High School Biology : Understanding the Endoplasmic Reticulum and Golgi Body

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #31 : Cell Structures And Organelles

Which of the following is not a function of the smooth endoplasmic reticulum?

Possible Answers:

Lipid synthesis

Detoxification of the cell

Transport of proteins

Protein synthesis

Transportation of cellular materials

Correct answer:

Protein synthesis

Explanation:

The smooth endoplasmic reticulum has a variety of functions. Proteins can be packaged and transported through the cell by the smooth endoplasmic reticulum, as can other cellular components and materials. The membrane around the smooth endoplasmic reticulum can be used to create intracellular vesicles. The smooth endoplasmic reticulum is also responsible for using these vesicles to interface with the plasma membrane, synthesizing phospholipids to repair and grow the membrane surface area. The smooth endoplasmic reticulum also contains enzymes responsible for degrading inorganic toxins, such as alcohol and drugs. This organelle is especially prevalent in hepatocytes (liver cells) where the blood if filtered and toxins are removed for degradation.

Protein synthesis requires the action of ribosomes, which can be found in the cytosol or embedded in the membrane of the rough endoplasmic reticulum.

Example Question #1 : Understanding The Endoplasmic Reticulum And Golgi Body

A researcher observes two organelles under the microscope. He notices that organelle A contains more amino acids than organelle B. What might the researcher conclude about the two organelles?

Possible Answers:

Organelle B is smooth endoplasmic reticulum and it contains ribosomes

Organelle B is rough endoplasmic reticulum and it contains ribosomes

Organelle A is rough endoplasmic reticulum and it contains ribosomes

Organelle A is smooth endoplasmic reticulum and it contains ribosomes

Correct answer:

Organelle A is rough endoplasmic reticulum and it contains ribosomes

Explanation:

The question states that organelle A has more amino acids. This means that organelle A has more proteins than organelle B. Remember that rough endoplasmic reticulum (rough ER) is termed ‘rough’ because it contains ribosomes on its surface. These ribosomes give it a rough appearance under the microscope. Ribosomes are the site of protein synthesis, therefore, rough ER will contain more proteins (and amino acids).

We cannot draw any conclusions about organelle B, since most organelles contain fewer amino acids and proteins than the rough endoplasmic reticulum.

Example Question #1 : Understanding The Endoplasmic Reticulum And Golgi Body

Which organelle is most important for a person who has consumed too much alcohol?

Possible Answers:

Rough endoplasmic reticulum

Mitochondria

Ribosomes

Smooth endoplasmic reticulum

Correct answer:

Smooth endoplasmic reticulum

Explanation:

The question states that the person has consumed too much alcohol, which means that the body must detoxify the chemicals from alcohol. You are therefore looking for the organelle that participates in detoxification of chemicals. In addition to synthesizing lipids, the smooth endoplasmic reticulum plays an important role in detoxification of chemicals. This detoxification process occurs in the liver, which contains an abundance of smooth endoplasmic reticulum.

Rough endoplasmic reticulum and ribosomes are involved in protein synthesis, and mitochondria are the site of energy (ATP) production.

Example Question #1 : Understanding The Endoplasmic Reticulum And Golgi Body

Steroids are an important component of cell membranes and gonadal hormones. What organelle is most important in the synthesis of steroids?

Possible Answers:

Rough endoplasmic reticulum

Golgi apparatus

Lysosomes

Smooth endoplasmic reticulum

Correct answer:

Smooth endoplasmic reticulum

Explanation:

Steroids are a type of lipid that include cholesterol (needed for cell membranes) and gonadal hormones (estrogen, testosterone, and progesterone). Since they are lipids, steroids are synthesized in the smooth endoplasmic reticulum, the site of lipid synthesis.

Remember that smooth endoplasmic reticulum also plays a role in detoxification of harmful chemicals.

Rough endoplasmic reticulum is used to produce proteins that will be secreted from the cell, including most peptide hormones. The Golgi apparatus is used to modify these proteins and create vesicles for protein transport. Lysosomes contain hydrolytic enzymes that digest cellular wastes.

