Mitosis in Onion Root tip Experiment

Summary

This video guides viewers through the process of preparing root tips of Allium species to observe mitosis under a microscope. Mitosis is a cell cycle stage where chromosomes replicate and separate to form two identical cells. The experiment requires an onion or garlic bulb, various chemicals, and lab equipment. After growing root tips, they are fixed, preserved, and stained to highlight chromosomes. The stained root tips are then squashed on a slide for microscopic observation. The video demonstrates steps to prepare, squash, and observe the cells under different magnifications, capturing various stages of mitotic division.

Takeaways

• 🧬 Mitosis is a cell cycle stage where chromosomes replicate and separate to form two genetically identical cells.
• 🧅 The experiment requires an onion or garlic bulb, beakers, toothpicks, and various chemicals and tools.
• 🌱 Allow roots to grow by submerging the base of the bulb in water for a few days.
• 🔪 Cut out root tips and place them in Carnoy fixative fluid to preserve the DNA.
• ⏳ Leave the root tips in the fixative for 48 hours for proper fixation.
• 💧 If storing for future use, transfer fixed root tips to 70% ethanol for dehydration and preservation.
• 🔬 Use 1N hydrochloric acid to soften cell walls and facilitate squashing of root material.
• 🌈 Stain the root tips with acetyl carbine or acido-orcin stain to color the nuclear material for observation.
• 📚 Create a slide by squashing the root tips between a slide and a coverslip, avoiding air bubbles.
• 🔍 Observe the slide under a compound light microscope, using different magnifications to view mitotic stages.
• 📸 Capture images of the cells using a mobile phone and a tripod for documentation.

Q & A

What is the purpose of preparing root tips of Allium species?

The purpose is to observe cells in various stages of mitotic division, where chromosomes replicate and separate to form two genetically identical cells.

What are the differences between mitosis and meiosis?

In mitosis, the chromosome number is maintained in both daughter cells, whereas in meiosis, the chromosome number is halved.

What materials are needed for the experiment described in the script?

Materials needed include an onion or garlic bulb, beakers, toothpicks, Carnoy's fixative fluid, 70% ethanol, one normal hydrochloric acid, acetyl carbine or aceto-orcein stain, glass slides and cover slips, a blade or scalpel, watch glasses or petri dishes, spirit lamp or Bunsen burner, blotting paper, droppers, thumb forceps, scissors, a compound light microscope, and immersion oil.

Why is it necessary to keep the base of the bulb in contact with water?

The base of the bulb needs to touch the water level to facilitate root growth for the experiment.

How long should the root tips be left in Carnoy's fixative fluid?

The root tips should be left in Carnoy's fixative fluid for about 48 hours.

What is the purpose of using 70% ethanol after fixing the root tips?

70% ethanol is used to dehydrate the root tissue, which helps preserve the DNA for potential future genetic studies.

Why is the root material softened with one normal hydrochloric acid?

Hydrochloric acid softens the cell walls and weakens cellular connections, making it easier to squash the root material for slide preparation.

What is the role of acetyl carbine or aceto-orcein stain in the experiment?

These stains are used to color the nuclear material of the root cells, making it easier to observe the cells under a microscope.

How long should the root tips be left in the stain before microscopic observation?

The root tips should be left in the stain for about 5 to 10 minutes.

What is the significance of squashing the root tips between the slide and the coverslip?

Squashing the root tips helps to spread out the cells evenly, allowing for clear observation of individual cells without overlapping.

Why is immersion oil used during high-power microscopic observation?

Immersion oil is used to reduce light refraction and improve the resolution of the image when observing under high magnification, such as with a 100x oil immersion lens.

