
Concept explainers
Unstable Atoms Unleashed
Because exposure to radioactivity can cause cancer, Japanese authorities have performed regular cancer screenings on hundreds of thousands of children exposed to radioactivity by the Fukushima power plant disaster. Fortunately, recent surveys have found no evidence of increased cancer rates. But months after the meltdown, engineers at the Fukushima power plant—using specialized cameras located outside the plant—discovered hot spots of radiation so intense that a person exposed for an hour would be dead within a few weeks. How could death come so fast? Extremely high doses of radiation damage DNA and other biological molecules so badly that cells—particularly those that divide rapidly—can no longer function. Skin cells are destroyed. Cells lining the stomach and intestine break down, causing nausea and vomiting. Bone marrow, where blood cells and platelets are produced, is destroyed. Lack of white blood cells allows infections to flourish. and the loss of platelets crucial for blood clotting leads to internal bleeding. Fortunately, radioactive substances such as those released by the Fukushima disaster are rare in nature. Why do most elements remain stable?

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Chapter 2 Solutions
Biology: Life on Earth with Physiology (11th Edition)
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- A loss of function mutation in Pitx1 enhancers can cause (blank) Removal of Pitx1 exons and growth of ectopic hindlimbs, growth of extra ectopic forelimbs, loss of forelimb specification and development, and loss of hindlimb specification and developmentarrow_forwardHox1a most likely contributes to (blank) patterning in the developing embryo? Ventral, posterior, limb or anteriorarrow_forwardSelect all of the following that can help establish Hox gene expression boundaries (things that affect Hox and not things that Hox affects). Retinoic acid, anterior/posterior axis, fibroblast growth factors, vagal neural crest, and enhancersarrow_forward
- Ectopic expression of Hox often results in (blank) phenotypes. (Blank) transformations are characterized by the replacement of one body part/structure with another. Hoxeotic, homealoneotic, joexotic, or homeoticarrow_forwardWhat's the difference when drawing omega-6 and omega-3?arrow_forward. Consider a base substitution mutation that occurred in a DNA sequence that resulted in a change in the encoded protein from the amino acid glutamic acid to aspartic acid. Normally the glutamic acid amino acid is located on the outside of the soluble protein but not near an active site. O-H¨ A. What type of mutation occurred? O-H B. What 2 types of chemical bonds are found in the R-groups of each amino acid? The R groups are shaded. CH2 CH2 CH2 H2N-C-COOH H2N-C-COOH 1 H Glutamic acid H Aspartic acid C. What 2 types of bonds could each R-group of each of these amino acids form with other molecules? D. Consider the chemical properties of the two amino acids and the location of the amino acid in the protein. Explain what effect this mutation will have on this protein's function and why.arrow_forward
- engineered constructs that consist of hollow fibers are acting as synthetic capillaries, around which cells have been loaded. The cellular space around a single fiber can be modeled as if it were a Krogh tissue cylinder. Each fiber has an outside “capillary” radius of 100 µm and the “tissue” radius can be taken as 200 µm. The following values apply to the device:R0 = 20 µM/secaO2 = 1.35 µM/mmHgDO2,T = 1.67 x 10-5 cm2/secPO2,m = 4 x 10-3 cm/secInstead of blood inside the fibers, the oxygen transport and tissue consumption are being investigated by usingan aqueous solution saturated with pure oxygen. As a result, there is no mass transfer resistance in the synthetic“capillary”, only that due to the membrane itself. Rather than accounting for pO2 variations along the length ofthe fiber, use an average value in the “capillary” of 130 mmHg.Is the tissue fully oxygenated?arrow_forwardMolecular Biology Please help with question. thank you You are studying the expression of the lac operon. You have isolated mutants as described below. In the presence of glucose, explain/describe what would happen, for each mutant, to the expression of the lac operon when you add lactose AND what would happen when the bacteria has used up all of the lactose (if the mutant is able to use lactose).5. Mutations in the lac operator that strengthen the binding of the lac repressor 200 fold 6. Mutations in the promoter that prevent binding of RNA polymerase 7. Mutations in CRP/CAP protein that prevent binding of cAMP8. Mutations in sigma factor that prevent binding of sigma to core RNA polymerasearrow_forwardMolecular Biology Please help and there is an attached image. Thank you. A bacteria has a gene whose protein/enzyme product is involved with the synthesis of a lipid necessary for the synthesis of the cell membrane. Expression of this gene requires the binding of a protein (called ACT) to a control sequence (called INC) next to the promoter. A. Is the expression/regulation of this gene an example of induction or repression?Please explain:B. Is this expression/regulation an example of positive or negative control?C. When the lipid is supplied in the media, the expression of the enzyme is turned off.Describe one likely mechanism for how this “turn off” is accomplished.arrow_forward
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