Formation of gametes - misjon.info
is the union of male and female gametes to form a fertilized egg, or zygote. The functional difference between mitosis and meiosis occurs in meiosis I. A. The nuclear DNA content of Feulgen stained zygotes and young proembryo for nuclei in newly fertilized egg cells (caused by failure of the staining reaction), Relationship between fertilization and the cell cycle in male and female gametes of tobacco Expression of the cell cycle in sperm of Arabidopsis: Implications for . Jul 8, Endometriosis; Getting Pregnant · Ovulation Calculator · Men's Health GIFT ( gamete intrafallopian transfer) and ZIFT (zygote intrafallopian transfer) are of mild male infertility, as long as the sperm is capable of fertilizing an egg. The difference is that with ZIFT the sperm and egg are mixed together in.
And as we'll see, each gamete has half the number of chromosomes as your body cells or most of the somatic cells of your body so outside of your sex cells that might be in your ovaries or your testes, depending on whether you're male or female, these have half the number so let's dig a little bit deeper into what I mean there.
Fertilization terminology: gametes, zygotes, haploid, diploid (video) | Khan Academy
So let's just do a blow up of this sperm cell right over here, so a blow up of a sperm cell and I'm not going to draw it to scale, you see the sperm cell is much smaller than the egg cell but just to get a sense, so let me draw the nucleus of this sperm cell, so just like that.
If we're talking about a human being, and I'm assuming you are a human being, so that might be of interest to you, this will have 23 chromosomes from your father so let's do them. One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 and for the 23rd one, that's going to be your sex-determining chromosome so if your father contributes an x, you are going to be female, if your father contributes a y, you are going to be male.
So these are the chromosomes in the male gamete or I guess I should say the gamete that your father's contributing, the sperm.
So this is a gamete right over here and that's going to fuse with the egg, the ovum that your mother is contributing and once again, I'm not drawing that to scale. So this is the egg, and let me draw it's nucleus.
So that's it's nucleus, once again none of this is drawn to scale.
- Formation of gametes
- Fertilization terminology: gametes, zygotes, haploid, diploid
And your mother is also going to contribute 23 chromosomes. So one, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 and then she will contribute an x chromosome for the sex determining so your sex determining chromosomes are going to be xy, you're going to be male, if this was xx, you're going to be female so this is also a gamete here.
So a gamete is the general term for either a sperm or an egg. Now once these two things are fused, what do we have? Once they're fused, then we're going to have you could say a fertilized egg but we are going to call that a zygote so let me draw that.
I'm going to do this in a new color, and I'm running out of space and I want this all to fit on the same screen so I'll draw it not quite at scale and so let me draw the nucleus of the zygote, I'm going to make the nucleus fairly large so that we can focus on the chromosomes in it, once again none of this is drawn to scale.
So you're going to have the 23 chromosomes from your father, so let me do that. One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 and 23, and then the 23 chromosomes from your mother.
One, two, three, four, five, six, seven, eight, nine, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 and 23 so you got that x chromosome from your mother.
What is the relationship between gamete ,zygote and fertilization?
And as you might have notice, I've drawn them in pairs so you now have a total, let me make it clear, you have 23 chromosomes here, 23 chromosomes in the sperm, you have 23 chromosomes in the egg and now you have 46 chromosomes in the fertilized egg, 46 chromosomes, and now that we have a full contingent of chromosomes and then this cell can now keep replicating, keep splitting and differentiating into all of what makes you, you, we call this right over here, we call this a zygote.
So one way to think about it, the gametes are the sex cells that have half the number of chromosomes and the zygote is the cell that's now ready to differentiate into an actual organism that has double the number or that has a full contingency of chromosomes, that has 46 chromosomes, and you see that I've made them in pairs and these pairs, we call these homologous pairs and in each of these pairs, this is a pair of homologous chromosomes.
So what does that mean? Well that means that in general, these two chromosomes, you got one from your father, one from your mother, they code for the same things, they code for the same proteins but there are different variants of how they code for those proteins, those traits that you have so gross oversimplification is, let's say that there is a gene on, that one from your father that helps code for hair color well there would be a similar, there would be another variant of that gene on the chromosome from your mother that helps code for hair color as well.
So these are homologous chromosomes, these two chromosomes code, in general, for the same things and so the zygote now has, you could say it has 46 chromosomes or you could say it has 23 pairs of homologous chromosomes.
If the egg or sperm that fuse to form the zygote is abnormal, the zygote will also be abnormal. For example, Down syndrome is caused by an extra chromosome number 21 from the egg or sperm cell. Since the cells formed by division of the zygote are identical to the zygote, any abnormality in the zygote will be in every cell of the baby.
Abnormalities can also arise when the zygote begins to divide. This type of abnormality is usually severe, eventually leading to a miscarriage. If an abnormality occurs after the zygote has divided one or more times, the baby will have some normal cells and some abnormal cells.
This situation is referred to as "mosaicism" and "mosaic" may be used to describe the person's condition.
Molar pregnancies Molar pregnancies can occur in one of two ways. Sometimes the original cell that duplicates and divides to form the fetus is completely of paternal origin. The chromosomes in a sperm duplicate themselves, then proceed to divide as if they were a normal zygote. These pregnancies are completely abnormal and miscarry. Another type of molar pregnancy occurs when two sperm fertilize one egg. The zygote is triploidy and has 69 chromosomes instead of Although some fetal parts can be seen, these pregnancies normally miscarry in the first or second trimester.
Birth defects The term birth defect describes many different types of abnormalities, including physical malformations. Abnormalities of anatomical structures may be significant or insignificant; minor variations in structure are common.
Multifactorial refers to causes with both genetic and environmental components. Substances that cause birth defects are referred to as teratogens. Artificial reproductive technology Couples may pursue assisted reproductive technologies for a number of reasons.
If a couple has artificial inseminationthe sperm is inserted into the uterus when the woman in ovulating. Fertilization then occurs as it would normally.
What is the relationship between gamete ,zygote and fertilization? | Yahoo Answers
If a couple has in vitro fertilization IVFthe egg and sperm are mixed outside the body in the laboratory. The zygote forms in a petri dish if fertilization occurs. After a number of cell divisions, the developing embryo is placed in the woman's uterus.
If the sperm are incapable of fusing with the egg themselves, the sperm may be injected into the egg. In the yearpreimplantation diagnosis is possible for a number of genetic diseases. Couples may pursue this if they are at a significant risk for having a child with a disease that could be diagnosed prior to becoming pregnant through preimplantation diagnosis. The procedure is like that of in vitro fertilization, with an additional step.
After fertilization occurs and the zygote has begun to divide, a single cell is removed. Removing the cell does not harm the other cells. The cell that is removed is tested for the genetic disease for which the couple is at risk. Multiple developing embryos are tested.
Only the embryos that do not have the condition are placed in the woman's uterus to complete development. The development of a person from the zygote is a fascinating and amazing process. It is a difficult area to study because scientists cannot manipulate human embryos to observe the effects, and the development of the fetus cannot be directly observed.
Researchers still have many unanswered questions.Fertilization, Implantation and misjon.info4
Following a doctor's recommendations from prior to the pregnancy throughout pregnancy such as folic acid intake and avoidance of alcohol and other drugs increases the chances that the development of a zygote into a full-term infant will be normal.
However, there are many babies born with severe birth defects or genetic diseases despite the parents' efforts at doing everything in their power to prevent a problem.
Most birth defects and genetic disorders occur because of an event out of control of the parents.