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:
La pata de un pato y la aleta de un pez son en ambos casos son elementos que les permiten tanto al pato como al pez moverse, además de sus funciones de estabilidad. La aleta de una ballena y el brazo del ser humano, sucede lo mismo que en el caso anterior. En el caso de la aleta de la ballena, es como la aleta del pez. En cuanto al brazo del ser humano permite realizar movimientos que contribuyen al desarrollo de sus funciones, como por ejemplo, agarrar distintos elementos. La pelvis reducida de los cetáceos no tiene actualmente ninguna función.
Explanation:
La pata de un pato es una extremidad que por su estructura le permita nadar perfectamente. En cuanto a la aleta de los peces y ballenas, es una parte de estos animales formada por tejido conjuntivo. Pueden tener distintos tamaños y su principal función no sólo es permitir el movimiento sino también la estabilidad. En cuanto a la pelvis reducida de los cetáceos era algo que tenía sentido en especies de antaño. Durante la evolución, su utilidad de fue perdiendo, como podría mencionarse el ejemplo en los humanos de las muelas de juicio.
<u>Answer:</u>
The correct answer is Uracil which is nitrogen base found in RNA.
<u>Explanation:</u>
Uracil is a nitrogenous base which is located within an RNA molecule but not within a DNA molecule.
Uracil, represented by the letters A, G, C and U, is one of the four nucleobases that are found in the nucleic acid of RNA which binds to adenine.
While thymine is present in the DNA and binds to adenine.
I filled out a few boxes for you to start you off. I also gave you a direct research sources for some animals that will take you to the necessary information.
This is what I have so far as examples for you. Again, I said I wouldn't do all of your work for you, however, I will help you through your research and graph.
Answer:
the citric acid cycle and preparatory steps