Outlines

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🔬 Preparing Allium Root Tips for Mitosis Observation

This video tutorial guides viewers through the process of preparing root tips from Allium species (onion or garlic) for observing cells in various stages of mitotic division. Mitosis is a critical stage in the cell cycle where chromosomes replicate and separate to form two genetically identical daughter cells. The experiment requires materials such as an Allium bulb, beakers, toothpicks, tap water, Carnoy's fixative fluid, 70% ethanol, one normal hydrochloric acid, acetic orcein stain, glass slides, cover slips, a scalpel, watch glasses, blotting paper, droppers, thumb forceps, scissors, a compound light microscope, and immersion oil. The process begins with growing roots in water, fixing them in Carnoy's fluid, dehydrating in ethanol, softening in hydrochloric acid, staining with acetic orcein, and finally squashing the root tips on a slide for microscopic examination. The video also covers the use of a microscope, including low and high-power observation, and the use of immersion oil for high-resolution viewing. Additionally, it suggests a method for capturing micro photographs of the cells.

Keywords

💡Mitosis

Mitosis is a stage in the cell cycle where chromosomes replicate and divide, leading to the formation of two genetically identical cells. In the video, mitosis is the core biological process being observed using root tips of Allium species, and it is contrasted with meiosis, where chromosome numbers are reduced.

💡Allium species

Allium species, such as onions and garlic, are used in the experiment to study mitosis. The root tips of these plants have cells actively undergoing cell division, making them ideal specimens for observing mitotic stages.

💡Chromosomes

Chromosomes are structures within cells that contain DNA. During mitosis, chromosomes replicate and separate into daughter cells. In the video, chromosomal staining is used to highlight these structures, enabling their observation under a microscope.

💡Carnoy’s fluid

Carnoy’s fluid is a chemical fixative used to preserve the DNA of the root tip cells. In the video, the root tips are transferred into this fluid to prepare them for further steps in the experiment, ensuring that cellular structures like chromosomes are well-preserved for observation.

💡Hydrochloric acid

Hydrochloric acid is used in the experiment to soften the cell walls of the root tips. This step is important for weakening cellular connections, making it easier to squash the cells on a slide for microscopic observation. The acid exposure also makes the staining process more effective.

💡Acetocarmine or Aceto-orcein stain

Acetocarmine or Aceto-orcein stain are used to color the chromosomes, making them easier to visualize under a microscope. These stains impart a deep red color to the chromosomal material, helping differentiate various stages of mitosis in the root tip cells.

💡Root tips

Root tips are the regions of the onion or garlic plant where active cell division occurs, making them suitable for observing mitosis. In the video, the root tips are cut, treated, and stained to reveal cells in various stages of division, demonstrating the dynamic process of mitosis.

💡Squashing

Squashing is a technique used in the experiment to spread out the root tip cells on a slide for microscopic observation. By gently pressing on the cover slip, the cells are flattened, allowing for a clearer view of individual cells and their chromosomes during mitosis.

💡Microscopic observation

Microscopic observation is a key part of the experiment where the prepared root tip slides are viewed under a compound light microscope. The video shows how different magnifications, such as 10x, 40x, and 100x with oil immersion, are used to examine the stages of mitosis in the root cells.

💡Immersion oil

Immersion oil is used when observing the root tip cells under the 100x objective lens of a microscope. This oil helps increase the resolution and clarity of the image by reducing light refraction, allowing for a detailed view of chromosomes and cell structures during mitosis.

Highlights

Preparing root tips of Allium species to observe cells in various stages of mitotic division

Mitosis is a stage in the cell cycle where chromosomes replicate and separate

Chromosome number is maintained in both daughter cells after mitosis, unlike meiosis

Required materials for the experiment include onion or garlic bulb, beakers, toothpicks, and various chemicals

Fixing the onion or garlic bulb in water to encourage root growth

Cutting out root tips and transferring them into Carnoy's fixative fluid

Carnoy's fluid fixes the DNA of the root tip cells

Preserving root tips in 70% ethanol for long-term storage

Using 1N hydrochloric acid to soften cell walls and weaken cellular connections

Warming the root tips in acid to prepare for staining

Rinsing root tips in distilled water after acid treatment

Staining root tips with acetyl carbine or acido-orcin stain for chromosomal visualization

