Cell membrane is a semipermable, which means that certain molecules will be able to pass through the membrane. It is contains phospholipids. But for smaller molecules such as CO2 and Water, it can pass through the membrane through simple diffusion. Cell membrane controls the movement of the materials into and out of the cell.
Sister chromatids have different alleles although carry same genes on same loci. So if it doesn't happen so, like if there are same alleles on sister chromatids then there is a problem in its formation. i.e., male and female alleles haven't contributed equally ( may be an error during their segregation process ). And obviously it doesn't happen in a real cell so we must understand this point. Because normally whenever it happens there's one half from the male and one half from the female. (i.e. maternal and paternal alleles contribute equally).
I hope you get the answer!!!
Answer/Explanation:
<h3>Incomplete dominance</h3>
In incomplete dominance, one allele is not entirely dominant over the other, so heterozygotes (organisms with two different alleles for the gene) show an intermediate or blended phenotype.
For example, consider flower colour.
- If the allele for red flowers (R) was dominant over the allele for white flowers (r), then there are three possible genotypes (RR, Rr, and rr) and two possible phenotypes. (Red (RR and Rr) and white (rr)).
- However, if the allele for red flowers (R) was incompletely dominant over the allele for white flowers (r), then there are three possible genotypes (RR, Rr, rr), and three possible phenotypes (red (RR), white (rr), and pink (Rr))
<h3>Co-dominance</h3>
In incomplete dominance, two alleles are both expressed, one is not dominant over the other. Therefore, heterozygotes (organisms with two different alleles for the gene) express both traits.
For example, consider flower patterns.
- If the allele for spots (F) was dominant over the allele for stripes (f), then there are three possible genotypes (FF, Ff, and ff) and two possible phenotypes. (Spots (Ff and ff) and stripes (ff)).
- However, if the allele for spots (F) was co-dominant to the allele for stripes (f), then there are three possible genotypes (FF, Ff, ff), and three possible phenotypes (spots (FF), stripes (ff), and spots and stripes (Ff))
