Answer:
The parent's genotypes are:
Ddpp - tall, white parent
ddPp - dwarf, purple parent.
Explanation:
This question involves two different genes coding for height and flower color in pea plants. The alleles for tallness (D) and purple color (P) are dominant over the alleles for dwarfness (d) and white color (p) respectively.
According to this question, a tall plant with white flowers is crossed with a dwarf plant with purple flowers to produce the following proportion of offsprings: 1/4 tall purple, 1/4 tall white, 1/4 dwarf purple, and 1/4 dwarf white.
Since some of the offsprings contain recessive alleles for both or either genes, the dominant traits of the parent is controlled by an heterozygous genotype. This means that the tall plant with white flowers has a genotype: Ddpp while the dwarf plant with purple flowers has the genotype: ddPp. In a cross between Ddpp × ddPp, 1/4 of each combination of alleles is produced in the offsprings (see punnet square in the attachment).
Answer:
Because Intercalary meristems are found in the the stem part of the sugarcane in whole length.
Explanation:
- As we have studied about meristem regions, that these are the regions found at the nodal areas which are able of cell division and growth. Intercalary meristem are present in the nodes of sugarcane stem which lead to the rapid increase in elongation of stem.
- Intercalary meristem are located at the base of leaves and nodes that leads to the increase in length.
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On the tip of sugarcane, apical or tip region meristem are found. When the tip region is removed, the presence of intercalary meristems play the role by facilitating the elongation of stems in sugarcane.
Please see attached image for better understanding.
Hope it helps!
Answer:
peptide antigens by MHC class II molecules
Explanation:
Helper T cells are activated by peptide antigens by MHC class II molecules. These antigens express on the surface of antigen-presenting cells (APCs). After activation, the T helper cells divide and secrete cytokines to assist the immune response.
The cell needs transcription because the DNA cannot leave the nucleus and therefore cannot transmit info to the other cells.
Answer:
Active transport:
- requires energy
- molecules move from low to high concentration sides
- Na+ and K+ move by active transport
Simple diffusion:
- molecules move from high to low concentration sides
- molecules pass between lipids
- small non-polar and polar molecules
Facilitated diffusion:
- molecules move from high to low concentration sides
- involves channel proteins
- move large molecules
Explanation:
- Simple Diffusion is the pathway of only small molecules that freely move through the membrane by momentary openings produced by the lipids' movements. Diffusion is a slow process that requires short distances and pronounced concentration gradients to be efficient. An example of diffusion is osmosis by which water is the transported molecule.
- Facilitated diffusion is the transport of hydrophilic molecules that can not freely cross the membrane. Channel protein and many carrier proteins are in charge of this transport. When uncharged molecules cross the membrane, they do it according to their concentration gradients, going from the more concentrated side to the lower concentrated one. When ions need to cross the membrane, the process depends on an electrochemical gradient. Glucose is an example of a hydrophilic protein that gets into the cell by facilitated diffusion.
Simple diffusion and facilitated diffusion are both passive transport processes because they only depend on electrochemical gradients, so they do not need any energy to occur.
- Active transport is the transport of molecules that move against the electrochemical gradient, so it does need energy to happen. Molecules move from the lower concentration side to the higher concentration side of the membrane. Carrier proteins are in charge of active transport. The needed energy might proceed from the ATP molecules or the membrane's electric potential. An example of molecules moved by active transport are the Na and K.
