CHROMOSOME mutations - A level biology. Nondisjunction in meiosis. Aneuploidy & polyploidy

[@torriches]

This has just saved my life not to be dramatic or anything but I’ve not understood this for over a year and now I do

[@MissEstruchBiology]

Hi Victoria, that's great! So glad you are more confident. Pleased it helped 😀

[@jamesklieve4620]

Just finished the AS playlist with a bunch exam questions after each unit to consolidate, all going more or less perfectly c: Thank you!

[@MissEstruchBiology]

Amazing 👏! Great consolidation and revision strategy. Hope they videos help with your studies 😊

[@rip_6998]

what grade did u get x

[@maris4416]

My oral biology A level exam is tomorrow and this was an absolute life saver, thanks!

[@omarmohammd5276]

oral?

[@sarahm5376]

Substation ans deletion ?

[@mahimaali9795]

This was the last video I watched before my exam and it came up!!

[@rip_6998]

how did u do x

[@hannahrhoda]

i hate meiosis omg

[@caitlinwhiteman8801]

Hi, at 1:35 you said that polyploidy results in a triploid gamete instead of a diploid gamete. I'm a bit confused because I thought gametes are haploid? Do you mean the offspring will be triploid?

[@MissEstruchBiology]

yes!!! That's right

[@i_am_gods_child]

this helped so much!! thankyou for explaining everything so well

[@MissEstruchBiology]

Hello 👋🏻 So glad it's helped you to understand 😊

[@MrMidoo2010]

Always fabulous Miss Estruch.

[@MissEstruchBiology]

That's very kind! I hope the video helped

[@nosleepdelirium1214]

Sorry just for clarification you don't ever have a diploid or triplioid gamete. Gametes are haploid so polyploidy creates a triploid zygote right ? I think ? Well you did explain this actually , I guess just a little misspoke in the beginning 😊

[@joshuacottrell2742]

Gametes are normally haploid as one gamete receives one copy when the chromatids separate in meiosis 2. If you get a non-disjunction mutation, you will get 2 copies in one gamete and 0 in the other. This means you have a diploid gamete and essentially an empty cell. This means you could potentially get a triploid zygote if the diploid gamete (from the non-disjunction e.g., in the Father) combines with a normal haploid (e.g., from the Mother) during random fertilisation. Hope this helps!

[@mynamemeanswish4445]

You don't know how good you are:) thaks💙💙💙💙💙

[@MissEstruchBiology]

awww thank you ☺😊

[@nitinagunawardhana]

Thank you very much. This did really help me to understand clearly what aneuploidy and polyploidy means.

[@MissEstruchBiology]

So glad it helped you!!!

[@userkk-hb4qh]

Thanks a lott miss ❤

[@MissEstruchBiology]

you're welcome 😊

[@The-Progress-Project]

what topic is mutagenic agents?

[@mani-jx7nb]

Hi Miss Estruch, just wanted to say that your videos are saving my life :) question, what would fertilisation look like for the non-disjunction in meiosis 2 (polyploidy & aneuploidy) ?

[@MissEstruchBiology]

It depends on the gametes made. For aneuploidy, n +1 or n-1 combing with a normal n gamete would result it trisomy or monosomy in the zygote. If it was a polyplooidy gamete, 2n, combining with a normal n gamete you'd get a 3n zygote which is polyploidy. The overall outcome is the same whether the mutation occurred in meiosis I or II. Hope that helps.

[@ardisrexha868]

hi, what spec point is this under for aqa a level biology.

[@nureeyakhan7451]

hi miss, love your videos, they're so helpful, thank you so much for making them :) at 1.30 you said 'diploid gamete' but I thought all gametes are haploid as they have half the usual number of chromosomes?

[@MissEstruchBiology]

all gametes should be haploid, but due to non-disjunction in chromosome mutations, some can be diploid.

[@khainojr2721]

Miss it help me so much thank you.

[@MissEstruchBiology]

So pleased it helped you!!!

[@mikail_medic862]

I prefer to study together rather than with lecturers at my university (:

[@MissEstruchBiology]

I hope these videos allow you to do that then ☺

[@ImranAwan-n9s]

Are we supposed to know this for AQA as our teacher told us this video specifically was off spec?

