Within the cell, what is the role of the endoplasmic reticulum (ER)?
The ER is involved in a variety of processes, with smooth ER and rough ER performing different functions. The smooth ER is involved in lipid anabolism and detoxification, while the rough ER, with its many ribosomes, is the site of protein translation.
Both types of ER help synthesize macromolecules and shuttle them to the Golgi apparatus to be secreted from the cell.
Key Terms
Within the cell, what is the role of the endoplasmic reticulum (ER)?
The ER is involved in a variety of processes, with smooth ER and rough ER performing different functions. The smooth ER is involve...
What biological products are synthesized in the rough endoplasmic reticulum?
proteins
These can include enzymes and peptide hormones, among other examples.
What is the cellular role of the Golgi apparatus?
It modifies molecules that arrive from the ER. It has the ability to break off into vesicles and can thus facilitate the exocytosis of these modifi...
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| Term | Definition |
|---|---|
Within the cell, what is the role of the endoplasmic reticulum (ER)? | The ER is involved in a variety of processes, with smooth ER and rough ER performing different functions. The smooth ER is involved in lipid anabolism and detoxification, while the rough ER, with its many ribosomes, is the site of protein translation. Both types of ER help synthesize macromolecules and shuttle them to the Golgi apparatus to be secreted from the cell. |
What biological products are synthesized in the rough endoplasmic reticulum? | proteins These can include enzymes and peptide hormones, among other examples. |
What biological products are synthesized in the smooth endoplasmic reticulum? | lipids These include steroid hormones and phospholipids, among other examples. |
What is the cellular role of the Golgi apparatus? | It modifies molecules that arrive from the ER. It has the ability to break off into vesicles and can thus facilitate the exocytosis of these modified products. |
What main cellular function is performed by the mitochondria? | They are involved in cellular metabolism, specifically the production of energy via aerobic respiration. In the mitochondria, the Krebs cycle produces electron carriers, while the electron transport chain facilitates the formation of a proton gradient. This gradient is used to produce ATP. |
What membranes and spaces are present in a mitochondrion? | It contains both an outer and an inner membrane. The intermembrane space is located between the two, while the mitochondrial matrix is the innermost space, bounded by the inner membrane. Both membranes are phospholipid bilayers. |
Binary fission is most relevant to the production of which organelle? | mitochondria Just like prokaryotic asexual reproduction, which produces identical daughter cells, this method of division yields identical organelles. |
Which organelle found in animal cells may have arisen as a result of mutualism? | Mitochondria may have evolved from a symbiotic relationship between small bacteria and larger cells. This is known as the endosymbiotic theory. Like all instances of mutualism, this situation is thought to have provided benefits to both organisms. The smaller bacterium was given a livable environment while providing energy for the larger host. |
What is the cellular role of lysosomes? | They break down engulfed pathogens, nutrient molecules, and components of the cell itself that are no longer functional. Like the stomach, a lysosome contains enzymes and an acidic interior. |
What are peroxisomes, and what cellular function do they perform? | They are small membrane-bound organelles that contain enzymes. They function in fatty acid breakdown, detoxification, and facilitation of the pentose phosphate pathway. Peroxisomes are named for hydrogen peroxide (H2O2), which can be both formed and broken down within the organelle. This is important because H2O2 is a poisonous radical initiator. |
Define: cytoskeleton | A structural web of protein that can change shape to perform a variety of cellular processes. The prefix "cyto-" means "cell," so the cytoskeleton is the "cell's skeleton." |
What main functions are executed by the cytoskeleton? |
Cytoskeletal proteins have the unusual ability to self-assemble into larger units, and can thus change shape based on the cell's needs. |
Name the three primary, protein-based components of the cytoskeleton. | microtubules intermediate filaments microfilaments |
Describe the structural role of microtubules. | They are thick, hollow tubulin polymers. Specifically, units of alpha- and beta-tubulin dimerize, and many of these dimers come together to form a microtubule. Microtubules form the spindle apparatus, an essential component of cell division. They also comprise cilia and flagella and perform various other functions. |
Describe the structure and role of microfilaments. | They are linear, thin filaments composed of many actin monomers. Microfilaments are thinner than either microtubules or intermediate filaments. As actin polymers, microfilaments play a crucial role in muscle contraction and also facilitate cytokinesis. |
Describe the structure and role of intermediate filaments. | They are fibers composed of various cell-specific proteins; many are composed of keratin. Intermediate filaments are thicker than microfilaments but thinner than microtubules. These fibers contribute to the rigidity of the cell and also form desmosomes, a type of cellular junction. |
What term refers to the tubular structure used for locomotion in some bacteria? | flagellum |
How do eukaryotic and prokaryotic flagella differ in their protein composition? |
Tubulin is the protein subunit of microtubules. Specifically, each eukaryotic flagellum consists of nine pairs of microtubules surrounding two individual ones. |
What structural and functional differences exist between cilia and flagella? |
In eukaryotes, both cilia and flagella have a 9+2 method of organization. This consists of 9 microtubule pairs arranged in a circle surrounding 2 single microtubules. |
Which organelles are membrane-bound? |
In plants, chloroplasts and vacuoles fall into this category as well. Ribosomes, on the other hand, are not membrane-bound; while some are attached to the ER, they are not surrounded by membranes of their own. |