Discuss the chain of events that led to the discovery of DNA as the heritable substance and the discovery of the structure of DNA. Ans> The chain of events led to the discovery of DNA as the heritable substance and the discovery of the structure of DNA. In the late nineteenth century‚ a German biochemist Friedrich Miescher found the nucleic acids which are long-chain polymers of nucleotides‚ and are made up of sugar‚ phosphoric acid‚ and several nitrogen-containing bases. Later it was found
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membranes hat maintained an internal chemistry different from that of their surroundings. 4. The origin of self-replicating molecules that eventually made inheritance possible. 5. The first cells to develop occurred in this order: Monomers > Polymers > Protobionts > RNA ‘world’ > DNA protobionts > first cell. 6. Fossils are the evidence of life and evolution. Organisms trapped in sediment > remain mineralized with hard and soft parts. 7. Fossils can be dated by two methods: Radiometric dating & Magnetism
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that the area is exposed to high amounts of sunlight which causes a loss of water in the leaves through transpiration. Since the wallum is so dry and hot; bush fires play a major cycle in the dry wallum which the trees have adapted to cope with. The roots of the plant and tree species have to cope with the leeching of nutrients because of the high porosity sand in the dry wallum. The Dry wallums topography is quite low and flat between high sand dunes covered in thick wallum vegetation. This creates
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Campbell’s Biology‚ 9e (Reece et al.) Chapter 31 Fungi Though fungal divisions have traditionally been based on modes of sexual reproduction‚ molecular considerations are becoming more important. Consequently‚ no emphasis has been placed on the vagaries of sexual and asexual reproduction among various fungi in this Test Bank. Instead‚ new questions assess students’ abilities to think logically about fungal morphology‚ genetics‚ and ecology. Two new sets of scenario questions deal with the biology
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observations are repressentative of cell division taking place in the oinon root tip. Firstly‚ this is because our numbers of the number of cells in each phase of mitosis are similar to the rest of the groups‚ so we can assume our results are most likely correct. We can also assume our calculations are right because we know that Interphase is the most active phase in the process of cell divison‚ which would agree with our calculations since we assume that approxiamtly 93% of cells are going though Interphase
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The cell cycle‚ or cell-division cycle‚ is the series of events that take place in a cell leading to its division and duplication that produces two daughter cells. In cells without a nucleus‚ the cell cycle occurs via a process termed binary fission. In cells with a nucleus‚ the cell cycle can be divided in three periods: interphase—during which the cell grows‚ accumulating nutrients needed for mitosis preparing it for cell division and duplicating its DNA—and the mitotic phase‚ during which the
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than mosses and liverworts)‚ contains several types of differentiated cells. These are grouped together in tissues. Some tissues contain only one type of cell. Some consist of several. Meristematic The main function of meristematic tissue is mitosis. The cells are small‚ thin-walled‚ with no central vacuole and no specialized features. Meristematic tissue is located in • the apical meristems at the growing points of roots and stems. • the secondary meristems (lateral buds) at the nodes of stems
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Animal Cells Vs. Plant Cells There are quite a few similarities and differences between plant and animal cells. Whether it be the internal parts of the cells‚ or the processes they go through. They also have differences in shape and sometimes size. These are only a few examples of similarities and differences between the two different cells. To begin with‚ both animal and plant cells are eukaryotic cells. This means that both cells have the same internal features‚ such as a cell membrane‚ a
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pH. Which cellular structure in elodea carries out the process that is most likely to result in increasing pH? Which structures‚ if found in a cell‚ would provide the best evidence that the cell is eukaryotic? Where in the cell do the following occur? Calvin cycle‚ glycolysis‚ Kreb’s cycle‚ electron transport chain. Students in a biology class tested the effects of antibiotics on the growth of bacteria. They cultured bacteria in four glass Petri dishes and then added different amounts
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Root Surface Caries Caries can affect any surface of the teeth. The most commonly seen caries are found on the crown of a tooth‚ above the cemento-enamel junction‚ it is also possible for caries to form on the root surface‚ below the cemento-enamel junction. Dental root caries has received a great deal of attention in the past few decades. A variety of different patients are at risk for root surface caries. Dentists use several methods of treatment. Root surface caries are also called cemental
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