BIOL 1201- FINAL EXAM QUESTIONS
& DETAILED CORRECT ANSWERS
What are the three types of cell signaling? - Correct Answer ✔✔ 1. Direct Contact
2. Local
3. Distant
Describe direct contact cell signaling and some examples. - Correct Answer ✔✔ One
cell actually physically touches another
i.e. Gap Junctions (diffusion of signals through a plasma membrane), Plasmodesmata
(diffusion of signals through a plasma membrane), and Cell-Cell Recognition (one cell
have a type of signal molecule while the other cell has a receptor, and they bind and
create a response)
Describe local cell signaling and some examples. - Correct Answer ✔✔ Cells are
signaling and the signal is released into the extracellular liquid; affects cells in the area
i.e. Paracrine (one cell is releasing signal molecules, diffusing into the area, affecting
the cells nearby, for example, a wound) and Synaptic (space between neurons where
neurotransmitters diffuse across the synapsis)
Describe distant cell signaling and some examples. - Correct Answer ✔✔ Signals cells
in another part of the body
i.e. Endocrine System (hormones are sent all over the body to initiate a response)
A compound that is secreted in one part of the body and travels through the
bloodstream to another part of the body where it has an effect is called a(n)
A. Receptor protein
B. Hormone
C. Transmitter
D. Activator - Correct Answer ✔✔ B. Hormone
When a platelet contacts a damaged blood vessel, it is stimulated to release
thromboxane A2. Thromboxane A2 in turn stimulates a vascular spasm and attracts
additional platelets to the injured site. In this example, thromboxane A2 is acting as
____________.
A. direct contact signal molecule
B. local signal molecule
C. distant signal molecule - Correct Answer ✔✔ B. local signal molecule
,What are the three steps of cell signaling? - Correct Answer ✔✔ 1. Reception
2. Transduction
3. Response
Where are receptors located? - Correct Answer ✔✔ plasma membrane and cytoplasm
Most receptors are _____________ attached to the plasma membrane. - Correct
Answer ✔✔ proteins
Since receptors are proteins, what does that tell us about the specificity of the
receptors? - Correct Answer ✔✔ Since receptors are proteins, then they are highly
specific and will only bind to a specific signal molecule.
Which molecules determine the tissue specificity of hormones?
A. Receptors.
B. Hormone-response elements.
C. Second messengers.
D. Agonists. - Correct Answer ✔✔ A. Receptors.
Assuming there are a 100 different signaling molecules in your body. What is the
minimum number of receptors that your body needs to make?
A. 1
B. 10
C. 100
D. 1000
E. 1000000 - Correct Answer ✔✔ C. 100
When receptors are bound to the plasma membrane, what does this tell us about the
properties of the signal molecules? - Correct Answer ✔✔ Since the receptors are
embedded in the plasma membrane, then the signal molecules for those receptors are
not permeable to the membrane and need help to pass through the membrane.
When receptors are located in the cytoplasm, what does this tell us about the properties
of these signals? - Correct Answer ✔✔ These signals are obviously membrane
permeable. Most cytoplasmic signals are steroids. Since steroids are lipids, then they
are permeable to the membrane.
Which of these extracellular signal molecules could diffuse through a plasma membrane
and bind to an intracellular receptor?
A. glucose
B. estrogen
C. glycerol
, D. cellulose
E. starch - Correct Answer ✔✔ B. estrogen
A(n) _____ is an example of a signal molecule that can bind to an intracellular receptor
and thereby cause a gene to be turned on or off.
A. steroid
B. nucleic acid
C. ion
D. protein
E. carbohydrate - Correct Answer ✔✔ A. steroid
Which type of hormone is lipid soluble?
A. DNA.
B. Amino acid derivatives.
C. Polypeptides.
D. Steroids. - Correct Answer ✔✔ D. Steroids.
Thyroid hormones bind to _____ receptors.
A. tyrosine-kinase
B. steroid
C. plasma membrane ion-channel
D. G-protein-linked
E. intracellular - Correct Answer ✔✔ E. intracellular
True or false: Lipid-insoluble hormones affect their target cells by binding to receptors
inside the cell.
A. True
B. False - Correct Answer ✔✔ B. False
Which of the following statements about lipid-soluble hormones is true?
A. They act by producing second messengers.
B. They act by affecting the transcription of genes.
C. They bind to DNA as soon as they enter a cell.
D. They bind to receptors on the plasma membrane. - Correct Answer ✔✔ B. They act
by affecting the transcription of genes.
Based on your understanding of membrane permeability, the signal molecules (ligands)
binding to the cytoplasmic receptors are _______.
