NCLEX : Cell Biology

Study concepts, example questions & explanations for NCLEX

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Example Questions

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Example Question #420 : Nclex

What organelle is considered to be the "powerhouse of the cell," due to it's role in production of ATP?

Possible Answers:

The rough endoplasmic reticulum

The Golgi apparatus

Mitochondria

The nucleus

Correct answer:

Mitochondria

Explanation:

Mitochondria are often called "the powerhouse of the cell" because they produce ATP, the body's most basic unit of energy. The nucleus houses the cell's DNA, the rough endoplasmic reticulum is the site of cellular protein manufacturing, and the Golgi apparatus packages protein manufactured in the cell for release and transport to the rest of the body. 

Example Question #1 : Cell Biology

Which of the following is not a function of the cell membrane?

Possible Answers:

Anchors the cytoskeleton to hold the shape of the cell

Regulates passage of substances into and out of the cell

Synthesize proteins

Attaches to the extracellular matrix and other cells to create tissues

Correct answer:

Synthesize proteins

Explanation:

The cell membrane has many purposes. It anchors the cytoskeleton to give the cell shape and structure. It houses proteins that both interact with signaling molecules from outside the cell and communicate with secondary messengers within the cell. It facilitates the absorption and release of electrolytes, water, and vesicles carrying proteins or other molecules. It forms junctions with other cells and connects the cell to the extracellular matrix.

One thing the cell membrane does not do, however, is act as a site of protein synthesis. That occurs primarily in the rough endoplasmic reticulum or on ribosomes in the cytoplasm.

Example Question #2 : Cell Biology

Which organelle is responsible for synthesis of lipids within the cell?

Possible Answers:

The nucleus

The mitochondria

The smooth endoplasmic reticulum (ER)

The Golgi apparatus

Correct answer:

The smooth endoplasmic reticulum (ER)

Explanation:

The majority of lipid production within the cell occurs within the smooth endoplasmic reticulum. It is also the site of production of steroids and phospholipids. The Golgi apparatus is responsible for packaging of cell products for transport outside of the cell. The mitochondria produce ATP, and the nucleus houses the DNA.

Example Question #3 : Cell Biology

Which of the following organelles is responsible for cellular respiration?

Possible Answers:

The centrioles

The ribosomes

The mitochondria

The peroxisomes

Correct answer:

The mitochondria

Explanation:

Aerobic cellular respiration occurs exclusively in the mitochondria. These organelles are present in greater number in cells that require a large supply of ATP, such as striated muscle cells, liver cells, and sperm cells. 

Example Question #4 : Cell Biology

The __________ makes up the structural framework of the cell.

Possible Answers:

Cytoskeleton

Nucleolus

Cytoplasm

Rough endoplasmic reticulum

Correct answer:

Cytoskeleton

Explanation:

The framework of the cell is make up by the cytoskeleton. The cytoskeleton gives the cell both shape and structure, and allows the cell to attach to extracellular connective tissue in order to form tissue types. There are three major fibers that make up cytoskeleton - microfilaments (actin), intermediate filaments, and microtubules.

Example Question #5 : Cell Biology

What role does cholesterol play in the cell membrane?

Possible Answers:

Production of steroids

Fluidity and stabilization of phospholipids 

Energy production

Detoxification

Correct answer:

Fluidity and stabilization of phospholipids 

Explanation:

Cholesterol is a vital component of the cellular membrane. It maintains both the fluidity and structural integrity of the cell. While cholesterol is an integral component of steroid production, this occurs outside of the cell membrane. Cholesterol does not play a significant role in cellular energy production or cell membrane detoxification.

Example Question #6 : Cell Biology

All of the cells of the human body except sex cells and undifferentiated stem cells are termed __________ cells.

Possible Answers:

Gamete

Somatic

Chromatic

Eukaryotic

Correct answer:

Somatic

Explanation:

All of the cells of the human body except sex cells are termed somatic cells. These are diploid cells, meaning that they contain two homologous copies of each chromosome. Sex cells (eggs and sperm) are haploid cells, containing just one set of chromosomes in each cell. All human cells are eukaryotic, because they contain a nucleus and organelles within a cellular membrane.

Example Question #7 : Cell Biology

Which of the following organelles is responsible for protein synthesis?

Possible Answers:

The nucleus

Ribosomes

Lysosomes

The smooth endoplasmic reticulum

Correct answer:

Ribosomes

Explanation:

While the nucleus houses the DNA and plays an integral role in the transcription of genetic code in order to produce specific proteins, actual protein synthesis is carried out by the ribosomes. These organelles consist of two subunits and are either independent in the cytoplasm of the cell or housed in the rough endoplasmic reticulum. Note that ribosomes can be in the cytoplasm or on the endoplasmic reticulum, hence making it rough.

Example Question #8 : Cell Biology

A hypertonic IV would cause some amount of __________ of red blood cells as water moved out of the cell across the osmotic gradient.

Possible Answers:

Crenation

A hypertonic IV would not affect blood cells

Lysing

Saturation

Correct answer:

Crenation

Explanation:

A hypertonic solution, or one which contains solutes in higher concentration than blood cells, would cause water to leave the red blood cell across the osmotic gradient. This causes a reversible crumpling or shriveling of the cell, termed crenation. A cell in a hypotonic solution, wherein the cell itself contained a higher level of solutes than the fluid, would take on water, potentially causing the cell to lyse (burst). 

Example Question #9 : Cell Biology

Ribosomal subunits are manufactured by what organelle?

Possible Answers:

Rough endoplasmic reticulum (RER)

Nucleus

Smooth endoplasmic reticulum (SER)

Nucleolus

Correct answer:

Nucleolus

Explanation:

Ribosomal subunits are manufactured by the nucleolus, which is contained within the nucleus. It's primary function is the production and assembly of ribosome subunits. The RER houses ribosomes for protein manufacture. The SER does not take part in ribosome production or functioning. Note that ribosomes are composed of rRNA and protein. Proteins are translated on ribosomes in the cytoplasm.

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