High School Biology : Cell Structures and Organelles

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #71 : Cell Biology

Which structures are responsible for breaking down proteins, nucleic acids, lipids, and carbohydrates?

Possible Answers:

Lysosomes

Cytoskeleton

Flagella

Mitochondria

Correct answer:

Lysosomes

Explanation:

Lysosomes are membrane-bound organelles that contain digestive enzymes which break down all four types of macromolecules. The mitochondria is responsible for synthesis of the majority of the cell's energy in the form of ATP. The cytoskeleton maintains cell shape and provides a "freeway" for transporting substances within the cell. Flagella are proteinaceous structures that aid in cell motility.

Example Question #72 : Cell Biology

Which is not part of the cell theory?

Possible Answers:

Every organism is composed of at least one cell

Cells are generated spontaneously

New cells only come from pre-existing live cells 

The smallest living things are cells

Correct answer:

Cells are generated spontaneously

Explanation:

Cell theory consists of three statements: all organisms considered to be alive are made of cells, the cell is the simplest unit of a living thing, and all cells arise from other live cells. Thus, the idea that cells arise spontaneously is not part of cell theory.

Example Question #73 : Cell Biology

In several important biochemical mechanisms, the cell's enzyme requires a particular enantiomer of a substrate in order to carry out the reaction. Why is this true?

Possible Answers:

Enzymes lower the activation energy of a biochemical reaction

Enzymes are highly dependent on temperature

Enzymes are highly specific in terms of shape in order to carry out a reaction

None of the other answer choices

The cell's enzymes have evolved to prefer a particular enantiomer becuase it is more abundant

Correct answer:

Enzymes are highly specific in terms of shape in order to carry out a reaction

Explanation:

This question requires the knowledge that several biological substrates come in enantiomer forms (think of them as your right and left hands). Effectively these molecules come in two mirror/opposite configurations. Having the right configuration or shape is crucial for enzymes to catalyze reactions due to highly shape-specific bnding sites on substrate molecules.  Thus, the correct answer to this qustion is "enzymes are highly specific on shape in order to carry out a reaction." The other answer choices, except "the cell has evolved to prefer a particular enantiomer becuase it is more abundant," do not allude to this underlying concept of  why cells need a particualr enantiomeritic form/shape in order to carry out a reaction and are not correct. Last, enantiomers typically appear in similar oncentrations due to equal potential energies; therefore, it is unlikely and incorrect to expect the cell to develop an evolutionary preference based upon abundance.   

Example Question #74 : Cell Biology

The central vacuole is not responsible for which of the following?

Possible Answers:

Storage of water

Cell rigidity

Aerobic respiration

Storage of waste

Digestion

Correct answer:

Aerobic respiration

Explanation:

The plant central vacuole is a membrane bound organelle containing water and other enzymes. The central vacuole functions as a storage space in the center of the plant cell, and is responsible for many functions including digestion, isolating harmful materials, maintaining internal hydrostatic pressure (turgor), storage of water and small molecules, cell rigidity, and more. Aerobic respiration occurs in the mitochondria, where:

Example Question #141 : High School Biology

Which of the following is found at the head of a sperm cell?

Possible Answers:

The tail

The terminal disc

The acrosome

A dense concentration of mitochondria

Correct answer:

The acrosome

Explanation:

The tail, terminal disc, and most mitochondria are found near the rear of the sperm cell (in order to facilitate movement). The acrosome is a cap-like organelle (derived from the Golgi apparatus) that develops over the anterior half of the head in the sperm cells of many animals. The acrosome contains digestive enzymes which allows the break down of the outer membrane of the ovum (zona pellucida). In short, the acrosome is located at the head of the sperm cell and allows penetration of the egg cell.

Example Question #76 : Cell Biology

What is the main function of lysosomes?

Possible Answers:

Digesting proteins and lipids

Synthesizing proteins

Sorting and shipping proteins

Producing messenger RNA

Correct answer:

Digesting proteins and lipids

Explanation:

Lysosomes serve as the "clean-up" crew in the cell, digesting excess proteins and lipids in the cell and breaking them down into smaller molecules.  Lysosomes do not produce messenger RNA, which is produced in transcription byDNA.  Ribosomes synthesize proteins, and the Golgi Apparatus sorts and ships proteins.

Example Question #77 : Cell Biology

A human sperm cell possesses a device that propels it forward known as a __________.

Possible Answers:

cilia

cytoplasm

flagellum

smooth endoplasmic reticulum

Correct answer:

flagellum

Explanation:

The flagellum (plural flagella) is the whip-like structure on the end of a human sperm cell that propels it forward.  Cilia are the hair-like structures on membranes on cells that aid in movement.  Smooth endoplasmic reticulum (ER) is the organelle involved in synthesizing lipids and detoxifying substances.  Cytoplasm is the jelly-like substance throughout the cell.

Example Question #78 : Cell Biology

Which of the following is not considered part of the eukaryotic endomembrane system?

Possible Answers:

Vesicle

Cell membrane

Endoplasmic reticulum

Mitochondria

Golgi body

Correct answer:

Mitochondria

Explanation:

The endomembrane system is a collection of membranes making up a cell that are connected either physically or via transport using vesicles. One of its main functions is to package and "ship" things made in the cell to other places in the organism, such as hormones like insulin. In order to do this, different organelles with different functions are necessary, just like there are different people with different jobs who make sure a package is mailed to the proper place.

Example Question #79 : Cell Biology

Where is ribosomal RNA formed?

Possible Answers:

Smooth endoplasmic reticulum

Golgi apparatus

Nucleolus

Rough endoplasmic reticulum

Mitochondria

Correct answer:

Nucleolus

Explanation:

The nucleolus is a specialized region found within the nucleus. It is responsible for synthesizing ribosomal RNA (rRNA), while transcription of messenger RNA (mRNA) and transfer RNA (tRNA) occurs in parts of the nucleus other than the nucleolus.

Example Question #1 : Cellular Differences

The shape of an animal cell is determined by which of the following?

Possible Answers:

Cytoskeleton

None of these answers

Plasma membrane

Cell wall

Cholesterol

Correct answer:

Cytoskeleton

Explanation:

The cytoskeletion determines cell shape. The cytoskeleton consists of three different types of filamentous proteins: microfilaments, intermediate filaments, and microtubules. Elements of the cytoskeleton can interact with the cell membrane and cell junctions to alter the cell's overall structure.

There are no cell walls in animal cells, although the cell wall does play a large part in determining cell shape in organisms that possess them (plants, bacteria, fungi).

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