1.1
Meiosis I
The first meiotic division: diploid → haploid
Prophase I: Chromosomes condense, nuclear membrane dissolves, homologous chromosomes join and occurs crossing over.
Metaphase-I: the homologous chromosomes align in the middle of the cell. Spindle fibers from the centrosomes connect to the chromosomes.
Anaphase -I: Spindle fibers contract and split the homologous chromosomes, moving them to opposite poles of the cell.
Telophase -I: Chromosomes decondense; cell divides to form two haploid cells.
1.2 Meiosis II
The second division: separates sister chromatids (these chromatids may not be identical due to crossing over in prophase I)
Prophase II: Chromosomes condense, nuclear membrane dissolves, centrosomes move to opposite poles (perpendicular to before)
Metaphase-II: the chromosomes align in the middle of the cell. Spindle fibers from the centrosomes connect to the chromosomes (at the centromere)
Anaphase-II: Spindle fibers contract and split the sister chromatids, and moves them to opposite poles of the cell.
Telophase-II: Chromosomes decondense,cells divides again to form another 2 haploid daughter cells. Final: 4 new cells.
2. The differences:
Mitosis:
- has 1 division per cycle
- one cell produces 2 new cells
- the genetic information in the mother-cell and the daughter-cells are the same. ( the number of chromosomes is also the same)
- it occurs in somatic cells
Meiosis:
- two divisions per cycle
- one cell when divides produces 4 new cells
- the new cells have different genetic information. mixes the genetic material from the parent cells
- the number of chromosomes of the daughter cells is half of the mother's.
3. Prokaryotic organisms don't divide through mitosis, they use a different process called binary fission. Only eukaryotic organisms, or those whose cells have a defined nuclei, undergo mitosis. Bacteria, for example, are prokaryotic organisms that use binary fission.
4.
It can't occur. Cross over is the exchange of DNA between homologous chromosomes. That will result in recombinant chromosomes during sexual reproduction. It can't occur on different chromosomes because they don't code for the same genes.
5. There are a lot of different theories about that, but it's mostly believed that meiosis must evolve before sexual reproduction. That's because The cell replicates their information first and then divides. Plus the cell does that even though it didn't recombine DNA with another organism (sexual reproduction).
Answer:
c. switching from beef to soy
Explanation:
Switching from beef to soy shall lead to the curbing of lifestyle diseases such as obesity.
At the same time, soy shall provide the nutrients that were needed by the body and could be obtained from beef.
Beef is much expensive compared to beef, thereby, there shall be experienced low expenditure compared to beef.
Therefore the switching from soy to beef shall be a more sustainable food system.
Hazards are placed at the root of the tree and determining the cause of the hazard is the correct option for the following hazard analysis questions.
Fault Tree Analysis (FTA) explores how selected “top” faults (abnormal conditions) or fault events such as accidental/unwanted releases of hazardous materials can be resolved to their causes. Hazard analysis is defined as the process of gathering and interpreting information about the hazards and conditions leading to their existence in order to determine what is food safety related and must be addressed in the HACCP plan. Hazard analysis is used as the first step in the risk assessment process. The result of hazard analysis is the identification of different types of hazards. A hazard is a potential condition that may or may not exist.
To know more about Hazard analysis visit:
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Answer: The Parathyroid gland
Explanation:
The Parathyroid gland secretes "Parathormone", an hormone that exerts
- direct influence on the bone by INCREASING the release of bone calcium ion (Ca2+) into the blood
- affects the kidney by stimulating the renal tubules to eliminate EXCESS calcium in the urine.
Thus, the calcium balance of the body depends on the secretion of the Parathyroid gland
Complementary nucleotides pair with one of the DNA strands to form an RNA molecule