Example Question #1 : Understanding The Endoplasmic Reticulum And Golgi Body

Bob, a biologist who was researching a new eukaryotic unicellular species, wanted to study a particular protein Y. After obtaining and purifying the sample, Bob discovered that this protein had 3 subunits: A, B, and C. Through substantive scientific analysis, Bob discovered that protein Y operated in a membrane; however, he could not deduce which particular membrane. Nonetheless, Bob found that only subunit B was traversed through the interior of the membrane. With Bob’s findings, please answer the following questions.

Where is this protein synthesized? 

Possible Answers:

Golgi apparatus

Smooth endoplasmic reticulum

Rough endoplasmic reticulum

Cytoplasm

Nucleolus

Correct answer:

Rough endoplasmic reticulum

Explanation:

The only possible answer choices are the Rough ER and Cytoplasm since proteins are synthesized in these two components. Proteins intended to be membranous are synthesized exclusively on the Rough ER. 

Example Question #1 : Understanding The Endoplasmic Reticulum And Golgi Body

Which of the following organelles is responsible for detoxification?

Possible Answers:

Rough endoplasmic reticulum

Mitochondria

Golgi apparatus 

Smooth endoplasmic reticulum

Ribosome

Correct answer:

Smooth endoplasmic reticulum

Explanation:

Smooth endoplasmic reticulum(ER) is responsible for the detoxification of a number of organic chemicals. The smooth ER converts organic substances into water and other soluble products to allow for excretion. Large amounts of smooth ER are found in liver cells, where products of natural metabolism, drugs, and alcohol are detoxified. Fun fact: the smooth ER can double its surface area within a few days then return to its normal size once the assault has subsided. 

Example Question #1 : Understanding The Endoplasmic Reticulum And Golgi Body

Lipid synthesis occurs in which of the following cell organelles?

Possible Answers:

Vacuole

Golgi apparatus

Smooth endoplasmic reticulum

Lysosome 

Rough endoplasmic reticulum

Correct answer:

Smooth endoplasmic reticulum

Explanation:

Smooth endoplasmic reticulum (ER) is devoted almost exclusively to the manufacture of lipids, and in some cases the metabolism of lipids and their associated products. Smooth ER synthesizes lipids, phospholipids, and steroids. It also carries out the metabolism of carbohydrates and drug detoxification. The smooth ER of the endoplasmic reticulum lacks ribosomes, hence the name smooth ER.

Example Question #32 : Common Cell Structures

What is the main function of the Golgi apparatus?

Possible Answers:

Sorts and ships proteins to the correct place

Produce DNA

Produce proteins

Produce enzymes

Correct answer:

Sorts and ships proteins to the correct place

Explanation:

The Golgi apparatus (body) sorts and ships proteins to the correct place. It does not produce proteins or enzymes, a type of protein. Rough ER and ribosomes produce proteins. The Golgi apparatus does not produce DNA, which is the genetic code produced in the process of replication, and occurs in the nucleus of eukaryotic cells.

Example Question #1 : Understanding The Endoplasmic Reticulum And Golgi Body

What is the function of rough endoplasmic reticulum (ER)?

Possible Answers:

Conversion of DNA to RNA

Synthesis of lipids

Synthesis of proteins

Production of DNA

Correct answer:

Synthesis of proteins

Explanation:

Rough endoplasmic reticulum (ER) is involved in the synthesis of proteins.  Smooth endoplasmic reticulum is involved in the synthesis of lipids.  The conversion of DNA to RNA is called transcription but does not involve rough ER. Production of DNA is replication and occurs in the nucleus, as does transcription.

Example Question #1 : Understanding The Endoplasmic Reticulum And Golgi Body

The smooth endoplasmic reticulum's main function is __________.

Possible Answers:

regulate water intake

synthesize lipids and detoxify harmful substances

synthesize RNA

synthesize proteins

Correct answer:

synthesize lipids and detoxify harmful substances

Explanation:

Smooth endoplasmic reticulum (ER) synthesizes lipids and detoxifies harmful substances.  RNA synthesis occurs in transcription but does not involve Smooth ER.  Proteins are synthesized by Rough ER and ribosomes.  Water intake is regulated by vacuoles, which are present in a few animal cell types.

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