Biochemistry Chapter No 13 Chemistry Class 10 Notes
CHAPTER NO.13 BIOCHEMISTRY
Q.1:
Define biochemistry.
Ans: Biochemistry:
"The
branch of chemistry which deals with the study of the synthesis, decomposition of substances and their
reactions in living organisms such as plants and animals are called biochemistry". OR
"The branch of chemistry that deals with
the chemical compounds and
processes occurring in the organism."
Q.2:
What are biological molecules?
Ans: Biological
molecules:
"The organic compounds present in living
organisms are called biological
molecules."
Biological molecules include carbohydrates,
proteins, lipids or fats, enzymes, vitamins and nucleic acids.
Q.3: What are carbohydrates? Explain the classification of carbohydrates
along with the uses of carbohydrates.
Ans: Carbohydrates:
Origin
of name:
Since most of the carbohydrates have
the general formula Cn(H2O)n. (n can have a value of 3 or more than 3) therefore, they are called carbohydrates meaning hydrates of carbon.
However, now a
days many carbohydrates have been discovered which do not have the general formula of Cn(H2O)n and cannot be called hydrates of carbon however the name
carbohydrate is still retained. e.g. Fructose(C6H12O5).
Definition:
"Polyhydroxy ketones or polyhydroxy
aldehydes are called carbohydrates."
OR
"Polyhydroxy derivatives of aldehydes
and ketones are called carbohydrates.
Polyhydroxy means having many hydroxyl
groups.
common
name:
Carbohydrates are commonly-known as sugars. They are also referred to as saccharides (Latin word Saccharum meaning sugar)
Composition:
Carbohydrates are poly
functional (alcohol + aldehydes or ketones) organic compounds which mainly consist of
carbon, hydrogen, and oxygen some time along with nitrogen (chitin) or Sulphur
(keratin sulfate). Classification of carbohydrates:
Carbohydrates are classified into the following three groups:
1. Monosaccharides 2. Oligosaccharides 3. Polysaccharides Their detail is given below:
1. Monosaccharides:
Definition:
"The simplest
carbohydrates which cannot be further hydrolyzed into smaller units are called
monosaccharides."
General formula:
They have the general formula of Cn(H2O)n, where n=3,4,5, and so on.
Composition:
Monosaccharides are either aldoses having aldehydic functional group (for example
glucose) or ketoses having a ketonic functional group for example fructose.
These may
be trioses (C3H603), tetroses (C4H6O4),
pentoses (C5H10O5) and
hexoses (C6H12O6).
General properties of monosaccharides:
Some general properties of monosaccharides are:
i.Solubility:
They are soluble in water.
ii. Physical state:
They are crystalline solids.
iii.
Taste:
They have a sweet taste.
iv.
Colour:
They are
colorless.
v. Hydrolysis:
They cannot be hydrolyzed further.