Biological Technique/Biology 314
Abia state polytechnic
Q&A Practice Quiz.
Question 1: Briefly describe the term fixatives.
Answer:
Fixatives are chemicals that are used to kill the cells of the tissue rapidly in a
life-like condition as much as possible.
Question 2: State the uses of fixatives.
Answer:
Used to preserve the tissue in a life-like condition as possible.
Used to prevent post-mortem decomposition that is purification normally occurs in
the alimentary canal where numerous bacteria cause the breakdown of tissue with
evolution of gas.
Used to prevent autolytic action that is dissolving the cells by enzymes action.
Hardens tissues sufficiently for sectioning.
Helps to render tissue insoluble during subsequent treatment.
Improves the refractive index of some cells.
Enhances staining reaction.
Some fixatives act as mordant to stains.
Question 3: Define simple and compound fixative.
Answer:
SIMPLE FIXATIVE: These are used in routine laboratory analysis. Simple fixatives
are alcohol,formalin,acetic acid,chromate chloride and mercuric chloride.
COMPOUND FIXATIVES: These may be described as the product of two or more simple
fixatives mixed together in order to obtain the combined effect of their individual
actions upon the cell and tissue constituents.
Question 4: Mention qualities of a good fixatives.
Answer:
It must kill the cell quickly without shrinking, or swelling or other distortion.
It must penetrate the tissue and cells rapidly and evenly.
It must render insoluble the substance of the cell and give good optical
differentiation.
It must inhibit bacterial decay and autolysis.
It must harden the tissue and render it insensitive to subsequent treatment.
It must permit at a later date the application of numerous staining procedures in
order to render the constituents to the tissue and cells more readily visible.
It should allow tissue to be stored for long period of time.
It should permit the restoration of natural colours for photography and mounting as
museum specimen.
It should be simple to prepare and economical to use.
Abia state polytechnic
Q&A Practice Quiz.
Question 1: Briefly describe the term fixatives.
Answer:
Fixatives are chemicals that are used to kill the cells of the tissue rapidly in a
life-like condition as much as possible.
Question 2: State the uses of fixatives.
Answer:
Used to preserve the tissue in a life-like condition as possible.
Used to prevent post-mortem decomposition that is purification normally occurs in
the alimentary canal where numerous bacteria cause the breakdown of tissue with
evolution of gas.
Used to prevent autolytic action that is dissolving the cells by enzymes action.
Hardens tissues sufficiently for sectioning.
Helps to render tissue insoluble during subsequent treatment.
Improves the refractive index of some cells.
Enhances staining reaction.
Some fixatives act as mordant to stains.
Question 3: Define simple and compound fixative.
Answer:
SIMPLE FIXATIVE: These are used in routine laboratory analysis. Simple fixatives
are alcohol,formalin,acetic acid,chromate chloride and mercuric chloride.
COMPOUND FIXATIVES: These may be described as the product of two or more simple
fixatives mixed together in order to obtain the combined effect of their individual
actions upon the cell and tissue constituents.
Question 4: Mention qualities of a good fixatives.
Answer:
It must kill the cell quickly without shrinking, or swelling or other distortion.
It must penetrate the tissue and cells rapidly and evenly.
It must render insoluble the substance of the cell and give good optical
differentiation.
It must inhibit bacterial decay and autolysis.
It must harden the tissue and render it insensitive to subsequent treatment.
It must permit at a later date the application of numerous staining procedures in
order to render the constituents to the tissue and cells more readily visible.
It should allow tissue to be stored for long period of time.
It should permit the restoration of natural colours for photography and mounting as
museum specimen.
It should be simple to prepare and economical to use.
