High School Biology : Understanding Specialized Cell Structures
Study concepts, example questions & explanations for High School Biology
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Example Questions
Example Question #77 : Cell Biology
The shape of an animal cell is determined by which of the following?
Plasma membrane
Cytoskeleton
None of these answers
Cell wall
Cholesterol
Cytoskeleton
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).
Example Question #151 : High School Biology
Which organelle works to synthesize an unstable form of energy?
None of the other answer choices is correct.
Rough endoplasmic reticulum
Mitochondria
Two of the other answer choices are correct.
Chloroplast
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 #2 : Understanding Specialized Cell Structures
The nucleolus __________.
is only found in prokaryotes
is a part of the nucleus responsible for assembling ribosomes
None of the other answer choices is true.
contains all the DNA of the cell
is found in prokaryotes and eukaryotes
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 #152 : High School Biology
Histones __________.
play a role in gene regulation
are protiens around which DNA coils
are only found in the nucleus
All of the answer choices are true.
are only found in eukaryotic cells
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 #153 : High School Biology
In which of the following organisms are vacuoles not usually found?
Plants
Mammals
Bacteria
Fungi
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.
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