Given these characteristics of life, which of the following objects is considered a living organism? W. X. Y. Z.

Transcription

1 Cell Structure and Organization 1. All living things must possess certain characteristics. They are all composed of one or more cells. They can grow, reproduce, and pass their genes on to their offspring. They can respond and adapt to their environment, maintain homeostasis, and evolve. Given these characteristics of life, which of the following objects is considered a living organism? W. X. Y. Z. X W C. Y D. Z 2. Prokaryotic and eukaryotic cells have many differences, but they also share some common features. Which of the following may be found in either type of cell? cell walls nuclei C. mitochondria D. Golgi bodies

2 3. All living organisms share many characteristics necessary for life. For example, all organisms, including both prokaryotic and eukaryotic, must obtain and use energy for life processes. have cells arranged into complex organ structures. can sexually reproduce to produce unique offspring. C. can use abiotic factors to make their own food. D. 4. Both eukaryotic cells and prokaryotic cells possess DNA and engage in genetic processes. Which of the following is true of their cellular genetics? Prokaryotic DNA cannot be translated into proteins because of the lack of a nucleus. Eukaryotic DNA is linear, whereas most prokaryotic DNA is circular. Eukaryotic and prokaryotic DNA use different genetic codes (i.e. nucleotides). C. Eukaryotic cells generally require fewer genes to operate than prokaryotic cells. D. 5. Mitosis is the cellular reproduction process which produces two genetically identical daughter cells from one parent cell. Mitosis occurs all over our bodies, replacing dead cells and keeping tissues and organs functioning properly. Mitosis cannot occur until the genetic material inside of a cell has been copied. Where in the cell is this genetic material located? in the cell membrane in the vacuole C. in the Golgi complex D. in the nucleus

3 6. How does the size of a eukaryotic organism normally compare to the size of a prokaryotic organism? Eukaryotes and prokaryotes are both usually very small organisms. Eukaryotes and prokaryotes are both usually very large organisms. Eukaryotes are usually much smaller than prokaryotes. C. Eukaryotes are usually much larger than prokaryotes. D. 7. The diagrams below display different types of cells as viewed by a microscope under low magnification. These diagrams demonstrate how cells can be differentiated by their sizes and densities. means of replication. C. modes of locomotion. D. cell structures. 8. Which of the following describes the fundamental difference between prokaryotic and eukaryotic cells? Prokaryotic cells do not have a true nucleus or membrane-bound organelles. Eukaryotic cells are the only type of cells that can possess a cell wall. Prokaryotic cells are all viruses and rely on the infection of a host cell to replicate. C. Eukaryotic cells are only found in protists, bacteria, and viruses. D. 9. are RNA and protein complexes that are found in all cells. These complexes help cells during protein translation by joining amino acids together to form polypeptides. Vacuoles Ribosomes C. Chloroplasts

4 D. Lysosomes 10. Cell theory states that cells are the basic unit of structure and function in living things. all living things are composed of cells. C. new cells are produced by existing cells. D. All of these answers are correct. 11. Which of the following is true of prokaryotic cells? They tend to be large and complex in comparison to eukaryotic cells. They function as individual organisms. They contain nuclei and other membrane-bound organelles. C. They may be found in unicellular or multicellular organisms. D. 12. Within eukaryotic cells, there is an intricate network of with unique functions. organelles mitochondria C. chromosomes D. lysosomes 13. All living organisms use energy. They also grow and reproduce. What is another characteristic of all living organisms? All living organisms can produce glucose through photosynthesis. All living organisms must consume food in order to acquire nutrition. C. All living organisms are composed of one or more cells. D. All living organisms consist of many cells with specialized organelles. 14. Which of the following organelles stores information and is considered the control center of the cell? Golgi complex nucleus C. endoplasmic reticulum D. mitochondrion

