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Cell Signaling Part 1 Concept Review

Last updated about 8 years ago

10 Nsɛmmisa

Hyɛ no nsow a efi ɔkyerɛwfo no hɔ:

An assignment to insure understanding of key concept concerning cell signaling.

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Asemmisa {{asɛmmisaAhyɛnsode}}

1.

Above is shown the 4 major types of cell communication. Match the following Biological events with the type of cell signaling that BEST matches what is happening in the organism.

Chemical Signals regulating rhythmic muscle contraction are propagated down the length of cardiac muscle fibers from one cell to the next.
T cells responding to the activated version of the antigun they produced and being stimulated to divide and reproduce more of the activated antigen type.
Mast cell in the respiratory system releasing histamine in response to the presence of an aborigine.
Bovine growth Hormone is released during development of a young calf.

autocrine signal
endocrine signal
paracrine signal
intercellular signaling

Figure 9.8 A receptor tyrosine kinase is an enzyme-linked receptor with a single transmembrane region, and

extracellular and intracellular domains. Binding of a signaling molecule to the extracellular domain causes the

receptor to dimerize. Tyrosine residues on the intracellular domain are then autophosphorylated, triggering a

downstream cellular response. The signal is terminated by a phosphatase that removes the phosphates from the

phosphotyrosine residues.

Figure 9.10 The epidermal growth factor (EGF) receptor (EGFR) is a receptor tyrosine kinase involved in

the regulation of cell growth, wound healing, and tissue repair. When EGF binds to the EGFR, a cascade of

downstream events causes the cell to grow and divide. If EGFR is activated at inappropriate times, uncontrolled

cell growth (cancer) may occur.

Asemmisa {{asɛmmisaAhyɛnsode}}

5.

What property prevents the ligands of cell-surface
receptors from entering the cell?

a. The molecules bind to the extracellular domain.

b. The molecules are hydrophilic and cannot

penetrate the hydrophobic interior of the plasma

membrane.

c. The molecules are attached to transport proteins

that deliver them through the bloodstream to

target cells.

d. The ligands are able to penetrate the membrane

and directly influence gene expression upon

receptor binding.

Asemmisa {{asɛmmisaAhyɛnsode}}

6.

The secretion of hormones by the pituitary gland is an
example of _______________.

a. autocrine signaling

b. paracrine signaling

c. endocrine signaling

d. direct signaling across gap junctions

Asemmisa {{asɛmmisaAhyɛnsode}}

7.

Why are ion channels necessary to transport ions into or
out of a cell?

a. Ions are too large to diffuse through the

membrane.

b. Ions are charged particles and cannot diffuse

through the hydrophobic interior of the

membrane.

c. Ions do not need ion channels to move through

the membrane.

c. Ions do not need ion channels to move through

the membrane.

d. Ions bind to carrier proteins in the bloodstream,

which must be removed before transport into the

cell.

Asemmisa {{asɛmmisaAhyɛnsode}}

8.

Endocrine signals are transmitted more slowly than
paracrine signals because ___________.

a. the ligands are transported through the

bloodstream and travel greater distances

b. the target and signaling cells are close together

c. the ligands are degraded rapidly

d. the ligands don't bind to carrier proteins during

transport

Asemmisa {{asɛmmisaAhyɛnsode}}

9.

What is the function of a phosphatase?

a. A phosphatase removes phosphorylated amino

acids from proteins.

b. A phosphatase removes the phosphate group

from phosphorylated amino acid residues in a

protein.

c. A phosphatase phosphorylates serine, threonine,

and tyrosine residues.

d. A phosphatase degrades second messengers in

the cell.