Question 1

Most proteins destined to enter the endoplasmic reticulum

Accepted Answer

A) are transported across the membrane after their synthesis is complete. 
B) are completely translated on free ribosomes in the cytosol. 
C) begin to cross the membrane while still being synthesized. 
D) remain within the endoplasmic reticulum. 
A) are transported across the membrane after their synthesis is complete. 
B) are completely translated on free ribosomes in the cytosol. 
C) begin to cross the membrane while still being synthesized. 
D) remain within the endoplasmic reticulum. C

Question 2

Which of the following statements about vesicle budding from the Golgi is FALSE?

Accepted Answer

A) Clathrin molecules are important for binding to and selecting cargoes for transport. 
B) Adaptins interact with clathrin. 
C) Once vesicle budding occurs, clathrin molecules are released from the vesicle. 
D) Clathrin molecules act at the cytosolic surface of the Golgi membrane. 
A) Clathrin molecules are important for binding to and selecting cargoes for transport. 
B) Adaptins interact with clathrin. 
C) Once vesicle budding occurs, clathrin molecules are released from the vesicle. 
D) Clathrin molecules act at the cytosolic surface of the Golgi membrane. A

Question 3

Using genetic engineering techniques, you have created a set of proteins that contain two (and only two) conflicting signal sequences that specify different compartments.Predict which signal would win out for the following combinations.Explain your answers.
A.Signals for import into the nucleus and import into the ER.
B.Signals for export from the nucleus and import into the mitochondria.
C.Signals for import into mitochondria and retention in the ER.

Accepted Answer

A.The protein would enter the ER.The signal for a protein to enter the ER is recognized as the protein is being synthesized and the protein will end up either in the ER or on the ER membrane.Cytosolic nuclear transport proteins recognize proteins destined for the nucleus once those proteins are fully synthesized and fully folded.
B.The protein would enter the mitochondria.For a nuclear export signal to work, the protein would have to end up in the nucleus first and thus would need a nuclear import signal for the nuclear export signal to be used.
C.The protein would enter the mitochondria.To be retained in the ER, the protein needs to enter the ER.Because there is no signal for ER import, the ER retention signal would not function.

Question 4

You are interested in Fuzzy, a soluble protein that functions within the ER lumen.Given that information, which of the following statements must be TRUE?

Accepted Answer

A) Fuzzy has a C-terminal signal sequence that binds to SRP. 
B) Only one ribosome can be bound to the mRNA encoding Fuzzy during translation. 
C) Fuzzy must contain a hydrophobic stop-transfer sequence. 
D) Once the signal sequence from Fuzzy has been cleaved, the signal peptide will be ejected into the ER membrane and degraded. 
A) Fuzzy has a C-terminal signal sequence that binds to SRP. 
B) Only one ribosome can be bound to the mRNA encoding Fuzzy during translation. 
C) Fuzzy must contain a hydrophobic stop-transfer sequence. 
D) Once the signal sequence from Fuzzy has been cleaved, the signal peptide will be ejected into the ER membrane and degraded.

Question 5

Vesicles from the ER enter the Golgi at the

Accepted Answer

A) medial cisternae. 
B) trans Golgi network. 
C) cis Golgi network. 
D) trans cisternae. 
A) medial cisternae. 
B) trans Golgi network. 
C) cis Golgi network. 
D) trans cisternae.

Question 6

Proteins that are fully translated in the cytosol do not end up in

Accepted Answer

A) the cytosol. 
B) the mitochondria. 
C) the interior of the nucleus. 
D) transport vesicles. 
A) the cytosol. 
B) the mitochondria. 
C) the interior of the nucleus. 
D) transport vesicles.

Question 7

Which of the following protein families are NOT involved in directing transport vesicles to the target membrane?

Accepted Answer

A) SNAREs 
B) Rabs 
C) tethering proteins 
D) adaptins 
A) SNAREs 
B) Rabs 
C) tethering proteins 
D) adaptins

Question 8

In a cell capable of regulated secretion, what are the three main classes of proteins that must be separated before they leave the trans Golgi network?

Accepted Answer

The three main classes of protein that m

Question 9

If a lysosome breaks, what protects the rest of the cell from lysosomal enzymes?

Accepted Answer

The lysosomal enzymes are all acid hydro

Question 10

In which cellular location would you expect to find ribosomes translating mRNAs that encode ribosomal proteins?

Accepted Answer

A) the nucleus 
B) on the rough ER 
C) in the cytosol 
D) in the lumen of the ER 
A) the nucleus 
B) on the rough ER 
C) in the cytosol 
D) in the lumen of the ER

Question 11

Which of the following organelles is not part of the endomembrane system?

Accepted Answer

A) Golgi apparatus 
B) the endosome 
C) mitochondria 
D) lysosomes 
A) Golgi apparatus 
B) the endosome 
C) mitochondria 
D) lysosomes

Question 12

Which of the following statements about nuclear transport is TRUE?

