IGCSE BIOLOGY REVISION [Syllabus 17] - Monohybrid Inheritance

Welcome to another revision video. We are finishing off the topic of inheritance today. Specifically, we are looking at how to use a punnet square and the concept of monohybrid inheritance.

The main thing you need to know is that a many of our inherited traits are governed by a pair of alleles. Alleles are basically gene variants which code for the same thing.

In this video, we use eye colour as an example of a trait, and that there are two different genes: One codes for blue eyes, the other codes for brown eyes. These are alleles.

We then take a look at how we can determine the chances of these traits appearing in the phenotypes of offspring produced by certain crossing of genetics via a punnet square. I hope you enjoyed the video!

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[Midlifecrisis]

Some teachers deserve Oscar's for saving lives of thousand of childrens

[callistomalady]

Personal notes
- Alleles are different versions of the same gene
- Genotype is the genetic make-up of organisms whereas phenotype are the characteristics that are visible in that organism
e.g. a person can have alleles for both brown and blue eyes but the color will visible will be
- Organisms can be homozygous or heterozygous
- Alleles can be either recessive or dominant
- Punnet squares: 1) parents - BB and bb, offspring Bb 100% chance
2) parents - Bb and bb, offspring Bb or bb 50% chance
- Co dominance: A pair of alleles neither of which are dominant to the other so they both have impact on the phenotype

[EvieDavies-zk]

human biology exam starting in an hour ... youve literally saved my life tysm!

[daliadarkazanli]

you are literally the only hope I have left for bio

[Aisha-gddq]

Even after 5 years this is so helpful thank you

[Melly]

thank you so much. You are really helping me and I can't forget anything that you have taught. I appreciate you hard work. I'M sure of my A* this year in Biology

[athenaenergyshine]

I am doing BTEC level 2 science instead of GCSE but were doing this topic. i find genetic hard maybe because theres so many terms. but love this so much you explain it so clearly

[f_xh]

Thank u so much your saving lives bro😭🤍🤍

[vaibhavmaloo]

i have a question
if there is a flower that has dominant white alleles(W) and dominant red allele(R)
the plant shows co-dominance
what will be the colour of RW


The mark scheme says pink but isn't is supposed to be a flower with equal white and red patches

[abdullahdurrani]

At 4:34 isnt the Bb supposed to b brown eyed u showed it as blue??

[heartkiller]

Is this channel Videos are enough in concept building ??

[abdulrahmanhammad]

@ 7:59
So the abnormal allele is recessive while the normal allele is dominant? And is this always the case?

[akshat_joshi]

at 4:23 the punette squre is incorrect