Answer:
Explanation:
Well the question was a little unclear, but for disaccharides:
(alpha) Glucose + (alpha) Glucose = Maltose
(alpha) Glucose + Fructose = Sucrose
(alpha) Glucose + Galactose = Lactose
More than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.
Within a gymnosperm megasporangium, the following developmental sequences that are correct, assuming fertilization occurs is: megaspore, female gametophyte, egg cell, sporophyte embryo. The last Option (Option D) is correct.
In gymnosperm megasporangium, the meiotic division produces four haploid megaspores from a single cell, three of which generally degenerate. The female gametophyte is formed by mitosis from the surviving megaspore.
Prior to fertilization, the male mature gametophyte needs to be transferred to the female gametophyte for fertilization to take place.
When the nuclei of the sperm encounter the nucleus of the egg cell in gymnosperms, it fuses with the egg nucleus to produce a diploid zygote.
Mitosis occurs in the fertilized egg to initiate the growth of a new sporophyte generation (the multicellular embryo of the seed.)
Therefore, we can conclude that we've understood the mechanism of developmental sequence in the gymnosperm megasporangium.
Learn more about the gymnosperm here:
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B) It is a fluid mosaic model, with proteins interspaced in the phospholipids, both of which can freely move laterally.
Explanation:
The fluid mosaic model proposed by Singer and Nicolson describes the plasma membrane’s structure as a mosaic pattern of components consisting of phospholipids, proteins, cholesterol, and carbohydrates; all of which provides the unique fluid character of the membrane.
According to this model, the phospholipids constitute the main fabric, cholesterol attaches between the phospholipids in between the layers, integral proteins embedded within the bilayers of the phospholipids, peripheral proteins along the peripheries of the layers and carbohydrates outside the membranous layers.
Answer:
e. Epistatic interaction of the two genes
Explanation:
The 9:7 ratio is typical of the Duplicate Recessive Epistasis.
The expected phenotypic ratiio of the offsrping of a dihybrid cross is:
9 A_B_
3 A_bb
3 aaB_
1 aabb
In the Duplicate Recessive Epistasis, the A_bb, aaB_ and aabb individuals all have the same phenotype, making for the ratio 9:7. What those three genotypes have in common is that in all of them at least one of the two genes is homozygous recessive (either <em>aa</em> or <em>bb</em>).
This usually happens one the products of genes A and B are enzymes of the same metabolic pathway.
Whenever both A and B are present, the pathway can produce the final product and a certain phenotype. However, if any of the dominant alleles is missing, the enzyme is not produced and therefore the final product of pathway is not produced, giving the other phenotype.