Desmosomes |
| | B) | Focal adhesions |
| | C) | Gap junctions |
| | D) | Plasmodesmata |
| | E) | Tight junctions |
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| 10 | |
A(n) ________ relies on a cell adhesion molecule called an integrin; a(n) ________ relies on a cell adhesion molecule called a cadherin. |
| | A) | hemidesmosome; focal adhesion |
| | B) | desmosome; hemidesmosome |
| | C) | adherins junction; desmosome |
| | D) | focal adhesion; hemidesmosome |
| | E) | focal adhesion; adherins junction |
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| 11 | |
E-cadherin in one cell will bind to E-cadherin in a neighboring cell, but not to N-cadherin in a neighboring cell. This property of cadherins is known as |
| | A) | amphipathic. |
| | B) | heterophilic. |
| | C) | homophilic. |
| | D) | uniphilic. |
| | E) | selective binding. |
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| 12 | |
Integrins |
| | A) | facilitate "inside-out" signaling. |
| | B) | facilitate "outside-in" signaling. |
| | C) | contribute to regulation of cell growth and migration. |
| | D) | connect cells to the extracellular matrix. |
| | E) | All of the statements about integrins are correct. |
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| 13 | |
Which type of protein(s) would be found in a tight junction? |
| | A) | Cadherin |
| | B) | Connexin |
| | C) | Claudin |
| | D) | Collagen |
| | E) | Innexin |
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| 14 | |
Which one of the following molecules would not be able to pass through a gap junction? |
| | A) | cAMP |
| | B) | leucine |
| | C) | IP3 |
| | D) | mRNA |
| | E) | Glucose |
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| 15 | |
Loewenstein and colleagues determined that the size exclusion of a gap junction is approximately |
| | A) | 10 Daltons |
| | B) | 900 Daltons |
| | C) | 10 kilodaltons |
| | D) | 1,000 Daltons |
| | E) | 9,000 Daltons |
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| 16 | |
True or False: Pectins can be found in both the primary cell wall and middle lamella in plants. |
| | A) | True |
| | B) | False |
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| 17 | |
Plasmodesmata |
| | A) | connect the cell wall of one plant cell to the cytoplasm of another plant cell. |
| | B) | allow for direction connection of the cytoplasm of a plant cell with the cytoplasm of an animal cell, facilitating horizontal gene transfer. |
| | C) | are the functional equivalent in plant cells of gap junctions in animal cells. |
| | D) | allow chloroplasts to be shared between adjacent plant cells. |
| | E) | All of the statements about plasmodesmata are correct. |
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| 18 | |
Which one of these following tissue types is not found in animals? |
| | A) | Connective |
| | B) | Nervous |
| | C) | Dermal |
| | D) | Muscle |
| | E) | Epithelial |
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| 19 | |
The removal of cells in order to maintain a morphological characteristic of an organism is known as |
| | A) | cell growth. |
| | B) | apoptosis. |
| | C) | differentiation. |
| | D) | migration. |
| | E) | mitosis. |
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| 20 | |
A simple epithelium has a polarity, but a stratified epithelium is an asymmetrical arrangement. |
| | A) | True |
| | B) | False |
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