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Example Questions
Example Question #2 : Understanding Specialized Cell Structures
Which organelle works to synthesize an unstable form of energy?
Two of the other answer choices are correct.
Chloroplast
None of the other answer choices is correct.
Mitochondria
Rough endoplasmic reticulum
Two of the other answer choices are correct.
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 #3 : Understanding Specialized Cell Structures
The nucleolus __________.
is a part of the nucleus responsible for assembling ribosomes
contains all the DNA of the cell
is only found in prokaryotes
is found in prokaryotes and eukaryotes
None of the other answer choices is true.
is a part of the nucleus responsible for assembling ribosomes
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 #4 : Understanding Specialized Cell Structures
Histones __________.
are only found in the nucleus
All of the answer choices are true.
are protiens around which DNA coils
are only found in eukaryotic cells
play a role in gene regulation
All of the answer choices are true.
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 #5 : Understanding Specialized Cell Structures
In which of the following organisms are vacuoles not usually found?
Fungi
Mammals
Bacteria
Plants
Mammals
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?
Nuclear envelope
Cytoplasm
Plasma membrane
Nucleoid
Ribosomes
Nuclear envelope
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 #2 : Cellular Differences
Which of the following cellular structures can be found in prokaryotes?
Chloroplasts
Ribosomes
Nucleus
Mitochondria
Ribosomes
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 #3 : Cellular Differences
Which structures are found in both prokaryotic and eukaryotic cells?
Cell membrane, nucleus, ribosomes
Cell wall, circular chromosome, RNA
Cell membrane, DNA, ribosomes
Cell membrane, DNA, mitochondria
Cell membrane, DNA, ribosomes
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 #82 : Cell Structures And Organelles
Which of the following statements is false?
Prokaryotes are smaller in size that eukaryotes
Prokaryotes and eukaryotes have identical ribosomes
Prokaryotes lack a nucleus
Prokaryotes do not undergo meiosis
Prokaryotes do not have membrane-enclosed organelles
Prokaryotes and eukaryotes have identical ribosomes
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 #4 : Understanding Prokaryotic Cell Differences
Which of the following statements is false with regard to prokaryotic cells?
Prokaryotic cells have nuclei
Prokaryotic cells have cell walls
Prokaryotic cells have DNA
Prokaryotic cells have ribosomes
Prokaryotic cells have nuclei
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 #1 : Understanding Prokaryotic Cell Differences
Which of the following is not present in eukaryotes but is present in prokaryotes?
Ribosomes
Plasma membrane
Cytosol
None of the other answer choices
Cell wall
None of the other answer choices
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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