Biological Sciences Answer Key, Part 1

1. The correct answer for this particular question is choice "A" as metabolism is the process by which an organism produces and uses energy. The process of metabolism consists of a variety of chemical reactions that occur within an organism that each help the organism's body produce and use energy. This is actually an essential function of the body as it allows the organism's cells to adapt to their environment, grow, remain healthy, retain their structures, and reproduce. Metabolism actually consists of two primary types of processes, which are known as catabolism and anabolism. Catabolism refers to the process where the organism actually creates energy by breaking down food and converting that food into energy. Anabolism, on the other hand, refers to the process where the organism actually uses that energy to construct proteins and other cellular components that each cell needs in order to continue functioning.

2. The correct answer for this particular question is choice "C" as mitosis is the process by which a cell divides itself into two completely new, but identical cells. In other words, mitosis is one of the processes that a cell commonly uses in order to duplicate itself. Most cells reproduce by dividing themselves in order to create a completely new, but identical cell in addition to the original cell. Mitosis refers to when a cell creates this completely new, but identical cell by dividing the original cell's nucleus into two completely independent nucleoli. It is important to note that after the original cell divides, the nucleus of the original cell and the nucleus of the new cell each have an identical number of chromosomes and both cells each contain an identical number of cellular components surrounding the nucleus. It is also important to note that the process of mitosis does not actually complete the cell's division as another process known as cytokinesis begins near the end of the mitosis process to complete the division.

3. The correct answer for this particular question is choice "B" as meiosis is the process by which a cell divides itself into four completely new cells. Most cells reproduce by dividing themselves in order to create a completely new, but identical cell in addition to the original cell. However, meiosis actually refers to the process by which a cell divides its nucleus twice in order to create four completely new cells that are not the same as the original cell. During the first division, the original cell's nucleus will divide to create a new nucleus that is identical to the original nucleus with the same number of chromosomes as the original. After this division, the nucleus of the original cell and the nucleus of the new cell will actually divide again, but both cells will not be able to replicate their chromosomes. As a result, the two cells that are dividing will have to share their chromosomes with the newly forming cells, which will result in four cells that each have half of the chromosomes that the original cell possessed.

4. Meiosis and mitosis are both types of cell division, but the two processes are actually very different. Mitosis is the most common way for a cell to divide and it is a relatively simple process where the nucleus of a cell divides to create a completely new, but identical cell in addition to the first cell. Meiosis, on the other hand, even though it begins in much the same way as mitosis, is slightly more complex as the nucleus of the original parent cell and the nucleus of the newly formed cell actually divide again so there are four cells in total. However, the four cells are not identical to the original cell as the original cell and the newly formed cell cannot replicate their chromosomes during the second division and therefore need to share them. As a result, the primary difference between the two processes is simply that mitosis results in the formation of a new cell that is identical to the original cell while meiosis results in four cells that are completely different from the original.

5. Meiosis is actually an extremely important function for certain types of cells such as ova cells and sperm cells, as it can be an extremely important part of an animal's ability to sexually reproduce. This is because the process of meiosis allows for the creation of cells that have some of the genetic traits that the original cell possessed, but that are ultimately different from the original parent cell. Cells that are created through meiosis, also known as gametes, only have half the number of chromosomes as the parent cell originally had. This is actually extremely important, as it allows gamete cells the ability to fuse with other gamete cells, as long as they belong to the opposite gender, in order to create a new cell-known as a zygote-which contains a combination of the chromosomes from the two gamete cells.

6. The correct answer for this particular question is choice "B" as mitosis actually consists of five stages, which are prophase, metaphase, anaphase, telophase, and interphase occurring in that order. Choice "A" is incorrect, even though it lists all of the correct stages, as it lists the stages in alphabetical order rather than the order in which the stages occur. Choice "C" correctly lists the stages for the process of meiosis, but the question is looking for the stages of mitosis so choice "C" is also incorrect for this particular question. Choice "D" is actually incorrect because it lists four of the stages in the wrong order and it replaces the telophase with cytokinesis, which is actually a completely separate process involved with cell division rather than one of the phases of mitosis.

7. The process of mitosis consists of four primary stages, each of which consists of a different part of the process related to the cell dividing, and a fifth stage that describes the period of time when the cell is not dividing. Prophase is the first stage of mitosis, where some of the specific DNA and protein contained in the nucleus of the cell, known as chromatin, is formed into chromosomes. Metaphase is the second stage of mitosis, where the chromosomes formed during the prophase form a line across the center of the cell. Anaphase is the third stage of mitosis, where the chromosomes separate and each group of chromosomes moves to an opposite side of the cell. Telophase is the fourth stage of mitosis, where the chromosomes begin to form into two separate nuclei at opposite ends of the cell and the process of cytokinesis-which is actually a separate process from mitosis-begins to divide the new cell from the original cell. The fifth stage, known as Interphase, actually refers to the period when cell division is not taking place.

8. The correct answer for this particular question is choice "A," as fungi can be characterized as any organism that absorbs nutrients from its environment, that is motionless, and reproduces by spreading spores. Choice "B" is incorrect for this particular question because it describes members of the Plant Kingdom rather than members of the Fungi Kingdom. Choice "C" is incorrect because it describes members of the Animal Kingdom rather than members of the Fungi Kingdom. Finally, choice "D" is also incorrect because organisms not belonging to the Plant Kingdom or the Animal Kingdom may be fungi, but they may also be members of the Protist Kingdom, the Arachea Kingdom, or the Bacteria Kingdom.

9. The correct answer for this particular question is choice "D" as osmosis is the physical process by which a fluid, such as water, moves through a membrane. During osmosis, a fluid will move through a partially permeable membrane, or in other words, a membrane that allows certain things to pass through, but not others, from an area with a higher concentration of solvents to an area with a lower concentration of solvents. Usually, this movement will continue until the solvents on each side of the membrane reach a state of equilibrium, or in other words, until each side has an almost equal concentration of solvents. The process of osmosis is actually essential for the survival of plants as it allows plants to absorb water and other nutrients from the soil through their roots. Osmosis is also extremely important to animals as it is the primary way that fluid is moved from one cell to another within the organism.

10. The correct answer to this particular question is choice "C" as the cytoskeleton is a collection of filaments located within the cytoplasm that helps to defend the cell, maintain the shape of the cell, and allows the cell to move. In fact, there are several different types of filaments found in the cytoplasm of each cell and each type helps to perform some combination of these functions. In eukaryotic cells, the actin filaments, also known as microfilaments, and intermediate filaments both help to maintain the shape of the cell and help defend the cell from outside forces by resisting any tension that might cause the cell membrane to elongate and possibly rip apart. Microfilaments also allow the cell to create pseudopodia that help the cell to move. Microtubules allow cells to move, retain their shape, and defend themselves from outside dangers as well, by allowing the cell to form cilia and flagella, and by acting as a means of resisting compression that might cause the cell membrane to collapse.