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Anton [14]
3 years ago
12

Help plz:

Biology
1 answer:
e-lub [12.9K]3 years ago
7 0

Answer:

1. Although most invertebrates have a nervous system, the complexity of the system varies from one organism to another.

Some invertebrates such as the hydra and starfish have a simplified system of nerves, which is called a nerve net. It consists of just nerves, capable of sense and touch only. Meanwhile, other invertebrates such as the planarian have a more developed nervous system, complete with a brain and nerve cord.

2. The key difference between radial and bilateral symmetry is that radial symmetry generates identical body halves around the central axis whereas bilateral symmetry generates only two sides as left and right.

Explanation:

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Explain how water is used by living organisms.
Savatey [412]

Answer:living organisms need water to survive.

Some such as fish can breathe in water.

Others need water to break down food molecules or to get energy.

Explanation:

6 0
3 years ago
What is the function of proteins and carbohydrates that are embedded in a cell membrane? They help control what enters and leave
laila [671]

Answer: They help control what enters and leaves the cell.

Explanation: carbohydrates also help the immune system identify if the cell is foreign or not.

7 0
3 years ago
What does the place theory of pitch perception suggest? different amplitudes of the basilar membrane are sensitive to sounds of
kodGreya [7K]
Answer;
The pitch perception suggests that <span>different portions of the Basilar membrane are sensitive to sounds of different frequencies.

Explanation; 
</span><span>According to the place theory; different portions of the basilar membrane are sensitive to sounds of different frequencies.
The base of the basilar membrane responds best to high frequencies and the tip of the basilar membrane responds best to low frequencies. Therefore, hair cells that are in the base portion would be labeled as high-pitch receptors, while those in the tip of basilar membrane would be labeled as low-pitch receptors.</span>
8 0
3 years ago
Read 2 more answers
Which adaptation would be most useful to an insect that lives in the grass?
amid [387]
<span>The adaptation that would be most useful to an insect that lives in the grass is A. green coloration. This would be a useful adaptation for them because now they could camouflage easily - grass is green, and if they are also green and hiding in grass, nobody can spot them easily, which is a perfect way for them to hide from predators that may want to eat them.</span>
3 0
4 years ago
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You know that (1) both
adoni [48]

Complete question

  • It has to be E. coli because it is positive for gapA
  • It can't be Salmonella, because it is negative for the invA marker but still makes people sick
  • It has to be used because it is positive for the apeE marker

Answer:

<u>1. It can't be Salmonella, because it is negative for the invA marker but still makes people sick </u>

  • A combination of positive results from the multiplex PCR inva, apee and gapa is used to definitively identify Salmonella.  
  • Pathogenic, or disease causing Salmonella is definitely not present, as inva is required for it to be pathogenic. The test did not detect the inva sequence, thus it is truly negative for this particular pathogen.

<u>2. It has to be E. coli because it is positive for gapA </u>

  • E. coli may be present, as gapa was detected- a presumptive positive. However, this may need to be definitively determined through further methods of sample analysis, such as 2D-gel electrophoresis.
  • apee may belong to another type of bacteria present within the initial sample, or there may be sample contamination

Explanation:

Polymerase chain reactions, PCRs are a form of nucleic acid amplification testing NAAT that exploit the mechanism of transcription by using a thermostable DNA polymerase. These require a sample of genetic material such as RNA or DNA; specific regions of the gene sequence are targeted for replication by primers.  In the presence of these specific gene sequences, the primers make billions of copies of the sequences.

However, if these gene sequences are absent, the primers are not capable of identifying and amplifying the sequence. This reaction is highly specific. Positives obtained have a high chance of being true positives and negatives have a high chance of being true negatives .

Pathogens or infectious agents that are capable of causing disease i.e. making people sick. Both E. coli and Salmonella are genuses of enteric bacteria capable of causing disease via fecal contamination. Common symptoms include

  • abdominal cramps
  • vomiting
  • fever
  • diarrhea

This test would include primers for the detection of each sequence: gapa, apee, inva. Salmonella's inva was not detected, thus it is not present.

Further steps may include a 2 D gel  electrophoresis- here an electrical current is utilized to separate bands of DNA within the sample. This should correspond with an expected DNA  size in base pairs or bp  for E.coli- this should be determined by running the sample in the gel with a positive control, containing genetic material for E coli, and a negative control, of purified water to determine contamination.

7 0
4 years ago
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