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pogonyaev
3 years ago
7

REALLY NEED HELP

Biology
1 answer:
Liono4ka [1.6K]3 years ago
4 0
T cell activation is initiated by an activated B cell.

The B cell presents antigens on its MHC receptors. The T cell recognizes the antigen bound to the MHC. There are other cosignals that fully activate the at cells but the antigen on the MHC receptor on the B cell is where it all starts.
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Which of the following is an example of post-transcriptional control of gene expression?a. gene amplification contributing to ca
MAVERICK [17]

The correct answer is: b. the removal of introns and alternative splicing of exons

Post-transcriptional regulation includes processes of regulation between transcription and translation such as RNA splicing, capping, addition of poly-A tail,  RNA editing.

RNA splicing represents the process of RNA processing in which newly synthesized pre-mRNA transcript is converted into a mature mRNA. This process occurs only in eukaryotic organism and includes the removal of introns and joining together the exons. RNA splicing might occur during or immediately after transcription and it is performed by spliceosome (complex of small nuclear ribonucleo proteins).

Alternative splicing is a regulated process in which a single gene can code for multiple proteins because particular exons of a gene may be included within or excluded from the final mRNA.

7 0
3 years ago
A student looks through a microscope and sees a dark spot. Upon moving the slide he notices that the dark spot does not move. In
Reil [10]
The substage condenser is either incorrectly positioned or the light stop is the wrong size for the objective- or there me be a smudge/mark on the eyepiece
6 0
3 years ago
Anyone got the answers to the UNIT: UNDERSTANDING ORGANISMS test?
wariber [46]

The Unit 'Understanding organisms' is not found here, but an organism is a biological system composed of cells.

<h3>What is an organism?</h3>

An organism is a living entity that is defined by the presence of cells, which are the basic structural unit of life.

Organisms have the ability to respond to external stimuli, perform metabolic activities and exhibit a internal state of equilibrium (homeostasis).

Organisms can be composed of single cells (e.g., bacteria, protists) or many cells (e.g., plants and animals).

In conclusion, the Unit 'Understanding organisms' is not found here, but an organism is a biological system composed of cells.

Learn more on the organisms here:

brainly.com/question/17259533

#SPJ1

5 0
2 years ago
DNA does all but which of the following?
siniylev [52]

Answer:

The correct answer will be option-is read by ribosomes during the process of translation.

Explanation:

The DNA is a nucleic acid made up of nucleotides which serves as a genetic material of the cell. It stores the information required by the cell in the form of codons made up of nitrogenous bases. The DNA after transcription forms a messenger molecule called mRNA which is read by the ribosomes to code for specific amino acid which binds to form the proteins, the building block of the body.  

Since the mRNA is read by the ribosomes during translation and not DNA directly, therefore, the selected option is the correct answer.

3 0
3 years ago
The contraction of auricular muscles around the ear produces a range of motions in the ears of domesticated animals as well as t
creativ13 [48]
The correct answer is letter C, in most primates, the inability to move the ear has been replaced by the ability to stand upright on two legs. This is because movement was much of a need to these primates than hunting for food. They needed to be agile to locate specific places where sources of food are abundant.
7 0
4 years ago
Read 2 more answers
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