Miracle In Cell No 7 English Subtitles Download
Cecelia Shane
But as ordinary as it seems, creating a new human being is no simple feat.Just think of it. No matter who you are, once upon a time you looked like this.From a single cell you built a body that has one hundred trillion cells. Youmade hundreds of different kinds of tissues and dozens of organs, including abrain that allows you to do remarkable things.
In almost every cell of your body you have thirty thousand or more differentgenes, spread out on very long strands of DNA called "chromosomes." Most cellshave two versions of every gene on a total of 46 chromosomes. Exactly half ofthose, 23, came from your mom, and 23 came from your dad. They come in pairswhere the partners are very similar but not quite the same. The only time theyget together is during meiosis.
Here's how it works inside a testicle that's making sperm. First, eachchromosome makes an exact copy of itself, keeping it attached at one point.They condense, creating an X-shape. Now the chromosome partners get togetherand the two, or actually four, will embrace. They cling so closely, big chunkscarrying whole bunches of genes get exchanged between the partners. The cellthen divides twice, each time pulling the pairs apart. The final result is asperm or an egg cell with 23 chromosomes, half the normal number.
Those who make it will face yet another challenge. Underneath the cloud ofcells, the egg itself is encased in a thick protein shell, called the "zona."To fertilize the egg, the sperm must break through the zona. But even thestrongest can't do it by brute force alone. The egg demands a properintroduction. Proteins protruding from the sperm's cap must hook up preciselywith a set of proteins on the egg's surface. If they match, the sperm is heldfast and undergoes a dramatic transformation. It sheds its outer coating,releasing powerful enzymes that dissolve a hole in the zona, allowing the spermto push its way through.
Since the moment the sperm entered the egg, 24 hours have passed. All thistime the fertilized egg is moving down the fallopian tube toward the uterus.Every few hours, the cells divide. Four...eight...sixteen...gradually creatingthe building blocks needed to construct an embryo.
Now called a "blastocyst," the bundle of cells must do two things to survive:break out of the zona and find a source of nourishment. At the beginning of thesixth day, it orchestrates an escape. It releases an enzyme that eats throughthe zona, and the ball of cells squeezes out. Free at last, the blastocystlands on the blood-rich lining of the mother's uterus. It has just passed onehurdle, but is immediately presented with another.
For in fact it is now in very grave danger. Stripped of its protectivecoating, the blastocyst could be attacked by the mother's immune system as aforeign invader. White blood cells would swarm in to devour it. In its ownself-defense, the ball of cells produces several chemicals that suppress themother's immune system inside the uterus, in effect, convincing the mother totreat it like a welcome guest.
Then it is free to get to work. Searching for food and oxygen, cells from theblastocyst reach down and burrow into the surrounding tissue. Eventually, theypull the entire bundle down into the uterine lining. And sooner or later, themother will notice.
One milestone event takes place just two weeks after conception, when theblastocyst is about the size of a poppy seed. This is the moment when the cellsstart to organize themselves into an embryo. The process is called"gastrulation."
With animals like frogs, whose embryos develop inside transparent eggs, it'seasy to see it in action. After the egg becomes a hollow ball of many cells,some cells dive into the center, forming layers which will go on to developinto different organs.
In humans, gastrulation happens deep inside the mother's uterine lining, so itcan't be photographed. But we think it works something like this:theblastocyst creates two oblong bubbles, one on top of the other. Sandwichedbetween them is a thin layer of cells. These are the cells which one day maybecome a baby. At the beginning of gastrulation, some cells begin moving towardthe center. Then they dive downwards, creating a new, lower layer. More cellsplunge through, squeezing in between, forming a third. The cells in the threelayers may not look different, but for each layer, a very different future liesahead.
The lower cells are destined to form structures like the lungs, liver, and thelining of the digestive tract. The middle layer will form the heart, muscles,bones and blood. And the top layer will create the nervous system, includingthe spinal cord and the brain, as well as an outer covering of skin, andeventually, hair.
This is a human embryo three weeks after fertilization. Less than a tenth ofan inch long, its neural tube, the beginning of the nervous system, is alreadyin place. A couple of days layer, the top of the tube is bulging outwards onits way to becoming a brain. With the primitive brain cells exposed, we can seesome are sending feelers, making connections to their neighbors.
