3.1 BIOLOGICAL MEMBRANES 3.1.1 Properties of Cell Membranes • Separates living cell from its nonliving surroundings. • 8 nm thick. • Selectively permeable - allows some substances to cross more easily than others. 4.1.2 Fluid Mosaic Model • Singer and Nicolson (1972) - plasma membrane is a mosaic of proteins dispersed within lipid bilayer‚ with only bilayer‚ the hydrophilic regions exposed to water. Hydrophilic region of protein Phospholipid bilayer Hydrophobic region of protein
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Biology Cell Study Guide Cell Theory 1.All living things are made of cells 2.Cells are made form other cells 3. Cells are the basic STRUCTURAL and FUNCTIONAL units of life Robert Hooke: discovered cells while looking at cork using a microscope Schleiden: all plants are made of cells Virchow: Cells come from other Cells Organelle- structure in a cell that performs a specific function Nucleolus- dark spot in the nucleus where ribosomes are made Lysosome- sac of digestive
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plasma membrane of a cell is extremely important to the transportation of substances into and out of the cell. The outer membrane of a cell is made up of lipids and proteins. Most of the lipids in plasma membranes are phospholipids. The phospholipids have a hydrophilic head and two hydrophobic tails. When engulfed in water‚ they arrange themselves such that all the hydrophobic tails clump together‚ surrounded by the hydrophilic heads‚ protecting the tails from the exposure to the water. In cells‚ which
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stress that various alcohols have on biological membranes. Using five solutions of differing alcohol concentration for each of the three alcohols; methanol‚ ethanol‚ and 1-propanol and a small slice of beet‚ the stirred solution was placed into a plastic cuvette and then into a spectrophotometer and the absorbance of alcohol solutions were determined in order to conclude which alcohol and concentration of alcohol had the greatest effect on biological membranes. The results showed that the most non-polar
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passive transport as energy does not need to be generated. Diffusion is complete when the concentration of molecules is equal on either side of the membrane. Diffusion rate can be influenced by many factors such as: Concentration gradient across the the membrane. Permeability of the membrane to the diffusing substance. Temperature. Surface area of the membrane. Question 2 2.1 Acetylcholine is an organic chemical that functions in the brain and body as a neurotransmitter it is an ester of acetic acid
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Bacteria Bacteria are microscopic organisms whose single cells have neither a membrane-enclosed nucleus nor other membrane-enclosed organelles like mitochondria and chloroplasts. Another group of microbes‚ the archaea‚ meet these criteria but are very different from the bacteria in other ways. In fact‚ there is considerable evidence that you are more closely related to the archaea than they are to the bacteria! Bacteria are living things that are neither plants nor animals‚ but belong to a group
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Cells‚ Cell Division‚ and Cell Specialization Fundamentally Different Types of Cell Prokaryotic Cell- single celled: only DNA+ structure (“before nucleus”) E.g. zygote-complete DNA Eukaryotic Cell-multi-celled (“after nucleus”) Prokaryotes Eukaryotes DNA In “nucleoid” region Within membrane-bound nucleus Chromosomes Single‚ circular Multiple‚ linear Organelles None Membrane-bound organelles Size Usually smaller Usually larger- 50 times Organization Usually single-celled Often multicellular
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2. In examining a picture of a cell taken with an electron microscope‚ a student observes that the cell has a nucleus and a cell membrane‚ but not a cell wall. The student can correctly conclude that the cell probably comes from A. a moss. B. a fungus. C. a bacterium. D. an animal. 3. A chemical interferes with a cell’s ability to make proteins. Investigations reveal that the cell parts responsible for making proteins are in working order. The cell can also encode instructions for
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Bio Notes 9/5/2012 * Biology- Study of living things * Characteristics of living organisms * Consist of one or more cells * Unicellular- one cell able to carry out life ex. Bacteria * Multicellular- Many cells‚ specialized cells * Observations with microscopes lead to Cell Theory‚ Robert Hook * All cells come from preexisting cells * All cells are similar in chemical composition * Chemical reactions occur within
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Implementation My aim for this experiment was to find the effect of temperature on the membrane permeability of beetroot. Since I was unfamiliar with this experiment‚ I first conducted a preliminary test. I considered my preliminary test as my trial for this experiment. My Hypothesis for this experiment was to found out the amount of pigment loss of beetroot when exposed to varying temperatures. Betalain pigment found in beetroot My method for this experiment is:- * Use a cork borer to cut about
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