The central dogma of molecular genetics states that
\[DNA\xrightarrow{\text{Transcription}}RNA\xrightarrow{\text{Translation}}\text{Protein}\]
Thus, option (C) is correct.
72.
Which of the following statement is not correct ?
A
Amylopectin is a branched polymer of $$\alpha $$ - glucose.
B
Cellulose is a linear polymer of $$\beta $$ - glucose
C
Glycogen is the food reserve of plants
D
All proteins are polymers of $$\alpha $$ - amino acids.
In $$DNA,$$ two helically twisted strands connected together by steps. Each strand consists of alternating molecules of deoxyribose at $$2'$$ - position and phosphate groups.
On the other hand, in $$RNA,$$ the pentose sugar has an identical structure with deoxyribose sugar except that there is an $$ - OH$$ group instead of $$ - H$$ on carbon atom $$2'.$$
Hence, it is only called ribose.
75.
Which of the following does not exihibit the phenomena of mutarotation?
Key Idea Reducing sugars that exist in hemiacetal and hemiketal forms, exhibit the phenomenon of mutarotation in aqueous solution. During mutarotation, the ring open upto give the open chain form which then reclose either in the inverted position or in the original position giving an equilibrium mixture of two anomers with a small amount of open chain form. Thus, all reducing monosaccharides and disaccharides undergo mutarotation in aqueous solution.
Among the given carbohydrates, only sucrose is a non-reducing sugar as in it the hemiacetal and hemiketal groups of glucose and fructose are linked together through $$O$$ - atom and thus, not free. Due to the absence of free hemiacetal or hemiketal group, sucrose does not exhibit mutarotation.
76.
Which of the following could act as a propellant for rockets?
Liquid hydrogen and liquid oxygen are used as excellent fuel for rockets. $${H_2}\left( \ell \right)$$ has low mass and high enthalpy of combustion whereas oxygen is a strong supporter of combustion.
77.
The $$\alpha {\text{ - }}$$ and $$\beta {\text{ - }}$$ forms of glucose are
A
isomers of $$D(+)$$ glucose and $$L(-)$$ glucose respectively
B
diastereomers of glucose
C
anomers of glucose
D
isomers which differ in the configuration of $$C{\text{ - 2}}$$
In aqueous solutions, amino acids mostly exist as zwitter ion or dipolar ion.
\[\underset{\text{zwitter ion}}{\mathop{\overset{+}{\mathop{N}}\,{{H}_{3}}\overset{\begin{smallmatrix}
R\,\,\, \\
|\,\,\,
\end{smallmatrix}}{\mathop{-CH-}}\,CO{{O}^{-}}}}\,\]
79.
Which of the following statements is true for proteins?
Antibodies, hormones, enzymes (biocatalyst) all are proteins.
80.
The $$\alpha {\text{ - }}D{\text{ - }}$$ glucose and $$\beta {\text{ - }}D{\text{ - }}$$ glucose differ from
each other due to difference in carbon atom with respect to its
The isomer having the hydroxyl group $$\left( { - OH} \right)$$ on the right is called $$\alpha {\text{ - }}D{\text{ - }}$$ glucose and one having the hydroxyl group $$\left( { - OH} \right)$$ on the left is called $$\beta {\text{ - }}D{\text{ - }}$$ glucose. Such pairs of optical isomers which differ in the configuration only around $${C_1}$$ atom are called amomers. Thus $$\alpha {\text{ - }}D{\text{ - }}$$ glucose and $$\beta {\text{ - }}D{\text{ - }}$$ glucose are anomers.