28. <u>Answer</u>: All mutations do not affect the organisms due to the following reasons:-
1. The DNA consists of both coding and non coding regions. The coding regions are known as exons and non coding regions are called as introns. The <em>non coding regions </em>do not make up the protein. Thus, if the mutations occur in non coding regions they do not affect the organism.
2. There are some mutations that result in the change of the codon but the new codon formed codes for the same amino as the previous one. This is possible because of the degeneracy of genetic code. For eg, AAA codes for lysine, however if the mutation changes this code to AAU then this also codes for lysine. Such mutations are called as <em>silent</em> mutations.
3. There are some mutations which result in the change in amino acid however the new amino acid formed is similar to the previous one in its properties for e.g leucine and isoleucine. Such mutations are called as <em>neutral</em> mutations and they do not affect the organism
29. <u>Answer</u>: 1. The process of mitosis results in the formation of <em>two diploid cells</em> whereas meiosis results in the formation of <em>4 haploid cells.</em>
2. The process of mitosis takes place to produce copies of the <em>body cells </em>whereas the process of meiosis takes place to produce the <em>gametes</em>.
<u>Explanation</u>:-
- <u>Mitosis</u> is a process in which a cell undergoes a single round of division to produce two identical copies of itself . It occurs in 4 phases Prophase, metaphase, anaphase and telophase. This process occurs in the body cells.
- <u>Meiosis</u> is a process in which a cell undergoes two rounds of cell division to produce 4 copies of haploid cells from a single diploid cell. This process takes place for the formation of gametes.
29. <u>Answer</u>:
<em>Pros</em>
1. Genetic engineering helps us to tackle several diseases. There are many diseases which are caused due to genetic mutations. Genetic engineering helps us to rectify these mutations and hence combat such diseases.
2. Genetic engineering helps us to produce new foods which can withstand adverse conditions such as high/low temperatures, low rainfall, are disease and pest resistant etc. This, genetic engineering helps to significantly improve crop production.
<em>Cons</em>
1. Genetic engineering leads to a decrease in genetic diversity.
2. It can lead to a decrease in the nutritional value of food as genetic engineering often causes an accelerated growth of animals and hence, the nutritional valie of poultry foods is compromised.
Answer:
Since sea urchins are picky, they are used as indicator organisms in public aquariums to determine if the system is functioning properly. This is because they are very "picky" about water quality. If the water is contaminated, the sea urchins will be the first to show signs of stress, spines laying down or falling off. Do use an aquarium filter and do clean up the day after feeding. Any metal exposed to the seawater will corrode and poison the tank. A dying sea urchin will often spawn out and rot out, causing the others in the tank to spawn and die as welll.
Explanation:
Answer:
b: 8;8
Explanation:
Mitotic or meiotic cell division constitute the m phase of the cell cycle. At the end of the m phase, the new cells enter the interphase stage of the cell cycle. The interphase is further sub-divided into;
- <em>the
phase,</em> - <em>the
phase,</em> - <em>the S phase; and</em>
- <em>the
phase</em>.
The
phase is essentially a resting phase. Cells that do not need to divide except when necessary move into this phase after exiting the m phase.
Actively dividing cells enter the
phase after exiting the m phase. Cell development and growth takes place. From there, the cells enter the S phase where DNA replication/synthesis takes place. The cells then enter the
phase where proteins are synthesized in preparation for division or m phase.
At the S phase, the amount of DNA a cell carries is doubled but the chromosome number remains the same. For example, if a cell enters the S phase with 2 g of DNA containing 10 chromosomes, at the end of S phase, the amount of DNA would have come 4 g while the number of chromosomes will remain 10.
Hence, if the average amount of DNA in the assayed cells immediately after mitosis is 4 picograms, the amount would be 8 picograms at the end of S phase and will still remains 8 picograms at the end of
phase.
The correct option is b.
Answer:
Recent studies of the veterinary profession have established a need for training in various areas beyond those directed toward building competence and proficiency as a clinician. To address this need, a workshop was designed whose objective was to develop a detailed outline of a model curriculum that would encompass the skills, knowledge, aptitudes, and attitudes deemed essential for economic success in the veterinary profession. The model curriculum was created from comprehensive input provided by consultants and educators. Constraints for implementation of this curriculum are identified, and future directions are discussed.
Nope it is not look it up on the Internet