Question

Most cell membranes are composed principally of
A: DNA and ATPs
B: Protein and lipids
C: Chitin and starch
D: Nucleotides and amino acids

Answer 1

Hint: A cell's cytoplasm is surrounded by a thin semi-permeable membrane called the cell membrane (plasma membrane). Its aim is to protect the cell's internal integrity by allowing some substances into the cell while preventing others from entering. In certain species, it also acts as a base of attachment for the cytoskeleton, and in others, it serves as a base of attachment for the cell wall. As a result, the cell membrane aids in the support and shape maintenance of the cell. Some cell organelles are encased in membranes, similar to the cell membrane. Two examples are the nucleus and mitochondria.

Complete answer:
Option A:
Nuclear DNA is DNA present in the nucleus of a cell. The genome refers to an organism's entire collection of nuclear DNA. Humans and other complex species have a small amount of DNA in cell structures called mitochondria, in addition to the DNA in the nucleus. The nucleobase adenine is part of adenosine, an ATP-derived molecule that is directly incorporated into RNA.
So, option A is incorrect.
Option B:
Proteins and lipids make up the majority of the cell membrane. Phospholipids make up a significant portion of cell membranes. Cholesterol is a lipid found in the membranes of animal cells. Glycolipids are lipids with a carbohydrate sugar chain attached that are found on cell membrane surfaces. There are two types of related proteins in the cell membrane: Peripheral membrane proteins and integral membrane proteins.
So, option B is correct.
Option C:
The key component of fungi cell walls is chitin. Glycogen is a multibranched polysaccharide of glucose that acts as a form of energy storage in animals' livers.
So, option C is incorrect.
Option D:
Nucleic acids are made up of nucleotides, which are the essential building blocks. Long chains of nucleotides make up RNA and DNA, which are polymers. Nucleotides are derived via the diet and are also synthesised by the liver from common nutrients. Peptidoglycan or murein makes up the cell wall of bacteria and cyanobacteria. It's a polymer composed of sugars and amino acids. Amino acids are involved in a variety of processes, including the transport of neurotransmitters and biosynthesis.
Option D is incorrect.

Hence, Option B is the correct answer.
Note:
The cell membrane is a biological membrane that protects the cell from its surroundings by separating the interior of all cells from the outside world. The cell membrane is made up of a lipid bilayer that includes cholesterols (lipid components) that sit between phospholipids to keep them fluid at different temperatures. Membrane proteins include integral proteins that cross the membrane and function as membrane transporters, as well as peripheral proteins that loosely bind to the cell membrane's outer (peripheral) side and act as enzymes that form the cell.