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SOVA2 [1]
2 years ago
12

The only haploid cells in humans (with 23 chromosomes and no matching pairs) are:

Biology
1 answer:
makvit [3.9K]2 years ago
6 0

Answer:

 

The only haploid cells in humans (with 23 chromosomes and no matching pairs) are:

A. sperm and egg cells

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Following antigenic stimulation, phosphorylation of _________ relieves inhibition of the transcription factor
Maru [420]

Answer: zap70, ITAM.

Explanation:

An antigen is any substance that is capable of stimulating an immune response by activating lymphocytes, which are the body’s infection-fighting white blood cells. Examples of antigens could be proteins that are part of bacteria or viruses or components of serum and red blood cells from other individuals, all of them are foreign antigens originated outside the body. However, there can also be autoantigens (which are self-antigens), originated within the body. In normal conditions, the body is able to distinguish self from nonself. <u>And the antigens that represent a danger induces an immune response by stimulating the lymphocytes to produce antibody or to attack the antigen directly</u>. This is called an antigenic stimulation of the immune system.

ZAP-70 (Zeta-chain-associated protein kinase 70) is a protein that is part of the T cell receptor, thereby it plays a critical role in T-cell signaling. When the TCR (receptor of T cells) is activated by the presentation of the specific antigen through the MHC, a protein called Lck acts to phosphorylate the intracellular CD3 chains and the ζ chains of the TCR complex, allowing the binding of the cytoplasmic tyrosine kinase, ZAP-70. Lck then phosphorylates and activates ZAP-70, which in turn phosphorylates another molecule in the signaling cascade called LAT (short for Linker of Activated T cells), a transmembrane protein that serves as an anchor site for several other proteins. The tyrosine phosphorylation cascade initiated by the Lck culminates in the intracellular mobilization of calcium ion (Ca2+) <u>and the activation of important signaling cascades within the lymphocytes.</u> These include the Ras-MEK-ERK pathway, which is based on activating certain transcription factors such as NFAT, NFκB and AP-1. These transcription factors regulate the production of of certain gene products, most notably cytokines such as interleukin-2 that promote the long-term proliferation and differentiation of activated lymphocytes.

The ITAM motifs (immunoreceptor tyrosine-based activation motif) are sequences of four amino acids present in the intracellular tails of certain proteins that serve as receptors within the immune system. Thus, <u>some receptors such as the TCR have ITAM sequences that, when activated, trigger an intracellular reaction based on consecutive phosphorylations</u>.  Kinases are recruited for this purpose.

So, ZAP-70 is a protein tyrosine kinase with a role in T-cell receptor signal transduction. During T-cell activation, ZAP-70 binds to ITAM and becomes tyrosine phosphorylated. The binding of ZAP-70 to the phosphorylated ITAM is able to activate its kinase activity, <u>and relieves the inhibition of the transcription factor which regulates genes that are involved in the immune reaction</u>.

6 0
2 years ago
Select a type of renewable energy. Compare it to fossil fuels by explaining two pros and two cons for its implementation on a la
myrzilka [38]

Answer:

Bio gas

Explanation:

Bio gas is gotten from the anaerobic breaking down of biomass especially animal waste.

PROS:

A. it is renewable: biogas is renewable and has an endless supply of material since animals are the main source when compared to fossil fuels.

B. It doesn't involve a rigorous mining exersice to get to like fossil fuels and it is in accessible abundance.

CON:

A. A lot of waste is needed for the product of biogas and the final waste (sludge) from the production process can be a huge problem to dispose off.

B. Some of the gases liberated in the manufacturing process are greenhouse gas, especially methane. These gases if let out, will contribute immensly to global warming.

8 0
2 years ago
Assess the effect of selective breeding on food crops
anastassius [24]
Selective breeding on food crops may create stronger, and more healthy crops. The idea is to find your best crops, and breed them with other crops sharing the traits you want.
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What type of macromolecule is an enzyme?
sleet_krkn [62]
The answer is proteins.
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What is the relationship between distance and magnetic attraction?
solniwko [45]
They are inversely related. As the distance increases the magnetic attraction decreases and when the distance decreases the magnetic attraction increases
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