266: Which one of the following pairs is not correctly matched ?
Recent Scientific Achievement : Country
(a) Creating the worlds first human chromosome : United Kingdom
(b) Cloning a human embryo for the first time : Germany
(c) Guiding a spacecraft for collision with a comet : USA
(d) Landing a spacecraft on an asteroid : Japan
267: With reference to the treatment of cancerous tumours, a tool called cyberknife has been making the news. In this context, which one of the following statements is not correct ?
(a) It is a robotic image guided system
(b) It delivers an extremely precise dose of radiation
(c) It has the capability of achieving sub-millimetre accuracy
(d) It can map the spread of tumour in the body
Explanation:
The Cyberknife is not actually a knife at all. It's a state-of-the-art piece of equipment that allows specialist oncologists to treat tumours and other medical conditions painlessly without the need for an operation. Cyberknife uses pencil beams of radiation which can be directed at any part of the body from any direction via a robotic arm.
The robotic arm tracks the tumour's position, detects any movement of the tumour or patient, and automatically corrects its positioning before targeting the tumour with multiple beams of high-energy radiation, destroying abnormal tissue without damaging surrounding areas.
The treatment is so accurate that it's now possible to treat tumours previously thought to be inoperable. Although the results of treatment do not always show immediately, in most cases the procedure will initially stop the growth of tumours before gradually reducing their size.
268: Which one of following is produced during the formation of photochemical smog?
(a) Hydrocarbons
(b) Nitrogen Oxides
(c) Ozone
(d) Methane
269: Population of cells derived from a single parent cell is called
(a) Haploid
(b) Diploid
(c) Symmetrical cell
(d) Clone
270: Which one among the following is not a good source of nutritional calcium?
(a) Egg
(b) Skimmed milk
(c) Ragi
(d) Rice
Explanation:
Rice is a poor source of calcium and therefore insufficiency of calcium is one of the main defects of diets largely based on rice.
Food value of 100 grams of egg is 13.3% proteins, 13.3% fat, 173 kcal of energy, 60 mg calcium, 220 mg of sulphur and iron and vitamins. Ragi and Skimmed milk are good sources of nutrient calcium.