can help right now Ryan K. 12. Through how many membranes would a molecule have
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can help right now Ryan K. 12. Through how many membranes would a molecule have to pass in going directly from: (3 pt s) A. the interior of the central vacuole to the cytoplasm B. the stroma of a chloroplast to the lumen of the SER C. matrix of the mitochondria to the outside of a cell D. the lumen of the lysosome to the outside of the cell E. the cystolic surface of the Golgi to the surface of a microtubule Questions 13-16 refer to the following This figure represents an experiment in which specific cells were incubated with radioactive, and traceable isotopes of amino acids for a brief period to establish a population of labeled proteins. Any labeled amino acids that were not incorporated into a protein were removed after 3 minutes. The dependent variable is, in effect, the amount of radioactivity detected in three cellular locations. Figure 1: rs Rough ER iolgi esicles Seerctory Vesicles 03 10 20 30 13. This type of experiment that allows for the labeling and suhsequent tracking of population of molecules is called a: experiment. (1pt) 14. In the graph below, draw the results you would expect if you tracked a Golgi-resident protein. Clearly draw the Rough ER data as a solid dark line, the Golgi data as a dashed line and the secretory vesicles as a dotted line, just as in the figure above. (2 Time af Chase imamites)Explanation / Answer
12. In eukaryotes, some of the organelles are bound by membranes.
A. Vacuoles are generally present in the plant cells. It is a membrane-bound organelle. Vacuolar membrane is called tonoplast and it encloses the fluid-filled cell sap. It is the cytoplasmic membrane of the vacuole that separates the vacuolar contents from the cell’s cytoplasm.
Hence, for a molecule to pass directly from the interior of the central vacuole to the cytoplasm, it has to pass through a single membrane called the tonoplast.
B. Chloroplasts are plant cell organelles which helps in photosynthesis. Chloroplasts are surrounded by two membranes. The stroma of a chloroplast is a fluid that surrounds the grana which consist of stacks of thylakoids.
Endoplasmic reticulum is a series of flattened sacs found in the cytoplasm. Smooth endoplasmic reticulum (SER) lacks ribosomes. A phospholipid membrane encloses the lumen (cisternal space) of the SER.
Hence, for a molecule to pass directly from the stroma of a chloroplast to the lumen of the SER, it has to pass through two membranes of chloroplast and the single membrane of SER. Therefore, molecules pass through 3 membranes when moving from the stroma to the lumen of the SER.
C. A mitochondrion consists of an outer and inner membrane composed of phospholipid layers and proteins. It encloses the cristae space and the matrix. Matrix forms the space enclosed by the inner membrane. These organelles are located in the cytoplasm.
Molecules pass from matrix of mitochondria into the cytoplasm before moving out of the cell.
Cytoplasm is enclosed in a thin semi-permeable membranous structure called the plasma membrane. It is made up of bilipid layer embedded with proteins and is referred to as unit membrane. Hence, the cytoplasmic membrane is a single membranous structure.
So, for a molecule to pass directly from matrix of the mitochondria to the outside of a cell, it has to pass though the inner and outer membrane of the mitochondria and the plasma membrane of the cell. Therefore, molecules pass through 3 membranes when moving from the matrix of the mitochondria to the outside of a cell.
D. Lysosome is a membrane-bound organelle, a type of vesicle consisting of enzymes, peptides, carbohydrates, lipids, etc. distributed in its lumen. The organelle is surrounded by a single membrane.
Molecules from the lumen of the lysosome move into the cytoplasm before travelling outside the cell.
Hence, for a molecule to pass directly from the lumen of the lysosome to the outside of the cell, it has to pass through the single membrane of the lysosome and the plasma membrane of the cell, which means it passes through two membranes.
E. Golgi apparatus is a membrane-bound organelle made up of several flattened sac-like membranes. It is responsible for transporting, modifying and packaging of proteins and lipids. It is made up of a single membrane.
Microtubules are hollow cylindrical structures found in the cytoplasm that give support and shape to the cell. They are components of cytoskeleton and are composed of protein tubulin.
Hence, for a molecule to pass directly from the cystolic surface of the Golgi to the surface of a microtubule, it has to pass through the single membrane of the Golgi body, which means it passes through only one membrane.
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