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3 years ago

Why is it necessary for DNA to replicate as the first step in mitosis?

2 answers:

8 0

It's necessary for DNA to replicate as the first step in mitosis because the whole point of mitosis is to create new cells, exactly like the old ones. Since DNA has all the genetic information that makes cells do what they do, it's necessary to replicate them in the act of mitosis.

Zepler [3.9K]3 years ago

7 0

DNA is a macromolecule composed of nucleotides which carry the genetic instructions used in the growth, development, functioning and reproduction of the cell. One of the most important characteristics of DNA is its ability to make several copies of it (to be copied via the process of replication). When the cell divides into two it must carry each copy of DNA into the divided cells. Through replication, the DNA transfers the information necessary for creating an exact copy of it in the new daughter cell. The transfer of the DNA to the next generation of cells is essential for the function of the whole organism.

DNA replication will make the organism to reproduce the genetic code and transfer it to the next generation (through the reproduction) and thus, to continue the species.

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What generally happens to the number of leaves as the leaf surface area decreases?

likoan [24]

As the leaf surface area decreases ; Number of leaves increase inmost plants.

As the leaf surface area increases, the rate of transpiration increases as well because leaves with large surface areas have bigger stomata. also the smaller the leave surface area of a plant/tree the denser the leaves the plants/tree will have.

Trees with tiny leaves tend to have a lot of leaves because of the decrease transpiration rate occurring in the leaves of the plants .

Hence we can conclude that what generally happens to the number of leaves as leaf surface area decrease is number of leaves increases in most plants.

Learn more : https://brainly.in/question/28299771

8 0

3 years ago

In this week's experiments, if you replaced glucose with the monosaccharide fructose, predict the results for fructose transport

lbvjy [14]

Answer: Fructose is transported by facilitated diffusion.

Explanation:

Glucose is a monosaccharide with the molecular formula C6H12O6.3 It is a hexose. It is a form of sugar that is found freely in fruits and in honey. Its energy yield is 3.75 Kcal/g under standard conditions.

Fructose is a type of carbohydrate found in vegetables, fruits, and honey. It is a monosaccharide with the same molecular formula as glucose, C6H12O6, but with a different structure, that is, it is an isomer of glucose. Its energetic power is the same as that of glucose, 4 kilocalories per gram, and it is a reducing carbohydrate.

Glucose is the main energy substance of a cell and for its entry it requires a transport protein in the cell membrane, called transporter. The transport of glucose through the cell membrane is carried out by two families of membrane proteins:

Sodium-coupled glucose transporters (SGLT sodium-glucose-transporters), which involves the co-transport of Na+ by the SGLT-1 by maintaining the Na+ gradient thanks to the Na+/K+ pump
Glucose transport facilitation proteins (GLUT)

On the other hand, fructose is absorbed by another type of transporter, called Glut-5, a protein that crosses the membrane 12 times. Finally, the passage of both glucose and fructose into the blood takes place through the Glut-2, a transporter with low affinity and high transport capacity.

If any Glut is considered within the context of a large family of proteins, it can be immediately noticed that they all possess common characteristics that in biochemical terms are called "molecular signature of glucose transporters" and that it is no more than a set of extremely conserved primary amino acidic sequences that determine secondary and tertiary structures (domains or motifs) that are responsible for the functional characteristics of the protein.

Facilitated diffusion is a type of cellular transport where the presence of a carrier or transporter (integral protein, Glut is this example) is necessary for substances to cross the membrane. It happens because the molecules are larger or insoluble in lipids and need to be transported with the help of membrane proteins. So, in the first step, fructose binds to the transport protein, and this changes shape, allowing the passage of this sugar. In this way, fructose concentrations inside the cell are always very low, and the external and internal concentration gradient favours diffusion.

Summarizing, fructose is transported by facilitated diffusion. So if we replaced glucose with fructose we would have seen no change in each conditions. And since fructose is transported by this type of mechanism, there is not a concentration gradient.

6 0

3 years ago

Genetics is the study of ________.

butalik [34]

Answer:

Option-B

Explanation:

Heredity refers to the passing of the traits from the parents to the offsprings or generation and also known as inheritance and Genetic variation is the difference in the genetic material in population which leads to the formation of a variety of traits.

Since the variation in traits is determined by factors (Gregor Mendel) later called "genes" which are passed on to the offsprings, therefore, the branch of biology which studies the pattern of inheritance and variation is known as "Genetics". Gregor Mendel is known as the Father of Genetics.

Thus, Option-B is the correct answer.

6 0

3 years ago

Choose the correct function of the mitochondria.

rewona [7]

D is the correct answer. everything said in all of the above is in the mitochondria to help it function.

4 0

3 years ago

In _______________, brain cells are stimulated using a powerful magnetic field produced by a wire coil placed on a person's head

Masteriza [31]

Answer:Transcranial Magnetic Stimulation (TMS)

Explanation:

Transcranial magnetic stimulation also known as repetitive transcranial magnetic stimulation. TMS is a noninvasive procedure that uses magnetic fields to stimulate nerve cells in the brain to improve symptoms of depression. In TMS, brain cells are stimulated using a powerful magnetic field produced by a wire coil placed on a person's head that temporarily inactivates neural circuits. TMS devices operate completely outside of the body and affect central nervous system activity by applying powerful magnetic fields to specific areas of the brain that we know are involved in depression.

4 0

3 years ago