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3 years ago

Oxidative damage to DNA can often result in the alteration of a single nucleotide.

Biology

2 answers:

Harman [31]3 years ago

5 0

Answer:

Repair mechanism for base cleavage (BER)

Explanation:

Repair by base cleavage (BER)

The altered bases are specifically recognized by glycosylases and removed, generating an AP site. The hole is filled by a DNA polymerase that takes the healthy strand as a template. This system arises not only by exposure to external agents, but also by the cell's own activity.

In case of damage in more than one nucleotide, repair by nucleotide excision (NER) is performed.

Nucleotide excision repair (NER)

The damaged area is recognized by UvrA and B, then A and B separate and UvrC enters which forms a complex with endonuclease activity with B. This enzyme cuts the T-dimer and the gap is filled by a DNA polymerase. There is also the TC-NER system (transcription-coupled nucleotide repair system). The alteration of these mechanisms gives rise to diseases such as: Xeroderma pigmentosum, Trichotiodystrophy or Cockayne Syndrome

Sergio039 [100]3 years ago

5 0

Answer:

Base Excision Repair

Explanation:

It is a field of biochemistry and genetics which deals with the repair of damaged DNA all through the cell cycle. Its main function is to remove small, non-helix-distorting base lesions away from the genome.

It prevents mutations from being incorporated into the DNA while it is being copied.

It is initiated by the enzyme DNA glycosylases (it helps pinpoint and exclude destroyed or mismatched nucleobases, allowing for recovering of the basic DNA sequence by follow-on BER enzymes).

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Tom [10]

A , a different form of DNA containing

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3 years ago

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quizlet chromosomes are composed of: please choose the correct answer from the following choices, and then select the submit ans

Anna11 [10]

Chromosomes are composed of deoxyribonucleic acid (DNA) mole

There are mainly two molecules that function as genetic material in living organisms.

These are ribonucleic acid(RNA) and deoxyribonucleic acid(DNA).

The organisms having DNA as genetic material require packaging of DNA as it is a long polymer of deoxyribonucleotides.

In the case of human beings, the length of DNA in a cell is approximately 2.2 meters which is very large as compared to the size of the nucleus( approximately 10^-6 meters).

So, the DNA has to be made compact for it to be present inside the nucleus of a cell.

Therefore, the DNA present inside the nucleus of a cell undergoes coiling and compaction through several stages before finally becoming a chromosome, which is shown in the adjoining diagram.

Thus, chromosomes are composed of deoxyribonucleic acid (DNA) molecules.

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2 years ago

Enzymes work by ___?

Gennadij [26K]

<span>Enzymes work by reducing the energy of activation increasing the potential energy difference between reactant and product decreasing the potential energy difference between reactant and product adding energy to a reaction reducing EA adding a phosphate group to a reactant</span>
aka B

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3 years ago

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(c) Based on the data in Table 1, describe why the dominant alleles for body color and wing shape are the alleles that produce a

Brrunno [24]

Answer:

Check the explanation

Explanation:

Consider the below table of F2 data of phenotypic flies: we can reconstruct the table as seen in the second attached image below:

From the above observations it is clear the Gray body long wings and Ebony body vestigial wings are the parental combinations and that the Gray body vestigial wings and Ebony body long wings are the recombinants.

Also the ratio indicates that Gray body is dominant over ebony body and that long wings is dominant over vestigial wings.

here the genes for the two characters have shown independent assortment which means that the genes are unlinked if located on the same chromosome or are located on different chromosomes.

Now F1 hybrid= GgLl (G for Grey and L for Long)

Cross between F1 hybrid and true breeding Gray vestigial (GGll)

GgLl x GG ll

Gametes-----------> GL Gl gL gl Gl

GL Gl gL gl

Gl GGLl GGll GgLl Ggll

(Gray long) (Gray vestigial) (gray Long) (Gray vestigial)

Therefore the probability of getting the flies with gray body vestigial wings= 2/4= 50%

b) The reason why the students obtained the above given F2 results involving a cross between true breeding Gray body and long wings with true breeding Ebony body and vestigial wings is that the genes for the two charcters asssort independently in F2 generation and that the genes are not linked as:

Parents------------------> GGLL x ggll

Gametes -----------------> GL gl

F1---------------------> GgLl (Gray long but in heterozous condition)

Now GgLl x GgLl

Gametes GL Gl gL gl GL Gl gL gl

Here gametes assorted independently and hence in F2 generation we got the above results (U can show the results in the form of punnett square.

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4 years ago

Many mammals have skins and mucous membranes that are sensitive to phenolic secretions of plants like poison oak (R h u s) . The

Pavlova-9 [17]

These secondary compounds are primarily adaptations that is inhibit herbivory.

Option D is correct.

What is meant by herbivory?

Herbivory may be a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that prey on autotrophs in general are known as primary consumers. Herbivory is typically limited to animals that eat plants

What is the herbivory effect?

Herbivory can affect the expansion form of plants by terminating shoot growth and initiating branching and by affecting shoot-to-root ratios. Changes in survival, productivity, and growth of individual plant species affect vegetation structure and community dynasty.

<h3>Why is herbivory important?</h3>

Herbivory can have substantial impacts on habitat health, the structure and variety of plant and soil invertebrate communities and the productivity of economically important crops. The positive impact of herbivory is widely debated within the scientific literature.

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1 year ago