Chapter 6
Why is ionizing radiation damaging to cells?
It knocks the electrons from the cell's molecules, forming ions and breaking bonds.
The concrete sarcophagus enclosing the damaged reactor is crumbling, allowing radiation to leak out into the environment. An animation of a new protective cover is shown in the video. Why hasn't the construction of this cover been completed?
It will be extremely expensive to build.
In the early 1950s, many researchers were racing to describe the structure of DNA using different approaches. Which of the following statements is true?
Jim Watson and Francis Crick built theoretical models, incorporating current knowledge about chemical bonding and X-ray data.
You can estimate the deadliness of each type of cancer by dividing the number of deaths by the number of cases. If nearly everyone who received a diagnosis of one particular type of cancer dies, the ratio will be near 1 (or 100% deadly). If many more people receive a diagnosis than die, the ratio will be near 0 (or 0% deadly). Rank these three cancer types from the most deadly to the least deadly.
Most- lung cancer middle- breast cancer least prostate cancer
After you have watched the tutor session, answer the questions. Estimated time: 15 minutes
Part A- Blue Part B- polyphosphate Part C- CGTG Part D- 4 Part E- sugar and phosphate only
Many of the first responders at the Chernobyl accident died within hours or days of working at the explosion site. What were they most likely to die from, and why?
acute radiation sickness due to exposure to ionizing radiation
In addition to the risk of accidents, which of the following is a problem when nuclear power is used as a method of generating electrical power?
storage and disposal of spent fuel rods
In the 1950s, when Watson and Crick were working on their model of DNA, which concepts were well accepted by the scientific community?
- Chromosomes are found in the nucleus. - Genes are located on chromosomes. - Chromosomes are made up of protein and nucleic acid.
What did the structure of DNA's double helix suggest about DNA's properties?
- DNA stores genetic information in the sequence of its bases.DNA can change. - Errors in copying can result in changes in the DNA sequence that could be inherited by future generations. - DNA can be replicated by making complementary copies of each strand.
Use the data table and your knowledge of cancer to identify which statements are true.
- The combined survivability of all types of cancer is about 65%. - Reducing risk factors might decrease the number of cancer cases, but would be unlikely to decrease the cancer deadliness percentages.
What are the chemical components of a DNA molecule?
- nitrogenous bases - sugars - phosphate groups
We may never know how many people became ill or died as a result of the Chernobyl accident. What is the main reason why this is so difficult to determine?
Cancer might not occur for many years after exposure to ionizing radiation.
What did Rosalind Franklin's famous photo 51 show?
DNA is a helix.
Early, flawed DNA models proposed by Watson and Crick and by Linus Pauling correctly described which property of DNA?
DNA is composed of sugars, phosphates, and bases.
Erwin Chargaff observed that the proportions of adenine (A) and thymine (T) bases were always equal, as were the proportion of guanine (G) and cytosine (C). Chargaff's observation suggests which of the following statements?
The data suggest that A would always pair with T and G would always pair with C in a DNA molecule.
Although the forest is growing quickly around Chernobyl, and some of the wildlife is thriving, studies show that biodiversity around Chernobyl has been reduced by over 50% since the accident. Why?
The ionizing radiation affects the DNA of the wildlife, just as it affects the DNA of humans.
Why is the town of Pripyat uninhabited?
The radiation levels in the town are still unsafe.