About this chapter
Take the most advanced computer today and it still won't compare to the complex yet elegant applications that take place on the cellular level. With three billion bases in the human genome, the DNA content in a single cell is a comprehensive cookbook containing recipes for life. You'll see how arrangements of chromatin, chromosomes, histones and nucleosomes allow this wealth of information to be packaged in a cell's nucleus. Still, how do we get from one cell to the trillions of cells that make up the human body?
Each cell in your body has a series of programmed events, known as the cell cycle, to keep you up and running. Much of the cell cycle is spent in preparation, and, from interphase to cytokinesis, we're going to show you how the cell cycle is just like decorating Christmas trees in the future. While this may sound crazy, just wait until we delve in to the intricacies of cell division. We'll come full circle as we journey through the cell cycle and see how replication leads to more replication.
We'll explore the exquisite machinery of mitosis, an entire process devoted to making sure that your DNA is properly preserved and packaged as cells divide. You'll also take a closer look at how the genome is organized into chromosomes and learn how to distinguish between homologs and chromatids. Line up along the equatorial plate and observe how centromeres, centrosomes, centrioles, kinetochores and the mitotic spindle bring it all together before pulling it apart at just the right moment.
We'll also journey from diploid cells to the haploid realm of gamete production, as we examine yet another type of cell division known as meiosis. Don't worry, many parts of the meiotic process are similar to mitosis, so we'll make sure that you understand those important differences, the crossover and recombination that occur. However, life isn't perfect, so we'll also explore the meiotic errors that can take place. By the end of our cell division section, you'll see how life propagates and how knowledge can lead to more knowledge.
There are approximately 3 billion bases in the human genome. In this lesson, you'll learn more about the genome and its organization into chromosomes.
Explore the structure of chromosomes and see how DNA fits inside the nucleus of the cell. In this lesson, you'll learn about histones, chromatin and nucleosomes.
Learn about the dividing and non-dividing states of the cell and discover the different phases of the cell cycle, including interphase, cytokinesis, and the stages of cell division.
Learn how DNA packaging makes it possible to fit approximately seven feet of DNA inside a single cell. You'll see how chromosome condensation helps cells get ready for cell division.
Learn all about chromosomes, including the different parts of a chromosome and the types of chromosomes in diploid organisms like humans. Learn the vocab used with chromosomes.
Condensation makes DNA ready / And microtubules hold it steady / A microtubule's a fancy rope / To move the DNA is the hope / From spindle poles they do extend / To align each chromosome in the end
Let's take a second look at mitosis and focus on the phases of chromosome segregation. As we concentrate on chromosomes, you'll learn the tricky dance that takes place through all five phases of mitosis.
What's a cell to do when it must divide in two? We'll explore cytokinesis and see how the process can differ in important ways when it comes to plant versus animal cells.
Did you know that some organisms can reproduce without a mate? Check out this video lesson on asexual versus sexual reproduction to discover the different ways organisms can reproduce and the main differences between mitosis and meiosis.
Welcome to meiosis, a realm of division doubled for reproduction untroubled. You'll get a preview of both divisions of meiosis and see what it takes to go from a diploid cell to a haploid gamete.
How does meiosis keep track of homologs and reduce the genome by half? Know these answers and more as we navigate the steps of meiosis I. This lesson will be tetradical!
Behold round two of meiotic cell division! You'll see how meiosis II keeps the genome intact and gives the final push to produce haploid gametes, which make the world go round.
Learn why proper chromosome segregation is essential during meiosis. We'll see how having an extra chromosome can lead to Down Syndrome and also examine the consequences of having too few chromosomes. Disruptions to the delicate balance of cell division can have far-reaching effects.
Watched all the videos in this chapter?