Question

(a) Name the chemical that cements animal cells.
(b) Name two contractile proteins.
(c) What is the difference between RNA and DNA in their nitrogen bases?

Answer 1

Cell theory emphasizes unity in the diversity forms. It is an organization of life forms. All organisms are composed of cells. Unicellular organisms are composed of just one cell, but multicellular organisms are composed of several cells. Animal cells and plant cells are two types of cells in cell theory. Nucleus was discovered by Robert Brown in $1831$ in a cell.

Complete answer:
a) The chemical which adjoins the animal cells is hyaluronic acid. Cytoplasm is the gelatinous liquid that is filled inside of a cell. It is composed of salts, water and inorganic molecules. The organs are placed inside the cell separate from the cytoplasm. It is a sticky substance which cements the animal cell.
b) Two contractile proteins are actin and myosin. They are known as muscle proteins. Actin and myosin are the structural and functional units of muscle. They have bands in between them. Z bands and M lines. Proteins as we know are macromolecules used in the building of the body hence, it is called as building blocks of the body.
c)

RNA	DNA
Commonly called ribonucleic acid.	Commonly called deoxyribonucleic acid.
Can easily and rapidly mutate than DNA.	Stable more than RNA and takes time to mutate.
Nitrogen bases have adenine, uracil, guanine and cytosine.	Nitrogen bases of DNA are adenine, thymine, guanine and cytosine.

Note:
These are the major differences in RNA and DNA. Both are equally important in transcription, translation gene regulation etc. the theory of cells proposed by two well-known scientists. They have discovered many things and their contribution is major in cell theory and they got many awards for their contribution. As cells possess the center of life. A life can be evolved, multiplied from a tiny single cell. Hence it is the greatest discovery so far known. Nucleus is enclosed in a nuclear envelope. It contains the most important material called chromosomes which contains DNA which are vital for transferring genetic information.