CELLS QUEST 2013! ANSWER KEY

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1 CELLS QUEST 2013! ANSWER KEY During this unit your QUEST has been to find out as much about cells as you can and to understand the value of this knowledge. Let s see how you ve done! I. Key question: How do living cells vary in types, structure and function? A. Eukaryote vs. Prokaryote 1. Define: Eukaryote an organism whose cells contain a nucleus(dna is contained by a nuclear membrane/ envelope) and other membrane bound organelles. Prokaryote an organism whose cells do not contain a nucleus (DNA forms a single loop and is free-floating in the cytoplasm) and the cells lack membrane bound organelles; these organisms have ribosomes, cytoplasm, a cell membrane and a cell wall 2. How are eukaryotic cells different from prokaryotic cells? How are they the same? Describe with an organizer or in writing. Structure Prokaryote Eukaryote Nucleus No Nucleoid(free floating nucleic acid) No Cell membrane Cell wall Usually Sometimes (for example plants, fungi) Ribosomes Cytoplasm All other organelles No B. Stem Cells 1. What are stem cells? Stem cells are unspecialized cells that can develop into nearly any type of body cell. 2. Define: Embryonic stem cell stem cells derived from human embryos very early in development. own cells. Somatic cell nuclear transfer process by which scientists create embryonic-like stem cells from a person s 3. Of what value is the stem cell in medical research? Scientists expect to use stem cells to treat numerous injuries and diseases including, broken bones, spinal cord injuries, brain injury, even burnt skin.

2 II. Key question: How do plant and animal cells compare? A. Type of cell: animal Label 12 structures B. Type of cell: plant Label 13 structures C. Compare and contrast plant and animal cells using the method of your choice. Structure Plant Animal Cell wall No Chloroplast No Large vacuole No Lysosome Rarely All other organelles

3 III. Key question: What are the fundamental structures that the processes of life rely on? A. Describe organelle structure and function Organelle Function P/A/? Seen under our microscopes? cell wall A rigid layer of nonliving material that surrounds the cells of plants and some other organisms. P cell membrane Cytoplasm A cell structure that controls which substances can enter or leave the cell. The region between the cell membrane and the nucleus; in organisms without a nucleus, the region located inside the cell membrane. nuclear envelope Selectively permeable membrane that surrounds the nucleus. Nucleus The dense area in a eukaryotic cell that contains nucleic acids, the chemical instructions that direct the cell s activities. Chromatin The dark staining material inside a nucleus; this is the DNA. Nucleolus The structure inside the nucleus that contains RNA and produces ribosomes. Sometimes Endoplasmic reticulum A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another. Ribosomes Golgi bodies A small grain like structure in the cytoplasm of a cell where proteins are made. A structure in a cell that receives proteins and other newly formed materials from the endoplasmic reticulum, packages them, and distributes them to other parts of the cell. Mitochondria (mitochondrion) Rod-shaped cell structures that convert energy in food molecules to energy the cell can use to carry out its functions. Chloroplast A structure in the cells of plants and some other organisms that captures energy from sunlight and uses it to produce food. Plant Vacuole Lysosome A sac inside a cell that acts as a storage area for food water or wastes. A small, round cell structure containing chemicals that break down large food particles into smaller ones. Large in plants; small in animals Animals; rare in plants Cytoskeleton An organized network of protein fibers that helps cell motility (movement) and helps to maintain cell shape. Centriole The centrioles play a role in animal cell division. Animals

4 IV. Important roles and concepts. 1. Which two organelles can be called the energy organelles? Two organelles that can be called the energy organelles are mitochondria and the chloroplasts. Chloroplasts collect the sun s energy and converts it to glucose during photosynthesis; mitochondrial release the energy from the nucleus for cell use. 2. Of what value is the nucleus to a living system? The nucleus contains the DNA of the cell. It is called the control center because DNA contains the instructions that direct all cell activities. Without the DNA a cell is unable to accomplish all of life s functions. 3. Ribosomes make protein. Why is protein important in a living system? Proteins are important in living systems for many reasons. The reason discussed in class is that a certain type of protein, the enzymes, direct the rate of chemical reactions in living systems. 4. What is the relationship between cells, tissues, organs and organ systems? Describe this relationship using your own method. In other words write a description or use pictures or an organizer. Cells Tissues Organs Organ system 5. What are the four basic types of tissue in the human body? The four basic tissue types are epithelial tissue, muscle tissue, nervous tissue and connective tissue. 6. All eukaryotic cells are very similar yet they are all very different from one another. Explain this statement. All eukaryotic cells are similar in that they are made up of the same basic structures and organelles such as the nucleus, cytoplasm, cell membrane, mitochondria, etc. Differences between types of cells are a result of the different roles they play in living systems. Because of the different roles cells have different shapes and often have different structures inside. For example, an elodea cell is brick shaped, it has large visible water vacuoles and it has green chloroplasts circulating in the cytoplasm. The onion skin cell lacks chloroplasts, has no visible water vacuole and it is also brick like in shape. the elodea and onion cell has a cell wall and a cell membrane. The cheek cell is somewhat round in shape, it lacks a water vacuole, and it lacks a cell wall.

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