Match each field of study to the correct piece of evidence. Tiles molecular biology comparative anatomy developmental biology Pairs embryo of a pig and a calf arrowBoth DNA of a pig and a calf arrowBoth limb structure of a pig and a calf arrow Both.
Answer:
4. B cells become activated by interacting with helper T cells.
1. B cells display antigens in MHC class II receptors on the cell surface.
2. Antibodies released by plasma cells bind to the antigen so they will be destroyed by other cells of the immune system.
3.B cells rearrange their DNA to create a unique B-cell receptor.
5. B cells undergo clonal expansion.
6. B cells digest antigens that bind to the antibodies on their surface.
Explanation:
B-cells get activated by interacting with helper T cells when they bind to the antigen to receptors i.e (MHC class II receptors on the cell surface) on the surface of the cell. Series of activities such as release by plasma cells which cause rearrangement of B cells causes the cell to divide and proliferate. The process through which daughter cells arise from a parent cell called clonal expansion.
The sole reason why red blood cells are unable to replace damaged proteins is that red blood cells lack DNA and cell organelles such as the nucleus, ribosomes, and mitochondria which are crucial for protein synthesis, assembly, and repair. In other words, they lack both the information and the machinery for making or repair of proteins.
Due to lack of DNA and cell organelles, red blood cells cannot be able to satisfy the central dogma which summarizes synthesis of proteins as DNA → RNA → proteins.
DNA has the genetic information on how proteins should be made, RNA is responsible for transferring the information from DNA in the cell nucleus to the ribosomes in the cytoplasm, then translating or decoding this information, which results in the making of protein.
<span>An element is a substance that cannot be broken into other substances further.An element is composed of one type of atoms all over. Like a molecule can be divided into atoms further. For example, Water is a molecule which is made up of Oxygen (O), Hydrogen (H). Here, Oxygen and Hydrogen are elements and cannot be further broken down into other substances.</span><span />
Answer: 1. Cyclin-dependent kinases.
2. The activation process is in two steps: binding of cyclin to cdk and then phosphorylation of cdk cyclin.
3. They are activated when cdks sends signals to cell that is pass already into the next stage of the cell cycle.
4. They are inactivated by the combination of P21 and Thr-14/Tyr-15 phosphorylation after uv induced DNA damage.
5. Changes are seen in target protein level when cdks level rises.
6. The targets are protein that promotes cell divisions.
Explanation:
