Unit 11: Genetic and Genetic engineering.
Learning Aim B: Explore how the process of cell division in eukaryotic cells
contribute to genetic variation.
How to prepare microscope slides
Risk assessment
Eye protection googles should be always worn. Also caution must be taken when
using scissors, the mounted needle and any other sharp objects used.
There are stains that can be corrosive and can cause skin burns, they can also be
an irritant to the skin. To avoid any problems, you need to wear protective eye
equipment and skin protection and need to wear gloves. Also, you need to avoid skin
contact, if any contact occurs these need to be dealt with immediate cleaning and
washing. Also, any spills need to be cleaned away as soon as possible. Hydrochloric
acid is dangerous and toxic, and caution must be used when managing it.
Preparing of the slide
Firstly, you need to produce the slides and organize the equipment prior to the
experiment. For the specimen you are making it by peeling the onion with tweezers
and apply this as the root tip. You need a coverslip, slide, Bunsen burner, a mounted
needle, and a paper towel. You also need a chemical that can remove stains.
A step-by-step process for the experiment
Step 1. Pull 6 mm section from the root tip and take off 1 mm from the very tip.
Step 2. Put 2-3 drops of hydrochloric acid onto the tip.
Step 3. Softly pass the slide from side to side through the Bunsen burner. This
shows that the cells are moving away from each other, and they are separating.
Step 4. Take off the acid from the tip of the cell using tissue.
Step 5. Add 2-3 drops of toluidine blue solution, reheat the slide with the same care.
The root tips are stained using toluidine blue because the stain joins the chromatin
DNA and the reason you want to stain it blue because the stains join the chromatin
DNA so it can be seen.
Step 6. Remove the stain using tissue and add another stain.
Step 7. Lower the coverslip slowly with a mounted needle, this ensure that there is
no air present if there is air present lower the coverslip.
,Step 8. Place the coverslip and slide on the paper towel and wrap the paper towel
around the coverslip. Be sure that it is on a smooth surface and delicately compress
your specimen with the palm of your hand.
The root tip is gently pressed to produce a layer one cell thick. This prevents the
layers of the cell going on top of each other and hiding the sight of the
chromosomes. The root tips are flattened gently as to prevent breakage of the slide
and excess damage to the cell.
Step 9. If any bubbles appear you can deal with these with more stain after
squashing it.
Step 10. Repeat process for three slides with root tip squash to see mitosis.
Step 11. Repeat process for three slides with alternative lily anther squash to see
stages of meiosis.
Key Terms
, Chromosomes
Definition
This is a tiny part of a cell that holds hereditary information. The biological method
that manages carrying traits from generation to another as the look of a gene.
Explanation
The order of size starts with the organism, cell, nucleus, chromosome, gene then
DNA. A genome is an individual with a full set of instructions.
Chromatin is a macromolecule which consists or DNA, RNA and protein which is in
the nucleus of the eukaryotic cells. The nucleosomes can be bent over to produce
chromatin fibre.
Chromatin fibres these are twisted and condensed to form chromosomes.
A nucleosome is a basic continual section found in the eukaryotic chromatin is the
little units that make up the chromatin. Each nucleosome consists of 150 base pairs
of DNA sequence these are, tightly coiled around proteins called histones. The
nucleosomes can be, seen under a microscope when the chromatin is, stretched.
Nucleosomes neutralize the charges of DNA. They help with packing the DNA as it
leaves through the beads of nucleotides.
Chromatid
Definition
This is one of two identical halves of a chromosome.
Explanation
Two chromatids are called a sister chromatid. A sister chromatid takes place before
the cell divides every single DNA molecule copy and this makes the chromatin
condense and wrap around each very tightly. The process of a sister chromatid is
that the DNA is surrounded by two type of protein histone and non-histone protein to
create a single chromosome. Every single chromosome has two DNA molecules that
are the same that are going to be divided in the cell division, they have two sister
chromatids.
The function of the chromatids is that it enables the cell to store two copies of their
information before cell division this ensures the daughter cells are working and can
transport the complete set of diploid DNAs.
