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3 years ago

1. Which of the following events is not a source of genetic variation in eukaryotic organisms?

Biology

1 answer:

Lunna [17]3 years ago

5 0

Answer:

Mitosis

Explanation:

Mitosis is not a source of genetic mutation because it take place mostly in the somatic cells. This is because it does not lead to the production of gametes . In mitosis, the parent cells divide into two daughter cells and each daughter cells are genetically identical to the parent cell because they carry the same number of chromosomes as the parent cell. There is no genetic variation in this.

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In this mass spectrum, which peak most likely represents the molecular ion?.

Finger [1]

The presence of the base peak at 45 in combination with our knowledge about the nitrogen rule suggests that the peak at m/z 60 is likely the molecular ion because even molecular ions usually produce odd molecular fragments by breaking single bonds.

5 0

2 years ago

Comparing amino acid sequences in proteins has been used to determine the relatedness of organisms. Below is a graphic that show

Tju [1.3M]

Answer:

A) Species A and E are more closely related than either species are related to species D.

B) Between A and B = 99.1%

Between species A and C =97.5%

Between species B and C = 97.3%

Similarity in amino acids sequence reflects similarity in DNA sequence

C) Species A and E are most closely related

D) Species A and E have the most similarity in amino acid sequence, and hence DNA sequence.

Explanation:

A) The amino acid sequences of the protein, keratin, in species A and D has a difference of about 19 whereas species A and E have a difference of only 1. Therefore, it means that keratin in species A and D will have differences in structure whereas between species A and E, they would have almost the same structure.

Also, species D and E have a difference of 20 in their amino acids sequence, therefore, the structure of keratin in both species will have differences in structure.

B) Similarity between A and B:

450 - 4 = 446

In percentage: 446/450 × 100% = 99.1%

Similarity between A and C:

450 - 11 = 439

In percentage: 439/450 × 100% = 97.5%

Similarity between B and C:

450 -12 = 438

In percentage: 438/450 × 100% = 97.3%

The sequence of DNA of species determines their amino acid sequences because information in DNA is transcribed to RNA which are then used to make proteins. Therefore, if a species are very closely related, they are expected to have very similar genetic sequences and thus proteins too. This is reflected in similarity between amino acid sequences in their proteins.

C). Species A and E are most closely related.

D) Species A and E have only a single difference in their amino acids sequence for Keratin. This translates to about 99.7% similarity which is the highest among all the species compared. Therefore, species A and E are most closely related.

7 0

3 years ago

A key difference between active transport and diffusion is that active transport __________.

snow_lady [41]

<span>A key difference between active transport and diffusion is that active transport needs energy</span>

3 0

3 years ago

-Present-day mitochondria and chloroplasts probably evolved as a consequence of early endosymbiosis: the ancestor of the eukaryo

nata0808 [166]

Answer:

The evidence suggests that these chloroplast organelles were also once free-living bacteria.

Explanation:

The endosymbiotic event that generated mitochondria must have happened early in the history of eukaryotes, because all eukaryotes have them.

5 0

3 years ago

Pesticides on foods are stored in body tissues in a process known as

Tom [10]

The Process in which pesticides are stored in body tissues is known as Bio-Accumulation.
When pesticides get into our body through eating food which is not go through the process of metabolism or which is not excreted, that is stored in fatty tissues of the body and as time passes we may build up high concentration of pesticides in our body. Pesticides are the chemical compounds used for killing pests, bacteria etc.

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3 years ago