High School Biology : Cell Structures and Organelles

Study concepts, example questions & explanations for High School Biology

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Example Questions

Example Question #1 : Cellular Differences

Which organelle works to synthesize an unstable form of energy?

Possible Answers:

Rough endoplasmic reticulum

None of the other answer choices is correct.

Mitochondria

Two of the other answer choices are correct.

Chloroplast

Correct answer:

Two of the other answer choices are correct.

Explanation:

The unstable form of energy that is syntheisized refers to ATP. ATP is an unstable; its three phosphate groups are all negatively charged and repel one another. Remember that BOTH the mitochondria and chloroplast participate in ATP synthesis via chemiosmosis; however, only the chloroplast participates in glucose synthesis via photosynthesis. Note that glucose is a stable form of energy and is not readily usable until it is broken down in the process known as glycolysis.

Example Question #81 : Cell Structures And Organelles

The nucleolus __________.

Possible Answers:

is only found in prokaryotes

contains all the DNA of the cell

None of the other answer choices is true.

is a part of the nucleus responsible for assembling ribosomes

is found in prokaryotes and eukaryotes

Correct answer:

is a part of the nucleus responsible for assembling ribosomes

Explanation:

The nucleolus is a subdivision of the nucleus; thus, it is only found in eukaryotes. It is the site of ribosome assembly. The nucleolus is made of RNA and proteins.

Example Question #1 : Understanding Specialized Cell Structures

Histones __________.

Possible Answers:

are protiens around which DNA coils

are only found in eukaryotic cells

are only found in the nucleus

All of the answer choices are true.

play a role in gene regulation

Correct answer:

All of the answer choices are true.

Explanation:

Histones are proteins found in the nucleus of eukaryotic cells. DNA wraps itself around histones to further condense. Also, depending on how tightly the DNA is wrapped around the histones, it may or may not be availible for activity (e.g. replication or transcription). Cells modify the interaction between DNA and histones around certain genes under certain conditions to make those genes available or unavailable as needed.

Example Question #1 : Cellular Differences

In which of the following organisms are vacuoles not usually found?

Possible Answers:

Bacteria

Mammals

Fungi

Plants

Correct answer:

Mammals

Explanation:

Vacuoles are membrane-bound structures that are found in bacterial, plant, fungal, and occasionally, animal cells. Vacuoles function in storage of water and waste and in maintenance of turgor pressure in plants. 

Example Question #81 : Cell Structures And Organelles

Which of the following structures is not found in prokaryotic cells?

Possible Answers:

Plasma membrane

Nucleoid

Ribosomes

Nuclear envelope

Cytoplasm

Correct answer:

Nuclear envelope

Explanation:

Prokaryotic cells are defined as cells that lack membrane-bound organelles, such as the nucleus. Prokaryotic cells still have DNA as their genetic material, however it is located in the cytoplasm in a circular structure known as the nucleoid. The nucleoid is unique to prokaryotes because it lacks a nuclear envelope.

Prokaryotic cells have cytoplasm contained inside of a plasma membrane, and often a cell wall. They also have ribosomes in the cytoplasm to carry out protein synthesis.

Eukaryotes are much more complex and have numerous organelles, including the endoplasmic reticulum, Gogli apparatus, lysosomes, and mitochondria.

Example Question #1 : Understanding Prokaryotic Cell Differences

Which of the following cellular structures can be found in prokaryotes?

Possible Answers:

Ribosomes

Chloroplasts

Nucleus

Mitochondria

Correct answer:

Ribosomes

Explanation:

Much like eukaryotes, prokaryotes are capable of translating their own proteins. Prokaryotes follow the same central dogma as eukaryotic cells, using DNA to transcribe mRNA and using mRNA and ribosomes to build proteins from amino acids. Ribosomes are primarily composed of rRNA, and are not bound by a membrane.

Prokaryotes lack a nucleus, as well as complex membrane-bound organelles such as mitochondria and chloroplasts.