5 15. The life forms exhibiting the simplest cellular structure are. organelles eukaryotes C. proteins D. prokaryotes 16. Cellular organelles have different structures. Mitochondria, for example, possess highly folded inner membranes in addition to their outer membranes. Vacuoles, on the other hand, are only surrounded by a single-layer membrane; they do not have an inner membrane.why do cellular organelles have different structures? The structures of cellular organelles are related to their functions. Organelles that are less important to the cell have less sophisticated structures. The structure of a cellular organelle mimics the appearance of the organism. C. All organelles in a particular organism are identical, but organelles in different organisms are unique. D. 17. Technology Enhanced Questions are not available in Word format. 18. are the basic building blocks of all living organisms. Organs Tissues C. Cells D. Organ systems 19. Multicellular organisms are composed of a variety of living structures that are formed when cells differentiate. How could the living structure pictured below be classified?

6 organ cell C. tissue D. organism

7 20. Which of the following organelles plays a role in the disposal of cellular waste and is responsible for processing, sorting, and modifying proteins? ribosome mitochondrian C. Golgi apparatus D. plasma membrane 21. What is the single most abundant compound in living organisms? fat sugar C. carbon D. water 22. Technology Enhanced Questions are not available in Word format. 23. There are many criteria that are used to define living things. Living things reproduce, grow, and develop. They respond to stimuli, use materials and energy, and evolve and adapt over time to their environment. What is another criteria used to define living things? All living things are intelligent. All living things are able to move. C. All living things are complex. D. All living things are made of cells. 24. What are the most basic building blocks of all organisms? cells muscles C. bones D. organs 25. Which of the following is true about cells? In general, prokaryotic cells do not have a true nucleus or membrane-bound organelles, whereas eukaryotic cells contain both a nucleus and organelles enclosed by membranes. Both eukaryotic cells and prokaryotic cells always contain both a true nucleus that is well-defined and organelles that are separated from the cytoplasm by membranes. C. Neither prokaryotic cells nor eukaryotic cells ever contain both a true nucleus that is well-defined and

8 D. organelles that are separated from the cytoplasm by membranes. In general, eukaryotic cells do not have a true nucleus or membrane-bound organelles, whereas prokaryotic cells contain both a nucleus and organelles enclosed by membranes. 26. To meet cellular needs for food, water, energy, and waste removal, multicellular organisms have developed various specializations, such as organs and organ systems. reproductive parental C. structural D. dietary 27. Membrane organelles known as contain enzymes specialized to break down ingested materials, secretions, and wastes. lysosomes chloroplasts C. ribosomes D. vacuoles

9 28. Stem cells are undifferentiated cells that have the ability to continue to grow and divide in their nonspecialized state for long periods of time (e.g., months or years). Although the genes found within stem cells are the same, stem cells differentiate into unique cell types (e.g., muscle cells, nerve cells, etc.) due to meiotic division and fertilization. mutations in their genetic code. C. random segregation and proliferation. D. different patterns in their gene expression. 29. When a group of cells work together, such as in bones, muscles, or nerves, they are known as. an organism a tissue C. an organelle D. an organ 30. The diagram below shows a bacteriophage. This virus consists of DNA enclosed in a protein capsule. Is this virus considered a living organism? No; viruses are not considered to be living organisms. Yes; since the virus contains protein, it is a living organism. C. No; living organisms must have two characteristics of life, and the T4 bacteriophage only has one. D. Yes; since the virus contains DNA, it is a living organism. Answers 1. C 2. A 3. A 4. B 5. D