Accepted Answer

A) mRNAs and proteins transit the nucleus through different types of nuclear pores. 
B) Nuclear import receptors bind to proteins in the cytosol and bring the proteins to the nuclear pores, where the proteins are released from the receptors into the pores for transit into the nucleus. 
C) Nuclear pores contain proteins with disordered segments that fill the channel and allow small water-soluble molecules to pass through in a non-selective fashion. 
D) Nuclear pores are made up of many copies of a single protein. 
A) mRNAs and proteins transit the nucleus through different types of nuclear pores. 
B) Nuclear import receptors bind to proteins in the cytosol and bring the proteins to the nuclear pores, where the proteins are released from the receptors into the pores for transit into the nucleus. 
C) Nuclear pores contain proteins with disordered segments that fill the channel and allow small water-soluble molecules to pass through in a non-selective fashion. 
D) Nuclear pores are made up of many copies of a single protein.

Question 13

N-linked oligosaccharides on secreted glycoproteins are attached to

Accepted Answer

A) nitrogen atoms in the polypeptide backbone. 
B) the serine or threonine in the sequence Asn-X-Ser/Thr. 
C) the N-terminus of the protein. 
D) the asparagine in the sequence Asn-X-Ser/Thr. 
A) nitrogen atoms in the polypeptide backbone. 
B) the serine or threonine in the sequence Asn-X-Ser/Thr. 
C) the N-terminus of the protein. 
D) the asparagine in the sequence Asn-X-Ser/Thr.

Question 14

Which of the following statements is TRUE?

Accepted Answer

A) Lysosomes are believed to have originated from the engulfment of bacteria specialized for digestion. 
B) The nuclear membrane is thought to have arisen from the plasma membrane invaginating around the DNA. 
C) Because bacteria do not have mitochondria, they cannot produce ATP in a membrane-dependent fashion. 
D) Chloroplasts and mitochondria share their DNA. 
A) Lysosomes are believed to have originated from the engulfment of bacteria specialized for digestion. 
B) The nuclear membrane is thought to have arisen from the plasma membrane invaginating around the DNA. 
C) Because bacteria do not have mitochondria, they cannot produce ATP in a membrane-dependent fashion. 
D) Chloroplasts and mitochondria share their DNA.

Question 15

Which of the following statements is TRUE?

Accepted Answer

A) The signal sequences on mitochondrial proteins are usually at the C-terminus. 
B) Most mitochondrial proteins are not imported from the cytosol but are synthesized inside the mitochondria. 
C) Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes. 
D) Mitochondrial proteins cross the membrane in their native, folded state. 
A) The signal sequences on mitochondrial proteins are usually at the C-terminus. 
B) Most mitochondrial proteins are not imported from the cytosol but are synthesized inside the mitochondria. 
C) Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes. 
D) Mitochondrial proteins cross the membrane in their native, folded state.

Question 16

Which of the following statements is TRUE?

Accepted Answer

A) Proteins destined for the ER are translated by a special pool of ribosomes whose subunits are always associated with the outer ER membrane. 
B) Proteins destined for the ER translocate their associated mRNAs into the ER lumen where they are translated. 
C) Proteins destined for the ER are translated by cytosolic ribosomes and are targeted to the ER when a signal sequence emerges during translation. 
D) Proteins destined for the ER are translated by a pool of cytosolic ribosomes that contain ER-targeting sequences that interact with ER-associated protein translocators. 
A) Proteins destined for the ER are translated by a special pool of ribosomes whose subunits are always associated with the outer ER membrane. 
B) Proteins destined for the ER translocate their associated mRNAs into the ER lumen where they are translated. 
C) Proteins destined for the ER are translated by cytosolic ribosomes and are targeted to the ER when a signal sequence emerges during translation. 
D) Proteins destined for the ER are translated by a pool of cytosolic ribosomes that contain ER-targeting sequences that interact with ER-associated protein translocators.

Question 17

For each of the following sentences, fill in the blanks with the best word or phrase selected from the list below.Not all words or phrases will be used; use each word or phrase only once.
$\begin{array}{lll}
\text { carbohydrate } & \text { endosome } & \text { lysosome } \
\text { disulfide bonds } & \text { exocytic } & \text { protein } \
\text { endocytic } & \text { Golgi apparatus } & \text { secretory } \
\text { endomembrane } & \text { hydrogen bonds } & \
\text { endoplasmic reticulum } & \text { ionic bonds } &
\end{array}$

Proteins are transported out of a cell via the __________ or __________ pathway.Fluids and macromolecules are transported into the cell via the __________ pathway.All proteins being transported out of the cell pass through the __________ and the __________.Transport vesicles link organelles of the __________ system.The formation of __________ in the endoplasmic reticulum stabilizes protein structure.

Accepted Answer

Proteins are transported out of a cell v

Question 18

Which of the following statements about phagocytic cells in animals is FALSE?

Accepted Answer

A) Phagocytic cells are important in the gut to take up large particles of food. 
B) Phagocytic cells scavenge dead and damaged cells and cell debris. 
C) Phagocytic cells can engulf invading microorganisms and deliver them to their lysosomes for destruction. 
D) Phagocytic cells extend pseudopods that surround the material to be ingested. 
A) Phagocytic cells are important in the gut to take up large particles of food. 
B) Phagocytic cells scavenge dead and damaged cells and cell debris. 
C) Phagocytic cells can engulf invading microorganisms and deliver them to their lysosomes for destruction. 
D) Phagocytic cells extend pseudopods that surround the material to be ingested.