A. polar molecules
B. non-polar molecules
& DETAILED CORRECT ANSWERS
What are the three types of cell signaling? - Correct Answer ✔✔ 1. Direct Contact
2. Local
3. Distant
Describe direct contact cell signaling and some examples. - Correct Answer ✔✔ One
cell actually physically touches another
i.e. Gap Junctions (diffusion of signals through a plasma membrane), Plasmodesmata
(diffusion of signals through a plasma membrane), and Cell-Cell Recognition (one cell
have a type of signal molecule while the other cell has a receptor, and they bind and
create a response)
Describe local cell signaling and some examples. - Correct Answer ✔✔ Cells are
signaling and the signal is released into the extracellular liquid; affects cells in the area
i.e. Paracrine (one cell is releasing signal molecules, diffusing into the area, affecting
the cells nearby, for example, a wound) and Synaptic (space between neurons where
neurotransmitters diffuse across the synapsis)
Describe distant cell signaling and some examples. - Correct Answer ✔✔ Signals cells
in another part of the body
i.e. Endocrine System (hormones are sent all over the body to initiate a response)
A compound that is secreted in one part of the body and travels through the
bloodstream to another part of the body where it has an effect is called a(n)
A. Receptor protein
B. Hormone
C. Transmitter
D. Activator - Correct Answer ✔✔ B. Hormone
When a platelet contacts a damaged blood vessel, it is stimulated to release
thromboxane A2. Thromboxane A2 in turn stimulates a vascular spasm and attracts
additional platelets to the injured site. In this example, thromboxane A2 is acting as
____________.
A. direct contact signal molecule
B. local signal molecule
C. distant signal molecule - Correct Answer ✔✔ B. local signal molecule
,What are the three steps of cell signaling? - Correct Answer ✔✔ 1. Reception
2. Transduction
3. Response
Where are receptors located? - Correct Answer ✔✔ plasma membrane and cytoplasm
Most receptors are _____________ attached to the plasma membrane. - Correct
Answer ✔✔ proteins
Since receptors are proteins, what does that tell us about the specificity of the
receptors? - Correct Answer ✔✔ Since receptors are proteins, then they are highly
specific and will only bind to a specific signal molecule.
Which molecules determine the tissue specificity of hormones?
A. Receptors.
B. Hormone-response elements.
C. Second messengers.
D. Agonists. - Correct Answer ✔✔ A. Receptors.
Assuming there are a 100 different signaling molecules in your body. What is the
minimum number of receptors that your body needs to make?
A. 1
B. 10
C. 100
D. 1000
E. 1000000 - Correct Answer ✔✔ C. 100
When receptors are bound to the plasma membrane, what does this tell us about the
properties of the signal molecules? - Correct Answer ✔✔ Since the receptors are
embedded in the plasma membrane, then the signal molecules for those receptors are
not permeable to the membrane and need help to pass through the membrane.
When receptors are located in the cytoplasm, what does this tell us about the properties
of these signals? - Correct Answer ✔✔ These signals are obviously membrane
permeable. Most cytoplasmic signals are steroids. Since steroids are lipids, then they
are permeable to the membrane.
Which of these extracellular signal molecules could diffuse through a plasma membrane
and bind to an intracellular receptor?
A. glucose
B. estrogen
C. glycerol
, D. cellulose
E. starch - Correct Answer ✔✔ B. estrogen
A(n) _____ is an example of a signal molecule that can bind to an intracellular receptor
and thereby cause a gene to be turned on or off.
A. steroid
B. nucleic acid
C. ion
D. protein
E. carbohydrate - Correct Answer ✔✔ A. steroid
Which type of hormone is lipid soluble?
A. DNA.
B. Amino acid derivatives.
C. Polypeptides.
D. Steroids. - Correct Answer ✔✔ D. Steroids.
Thyroid hormones bind to _____ receptors.
A. tyrosine-kinase
B. steroid
C. plasma membrane ion-channel
D. G-protein-linked
E. intracellular - Correct Answer ✔✔ E. intracellular
True or false: Lipid-insoluble hormones affect their target cells by binding to receptors
inside the cell.
A. True
B. False - Correct Answer ✔✔ B. False
Which of the following statements about lipid-soluble hormones is true?
A. They act by producing second messengers.
B. They act by affecting the transcription of genes.
C. They bind to DNA as soon as they enter a cell.
D. They bind to receptors on the plasma membrane. - Correct Answer ✔✔ B. They act
by affecting the transcription of genes.
Based on your understanding of membrane permeability, the signal molecules (ligands)
binding to the cytoplasmic receptors are _______.
A. polar molecules
B. non-polar molecules