10 6. D 7. D 8. A 9. B 10. D 11. B 12. A 13. C 14. B 15. D 16. A C 19. A 20. C 21. D D 24. A 25. A 26. C 27. A 28. D 29. B 30. A Explanations 1. The only object that meets all of the given characteristics of life is the plant. Batteries, rocks, and seashells are not living organisms. 2. Prokaryotic cells do not possess true nuclei or any other membrane-bound organelles. They do, however, possess plasma membranes, cytoplasm, cell walls, ribosomes, and DN Eukaryotic cells can possess all of these features, too. 3. All living organisms must have an organized structure, obtain and use energy and materials, maintain homeostasis, grow, reproduce and pass on genetic information, and respond to stimuli and evolve/adapt to their environment. Not all living organisms have complex structures such as organs, can make their own food, or can sexually reproduce. Prokaryotic organisms, for example, are single-celled and can only reproduce asexually. 4. Both eukaryotic and prokaryotic cells possess DNA constructed from the same genetic code (i.e. the same four nucleotides - A, T, C, G). However, eukaryotic DNA is linear, organized into chromosomes, and packaged in nuclei for greater efficiency, whereas most prokaryotic DNA is circular and free-floating in the cytoplasm. There are a few cases in which prokaryotes possess linear DNA, but this is more the exception than the norm. Both cells also possess ribosomes which enable them to perform protein translation.

11 5. The cell's nucleus acts as the "control center" of the cell, directing the cell's growth and development. It houses the genetic material of the cell, and this material must be duplicated before mitosis, one form of cell reproduction, can occur. 6. Most large organisms, such as plants and animals, are eukaryotes, although in a few instances, some microscopic protists are eukaryotic as well. So, in general, eukaryotes are much larger than prokaryotes. In addition, there are significant differences between the cells of eukaryotes and prokaryotes. Eukaryotic cells are generally larger and more complex than prokaryotic cells. This is because eukaryotic cells contain many membrane-bound organelles. Prokaryotic cells, on the other hand, do not contain any membrane-bound organelles. However, they do possess ribosomes, which are non-membranous complexes of protein and RN The ribosomes in prokaryotic cells have less RNA and fewer proteins than do eukaryotic ribosomes. 7. Organisms differ from each other in many ways. This diversity ranges from simple prokaryotic cells to complex multicellular organisms. The diagrams demonstrate how cell structure can be used to differentiate organisms. Organisms may also be classified using other factors, including their cell number, their mode of nutrition, their means of movement, and their method for reproduction. 8. The most fundamental difference between prokaryotic and eukaryotic cells is the presence or absence of a true nucleus and membrane-bound organelles, such as mitochondria and chloroplasts. Eukaryotes have them; prokaryotes do not. In fact, the name prokaryote means "before a nucleus". 9. Ribosomes are RNA and protein complexes that are found in all cells. These complexes help cells during protein translation by joining amino acids together to form polypeptides. Ribosomes are composed of two subunits. These subunits attach to and travel along strands of mrna during translation. As the anticodons on trna molecules attach sequentially to the codons on an mrna strand, the amino acids carried by the trna molecules take up the proper position to be joined by peptide bonds and form a polypeptide. 10. According to cell theory, all living things are composed of cells. Some have only one cell, others have many cells, but the way in which cells function is similar in all living organisms. Cell theory also states that cells are the basic unit of structure and function in living things, and new cells are produced by existing cells. 11. Prokaryotic cells are fairly small, simple cells. However, since they are only found in unicellular organisms, they are versatile enough to provide for all of an organism's functions. Still, since they lack nuclei and membrane-bound organelles, they are less efficient than eukaryotic cells. Eukaryotic cells are found in both unicellular and multicellular organisms. These cells tend to be larger, more complex, and require more genes to operate than prokaryotic cells. 12. Cells have characteristic structures and functions that make them distinctive. Organelles are the membrane-bound structures found in eukaryotic cells that play important roles, such as maintaining homeostasis and aiding in cell reproduction. All of the other answer choices listed are types of organelles. 13. All living organisms are composed of one or more cells.

