Unit 2: Topic 1 - Cell Structure: Subcellular Components Flashcards
What is the main job of the ribosome?
Ribosomes synthesize proteins using amino acids, which are specified by an mRNA molecule.
How does the location of the ribosome impact its function?
Ribosomes can be located in one of two places: attached to the rough endoplasmic reticulum (RER), or free-floating in the cytoplasm. Ribosomes that are attached to the RER are signaled to do so by certain nucleotide sequences in an mRNA molecule. They then synthesize amino acid chains that enter into the lumen (of the RER) directly after their synthesis, which become proteins that are either secreted or incorporated into the cell membrane. Free-floating ribosomes, on the other hand, synthesize proteins that are used inside the cell.
What is the structure of a ribosome?
A) Flattened membranous sacs
B) Two subunits composed of RNA and proteins
C) A double membrane surrounding a matrix
D) A single membrane surrounding digestive enzymes
B) Two subunits composed of RNA and proteins
How do ribosomes provide evidence for common ancestry?
Since ribosomes are found in all living things, the existence of ribosomes suggests that all living organisms evolved from a common ancestor.
How are the structures of the Rough and Smooth Endoplasmic Reticulum similar?
The Rough and Smooth ER both have a lumen surrounded by a membrane. While the lumen may have different functions in the two different types of ERs, the structure is still the same– a liquidous compartment kept separate from the cytoplasm by the membrane surrounding it.
How does the phrase “structure determines function” apply to the two different types of Endoplasmic Reticulums?
The main difference in structure between the Rough and Smooth ERs is the ribosomes attached to the Rough ER (which aren’t present in the Smooth ER). The function of the Rough ER is to transport and package (package, in this context, means that the Rough ER chemically modifies the amino acid chains to give them a 3D structure and tag them for delivery to a particular location) proteins created by the ribosomes attached to it. The Smooth ER, on the other hand, does not have attached ribosomes, and instead has a variety of other functions. The functions of the Smooth ER include the detoxification of small molecules, glycogen degradation (in animals only), synthesis of lipids and steroids, and storage of calcium ions.
What is the structure of the Golgi Complex?
A) Flattened membranous sacs
B) A double membrane that surrounds the cell’s genetic material
C) A double membrane surrounding a matrix
D) A single membrane surrounding digestive enzymes
A) Flattened membranous sacs
These membranous sacs are called cisterna, and they each have their own lumen inside the membrane.
What role does the Golgi Complex play in the cell?
The Golgi Complex (also known as the Golgi Apparatus) is responsible for chemically modifying proteins before they get sent to their destination. This modification can include adding carbohydrates to certain proteins (so that those proteins are able to perform their function). Similarly to the Rough ER, the Golgi Complex also “packages” proteins to let the cell know where the intended location of the protein is.
What is the structure of the Mitochondria?
A) A single membrane surrounding a lumen
B) A double membrane that surrounds the cell’s genetic material
C) A double membrane surrounding a matrix
D) A single membrane surrounding digestive enzymes
C) A double membrane surrounding a matrix
The mitochondria consists of the mitochondrial matrix (which is a fluid-filled region similar to the lumen) surrounded by the smooth outer membrane and folded inner membane.
Explain the meaning of the phrase “the mitochondria is the power house of the cell.”
This phrase means that the mitochondria is the site of cellular respiration (most of the cell’s ATP is generated in the mitochondria). This relates to the structure of the mitochondria since the folds of the inner membrane serve the purpose of increasing surface area for the cellular respiration reactions to occur (which increases overall ATP output).
What is the structure of the lysosome?
A) A double membrane that surrounds the cell’s genetic material
B) A single membrane surrounding digestive enzymes
C) A single membrane surrounding a lumen
D) A large membranous sac
B) A single membrane surrounding digestive enzymes
The lysosome is an organelle composed of a single membrane surrounding a featureless interior that contains hydrolytic enzymes (these enyzmes break macromolecules down).
What is the general function of a lysosome?
In general, lysosomes are the site where cells hydrolyze (break down) macromolecules into their monomers. This organelle plays a big role in other processes as well, such as phagocytosis and autophagy. Autophagy is when the cell breaks down its own components (this process is triggered by the cell itself), and the lysosome is where this occurs. During the process of autophagy, the lysosome breaks down components of the cell, such as proteins and even whole organelles.
What role does the lysosome play in phagocytosis?
In the process of phagocytosis, the cell engulfs large materials from outside the cell through the formation of a pocket in the cell membrane. This pocket then pinches into the cell and forms a vesicle (a single membrane surrounding material that gets transported around the cell) containing the macromolecules from outside the cell, which is called a phagosome. The phagosome fuses with the lysosome to form the secondary lysosome, where hydrolysis of the materials from outside the cell occurs.
What is the structure of the vacuole?
A) A double membrane that surrounds the cell’s genetic material
B) A double membrane surrounding a matrix
C) Short cylinders of microtubules
D) A large membranous sac
D) A large membranous sac
The structure of vacuoles is simply a membrane surrounding material. The differences between vacuoles and vesicles are that vacuoles are generally larger than vesicles and that vacuoles do not fuse with the membranes of other cell components (while vesicles do).
What are some examples of the functions of vacuoles?
One extremely important use of the vacuole is the central vacuole in plants. This vacuole is very large (it can take up up to 90% of the plant cell) and it contains various materials, including water, pigment molecules, and sugars. The most important function this vacuole plays is maintaining the turgor pressure of the plant (this means that it maintains the structure of the cell, and the plant as a whole, by keeping it rigid), but it can also act as waste dump and storage region. Another example of vacuoles being used is the contractile vacuole. Contractile vacuoles are in protists, and the function of it is to regulate the amount of water in the cell through forcing excess water out.
