Answers to Practice Items

Transcription

1 nswers to Practice Items Question 1 TEKS 4 This cell is a plant cell. It is a type of eukaryotic cell. This cell is an animal cell. It is a type of eukaryotic cell. This is a bacterium cell. This cell is prokaryotic. This is the correct answer. Some of these cells are eukaryotic, so this answer is incorrect. Question 2 TEKS 4 Some bacteria have flagella, and since bacteria are generally prokaryotic, this is not the correct answer. N is the hereditary material. ll organisms, prokaryotic and eukaryotic, contain N. Some bacteria have cell walls, and since bacteria are generally prokaryotic, this is not the correct answer. The distinguishing characteristic of eukaryotes over prokaryotes is that eukaryotes have a nuclear membrane. This is the correct answer. Question 3 TEKS 4 This answer is not likely correct because the cell observed has a nucleus, and bacteria are generally prokaryotes. The presence of a nucleus means that this cell is not prokaryotic. Plant cells have cell walls and chloroplasts. ell Y is a plant cell, but ell X is not. This is the correct answer. The presence of a nucleus and the lack of a cell wall and chloroplasts means this is most likely an animal cell. Question 4 TEKS 4 Prokaryotic cells are excellent growers and reproducers. This is a direct result of their simplicity. Prokaryotic cells respond to their environment by regulating cell functions and growth. In inhospitable environments, prokaryotic cells do neither. The simplicity of prokaryotic cells prevents them from specialization and differentiation. This is the correct answer. Many prokaryotes are equipped with flagella and can move freely in the environment.

2 Question 5 TEKS 4 ellular nutrients are produced by enzymes and various organelles. side from containing the cell, cell membranes also help the cell maintain homeostasis through the regulation of materials taken in and out of cells through various processes. This is the correct answer. hemicals are neutralized by enzymes throughout the cell. ellular wastes are preserved in vacuoles. Question 6 TEKS 4 The question states that the selectively permeable membrane is permeable to both types of solutes. Therefore, both molecules will move to reach equilibrium. This is the correct answer. The drive is for molecules to distribute themselves at equal concentration across the membrane. ll of a molecule on one side of the membrane is not likely to take place. The drive is for molecules to distribute themselves at equal concentration across the membrane. ll of a molecule on one side of the membrane is not likely to take place. Systems want to establish equilibrium by making sure the concentration of particles is the same on both sides of a membrane. Since all of particle is on one side of the membrane initially, some of the particle must migrate to the other side of the barrier to establish equilibrium. Question 7 TEKS 4 Isotonic solutions are solutions in which the cells are in equilibrium with their surrounding environments. iagram, which shows water moving both into and out of cells, is a diagram of an isotonic solution. Hypertonic solutions are more concentrated in solute than the cells. This has the effect of drawing water out of cells. iagram shows cells in a hypertonic solution. Hypotonic solutions are less concentrated in solute than the cells. The result are cells which draw water into them in an effort to dilute their concentrations to the surrounding environment. iagram shows cells in a hypotonic environment. This is the correct answer. Hydrotonic is not a word.

3 Question 8 TEKS 4 The difference in mass of the eggs is caused by water moving into or out of eggs. In this answer choice, the opposite is true. orn syrup must be hypertonic because it drew water out of the egg, and distilled water must be hypotonic because the egg drew water into it. This is the correct answer. See the reasoning in the above answer choice. It is correct that corn syrup is a hypertonic solution, but distilled water is not an isotonic solution. If an egg were in an isotonic solution, the egg would neither absorb nor lose water. gain, neither solution is isotonic for the reasons outlined in the other answer choices. Question 9 TEKS 4 Water would move into a cell if the surrounding concentration of solute outside the cell were less than the concentration of solute inside the cell (a hypotonic solution). However, protein is not the only factor of water movement into or out of the cell. Other solutes, such as salt and sugar, are more determinable of osmotic movement. Therefore, another answer is a better choice. 95% water inside the cell means 5% solute inside the cell. 90% water outside the cell means 10% solute outside the cell. In this case, a hypertonic solution is described, which would draw water out of the cell. In this case, there is 10% solute inside the cell and 5% solute outside the cell. This means that the water will want to move into the cell to decrease the solute concentration inside the cell in an effort to make the solute concentration equal on both sides. Since this is the case with this answer choice, this is the correct answer. gain, protein is not the determining osmotic factor. You should be looking to the concentrations of salt, sugar, and other solutes. In any case, this concentration gradient is indicative of a hypertonic solution, which would draw water out of the cell. Question 10 TEKS 4 Reading the passage before the question, it clearly states that paramecia live in a hypotonic environment in which water diffuses into the cell. This is the correct answer. The passage before clearly states that water diffuses into the cell in a hypotonic environment. The passage states that water, not salt, is pumped out of the cell by the contractile vacuole. The passage states that water, not salt, is pumped out of, not into, the cell by the contractile vacuole.

