Nucleic acids / aka nucleotides
Answer:
True.
Explanation:
This is true because Meteorites originate range from 4.5 billion years old to 200 million years old.
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).
<u>Answer:</u>
To help relieve heartburn, a person should take medicine that is 'Over-the-counter (OTC) antacids and acid blockers'.
<u>EXPLANATION:</u>
- Heartburn is a very common symptom of a condition called Gastroesophageal reflux disease.
- This affects the lower part of the esophageal sphincter and also the muscle ring-like connection between the 'esophagus and stomach' which tends to infuse a backward flow of the stomach secretions.
- Along with some dietary and life style changes, the intake of antacids and acid blockers can help in the relieve of the symptoms of occasional heartburn.
Answer:
It could lead to several later problems in the cell.
Explanation:
Removing a piece of DNA could severely affect the cell but it could also cause nothing. Depending on the part that is damaged, it could codify for a vital protein but it could also be an intron, which are pieces of DNA that don't codify for any protein. This has been recently researched and even though there are introns that could cause some serious trouble, most of them are an unknown matter to nowadays scientists. Anyway, a wrongly repaired sequence could end in a mutation that can potentially damage the cell and therefore the organism.