Question 19

You are working in a biotech company that has discovered a small-molecule drug called H5434.H5434 binds to LDL receptors when they are bound to cholesterol.H5434 binding does not alter the conformation of the LDL receptor's intracellular domain.Interestingly, in vitro experiments demonstrate that addition of H5434 increases the affinity of LDL for cholesterol and prevents cholesterol from dissociating from the LDL receptor even in acidic conditions.Which of the following is a reasonable prediction of what may happen when you add H5434 to cells?

Accepted Answer

A) Cytosolic cholesterol levels will remain unchanged relative to normal cells. 
B) Cytosolic cholesterol levels will decrease relative to normal cells. 
C) The LDL receptor will remain on the plasma membrane. 
D) The uncoating of vesicles will not occur. 
A) Cytosolic cholesterol levels will remain unchanged relative to normal cells. 
B) Cytosolic cholesterol levels will decrease relative to normal cells. 
C) The LDL receptor will remain on the plasma membrane. 
D) The uncoating of vesicles will not occur.

Question 20

Where are chloroplast proteins translated?

Accepted Answer

A) in the cytosol 
B) in the chloroplast 
C) on the endoplasmic reticulum 
D) in both the cytosol and the chloroplast 
A) in the cytosol 
B) in the chloroplast 
C) on the endoplasmic reticulum 
D) in both the cytosol and the chloroplast

Most proteins destined to enter the endoplasmic reticulum

Which of the following statements about vesicle budding from the Golgi is FALSE?

You are interested in Fuzzy, a soluble protein that functions within the ER lumen.Given that information, which of the following statements must be TRUE?

Vesicles from the ER enter the Golgi at the

Proteins that are fully translated in the cytosol do not end up in

Which of the following protein families are NOT involved in directing transport vesicles to the target membrane?

In a cell capable of regulated secretion, what are the three main classes of proteins that must be separated before they leave the trans Golgi network?

If a lysosome breaks, what protects the rest of the cell from lysosomal enzymes?

In which cellular location would you expect to find ribosomes translating mRNAs that encode ribosomal proteins?

Which of the following organelles is not part of the endomembrane system?

Which of the following statements about nuclear transport is TRUE?

N-linked oligosaccharides on secreted glycoproteins are attached to

Which of the following statements is TRUE?

Which of the following statements is TRUE?

Which of the following statements is TRUE?

Which of the following statements about phagocytic cells in animals is FALSE?

Where are chloroplast proteins translated?

Cells: The Fundamental Units of Life

Chemical Components of Cells

Energy, Catalysis, and Biosynthesis

Protein Structure and Function

DNA and Chromosomes

DNA Replication and Repair

From DNA to Protein

Control of Gene Expression

How Genes and Genomes Evolve

Analyzing the Structure and Function of Genes

Membrane Structure

Transport Across Cell Membranes

How Cells Obtain Energy From Food

Energy Generation in Mitochondria and Chloroplasts

Cell Signaling

Cytoskeleton

The Cell-Division Cycle

Sexual Reproduction and the Power of Genetics

Cell Communities: Tissues, Stem Cells, and Cancer

Filters

Exam 15: Intracellular Compartments and Protein Transport

Most proteins destined to enter the endoplasmic reticulum

Which of the following statements about vesicle budding from the Golgi is FALSE?

You are interested in Fuzzy, a soluble protein that functions within the ER lumen.Given that information, which of the following statements must be TRUE?

Vesicles from the ER enter the Golgi at the

Proteins that are fully translated in the cytosol do not end up in

Which of the following protein families are NOT involved in directing transport vesicles to the target membrane?

In a cell capable of regulated secretion, what are the three main classes of proteins that must be separated before they leave the trans Golgi network?

If a lysosome breaks, what protects the rest of the cell from lysosomal enzymes?

In which cellular location would you expect to find ribosomes translating mRNAs that encode ribosomal proteins?

Which of the following organelles is not part of the endomembrane system?

Which of the following statements about nuclear transport is TRUE?

N-linked oligosaccharides on secreted glycoproteins are attached to

Which of the following statements is TRUE?

Which of the following statements is TRUE?

Which of the following statements is TRUE?

Which of the following statements about phagocytic cells in animals is FALSE?

Where are chloroplast proteins translated?

Cells: The Fundamental Units of Life

Chemical Components of Cells

Energy, Catalysis, and Biosynthesis

Protein Structure and Function

DNA and Chromosomes

DNA Replication and Repair

From DNA to Protein

Control of Gene Expression

How Genes and Genomes Evolve

Analyzing the Structure and Function of Genes

Membrane Structure

Transport Across Cell Membranes

How Cells Obtain Energy From Food

Energy Generation in Mitochondria and Chloroplasts

Cell Signaling

Cytoskeleton

The Cell-Division Cycle

Sexual Reproduction and the Power of Genetics

Cell Communities: Tissues, Stem Cells, and Cancer

Filters