Download Ch. 1 The Cell 1.1: The cell is the basic unit of living things. 1. Living

Ch. 1 The Cell 1.1: The cell is the basic unit of living things. 1. Living things are different from nonliving things. A. Organisms are individual forms of life that use energy to carry out activities. B. Living things, or organisms, have needs and characteristics that make them different from nonliving things. a. Characteristics of life: b. Be organized c. Grow and develop d. Respond to its environment e. Be able to reproduce f. Needs of life are energy, materials, and living space. g. All energy used by life on Earth comes from the Sun. 2. All living things are made of cells. A. The cell is the smallest unit that can perform the basic activities of life. B. All living things are made of cells. C. The cell is the smallest unit of a living thing. D. Multicellular organisms have specialized cells that, together, meet the basic needs. a. Unicellular organisms are made of a single cell. b. Multicellular organisms are made of many cells. 3. The microscope led to the discovery of cells. A. Robert Hooke and Anton van Leeuwenhoek first described cells in the 1660s and 1670s. B. Microscopes were the new technology that led to their discoveries. C. They realized that a huge amount of life existed that could not be seen by the eye alone. 4. Cells come from other cells. A. In the 1850s people knew for sure that cells come from other cells. B. This fact is part of the cell theory: a. All living things are made of one or more cells. b. Cells carry out the functions needed to support life. c. Cells come only from other living cells. C. Louis Pasteur did research that showed that cells came only from other cells and did not spontaneously generate from nonliving materials. D. He also developed a way to make food and drinks safer by pasteurizing them, or killing off harmful bacteria with heat. 5. The cell theory is important to the study of biology. A. A theory is an explanation of what is observed, and must be supported by evidence. B. Louis Pasteur used the cell theory as a foundation for his studies. C. He found that: a. Bacteria causes food to spoil, sour milk, and many diseases. b. Living things do not arise by spontaneous generation. 6. Cells take in materials from their surroundings and use them in complex ways. A. Each cell has an orderly structure and contains hereditary material. B. The hereditary material has instructions for the cell organization and function. C. All the things organisms can do are possible because of what their cells can do. 7. Living things interact with their environment. A. Anything that causes some change in an organism is a stimulus. B. The reaction to a stimulus is a response. a. Often that response results in movement. C. Living things respond to external and internal stimuli. a. Examples of external stimuli: light and weather. b. Examples of internal stimuli: thrust and hunger. D. An organisms ability to keep the proper conditions inside no matter what is going on outside the organism is called homeostasis. 8. Living space is limited by the environment. A. Not many organisms can live in extremely hot or extremely cold environments. B. Most can not live at the bottom of the ocean or on the top of mountains. 9. Spontaneous generation was the theory Louis Pasteur disproved. A. Spontaneous generation was an idea that living things come from nonliving things. B. That theory was replaced with biogenesis. a. Biogenesis is the theory that living things come only from other living things. 10. Breaking A Misconception: The cell is the basic unit of function. It is also the basic unit of structure. 1.1 Key Terms 1. Organism ‐ An individual living thing, made up of one or many cells, that is capable of growing and reproducing. 2. Unicellular ‐ A term used to describe an organism that is made up of a single cell. 3. Multicellular ‐ A term used to describe an organism that is made up of many cells. 4. Microscope ‐ An instrument that uses glass lenses to magnify an object. 5. Bacteria ‐ A large group of one‐celled organisms that sometimes cause disease. Bacteria is a plural word; the singular is bacterium. 1.2: Microscopes allow us to see inside the cell. 1. The microscope is an important tool. A. Three types of microscopes are useful in studying cells. a. Light microscopes can magnify living cells. b. Scanning electron microscopes and transmission electron microscopes can magnify smaller objects, but preparation of living specimens kills them. B. Today there are simple and compound microscopes. a. A simple microscope has just one lens. It is like a magnifying lens. b. The compound light microscope has two sets of lenses – eyepiece and objective. 2. Cells are diverse. A. All cells have cell membranes as a protective covering. B. They all contain cytoplasm, a thick fluid where most of the work of the cell is done. C. Most cells also have genetic material, DNA. a. In prokaryotic cells, DNA is in the cytoplasm. Ex: A bacterium consists of a single prokaryotic cell. b. In eukaryotic cells, DNA is separated from the rest of the cytoplasm in a nucleus. It is more complex, with many different organelles inside it. 3. A cell’s shape may tell you something about its function. A. A nerve cell in your leg could be a meter long. B. A human egg cell is no bigger than the dot on this i. C. A human blood cell is much smaller than the egg. D. A bacterium is even smaller – 8,000 of the smallest bacteria can fit inside one red blood cell. 4. A nerve cell can not change its shape. Muscle cells and some blood cells can change shape. Some cells in plant stems are long and hollow and have openings at their ends. These cells carry food and water throughout the plant. 