INTRACELLULAR

Many cells in our body have a certain degree of space between them. Generally, there is water or fibrous products within that space; however, some cells don't have a space between them and are tightly bound to each other. Which of the following cell junctions is designed in such a manner to create a “tube” connecting one cell to the other such as in cardiomyocytes?

• Gap junctions

• Integrins

• Tight junctions

• Desmosomes

Which of the following statements is true regarding gap junctions?

• Gap junctions are found in plant cells.

• Gap junctions form in order to seal off openings in animal cells and prevent liquids from leaking.

• Gap junctions form when connexons align in adjacent animal cells to form a channel.

• Gap junctions are narrow passages that form when holes are punched the cell walls of neighboring plant cells, allowing direct cytoplasmic exchange.

Which of the following types of junctions have protein that extends from one cell to another, thus “attaching” one cell to the other such as in the cells of the stratum spinosum?

• Gap junctions

• Integrins

• Tight junctions

• Desmosomes

Which of the following junctions form a watertight seal between neighboring cells?

• Gap junction

• Tight junction

• Desmosomes

• Plasmodesmata

Enzyme-linked receptor triggered only one cell response.

• Yes

• No

Following receptors are slow-intracellular receptors, except

• Steroid hormones

• Nitrite oxide

• Thyroid hormone

• Vitamin D

Ligands are signaling molecules that bind to receptors.

Which of the following statements is true of ligands?

• The binding of a ligand to a receptor molecule causes the receptor to change shape.

• All ligands are proteins.

• Each ligand is only able to bind to one specific receptor.

• Ligands can bind to cell-surface receptors, but they cannot enter the cell.

Which of the following statements regarding cell signaling is true?

• In endocrine signaling, signals are released from a cell and bind to receptors on its own cell membrane.

• Paracrine signaling allows neighboring cells to communicate over relatively short distances.

• Synaptic signaling is a type of autocrine signaling.

• Direct signaling is a type of signaling found only in plant cells.

Place the following steps of a signal transduction pathway in order from beginning to end.

I. A ligand binds to the cell-surface receptor.

II. Second messenger molecules are released.

III. The receptor activates a protein at the membrane.

IV. Final target causes response.

• I, II, III, IV

• I, III, II, IV

• II, I, III, IV

• III, II, I, IV

There are several types of receptors that allow cells to communicate.

Which of the following is true regarding these cell receptors?

Please choose more than one.

• Intracellular receptors can be found in the cytoplasm or nucleus.

• Binding of a ligand to receptor tyrosine kinases causes a direct change in ion distribution across a membrane.

• Ligand-gated ion receptors are receptors for a group of signaling molecules called growth factors.

• G protein-coupled receptors (GPCRs) are the most diverse type of cell receptor.