12 All of the other listed characteristics are true of some living organisms but not all living organisms. For example, only plants and some microorganisms perform photosynthesis, and only eukaryotes contain specialized membrane-bound organelles. 14. The nucleus of the cell stores information in the form of DN The DNA inside the nucleus directs the cell's growth and development. Because DNA controls all of a cell's major functions, the nucleus containing the DNA is considered the cell's control center. 15. The life forms exhibiting the simplest cellular structure are prokaryotes. They exist in two major forms: eubacteria and archaebacteria. Prokaryotes were first life forms to develop on Earth and are the most abundant inhabitants. They can survive in a wide range of environments and obtain energy in a variety of ways. 16. The structures of cellular organelles are related to their functions. For example, many chemical reactions occur in the mitochondria in order to provide the cell with energy. Having a highly folded inner membrane increases the surface area upon which these reactions can occur. Vacuoles, on the other hand, must be able to easily expand and contract as water moves in and out. Thus, a single-layer membrane is necessary to support the vacuoles' function Cells are the basic building blocks of all living organisms. Cells contain smaller, specialized structures called organelles, which carry out specific functions in the cell. Organisms can have one cell (unicellular organisms) or more than one cell (multicellular organisms). 19. The picture shows a human heart which can be classified as an organ. 20. The Golgi apparatus processes, sorts, and modifies proteins in a cell. In fact, the formation of complex biomolecules is possible because of the modifications that proteins undergo while they are moved through the Golgi apparatus. The Golgi apparatus also processes and transports materials, including wastes, out of the cell. Thus, the Golgi apparatus plays an important role in waste disposal. 21. Water is the single most abundant compound in all living organisms. In fact, about two-thirds of the weight of cells is accounted for by water. Water is what gives cells so many of their properties In addition to the other named criteria, all living things are composed of cells. Although some living things are complex or intelligent and some living things can move, these are not requirements for all living things. 24. All living things are made of one or more cells. Cells are the basic building blocks of all organisms. Bones, muscles, and organs are all made up of cells organized in different levels of complexity. 25. Prokaryotic cells do not have a true nucleus or membrane-bound organelles. Prokaryotic organisms are usually unicellular. Eukaryotic cells have nuclei and organelles that are separated from the cytoplasm by membranes. Eukaryotic

13 organisms are usually multicellular. In general, prokaryotic cells do not have a true nucleus or membrane-bound organelles, whereas eukaryotic cells contain both a nucleus and organelles enclosed by membranes. 26. Many cellular processes are the same across the plant and animal kingdoms. Organisms in these kingdoms have developed similar structural specializations for supporting these cellular processes. Specifically, a version of respiratory, skeletal, circulatory, and reproductive tissues, organs, and organ systems can be found in most multicellular organisms. 27. Membrane organelles known as lysosomes contain enzymes specialized to break down ingested materials, secretions, and wastes. Lysosomes, along with the Golgi complex, are responsible for the disposal of cellular waste within a cell. 28. The specialization of cells in multicellular organisms is usually due to different patterns of gene expression rather than to differences of the genes themselves. However, what causes cells with similar genes to differentiate into unique cell types is not fully understood. It may be due to the presence of different environmental conditions that signal some genes to be expressed while other genes remain dormant. It may be due to internal regulators or any of a number of factors that researchers are currently studying. Think of it this way: you and three friends are each given 10 cards with the same letters on them (i.e., you all have the same genes). However, you each choose to use the letters to spell four different words (i.e., you each expressed your genes in a different way). No one knows why you each chose to arrange your letters in different ways despite being given the same set of starting letters, but the end result is four different words (i.e., specialized cells). 29. When a group of cells work together, such as in bones, muscles, or nerves, they are known as a tissue. Tissues include bone, blood, nerves, muscles, and skin. A group of tissues that work together, such as the muscles that make up the heart, form an organ. 30. All living organisms must have an organized structure, obtain and use energy and materials, maintain homeostasis, grow, reproduce and pass on genetic information, and respond to stimuli and evolve/adapt to their environment. Although viruses contain DNA and pass their DNA on to their offspring, they cannot do this unassisted, nor do they meet all the other criteria for living organisms. Thus, viruses are not considered to be living organisms.