4 Question 11 TEKS 4 The diagram shows the cell actively engulfing the bacteria into the cell. This is active transport; however, the bacteria is going into the cell. Exocytosis describes materials being ejected from cells. Facilitated diffusion moves material through proteins embedded in the membrane. The diagram clearly shows a part of the cell surrounding the bacteria. This is the correct answer. This is active transport since the cell takes action to bring something into the cell, and it s endocytosis since the bacteria are going into the white blood cell. iffusion is movement across the membrane with no change of shape and no active effort. Question 12 TEKS 4 If this were respiration, carbon dioxide would be shown to leave the leaf, not enter it. This shows photosynthesis since water and carbon dioxide are entering the leaf and oxygen is being produced. Since oxygen leaves the leaf, this is also an example of excretion. This is the correct answer. igestion is the processing of food and the absorption of nutrients. Recycling is the reuse of materials within the system. irculation is the movement of materials through a system. oordination requires different parts of a process occurring in different parts of an organism to create one product. Question 13 TEKS 4 ellular respiration occurs in all cells, even in those which produce their own food in photosynthesis. Respiration converts the chemical energy stored in glucose into a more useable form for cellular processes, called TP. This is the correct answer. Photosynthesis uses carbon dioxide and forms oxygen. Photosynthesis stores energy in food (glucose) molecules. Question 14 TEKS 4 mitochondrion is where cellular respiration takes place. Glucose would enter a mitochondrion. This is the correct answer. arbon dioxide would leave a mitochondrion as a result of cellular respiration. Oxygen would enter a mitochondrion as a necessary ingredient of cellular respiration. N neither enters nor leaves a mitochondrion and is neither a reactant nor a product of cellular respiration.

5 Question 15 TEKS 4 Respiration would give off carbon dioxide and require oxygen. dditionally, it would release energy instead of drawing it from the sun. This is the correct answer. Photosynthesis draws in carbon dioxide, releases oxygen, and requires energy from the sun. Solar energy is energy that comes from the sun. While this process uses solar energy, it converts carbon dioxide into oxygen. Respiration converts oxygen into carbon dioxide. Question 16 TEKS 4 ellular respiration converts chemical energy from glucose into the chemical energy of TP, which is more usable for cellular processes. This is the correct answer. ellular reproduction uses the energy of TP, but it doesn t produce TP. iffusion is a process of moving materials across the cell membrane which does not require the use of TP (nor does it produce TP). igestion results from the interaction of enzymes in the digestive tract and does not require the use of TP (nor does it produce TP). Question 17 TEKS 4 Oxygen is released by photosynthesis, which occurs in plants. Protein synthesis is a form of dehydration synthesis, which produces water. Glucose would be soluble in water, not a gas. dditionally, the gas produced by photosynthesis is oxygen. Starch is a polymer of glucose molecules, which is how some cells in the body store energy. This is not the correct answer. ellular respiration produces carbon dioxide and TP from glucose and oxygen. Substance X is carbon dioxide. This is the correct answer. Question 18 TEKS 5 Muscles provide movement and action. This requires a lot of energy, which is what mitochondria are able to provide. Protein synthesis occurs through other processes. Since muscles provide movement and action and that requires a lot of energy, a logical conclusion is that muscle cells contain a higher percentage of mitochondria. This is the correct answer. Water and nutrients are stored in vacuoles, not mitochondria. Light energy is converted into carbohydrates by chloroplasts, not mitochondria. hloroplasts are only in plant cells.

6 Question 19 TEKS 5 The function of chloroplasts is to convert light energy into carbohydrates (sugars). This is the correct answer. Energy is provided in cells by mitochondria. Water and nutrients are stored in vacuoles. Proteins are synthesized by ribosomes. Question 20 TEKS 5 The integumentary system is your skin. Epidermal tissue comprises the integumentary system. This is the correct answer. Vascular tissue would transport materials to different parts of an organism. Plant ground tissue provides structure and support for plants, stores nutrients, and provides a host of other functions. These cells are not on the outside of the cell. Meristematic cells are undifferentiated cells where plant growth takes place. Question 21 TEKS 9 iagram shows photosynthesis. This reaction shows respiration, except energy is in the wrong place. This is the correct reaction that describes the overall process of photosynthesis. This is the correct reaction for cellular respiration, not photosynthesis. This reaction happens in iagram. This is the reaction for cellular respiration, except energy is in the wrong place. Question 22 TEKS 9 Hormones are synthesized by enzymes in some specialized cells. hlorophyll a and chlorophyll b are the catalysts for photosynthesis. They are not used in cellular respiration. TP is synthesized from P during cellular respiration, but TP and P are not involved in photosynthesis. Glucose and oxygen are the missing reactants of respiration and products of photosynthesis missing from the diagram. Question 23 TEKS 9 escription describes cellular respiration, which occurs in all cells. escription describes photosynthesis, which occurs only in plant cells. ellular respiration (escription ) occurs in both plant and animal cells. This is the correct answer since cellular respiration (escription ) occurs in all cells. ellular respiration (escription ) occurs in plant cells, too.

7 Question 24 TEKS 9 The products of photosynthesis are the reactants of respiration. They don t stop it! The products of photosynthesis are the reactants of respiration. The products of respiration are the reactants of photosynthesis. The reactants of photosynthesis are the products of respiration. This is the correct answer.