[@MissEstruchBiology]

Non disjunction and chromosome mutations is in topic 4 for AQA A-level

[@ImranAwan-n9s]

@@MissEstruchBiology Do we need it in this level of detail, etc. with the name of each specific case?

[@poppydowse7753]

SO HELPFUL!!!!

[@MissEstruchBiology]

Really pleased you found it so helpful 😀

[@ell6311]

Hey, could you tell me what topic gene mutations is in please

[@MissEstruchBiology]

Hello, it comes up on both topic 4 and topic 8 😊

[@ell6311]

@@MissEstruchBiology thank you

[@LakmalPerera-or3nx]

teacher can you explain how to make 4n cells

[@shhlarsd]

hi, why polyploidy rarely found in animals?

[@MissEstruchBiology]

Hi, Because it is usually lethal , meaning the fetus wouldn't survive if it was polyploidy.

[@avrilstacy3133]

It's a miracle that human survive. So many natural miscarriages occur due to undeveloped fetuses. I am a healthy biological female, but have mild endometriosis with some scar tissue in 1 fallopian tube which does effect conception in pregnancy. At my age now, I feel grateful that was my only medical issue I've ever had to deal with.

[@MissEstruchBiology]

So true. Glad you are otherwise doing g well 🙏🏻

[@iluvdawgs00]

Is this part of as lvl chap 5?

[@reecehaddock8274]

What happens if an n+1 gamete fuses with an n-1 gamete

[@MissEstruchBiology]

Depends if it is the same chromosome that they have 1+ and 1- of. It would be exceptionally unlikely that would ever happen, but if it did then it would result in a 2n cell.

[@destinyosaghae]

Is polypoidy and aneuploidy on the spec?

[@saraszymonczyk2814]

no

[@pera_peric]

Thank you!

[@MissEstruchBiology]

you're welcome 😊

[@ahmedsharaf2695]

Thank you so much 👍👍👍

[@MissEstruchBiology]

You're so welcome ☺️ Hope it helps you

[@easytolearn5275]

wondefully explained

[@MissEstruchBiology]

Thank you!

[@favourebohon5259]

Hi Miss, I'm in Year 12. Thank you so much for your videos. Do we have to know the meiosis process for both non-disjunction mechanisms or is just the theory? Thank you.

[@danielmoore4024]

Favour Ebohon, You will if you want to pass a standardised test, but if you want to actually be a biologist you can't keep swallowing what people tell you without challenging it. In the mid 19th century scientists twisted biology and pathology and because no one challenged the dogmatic assumptions there's now a lot of dogma in human biology. I challenge those who view themselves as scientists, they can never overcome my scrutiny because they are using dogma. If you want to see the real science you will have to leave the box. If you scrutinise what you've been taught you will be able to see most scientists are trying to prevent human evolution. I'll share just a little from scientists outside of the box not basing their work on man-made narratives, whenever the term "normal" is mentioned beware, you are heading towards science discourse. Molecular biologist Miroslav Radman writes, "Mutagenesis has traditionally been viewed as an unavoidable consequence of imperfections in the process of DNA replication and repair. But if diversity is essential to survival, and if mutagenesis is required to generate such diversity, perhaps mutagenesis has been positively selected for throughout evolution." Evelyn Fox Keller of MIT explains: "We now know that mechanisms for enduring genetic stability are a product of evolution. Yet a surprising number of mutations in which at least some of these mechanisms are disabled have been found in bacteria living under natural conditions. Why do these mutants persist? Is it possible that they provide some selective advantage to the population as a whole? Might the persistence of some mutator genes in a population enhance the adaptability of that population? Apparently so. New mathematical models of bacterial populations in variable environments confirm that, under such conditions, selection favors the fixation of some mutator alleles and furthermore, that their presence accelerates the pace of evolution." The mutants behind things like Down Syndrome, Autism, ADHD etc... offer some great advantages to the human race, diminishing the genes is a great risk because without those mechanisms there is no asurety of genetic stability pushing us in the direction of extinction. "You gotta challenge all assumptions. If you don’t, what is doctrine on day one becomes dogma forever after." John Boyd