Is Meiosis happening in our body all the time?
Or is it just before the sperm and ova meet?
Hi Rudy,
Great question. Recall that meiosis is the production of gametes, or sperm and egg/ova cells in animals, pollen or ovule in plants. In humans, male gametes are formed continuously following puberty, right up to death. In females, egg cells are formed by meiosis while the female is still in her mothers womb. The process then pauses and continues after puberty at a rate of one egg cell every month or so. Sperm can remain in the testes of a male for about 72 days before being recycled if not ejaculated.
Fertilisation is the joining of a sperm and egg cell, which can only happen after the gametes have been produced by meiosis. Normally quite some time after.
I hope that answers your question. Please feel free to ask if you would like further clarification.
Both meiosis and fertilisation were discussed in this webinar: NCEA Level 1 Science: Genetics AS 90948 Exam Preparation Webinar - YouTube
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Hey Rudy,
Just to add on to what Doug has already mentioned, a common misunderstanding from students is that meiosis happens in the sperm and egg. This is incorrect.
Meiosis occurs in your gonads (testes and ovaries) and it produces the gametes (sperm/egg)
If you go through the definition of meiosis (which is important for your upcoming external) - it is a process of cell division that occurs in the sex organs/gonads (not cells), that produces 4 genetically non-identical gametes.
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Wait so meoisis occurs every 72 days after being recycled in males?
But how come in the diagram, in your genetics presentation there is a blue and red chromosome? Doesn’t that mean one female and male chromosome?. And then it goes through to fertilize an egg and then become a zygote, with it going through crossing over and other processes
Wait so meoisis occurs every 72 days after being recycled in males?
But how come in the diagram, in your genetics presentation there is a blue and red chromosome? Doesn’t that mean one female and male chromosome?. And then it goes through to fertilize an egg and then become a zygote, with it going through crossing over and other processes
But isnt there like millions of sperm not just 4 non identical sperm?
Nope. You don’t have to know how often meiosis happens. It would also be different for different people and species - so not quite important.
I’m assuming this is the one from the webinar Doug linked.
Chromosomes come in homologous pairs. The Blue and Red chromosomes indicate that one comes from the mum, while the other comes from the dad. Both of them are a “pair”.(In the same way you would have a left and right glove.)
A sperm receives 23 chromosomes from the dad, while the egg receives 23 from the mum. When they fuse during fertilisation, they form a zygote which has 23 “pairs” (Hence 46 chromosomes in total)
Meiosis describes the process of it happening in one cell. So when meiosis occurs, it produces 4 genetically non-identical cell. However, meiosis is happening in the (cells in the) testes/ovaries.
Hope that helps.
But as Doug said “Recall that meiosis is the production of gametes, or sperm and egg/ova cells in animals, pollen or ovule in plants. In humans, male gametes are formed continuously following puberty, right up to death.” Then how can a female sex cell mix with a male sex cell if it’s a male body?
But as Doug said “Recall that meiosis is the production of gametes, or sperm and egg/ova cells in animals, pollen or ovule in plants. In humans, male gametes are formed continuously following puberty, right up to death.” Then how can a female sex cell mix with a male sex cell if it’s a male body?
Hi Rudy,
During sexual reproduction some of the male gametes, which have already been produced by meiosis, are released from the male’s body into the female’s reproductive system, and one successful sperm will fertilise the egg. In humans the egg is still inside the female’s reproductive system when fertilisation takes place. In other species both the sperm and the egg are released and fertilisation takes place externally (eg. most fish). This video might help your understanding of meiosis and fertilisation - just be aware that there is far more detail in the meiosis mentioned here than what you need for L1 Genetics.
In response to your earlier question, the sperm are created continuously. kloh is correct in that you don’t need to know this for your exam. However to try and clear up your understanding, human males produce around 1,500 sperm cells per second, through the process of meiosis. These are stored until released. They are only recycled (after about 72 hours) if not released.
Thank you so much for the help it helped my understanding.
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Hello could I pls get feedback and a grade on this pls. Thank you i really need it
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Hello could I pls get feedback and a grade on this pls. Thank you i really need it
English Level 1
1.1 Written text study
as90849
rudy
1d
Question: Describe at least one character or individual in the text.
Explain how the character or individual helped you to understand an important message.
