The carcinogenic nature of N-nitrosamines depends on the organs. For example‚ their targets for cancer in rodents include thyroid‚ pancreas‚ urinary bladder‚ trachea‚ lung‚ oral and nasal cavities‚ esophagus‚ kidney and liver. With respect to N-nitrosamides‚ skin‚ bone‚ peripheral nervous system‚ brain‚ small intestine and glandular stomach are targeted organs for cancers. Besides cancer‚ acute myelocytic leukemia and T and B cell lymphoma have also been triggered by N-nitrosamides. In table 8.1
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Epigenetics is the series of chemical modifications of DNA and its connected proteins that contain phenotypic information during cell division. These modifications alter gene expression without changing DNA sequence. They differ among tissues and change over throughout the organism’s lifetime. A well-understood example of epigenetic modification is DNA methylation‚ the process by which a methyl group is covalently bonded to cytosine. During DNA replication‚ a specific enzyme recognizes unmethylated
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organisms‚ the organs and appendages of each individual are normally in proportion with the body as a whole. What controls the size of organisms and their components? For the most part‚ the answer lies in the genes. Genetic variations control the size to which organs or organisms can grow. Genes control the synthesis and transport of hormones and growth factors‚ which act on different tissues to control overall body growth. However‚ environmental factors are also important. A good laboratory example
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one of the following statements is false? Selected Answer: a. Factors that alter DNA and make cells cancerous are called carcinogens. Which one of the following is false? Selected Answer: b. DNA packing tends to promote gene expression. Silencers are sites in DNA that Selected Answer: c. bind repressor proteins to inhibit the start of transcription. Proteins that bind to DNA and turn on operons by making it easier for RNA polymerase to bind to
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1.1.1 In small unicellular organisms‚ substances move around slowly by diffusion. Diffusion is too slow to move substances round the larger bodies of multicellular organisms. They have a circulatory system: substances are carried in blood pumped by a heart. In a closed circulatory system (eg in vertebrates) blood is enclosed in narrow blood vessels. This increases efficiency: blood travels faster as a higher pressure is generated. Valves ensure blood flows in one direction:
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the inner cell masses (ICM) of blastocysts also known as Embryonic Stem (ES) Cells and the embryos possibility of one day being born. To help with this problem a unique experiment was conducted and the Embryonic Stem (ES) cells by introducing four genes (Oct3/4‚ Sox2‚ Klf4‚ c-Myc) into mice dermal fibroblast cells. These cells are called embryonic germ (EG) Thus making the use of stem cell factors no longer needed. Direct reprogramming of a patient’s somatic cells into pluripotent stem cells can
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1. The nurse is caring for a patient suffering from anorexia secondary to chemotherapy. Which strategy would be most appropriate for the nurse to use to increase the patient’s nutritional intake? A. Serve three large meals per day plus snacks between each meal. B. Add items such as skim milk powder‚ cheese‚ honey‚ or peanut butter to selected foods. C. Increase intake of liquids at mealtime to stimulate the appetite. D. Avoid the use of liquid protein supplements to encourage eating
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when the DNA of a cell become’s damaged or changed‚ producing mutations that warp normal cell growth and division. Cancer cells do not die when regular cells would and new cells continue form. The extra cells may form tumours. Benign tumours that aren’t cancerous and malignant tumours that are. Cancer can spread to other parts of the body through the blood system. There are more than 100 different types of cancer that affect things from the lungs to the brain. Some cancers are “Aggressive Cancer’s”
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diagnosis or PGD. Once they have selected an embryo‚ they use a technology called CRISPR. It allows geneticists to engineer a RNA strand with the desired gene and implant it into the cell. The RNA then goes through the natural process of trying to fix the DNA. The RNA uses an enzyme to cut the desired piece of DNA and replace it with the desired gene. Even though the technology exists‚ designer babies should not be an option because of the potential side effects on society and the child. There are already
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signaling and signal transduction; Biochemical and biophysical techniques for macromolecular analysis. Molecular Biology and Genetics: Molecular structure of genes and chromosomes; DNA replication and control; Transcription and its control; Translational processes; Regulatory controls in prokaryotes and eukaryotes; Mendelian inheritance; Gene interaction; Complementation; Linkage‚
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