Ans.
Chromatin molecules are made up of DNA and histone proteins. Modification of chromatin structure include covalent, post-translational changes in histone proteins, present in chromation. Acetylation and methylation are two important histone modifications that affect structure of chromatin molecules.
Acetylation involves addition of an acetyl group to histones that increases transcription of DNA by loosen the association between DNA and nucleosome.
Methylation involves addition of a methyl group to histones that results in condensation of chromatin molecule and thus, decreases transcription of DNA.
Both acetylation and methylation are reversible processes.
Many chromatin modifications are genetic, means they can pass from one generation to another generation, called epigenetic modifications.
Thus, options B), C), D), E), and F).
Answer:
1. Mitosis c) The process of cell reproduction of human tissues that occurs when the cell divides into two identical cells
2. Nucleus a) The dense, active protoplasm found in the center of the cell
3. Cytoplasm b) The watery fluid that surrounds the nucleus of the cell and is needed for growth, reproduction, and self-repair
4. Cell membrane d) The part of the cell that encloses the protoplasm and permits soluble substances to enter and leave the cell
Explanation:
- Mitosis is the process that undergoes a cell to give two new identical cells. This is how our body makes or renovates tissues.
- The nucleus is the part of the cell that contains the DNA, which is necessary to synthesize the proteins that the cell and our body need. It is in the center of the cell and has a nuclear membrane that separates it from the rest of the organelles.
- The cytoplasm is a solution that surrounds the nucleus, and it contains the rest of the organelles that the cell needs for its functions.
- The cell membrane is the structure that encloses all the cytoplasm and the nucleus. It is made of phospholipids, proteins, and cholesterol, which allows the passage of certain substances.
Because they want to know the existence of aliens
Answer:Cells are the basic building blocks of all living things. ... Cells also contain the body's hereditary material and can make copies of themselves. Cells have many parts, each with a different function. Some of these parts, called organelles, are specialized structures that perform certain tasks within the cell.
Explanation:look it up
