Endocytosis is when a a cell engulfs material into the cell and exocytosis a form of waste where the cell gets rid of materials.
Answer:
The correct answer will be option-B.
Explanation:
The plant tissues are composed of three types of cells: parenchyma, collenchyma and sclerenchyma.
The parenchyma and collenchyma remain alive at their maturity but sclerenchyma loses their protoplasm and become dead. These cells deposit lignin in their secondary walls and form hard tissues of the plant-like hard shell of a coconut. Sclerenchyma provides mechanical strength to the plant.
Thus, Option-B is the correct answer.
Answer:
"Last week, you looked at both animal & plant cells. Both of these cells were diploid somatic eukaryotic. This week, you'll be looking at a different, but very important, type of cell: sexual cells. Two gametes, one from a female & one from a male, merge during the process of fecundation/fertilization to form a zygote. All in the organism will develop from this initial diploid cell".
Explanation:
There are two principal types of cells in the organism: Somatic cells that can not form any gametes, and germ cells that are in charge of gamete production. Both somatic cells and germinal cells will end their cycle dividing and becoming two daughter cells with the same genetic dotation after mitosis.
Somatic cells are any cell in the body excepting from sperm and egg cells. These somatic cells are diploid, they contain two chromosomes sets, each one inherited from each parental. Mutations in somatic cells affect the individual but the progeny does not inherit them. In this sense, these cells do not contribute to anything to inheritance terms through genetics.
Germ cells are the reproductive diploid cells, and the sexual organs (testes and ovaries) are the ones that produce them. These cells might suffer mitosis to form more sexual cells, and then a few of them suffer meiosis giving place to haploid gametes called sperm and egg cells through the gametogenesis process. Each germ cell produces 4 haploid gametes after meiosis.
Gametes´destiny is to merge in the process of fecundation, during which a new diploid cell called zygote emerges through fertilization. The zygote is a complete cell from the structural point of view that suffer successive mitosis to form the new organism.
Answer: Answer below
Explanation: pH is a measure of the acidity or alkalinity of a solution. What the pH scale measures is basically the concentration of hydrogen and hydroxyl atoms in a solution. So, the last option is the answer. Another thing to keep in mind is solutions with a pH under 7 are acidic, solutions with a pH of 7 are neutral, and solutions with a pH over 7 are alkaline or considered a base. I hope this helped! Good luck:)
Diagram found elsewhere attached
Answer:
Clockwise from bottom
3. formation of mRNA in the nucleus
6. secretion of hormone by tissue
4. initiation of DNA replication because of a signal given by the hormone
2. synthesis of protein molecule by mRNA and tRNA
1. secretion of protein by the cell
5. binding of the hormone molecule with its receptor of the cell
Explanation:
The tissue in the top left releases a hormone. For example, a steroid hormone such as estrogen, which can impact gene expression at the level of transcription. This hormone then travels to a different cell to carry out its function. The hormone is able to enter the cell and binds receptors which recognise it. In this case, these receptors are present in the nuclear envelope. When the hormone has bound the receptor, it initiates a signalling cascade that the cell responds to.
In this case, the effect of the signal from the hormone is to initiate DNA replication. This is a common effect of hormones such as growth factors that signal the cells to proliferate.
The initiation of the signalling can also affect how genes are expressed. In this case, an mRNA is produced in the nucleus, which is created as a result of transcription. This mRNA molecule then moves to the cytoplasm, where it becomes translated into a polypeptide sequence at a ribosome, with the help from transfer RNAs (tRNAs).
This polypeptide forms a mature protein by progressive folding and potential modifications, and is released by the cell to perform its functions.
