1. Plant breeders wanted to produce a better variety of tomato by selective breeding. Two plants‚ of the varieties Tangella and Piranto‚ were crossed. (a) Some flowers of each variety were covered with cellophane bags. The diagram shows a covered flower and a brush. (i) Explain why some flowers were covered with cellophane bags during the selective breeding. .......................................................................................................................... ........
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Simple diffusion The term simple diffusion refers to a process whereby a substance passes through a membrane without the aid of an intermediary such as a integral membrane protein. The force that drives the substance from one side of the membrane to the other is the force of diffusion. In order for substances to pass through a cell membrane by simple diffusion it must penetrate the hydrophobic core of the phospholipid bilayer. The types of molecules that can do this are themselves substantially
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Discussion: 1. Peter was preparing some potatoes for cooking. He put some water in a pot and added some salt. He cut up the potatoes and put them in the salt solution. Then the telephone rang and he spent 30 minutes talking to George. When he returned to put the potatoes on the stove they were flaccid (soft). Explain what happened to the potatoes. The concentration of free-moving water molecules is higher in potato cells‚ the cytoplasm of the cell is hypertonic. The water molecule will flow from
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Absorption- The process by which the products of digestion are transferred into the body’s internal environment‚ enabling them to reach the cells. adenosine triphosphate (ATP) A common form in which energy is stored in living systems; consists of a nucleotide (with ribose sugar) with three phosphate groups. The energy coin of the cell.aerobic -relating to or denoting exercise that improves or is intended to improve the efficiency of the body’s cardiovascular system in absorbing and transporting
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Introduction In this investigation‚ me and my partners performed an experiment to find the different energy contents in food and different amounts of energy released when consumed. Throughout this experiment our procedure was to take different food samples and use a device known as a calorimeter made from a can of aluminum‚ one large paper clips and a string of copper wire to measure the amount of thermal energy released during a reaction. By measuring the temperature difference before and after
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9 Meiosis CHAPTER OUTLINe Meiosis (p. 172) 9.1 Discovery of Meiosis (p. 172; Figs. 9.1‚ 9.2) A. In 1882‚ Belgian cytologist Pierre-Joseph van Beneden discovered that the gametes of the roundworm Ascaris contained two chromosomes while somatic cells contained four. B. Fertilization 1. van Beneden proposed in 1887 that an egg and sperm could fuse to form a zygote. 2. The fusion of gametes is called fertilization or syngamy. C. Meiosis 1. A reduction division is required to reduce the number
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Phylum Mollusca Unit 4 Mollusk Introduction Phylum Mollusca Molluscus = soft Soft-bodied animals that usually have an internal or external shell. Includes snails‚ slugs‚ clams‚ squids‚ and octopi. True coelom Complex‚ interrelated organ systems Body Plan The body plan of most mollusks have 4 main parts: foot 2. mantle 3. shell 4. visceral mass 1. Foot: muscular; may be used for crawling‚ burrowing‚ or tentacles for capturing prey Mantle: thin tissue layer
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Midterm Study Guide Answers 1. A hypothesis is an explanation of observations. “If the floor is wet‚ I will slip.” 2. A controlled experiment is when only one variable is changed. 3. If the plant you are experimenting with has a disease that is an unavoidable experimental error. 4. An enzyme speeds up reactions and lowers the energy it takes to produce something‚ a lock and key. 5. Autotrophs make their own food by producing sugars from sunlight and various chemicals. 6
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Andrew Schwartz 1-19-2011 Assignment 1 * Fish- Channel Catfish‚ May 23‚ 1997. It is slender‚ with a deeply forked tail. The young have spots that fade away with age. It feeds on animal and plant material by using it’s whiskers. * Fossil- Crinoid‚ June 16‚ 1989. It is the mineralization of an animal which has a plant-like appearance‚ so it is known as the “sea lily.” * Mineral- Galena‚ July 21‚ 1967. It is the major source of lead ore. It is dark gray in color and breaks into small
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1. Phospholipid: Molecule that forms a double-layered cell membrane; consists of a glycerol‚ a phosphate group; and two fatty acids. 2. Selectively permeable (Semi): Condition or quality of allowing some‚ but not all‚ materials cross a barrier or membrane. 3. Receptor: Protein that detects a signal molecule and performs an action in response. 4. Diffusion: Movement of dissolved molecules in a fluid or gas from a region of higher concentration to a region of lower concentration. 5. Osmosis: Diffusion
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