Transferring stained root tips onto a glass slide for microscopic observation

Squashing the root tips between a slide and a coverslip to spread out the cells

Observing the spread-out root tip cells under a compound light microscope

Using a 40x or 100x oil immersion lens for high magnification observation

Adding immersion oil and using fine adjustment for focusing under high magnification

Taking micro photographs of mitotic stages using a mobile phone and tripod

Slideshow of various mitotic stages of cell division in Allium species

Transcripts

in this video we'll be preparing root

tips of allium species to observe cells

in various stages of mitotic division

mitosis is one of the stages in the cell

cycle where the chromosome of a cell

replicate and separate to eventually

form two genetically identical cells

unlike in meiosis chromosome number is

maintained in both daughter cells for

the experiment you will need onion or

garlic bulb

beakers toothpicks car noise fluid 70

ethanol one normal hydrochloric acid

acetyl carbine or acetyl or seen stain

glass lights and cover slips

blade or scalpel

watch glasses or petri dishes tiny vials

or containers spirit lamp or bunsen

burner or any flame source

blotting paper droppers

thumb forceps and a pair of scissor

compound light microscope and immersion

oil

to begin the experiment take a onion or

garlic bulb and fix it on a beaker

containing tap water using toothpicks

like you see here

make sure the base of the bulb touches

the water level

keep this in a safe corner for a couple

of days

once the roots have grown about two to

three centimeters cut out one centimeter

of root tips and transfer them into a

tiny vial containing carnous fixative

fluid

carnose fluid fixes the dna of the root

tip cells

leave the roots in the fixative for

about 48 hours

if you are planning on storing the root

tips for a longer time for use in future

you may transfer the fixed root tips in

a second vial containing 70 ethanol

ethanol dehydrates the root tissue and

thereby preserves dna

root tips preserved in ethanol and

preferably refrigerated will keep well

for a couple of years for genetic

studies

either ways take a few root tips from

carnous fluid or ethanol and transfer

them onto a watch glass containing one

normal hydrochloric acid

acid will soften the cell walls and

weaken cellular connections so it

becomes easy to squash the root material

later

gently warm the watch glass on a flame

for about 5 seconds

expose the root tips in the acid for

about 2 minutes

give the root tips a couple of washings

in distilled water

now transfer the roots onto a watch

glass containing acetyl carbine or

acido-orcin stain

these are excellent chromosomal stains

and will impart a deep red coloration to

the nuclear material of the root cells

warm the stain on the flame for about 5

seconds and leave the root tips in the

stain for about 5 to 10 minutes

now transfer the root tips onto a clean

glass light containing a drop of water

using a sharp blade or scalpel remove

about a millimeter of the root tip and

discard the rest

the very tips of the roots are the

regions with active cell division and

they are all that we require for mitotic

experiments

gently lower a cover slip on the root

tips making sure to avoid any air

bubbles

using the blunt end of a forcep or a

pencil gently tap the coverslip a few

times until the root tips are uniformly

squashed in between the slide and the

coverslip

a properly squashed slide will appear

faint cloudy pink to almost colorless

the root tip slide is now ready for

microscopic observation

this is how a finely squashed root tip

appears under 10x of the microscope

as you can see the cells of the root

tips are nicely spread out with almost

no overlappings

if root tips are not squashed enough you

may repeat the squashing process until

you get well spread root cells

scan the slide for cells showing mitotic

division stages under low power and then

proceed to observation under high power

such as 40x or 100x oil immersion lens

for observations under 100x objective

you will need to add a drop of immersion

oil on top of the coverslip and gently

lower the objective lens until it

touches the oil surface

from there use the fine adjustment knob

for focusing

you may take micro photographs of the

rare stages by employing a simple

technique using a mobile phone and a

tripod like so

and here's a quick slideshow of the

various mitotic stages of cell division

in root tip cells of allium species

you