Summary
Summary Investigating totipotency practically.
- Course
- Institution
Pearson Edexcel Advanced Level biology Unit 3 notes. Describe how totipotency can be demonstrated practically using plant tissue culture techniques.
[Show more]
Seller
Follow
Monai
Reviews received
Content preview
Monai ElnaasaniDescribe the stages of mitosis and how to prepare and stain a root tip squash
in order to observe them practically.
Past paper - June 2013, June 2017
1. Cut off 5-10mm from a root tip
2. Heat the root tip at 60ºC in 2cm3 dilute hydrochloric acid in a waterbath
3. Transfer the tip on a glass slide
4. Break the cells apart using a needle
5. Place a drop of orcein ethanoic acid stain or tuluidine blue
6. Heat the slide to intensify the stain
7. Squash the root tip gently with the slide and the coverslip to separate the cells
8. Observe the cells under the microscope
9. Count the number of cells undergoing mitosis and calculate mitotic index
Safety;
• Staining clothes from orcein ethanoic, wear lab coat
• Hydrochloric acid irritating hands, wear gloves
• Harm using the knife, cut root tip away from the body
Orcein Etanoic acid stain is used to make the chromosomes visible, its blue in color
Hydrochloric acid separates the cells by breaking down the middle lamella softening the tissue
Variables to control;
• Temperature by growing seeds in an incubator or water-bath
• pH by using a buffer
• Humidity by air conditioning
• Variety or type of seed, collect seeds from same parent plant
• Light intensity by using same light source
• Availability of water
Observe with several root tips;
• To calculate a mean and standard deviation
• To then measure the rate of reliability and repeat any anomalous results
The cell cycle;
• A source of all the new cells needed for organisms to grow and to replace worn out cells and
method by which organisms under go asexual reproduction
• Function;
• Control growth of organism and replace dead cells and repair damaged tissue
• Increase in cell numbers by producing new cells
• Production of clone by asexual reproduction
• Synthesis of new organelles
• Controlled by a number chemical signals called cyclins brought about at a number of
checkpoints where the cell cycle moves from one phase to the next
1. Interphase which is a non-division period where the cells increase in mass and size
(G1), replicate their DNA (S) and carry out normal cellular activities, sufficient new
proteins, cytoplasm and cell organelles are synthesized for the new cell (G2)
2. Prophase,
• Nucleolus and nuclear envelope break down
• Centrioles separate and move to opposite poles
• Spindle fibers form from centrioles
• Chromosomes condense DNA coils and they become visible
Pearson Edexcel Advanced Level Biology Unit 3 - notes for success
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller Monai. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.49. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75632 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now