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Cerrena [4.2K]
3 years ago
8

Most cells can only be seen with:

Biology
2 answers:
REY [17]3 years ago
4 0

Answer: a microscope

Explanation:

GrogVix [38]3 years ago
3 0

Most cells can only be seen with the help of a microscope

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What is the relationship between the temperature of internal material and volcanic eruptions?
OLga [1]

Answer:

Direct relationship.

Explanation:

There is direct relationship between the temperature of internal material and volcanic eruptions because the temperature of internal material causes the volcanic eruptions. The temperature of the internal material puts pressure on the rocky surface and the gases that releases from heating processes will cause pressure which leads to the eruption of the volcano so we can say that there is a direct relationship between temperature and eruption.

3 0
3 years ago
In a particular species of frogs, black spots are a dominant trait and their absence is a recessive trait. In a population of fr
kipiarov [429]

The expression which is the correct way to calculate the frequency of the dominant allele is 134/200. Thus, the correct option is D.

<h3>What is Allelic frequency?</h3>

The allelic frequency may be defined as the sum total of all the alleles of a gene in a population. It represents the overall genetic diversity within a population.

The allelic frequency is calculated by the formula when the genotypes are given in number. It is as follows:

2 × Number of Purebred dominant + Number of heterozygous/ 2× Total number of individuals in a population.

∴ Allelic frequency of dominant allele = 2 × 50 + 34/ 2× 100 = 134/200 = 0.67.

The allelic frequency of the Dominant allele is 0.67 while the allelic frequency of the recessive allele is 0.33.

Therefore, it is well described above.

To learn more about Allelic frequency, refer to the link:

brainly.com/question/14649601

#SPJ1

5 0
2 years ago
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
Where is amyglada located in a brain ? How does it function ?​
Sedbober [7]

Short Answer: The amygdala is located in the brain and its functions are related to emotional learning.

Explanation

The amygdala is a brain structure located in the temporal lobe of the brain. Its functions are related to the emotional system of the brain, and memory. In addition, the amygdala has been shown to influence the emotional learning process. The amygdala is mainly responsible for the formation and storage of memories associated with emotional events, so external sensory stimuli reach the basolateral group of the amygdala, where associations are formed with memories of the stimulus (mainly related to fear).

7 0
3 years ago
What percentage of alleles are<br> homozygous recessive?<br> 50%<br> 25%
zepelin [54]
The percentage of alleles for homozygous recessive would be 50%
8 0
3 years ago
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