Question 1

From what cell organelle does the desmotubule appear to be derived?

Accepted Answer

The desmotubule is derived from the smooth endoplasmic reticulum (SER) of the two cells.

Question 2

You are given a tissue that has a large fibrillar component.The fibers are aligned parallel to each other and the long axis of the tissue.What can you conclude about the pulling forces experienced by this tissue?

Accepted Answer

The answer of You are given a tissue that has...

Question 3

What type of protein also seen in animal cells spans the plant plasma membrane and is thought to transmit signals from the cell wall to the cytoplasm?

Accepted Answer

Protein kinases are enzymes that modify other proteins by chemically adding phosphate groups to them (phosphorylation). This process is crucial for signal transduction, allowing the transmission of signals from the cell wall to the cytoplasm, and is a mechanism seen in both plant and animal cells.

Question 4

How is the structure of the mature plant cell wall similar to the structure of the corneal stroma of the chicken embryo?

Accepted Answer

Both the mature plant cell wall and the corneal stroma of the chicken embryo contain adjacent layers of fibers that are arranged perpendicular to each other. While the plant cell wall contains cellulose as its main component, the corneal stroma is composed of collagen. Therefore, option D is the correct choice.

Question 5

Which of the following is not a function of the plant cell wall?

Accepted Answer

The plant cell wall does not prevent cell-cell interactions, rather it plays a vital role in cell-cell communication and signaling. The other options are all functions of the plant cell wall.

Question 6

What lines the plasmodesmata?

Accepted Answer

The plasma membrane lines the plasmodesmata, forming a continuous membrane connection between adjacent plant cells.

Question 7

In the intercellular junctional complex,why is the tight junction closer to the surface of the epithelium (the apical end of the cell)than the belt desmosome?

Accepted Answer

The answer of In the intercellular junctional complex,why is the...

Question 8

You are studying a plant and inject fluorescein,a fluorescent dye,into a single cell on the surface of the plant.After a brief period of time,the dye spreads to cells neighboring the injected cell.What do you conclude?

Accepted Answer

The spread of fluorescein dye to neighboring cells indicates that the cells are connected through plasmodesmata, which are channels in the cell wall that allow for communication and transport between adjacent plant cells. Tight junctions and gap junctions are found in animal cells, while zonulae adherens are a type of cell junction found in epithelial tissues.

Question 9

The enzyme embedded in the plant cell membrane that catalyzes the growth of a cellulose molecule is called _________.

Accepted Answer

The enzyme that catalyzes the growth of a cellulose molecule in plant cells is called cellulose synthase. Options A, C, D, and E are not related to the synthesis of cellulose.

Question 10

What class of plant cell proteins facilitates plant cell growth by causing a localized relaxation of the cell wall,which allows the cell to elongate at that site in response to turgor pressure generated within the cell?

Accepted Answer

Expansins are a class of plant cell proteins that facilitate plant cell growth by causing a localized relaxation of the cell wall, which allows the cell to elongate at that site in response to turgor pressure generated within the cell. Extensins are also plant cell proteins, but they play a role in providing structural support to the cell wall. Desmins are not plant cell proteins, but rather intermediate filaments found in animal cells. Protein kinases and phosphatases are involved in cell signaling and regulation rather than cell wall growth.

Question 11

A scientist is growing cartilage cells in culture.He accidentally spills into the culture enzymes that enzymatically digest the ECM surrounding the cartilage cells.What happens to the behavior of the cartilage cells? How could any change in behavior be reversed?

Accepted Answer

The answer of A scientist is growing cartilage cells in...

Question 12

Why would the collagen found in basement membranes have molecular arrangements and structure different from that found in other collagens and what are some of these differences?

Accepted Answer

The answer of Why would the collagen found in basement...

Question 13

Which plant cell wall molecule is economically important as a component essential for the production of jams and jellies?

Accepted Answer

Pectin is a plant cell wall molecule that is economically important as a component essential for the production of jams and jellies. It is a polysaccharide that is mainly found in the primary cell walls of fruits, particularly in citrus fruits and apples. Pectin provides a gel-like consistency to jams and jellies by forming a network of polymers that trap water and make the mixture thick and spreadable.

Question 14

The thicker walls seen in mature plants that no longer allow extensive growth of the cell wall are known as _______.

Accepted Answer

Secondary walls are thicker and stronger than primary walls and are found in mature, specialized cells such as xylem and sclerenchyma. They are formed after the cell has completed its growth and no longer needs to expand, therefore they do not allow for growth.

Question 15

You study another tissue that also contains a fibrillar component.In this tissue,however,the fibers are arranged in layers with each layer perpendicular to those above and below it.In addition,the fibers are uniform in size.What properties would such a tissue have?

Accepted Answer

The answer of You study another tissue that also contains...

Question 16

Cell walls of young,undifferentiated plant cells must be able to grow along with the cells of which they are a part and thus exhibit extensibility.What are they known as?

Accepted Answer

Primary walls are the outermost layer of young, undifferentiated plant cells and are able to grow along with the cell, exhibiting extensibility. Secondary walls are formed after the cell has matured and are thicker and more rigid, providing support and protection to the cell. "Expandophiles," complete walls, and incomplete walls are not commonly used scientific terms.

Question 17

The dense central structure that is derived from the smooth endoplasmic reticulum and usually seen in the plasmodesmata is called a(n)________.

Accepted Answer

The dense central structure derived from the smooth endoplasmic reticulum and seen in plasmodesmata is called a desmotubule. Desmosomes and hemidesmosomes are types of cell junctions found in animal cells, while an annulus is a structure found in fungi. Desmoglein is a protein found in desmosomes, but is not relevant to the given description.

Quiz 7: Interactions Between Cells and Their Environment