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3 years ago

Which macromolecule forms a double layer as the primary structure of cell membranes?

2 answers:

6 0

Answer;
Phospholipid.

Phospholipid forms a double layer as the primary structure of cell membranes.

Explanation;
Cell membranes contains of lipids (phospholipids and cholesterol), proteins and carbohydrates groups that are attached to some of the lipids and proteins.
Phospholipids are composed of a polar head and non-polar (hydrophobic) tail. They line up such that the heads and the tail groups are side by side to form a single layer due to the interactions between the head groups and the tail groups. Two of these layers line up with the hydrophobic tail groups facing each other to prevent the hydrophobic groups away from the polar head groups of other phospholipids and from the water in the surrounding environment.

kozerog [31]3 years ago

4 0

Phospholipids form the lipid bilayer that are the basis of cell membranes.

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Most of the nucleated cells in a multicellular organism contain all of the genetic information for the organism. Which of the fo

vova2212 [387]

Answer: Sperm cell

Explanation:

Amongst all the 4 options given, only the Sperm cell is a gamete (sex cell) while all the three are somatic cells.

A somatic cell is the one which forms the body of an organism and contains all the genetic information.

A gamete is the one which is required for the purpose of fertilization. A gamete of male fuses with the gamete of female in a process called fertilization to form a zygote to give rise to a new individual.

A Sperm cell is basically a male gamete. It contains only half the amount of genetic information as the other half is contributed by the female gamete.

This difference in the amount of genetic information arises due to the type of cell division that occurs. The somatic cells undergo mitosis whereas a gamete requires meiosis to occur for its formation.

During mitosis there is a single round of cell division which divides the parent cell into two daughter cells each with the complete genetic information.

During meiosis the cell undergoes two rounds of cell division such that a total lf 4 cells are produced each with half the amount of genetic material as present in the parent cell.

Since, sperm is a male gamete and is formed by meiosis it contains only half the genetic information as compared to the other cells.

3 0

3 years ago

Boris Magasanik collected data on the proportion of each base in RNA from different species. To compare the relative amount of e

just olya [345]

Answer:

The nucleic acid is a macromolecule present in living systems in the form of either DNA or RNA, whose molecule consists of many nucleotides which are linked with each other to form long chains. The presence of DNA or RNA in an individual promotes continuity of life. The variability and complexity of nucleic acid are dependent on its constituent molecules as, sugar, a phosphate group, and a nitrogenous base. However, two monocyclic nitrogenous bases were classified purines (adenine:A, guanine:G) and pyrimidines (thymine:T, cytosine:C, and uracil:U).

In addition, RNA is a single-stranded structure which differs from DNA in two aspects, the sugar content of RNA is ribose, and pyrimidine base uracil replaces the thymine base of DNA. A ratio between two strands of DNA can be calculated by using Chargrff's rule which states that "DNA from any cell of all organisms possess a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases'.

The purine to pyrimidine ratio in RNA with different bases is given below in the following table:

Presence of single strand in RNA does not follow chargaff's rule and alters the purine: pyrimidine ratio. The above ratio of each base in the given information is not equal, due to which the ratio of purines to pyrimidines is different. The ratio of DNA and RNA is not equal because DNA has its complementary DNA strand. However, bases in RNA might vary due to its single-strandedness property, but its ratio is dependent on the species.

Therefore, it can be concluded that the ratio of purines to pyrimidines is dependent on the species due to its genetic makeup. Hence, option (c) is correct.

7 0

2 years ago

I need help on question 1. 6th grade Science question.

Free_Kalibri [48]

The answer is A. it belongs to a different family.

It can't be B because all the plants have different species.
It can't be C because not all plants listed are cherry trees.

Hope this helps :)

5 0

2 years ago

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What caused the End Ordovician extinction

attashe74 [19]

Answer:

the first wave of extinction may be related to rapid cooling at the end of the Ordovician Period, and the second phase is widely regarded as having been caused by the sea-level fall associated with the glaciation.

5 0

3 years ago

NEED ASAP PLS HELP

pychu [463]

Answer:

Explanation:

C is what the circulitory system dosent do so its C :) Sorry, i sent this a bit late.

7 0

2 years ago

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