Bio 93 Quiz 3: Master Copy
1. Choose 1 of the following questions per section
Draw the sequence of activation by a signaling molecule of a:
1. G protein-coupled receptor
2. Tyrosine kinase receptor
3. Ligand- or voltage-activated ion channel
4. Intracellular receptor
2. Choose 1 of the following questions per section
1. What are the main differences between paracrine and hormonal signaling?
Paracrine signaling (local signaling, short distance) vs. hormonal signaling (long distance). For
paracrine signaling, a secretory cell will release growth factors through exocytosis into the extracellular
space. Only a few cells within the vicinity will receive that signal. In hormone signaling, hormones are
released through exocytosis and they can travel through vessels to distant cells.
2. What are the main differences between paracrine and synaptic signaling?
Both are secreted signals that act locally. For paracrine signaling, the growth factors in the extracellular
space via exocytosis. This signal will diffuse in a particular region that will reach cells within that
vicinity. In synaptic signaling, the signal reaches directly onto another cell (i.e., neuron to muscle). It’s
much faster and more specific than paracrine signaling.
3. Name the four type of signaling mechanisms we studied in class. Which ones act at distant sites?
Secreted signals that act locally (paracrine and synaptic), secreted signals that act at distant sites
(hormones), cell surface signals (antibodies), and intracellular signals (gap junctions in animal and
plasmodesmata in plants). Hormone signaling act at distant sites.
4. What is the difference between synaptic and cell-to-cell signaling?
Both are specific in their target cell. For synaptic signaling, specific neurotransmitters are released into
the synaptic cleft through exocytosis. The neurotransmitters diffuse and find receptors on the postsynaptic membrane. In intracellular signaling, neighboring cells are connected via gap junctions
(animals) or plasmodesmata (plant cells). The signal molecule travels through channels from one
cytoplasm to another and these channels are not specific on which molecules pass through.
3. Choose 1 of the following questions per section
1. The main job of the liver is to filter and detoxify the blood from drugs and poisons. Therefore, it isn’t
surprising that liver cells contain more:
A.
B.
C.
D.
E.
Rough ER
Mitochondria
Golgi
Smooth ER
Transport vesicles
2. Pancreatic cells secrete large amounts of signaling molecules like insulin. Therefore, it isn’t surprising
that pancreatic cells contain a large:
A. Rough ER
B. Mitochondria
C. Golgi
D. Smooth ER
E. Transport vesicles
3. In muscle cells the______________ plays an important role as an intracellular store of calcium ions:
A. Rough ER
B. Mitochondria
C. Golgi
D. Smooth ER
E. Transport vesicles
4. In cells with high energy demands like neurons or muscle cells, __________play a crucial role
synthesizing ATP.
A. Rough ER
B. Mitochondria
C. Golgi
D. Smooth ER
E. Transport vesicles
4. Choose 1 of the following questions per section
1. Explain why the presence of proton pumps is important in the membrane of lysosomes.
Proton pumps allow it so that lysosomes maintain a low internal pH needed for digestive enzymes.
Having a more acidic environment isolates digestive enzymes from the rest of the cell.
2. List 2 important functions of the Golgi apparatus.
The main functions of the golgi is protein post-translational modification (phosphorylation,
glycosylation, etc.), synthesis of polysaccharides, and modification of phospholipids.
3. List 2 important functions of the rER.
The 2 important functions of the rER are processing of proteins formed on bound ribosomes (secreted
and membrane proteins) and to synthesize phospholipids from precursors in the cytosol (membrane
factory)
5. Choose 1 of the following questions per section
1. Multiple chemical reactions catalyzed by enzymes take place simultaneously in the cytosol of eukaryotic
cells. Enzyme proteins that carry out their reactions in the cytoplasm are synthesized in which of the
following structures:
A. Bound ribosomes
B.
C.
D.
E.
Rough ER
Nucleolus
Free ribosomes
Small ribosomal subunits
2. Multiple chemical reactions catalyzed by enzymes take place in the Golgi apparatus of eukaryotic cells.
Enzyme proteins that carry out these reactions are synthesized in which of the following structures:
A. Bound ribosomes
B. Rough ER
C. Nucleolus
D. Free ribosomes
E. Small ribosomal subunits
3. Many different hydrolysis reactions catalyzed by enzymes take place in lysosomes. Enzyme proteins
that carry out these reactions are synthesized in which of the following structures:
A. Bound ribosomes
B. Rough ER
C. Nucleolus
D. Free ribosomes
E. Small ribosomal subunits