Book: They Both Die at the End
Author: Adam Silvera
In the book They both die at the end, written by Adam Silvera, an important message was that no one should be afraid of death, this was shown through Silvera use of Mateo’s character development throughout the film. It was shown through a series of events, an event that showed the important message was when Mateo receives the dreadful phone call from Deathcast. Another event that showed the important message was Mateo coming to terms with himself after hanging out with Rufus. Through these events Silvera helped me understand how noone should be afraid of Death because it can lead to regret and despair
The fear of dying shouldn’t stop you from doing the things you want to do. This is important because it shows how being afraid of death can cause regret and despair. In the beginning of the book Mateo receives a dreadful phone call from DeathCast, he instantly regrets it “ The number one person I’m going to miss is future Mateo, who maybe loosened up and lived”. Mateo is already looking back at his life, thinking about all the opportunities he missed out on. Because he was afraid of death, he was scared of trying new things and now that is causing him regret and despair. Silvera uses “ loosened up and lived” to show how mateo sadness and anxiety stopped him from doing the things he wanted to do and shows the amount of regret he has because of his fear of death. Mateo later goes on to think about what his headstone should say “what a waste of life, I have to do better, I have to honor this”, mateo is beginning to look forwards and is starting to realize how much of a better life he can live if he gets the fear of death out of his mind. SIlvera’s use of repetition of “I have to” really draws in the reader and makes them feel that they can do it too, they can have the same urgency that Mateo has and make their lives better. Silvera has used this event to show how much the readers can benefit from letting go the fear of death.This is especially important because society has made fear death at a stage where people just stay enclosed in their homes absorbed in video games and are not realizing the enormous benefits of going outside and exploring the world something mateo couldn’t do because he always wanted the safety of his own home. Aso how people are scared of trying new things eg. skydiving. Society has made death a thing to be afraid of but it is not, death is inevitable it is going to happen to everybody, so why can’t people just let go of the fear of death and live freely?.. Therefore Silvera has helped me understand how we should get the fear of death out of our minds because no one wants to be regretting the things they didn’t do when they are lying on their deathbeds, as that is the worst thing that can happen. It shows how us humans have a lot of potential to be doing great things without lives and not by living our life enclosed in our homes.
Throughout They Both Die at the End SIlvera encourages us to let go of the fear of death and I’ve honestly, happily and freely. This message is important because it demonstrates how much our lives can improve without having the fear of death constantly roaming around in our heads. Mateo coming to terms with himself is another event that progresses this message. Mateo finally realizes what he can do with his life without having the fear of death. “The important goodbye is the one I said to past Mateo. Twelve hours ago I received a phone call telling me I’m going to die today and I’m more alive now than I was then. This shows the growth and quality of life Mateo has just developed. By just deciding to live and explore the world with Rufus he has gained so much. Silvera uses “I’m more alive now than I was then” to show how much Mateo has changed, to show how much he benefited from just hanging out and exploring the world with Rufus. It makes the readers feel a want to also have this understanding. Because if Mateo can live his whole lifetime in one day, how much can the readers live? Silvera’s purpose is to show how much us humans can gain a lot from just living freely and exploring the world with or without a friend. And this is the problem with society, society is so into a world on the web everything is electronic. Because of this, people stay home and don’t socialize. People are so addicted to electronics that they don’t bother going outside and exploring the world without knowing the massive benefits that can be gained. People are so into social media that they do not care about themselves. They are not trying to improve themselves and are falling into other people’s traps. People can live their lives so well without the need of social media, because it causes people to stay at home and look at unwanted stuff, and are ignoring the benefits from going outside and exploring the world. If Mateo can go explore the world and make his life go from bad to great in a couple of hours without having the fear of death, then why can we not do that. Silvera has therefore given us a chance to come to terms with reality and has intended us humans to try and live a better life since we all live once, why can’t we live it to the fullest potential. Silvera has not used this event as a fairytale ending mateo and Rufus do not live “happily ever after” like other wider literature, Instead with Mateo and Rufus both dying gives the reader a urge to live their lives to the fullest potential by getting the fear of death out of their minds. Therefore Mateo has helped me understand how important it is that we get the fear of death out of our minds and by going that we can succeed in life. Because society opposes this message and it can cause regret and despair if we keep on living with the fear of death in our minds.
Silvera has therefore showed us how much better lives we can live without having the fear of death. Slvera skillfully illustrated this through Mateo’s character development. At first he was a soft depressed teenager and he became a fulfilled and happy teenager when he let go of the fear of death. Silvera also showed how society opposes this important message, with society not getting the fear of death out of their minds. Overall Silvera and Mateo helped me understand how having a fear of death can really set you back from doing the things you want to do.