This is also visible when examined under a microscope.
Learning Aim B: Explore how the process of cell division in eukaryotic cells
contribute to genetic variation.
How to prepare microscope slides
Risk assessment
Eye protection googles should be always worn. Also caution must be taken when
using scissors, the mounted needle and any other sharp objects used.
There are stains that can be corrosive and can cause skin burns, they can also be
an irritant to the skin. To avoid any problems, you need to wear protective eye
equipment and skin protection and need to wear gloves. Also, you need to avoid skin
contact, if any contact occurs these need to be dealt with immediate cleaning and
washing. Also, any spills need to be cleaned away as soon as possible. Hydrochloric
acid is dangerous and toxic, and caution must be used when managing it.
Preparing of the slide
Firstly, you need to produce the slides and organize the equipment prior to the
experiment. For the specimen you are making it by peeling the onion with tweezers
and apply this as the root tip. You need a coverslip, slide, Bunsen burner, a mounted
needle, and a paper towel. You also need a chemical that can remove stains.
A step-by-step process for the experiment
Step 1. Pull 6 mm section from the root tip and take off 1 mm from the very tip.
Step 2. Put 2-3 drops of hydrochloric acid onto the tip.
Step 3. Softly pass the slide from side to side through the Bunsen burner. This
shows that the cells are moving away from each other, and they are separating.
Step 4. Take off the acid from the tip of the cell using tissue.
Step 5. Add 2-3 drops of toluidine blue solution, reheat the slide with the same care.
The root tips are stained using toluidine blue because the stain joins the chromatin
DNA and the reason you want to stain it blue because the stains join the chromatin
DNA so it can be seen.
Step 6. Remove the stain using tissue and add another stain.
Step 7. Lower the coverslip slowly with a mounted needle, this ensure that there is
no air present if there is air present lower the coverslip.
,Step 8. Place the coverslip and slide on the paper towel and wrap the paper towel
around the coverslip. Be sure that it is on a smooth surface and delicately compress
your specimen with the palm of your hand.
The root tip is gently pressed to produce a layer one cell thick. This prevents the
layers of the cell going on top of each other and hiding the sight of the
chromosomes. The root tips are flattened gently as to prevent breakage of the slide
and excess damage to the cell.
Step 9. If any bubbles appear you can deal with these with more stain after
squashing it.
Step 10. Repeat process for three slides with root tip squash to see mitosis.
Step 11. Repeat process for three slides with alternative lily anther squash to see
stages of meiosis.
Key Terms
, Chromosomes
Definition
This is a tiny part of a cell that holds hereditary information. The biological method
that manages carrying traits from generation to another as the look of a gene.
Explanation
The order of size starts with the organism, cell, nucleus, chromosome, gene then
DNA. A genome is an individual with a full set of instructions.
Chromatin is a macromolecule which consists or DNA, RNA and protein which is in
the nucleus of the eukaryotic cells. The nucleosomes can be bent over to produce
chromatin fibre.
Chromatin fibres these are twisted and condensed to form chromosomes.
A nucleosome is a basic continual section found in the eukaryotic chromatin is the
little units that make up the chromatin. Each nucleosome consists of 150 base pairs
of DNA sequence these are, tightly coiled around proteins called histones. The
nucleosomes can be, seen under a microscope when the chromatin is, stretched.
Nucleosomes neutralize the charges of DNA. They help with packing the DNA as it
leaves through the beads of nucleotides.
Chromatid
Definition
This is one of two identical halves of a chromosome.
Explanation
Two chromatids are called a sister chromatid. A sister chromatid takes place before
the cell divides every single DNA molecule copy and this makes the chromatin
condense and wrap around each very tightly. The process of a sister chromatid is
that the DNA is surrounded by two type of protein histone and non-histone protein to
create a single chromosome. Every single chromosome has two DNA molecules that
are the same that are going to be divided in the cell division, they have two sister
chromatids.
The function of the chromatids is that it enables the cell to store two copies of their
information before cell division this ensures the daughter cells are working and can
transport the complete set of diploid DNAs.
This is also visible when examined under a microscope.
