Answer:
Repair mechanism for base cleavage (BER)
Explanation:
Repair by base cleavage (BER)
The altered bases are specifically recognized by glycosylases and removed, generating an AP site. The hole is filled by a DNA polymerase that takes the healthy strand as a template. This system arises not only by exposure to external agents, but also by the cell's own activity.
In case of damage in more than one nucleotide, repair by nucleotide excision (NER) is performed.
Nucleotide excision repair (NER)
The damaged area is recognized by UvrA and B, then A and B separate and UvrC enters which forms a complex with endonuclease activity with B. This enzyme cuts the T-dimer and the gap is filled by a DNA polymerase. There is also the TC-NER system (transcription-coupled nucleotide repair system). The alteration of these mechanisms gives rise to diseases such as: Xeroderma pigmentosum, Trichotiodystrophy or Cockayne Syndrome
Answer:
Explanation:
A gene can be turned on or off by environmental factors or from other cells that activate proteins known as transcription factors.
Answer:
1. Antonie van Leeuwenhoek made the first microscope and used it to look at bacteria and study bacteria, and Robert Hooke studied cells and saw cavities in the cells that looked like small boxes - he discovered plant cells! he recognized cells as the basic unit of life, a basis for Cell Theory.
2. cell theory is: every living organism is made of one or more cells, cells are the smallest units of life ( that have the properties of a living thing), All cells come from other cells - all living things come from other living things. This relates to every living thing because all living things come under cell theory - like all living things are made of cells
3. prokaryotes, like bacteria, doesn't have a nucleus covered in a membrane. a eukaryotic cell, like an animal cell, has a membrane covered nucleus. just like the nucleus, in eukaryotes the organelles are not membrane bound. in prokaryotes, the organelles are membrane bound. In prokaryotes the DNA form is circular, while the DNA form in eukaryotes is linear. there are more, but i couldn't list them.
4. Example for prokaryote: the famous (or infamous) E. Coli bacterium. example for eukaryote: Humans!
5. Single-celled organisms (unicellular organisms) have all the functions necessary for their survival in the single cell. Multicellular organisms (many celled organisms), however, need many cells to survive and carry out all the functions necessary for their survival and do the different tasks each cell is supposed to do.
I hope this helped, please do correct me if I am wrong!
Explanation:
