A codon is basically a "word" in the genetic code.
Let's start at the base. A base is the smallest unit of information in genetics. It is a chemical represented by either A, T , C, G or U.
These genetic "letters" are combined into "words" which are called codons. What is useful is that each codon is only made of 3 bases. You'll have CCT, GAT, TTA etc. So what do these words represent? Well they can be instructions, like START or STOP, but usually they represent an amino acid, the LEGO building blocks of proteins. There are around 20 AAs but a bit of maths tells us we have a lot more codon combinations than AAs. This means we have some synonyms where several codons can represent one AA.
To take the analogy further, the codons combine into "sentences" and then "chapters". The chapters are a gene, usually instructions for a complete protein, but some of the sentences are useless and will be ignored when translating into a protein.
Then we have the "Book" which is the chromosome. The reason I like to think of it as a book is that at this point it is a contained unit, a massive molecule. You can separate up your books and even lend one to a friend, but you can't do that with a chapter unless you destroy the book.
Finally you have you "library" or genome. It's not a big collection, 46 books in total, and in fact you have 2 copies of each. It's like inheriting 2 sets of encyclopaedias from your parents. They both have the same information, it is just explained in different ways.
And there is my book analogy of genetics. It's not perfect but works when used on small children.
The Deepwater Horizon oil spill happened in 2010 and is known as the worst oil spill that has ever happened in the Gulf of Mexico. In this event, 5 million barrels of oil were poured into the sea, which resulted in the death of 7 workers, in addition to the destruction of much of the local ecosystem.
This spill lasted 87 days and spread for about 1500 km in the Gulf of Mexico, contaminating the water and killing thousands of animals. Although a team from Deepwater Horizon carried out a cleaning of the site, there are still traces of the leaked oil, which indicates that the ecosystem has not fully recovered. In addition, researchers were able to find petroleum compounds in many animals in the region and even in bird eggs.
Answer:
A. Plants will only flower during long day periods when the day length exceeds their necessary photoperiod
Explanation:
Photoperiodism is a phenomenon that refers to the response of an organism to the length of day. This phenomenon causes a physiological change in the organisms involved (plants or animals). However, the best studied example of change caused by photoperiodism is that of FLOWERING IN PLANTS.
Different plants flower at different times in response to the day length. Certain plants called LONG DAY PLANTS e.g. spinach and potato etc only flower when the length of day exceeds their photoperiod (threshold), which is usually 12 hours. These plants require very short periods of darkness to flower.
Hence, according to the question, FLOWERING response in plants is the best explanation to describe photoperiodism.
Answer:
crossing over
Explanation:
This occurs during prophase I and metaphase two of the cell cycle. Two homologous sister chromatids pair up and exchange DNA in order to increase genetic variation.
Answer:
The correct answer is- Rhizoids
Explanation:
Mosses are the small plants that don't bear flowers, stems, and roots and they grow in clumps. As they do not have root they developed root-like structures to anchor in the soil called rhizoids. They show a similar structure with the root hairs of higher land plants and also perform similar functions.
As mosses do not contain any stem and roots for transporting water therefore they usually grow in moist conditions where water is plenty and dry very quickly when surface water is removed.
Therefore rhizoids are the anchoring structures that mosses have instead of roots.