5. Plants and animals have eukaryotic cells. A. Eukaryotic cells are much larger than prokaryotic cells. B. They have many complex structures, including organelles. C. Your body has a certain job to do. Cells take in nutrients, release and store chemicals, and break down substances 24 hours a day. D. Organelles: a. Structures That Process Information b. Organelles That Provide Energy c. Organelles That Process and Transport d. Organelles for Storage, Recycling, and Waste E. Organelles called chloroplasts use energy from sunlight to make sugar. a. Chloroplasts contain chlorophyll, which captures light energy that is used to make a sugar called glucose. b. Animal cells and some other cells do not have chloroplasts. c. Animals must get food from their environment. F. Cells have mitochondria to make energy for the organism. a. The energy in food is stored until it is released by the mitochondria. b. Mitochondria release energy by breaking down food into carbon dioxide and water. c. Some types of cells, such as muscle cells, are more active than other types of cells. These cells have large numbers of mitochondria. G. The nucleus directs all cell activities. a. The nucleus usually is the largest organelle in a cell. It is separated from the cytoplasm by a membrane. b. Materials enter and leave the nucleus through openings in the membrane. c. The nucleus contains DNA, the chemical that contains the code for the cell’s structure and activities. H. The endoplasmic reticulum, ribosomes, and Golgi apparatus process and transport materials. 6. Protein takes part in almost every cell activity. A. Cells make their own proteins on structures called ribosomes. B. Ribosomes are considered organelles, even though they are not membrane bound. C. Hereditary material in the nucleus tells ribosomes how, when, and in what order to make proteins. D. Ribosomes are made in the nucleolus and move out into the cytoplasm. E. Some ribosomes are free‐floating in the cytoplasm and some attach to the endoplasmic reticulum. 7. The endoplasmic reticulum , or ER, is a series of folded membranes in which materials can be processed and moved around inside the cell. A. Smooth ER processes materials such as lipids that store energy. B. Rough ER has ribosomes that make proteins. a. The proteins are used within the cell or moved out of the cell. 8. The Golgi bodies sort proteins and other cellular materials and put them into structures called vesicles. A. Vesicles deliver the cellular materials to areas inside the cell and to the cell membrane where they are released. 9. Cells also have membrane‐bound spaces called vacuoles. A. Vaculoles store cellular materials, such as water, wastes, and food. 10. Active cells break down and recycle materials. A. An organelle called a lysosome contains digestive chemicals that help break down materials in the cell. B. The lysosome’s membrane stops the digestive chemicals from leaking into the cytoplasm and destroying the cell. C. When a cell dies, a lysosome’s membrane breaks down. The released digestive chemicals destroy the cell’s contents. Ch. 1.2 Key Terms 1. Cell membrane ‐ The outer boundary of the cytoplasm, a layer that controls what enters or leaves the cell; a protective covering enclosing an entire cell. 2. Cytoplasm ‐ A thick, gelatin‐like material contained within the cell membrane. Most of the work of the cell is carried out in the cytoplasm. 3. Nucleus ‐ The structure in a eukaryotic cell that contains the genetic material a cell needs to reproduce and function. 4. Eukaryotic cell ‐ A cell in which the genetic material is enclosed within a nucleus, surrounded by its own membrane. 5. Prokaryotic cell ‐ A cell that lacks a nucleus and other organelles, with DNA that is not organized into chromosomes. 6. Chloroplast ‐ An organelle in a plant cell that contains chlorophyll, a chemical that uses the energy from sunlight to make sugar. 7. Mitochondria ‐ Organelles that release energy by using oxygen to break down sugars. 8. Organelle ‐ A structure in a cell that is enclosed by a membrane and that performs a particular function. 9. Cell wall ‐ A protective outer covering that lies just outside the cell membrane of plant cells. 1.3: Different cells perform various functions 1. When you place similar items together, you classify them. A. Libraries group similar types of books together. B. Organisms also are classified into groups. a. Archaea – are prokaryotes that mostly live in extreme environments. b. Bacteria – are prokaryotes that share some similarities with archaea, but grow virtually everywhere on Earth. c. Eukarya – are eukaryotes, which include multicellular organisms (plants, animals, fungi, and some protists) and unicellular organisms (some protists). C. Domains, kingdoms, and other classifications constantly change and are debated within the scientific community. Some scientists recognize just five kingdoms (rather than six). 3. Cells in multicellular organisms specialize. A. All multicellular organisms begin life as a single fertilized egg. B. As cells divide, they specialize to perform specific jobs. C. The more specialization there is, the more complex the organism is. 4. A multicellular organism is a community of cells. A. Organisms have different degrees of organization. B. For example, sponges have specialized cells, but are not strictly organized. a. Similar cells group together to form tissues. Each cell works to keep the tissue alive. b. Tissues act together to form organs. * Example: Your heart is an organ that is made up of cardiac tissue, nerve tissue, and blood tissues. c. Organs and tissues act together in organ systems. Your cardiovascular system is made up of your heart, arteries, veins, and capillaries. d. Organ systems work together to keep an organism alive. 5. Scientists use models to study cells. A. Scientists use models to make complicated structures or processes easier. B. Examples: mathematical or chemical equations, diagrams, process models, or physical models. 1.3 Key Terms 1. Specialization – the specific organization of a cell and its structure that allows it to perform a specific function. 2. Tissue – a group of similar cells that are organized to do a specific job. 3. Organ – a structure in a plant or an animal that is made up of different tissues working together to perform a particular function.