Answer:
DNA is made up of six smaller molecules -- a five carbon sugar called deoxyribose, a phosphate molecule and four different nitrogenous bases (adenine, thymine, cytosine and guanine)
Explanation:
Answer:
Chloroplasts are not visible in the onion bulb, only in its leaves and stem.
Explanation:
Chloroplast is an organelle found in the cells of green plants, and in photosynthetic algae, where photosynthesis takes place.
Note that onion bulb do lack chloroplasts because the bulb is usually situated under the ground where light cannot penetrate; so it does not need chloroplasts.
However, the green leaves and stem of an onion plant (the shoot system situated above the ground) are normally exposed to daylight and so have chloroplasts for the production of sugars stored in the bulb, but the onion bulb does not.
In spite of all that has been mentioned, onion contains plant cells not animal cells.
The antibiotic penicillin is isolated from <u><em>Penicillium notatum</em></u> fungi
Penicillin was first discovered in 1928 and was used at St. Mary's Hospital, London, by Alexander Fleming to heal wounds due to its antibacterial properties.
Explanation:
Fungi and bacteria usually produce antibiotics (as secondary metabolites) for defense mechanism. They do so to limit competition for resources with other neighboring fungi or bacteria in their environment. This is why when a fungus or bacteria establishes itself in an environment, you hardly see other fungi or bacteria types growing in their vicinity.
Learn More:
For more on antibiotics check out;
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Answer:
C-14 can be used for dating fossils (50,000-70,000 years)
Explanation:
A fossil is a preserved remains of a once-living organism from a past geological age. Moreover, radioactive decay is a natural process by which an unstable atomic nucleus loses energy by emitting radiation. C-14 (Carbon 14) is a radioactive isotope of carbon that emits radiation which is widely used for dating fossils. C14 decays into the stable isotope C 12 and this radioactive isotope (C-14) has a half-life of 5730 yrs, thereby it is possible to use this rate of decay in order to calculate the age of an object according to the proportion of C14 remaining. The short half-life of C-14 indicates that this radioactive isotope cannot be used to date extremely old fossils (after 50,000-70,000 years, the C-14 dating method is no longer valuable for estimating the age).