Example Question #2 : Understanding Prokaryotic Cell Differences

Which structures are found in both prokaryotic and eukaryotic cells?

Possible Answers:

Cell membrane, nucleus, ribosomes

Cell membrane, DNA, mitochondria

Cell membrane, DNA, ribosomes

Cell wall, circular chromosome, RNA

Correct answer:

Cell membrane, DNA, ribosomes

Explanation:

The primary difference between prokaryotes and eukaryotes is the presence of membrane-bound organelles. Prokaryotes lack any membrane-bound organelles, including a nucleus, while eukaryotes possess these structures. All cell types have an outer cell membrane, which contains the cytosol, DNA, and ribosomes. Ribosomes are not bound by membranes, and are essential for translating proteins. Both prokaryotes and eukaryotes use transcription to convert DNA to RNA and translation to convert RNA to proteins.

Mitochondria are only found in eukaryotes and are used to produce ATP via oxidative phosphorylation. A circular chromosome is characteristic of prokaryotes, since they lack a nucleus. Both prokaryotes and eukaryotes can have cell walls.

Example Question #2 : Understanding Prokaryotic Cell Differences

Which of the following statements is false?

Possible Answers:

Prokaryotes do not undergo meiosis

Prokaryotes do not have membrane-enclosed organelles

Prokaryotes and eukaryotes have identical ribosomes

Prokaryotes are smaller in size that eukaryotes

Prokaryotes lack a nucleus

Correct answer:

Prokaryotes and eukaryotes have identical ribosomes

Explanation:

Prokaryotes are much smaller in size than eukaryotes. Eukaryotes are known for their membrane-bound organelles, such as the mitochondria, vesicles, and vacuoles. Prokaryotes do not have membrane-bound organelles. Some eukaryotic organisms go through the process of meiosis in order to produce variation for sexual reproduction.

Prokaryotes undergo a different process to reproduce asexually, called binary fission. The DNA of prokaryotes are contained in a circular chromosome called a nucleoid, which is replicated completely. The cell then splits in two, with each having an exact copy of the same plasmid. Prokaryotes lack a nucleus by definition. 

The prokaryotic ribosome is smaller, at 70S, while the eukaryotic ribosome is larger, at 80S. The ribosomes also contain different sized subunits. Prokaryotic ribosomes are made of a 30S and 50S subunit to form the full 70S structure. Eukaryotic ribosomes are made of a 40S and 60S subunit to form the full 80S ribosome.

Example Question #3 : Understanding Prokaryotic Cell Differences

Which of the following statements is false with regard to prokaryotic cells?

Possible Answers:

Prokaryotic cells have cell walls

Prokaryotic cells have ribosomes

Prokaryotic cells have DNA

Prokaryotic cells have nuclei

Correct answer:

Prokaryotic cells have nuclei

Explanation:

Eukaryotes and prokaryotes split during evolution when eukaryotic cells adapted membrane-bound organelles. These organelles include the endoplasmic reticulum, mitochondria, chloroplasts, Golgi apparatus, and nucleus (among others). Prokaryotes lack all of these structures.

All cells, however, contain DNA and ribosomes in order to synthesize proteins and maintain metabolic processes. Ribosomes are not bound by membranes, and are instead made of ribosomal RNA (rRNA) and proteins. Both prokaryotes and eukaryotes can have cell walls, though the structure and composition of the cell wall can vary.

Example Question #83 : Cell Biology

Which of the following is not present in eukaryotes but is present in prokaryotes?

Possible Answers:

Ribosomes

None of the other answer choices

Cytosol

Cell wall

Plasma membrane

Correct answer:

None of the other answer choices

Explanation:

It is important to remember that there are multiple types of eukaryotes. All eukaryotes have a plasma membrane, ribosomes, and cytosol since these are fundamental organelles necessary for basic cellular function. Plant and fungi cells, which are eukaryotic, also possess cell walls. Thus, the answer is "none of the other answer choices."

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