As the days pass, changes proceed at a rapid-fire pace throughout the embryo.Everywhere, cells are multiplying. And they're on the move. Some reach out toone another, forming blood vessels. A heart begins to beat. As the embryolengthens the precursor to the backbone forms. Groups of cells bulge out on thesides, the beginnings of arms and legs.
Part of the answer seems to be location. Once the basic body plan isestablished, with a head on one end, back and front, and left and right sides,cells seem to know exactly where they are and what they are supposed to become.This is because cells talk to each other in the form of chemicalmessages.
If all the DNA in a single cell were stretched out, it would be about six feetlong. But it's all wound up very tightly, coiled around balls of protein. For agene to be turned on, something has to come in and loosen up the right section.Then the cell's machinery can latch on and read the DNA, the first step on thelong road to building a protein. Those molecules that can turn genes on play akey role in every aspect of development, including the process that transformsthe embryo into a boy or a girl.
Of course there is one way to tell the difference: look at the chromosomes ina cell from the embryo. One pair among the 23 determines sex. An embryo withtwo X chromosomes usually becomes a girl. If one of those Xs is a Y, it willmost likely be a boy.
SRY turns on for a day or two, and the cells churn out its protein. But inthat short time, SRY sets off a chemical chain reaction, turning on othergenes, eventually turning the gonads into testicles, which begin to maketestosterone. Testosterone travels throughout the body. If it reaches thegenitals then the cells here will build a penis.
Sometimes genes send the message to multiply and grow, as with the arm and legbuds. Sometimes the message is to die, as it is a few days later, to the cellsbetween the fingers. As the weeks pass, the embryo's genes send billions ofindividual messages, constructing new kinds of cells and building organs andlimbs.
In the sixth month, genes in the brain order the manufacture of a fattysubstance called "myelin," which wraps around the long connections betweenbrain cells. This fatty covering allows nerve impulses to travel up to 100times faster, greatly enhancing brainpower. The process will continue for yearsafter the baby is born.
Dr. Aasi performs surgeries regarding lesions on the skin that can take the form of basal or superficial squamous cell carcinomas, cysts, lipomas, or keloids. Basal and squamous cell carcinomas are skin cancers that are contained in the outermost layer of the skin, the epidermis. The cells on the topmost layer of skin are called squamous cells, which are constantly shedding and being replaced by basal cells, located in a lower layer of the epidermis. Basal and sqaumous cell cancers are most commonly developed from sun exposure and poor sun protection. They are found in areas such as the face, back of the neck, arms, ears, or hands. The most common type of skin cancer is a basal cell carcinoma, a slow growing cancer that is minimally invasive and rarely spreads throughout the body. A squamous cell carcinoma is less likely but has a higher likelihood of spreading to other parts of the body because it is found in deeper layers of the skin.
Through my time at Stanford I learned so much more than I thought I would. Not just about the nature of dermatologic surgery, which proves to be a job for a doctor, artist, and perfectionist all in one, but also about the unforeseeable speed at which life moves and the pure joy that comes from being able to help people. From hearing the stories of hundreds of patients and watching the doctor cure their illnesses, I got a firsthand glance into the miracles of medicine. After witnessing the pain and suffering associated with cancer, I was moved by the resilience of patients faced with circumstances beyond their control. I was stirred by the selflessness of doctors and the amazed by the rhythm of hospital clinics. I learned more from this experience than could ever be written in a textbook, urging me to learn by facing a constant rollercoaster of emotions. But most importantly I learned to never forget sunscreen.
My story starts when I had a serious fall and nearly broke my back, which made me available, by some miracle, to be there for my dear wife when she took ill with leukaemia, AML leukaemia. I needed a lot of help at the beginning. But I fought through that horrendous start and became the helper.
In 2005 Saibil and her group described structures of the pore-forming toxin pneumolysin, from Streptococcus pneumoniae, in complex with a model cell membrane. They found that the proteins formed two distinctly different ring-shaped structures. Initially, they formed into a ring sitting on top of the membrane, which was termed the pre-pore; then they changed shape to burrow part of each protein deep into the membrane and form the pore itself. Each monomer in the pre-pore had a structure that was similar to that of the molecule in solution, but they underwent large structural changes to form the pore.
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