Skip to main content
Pearson+ LogoPearson+ Logo
Start typing, then use the up and down arrows to select an option from the list.

General Biology

Learn the toughest concepts covered in Biology1&2 with step-by-step video tutorials and practice problems by world-class tutors

11. Cell Division




Play a video:
Was this helpful?
in this video, we're going to begin our introduction to cancer. And so cancer is a disease characterized by uncontrollable cell growth or cell division. And so this uncontrollable cell division is going to lead to the development of malignant tumors. Now a tumor is defined as an overgrowth of cells or, in other words, an abnormal mass of tissue. And tumors typically can cause health complications. And really, there are two main types of tumors that you should be familiar with. The first main type of tumor are the malignant tumors, which are an overgrowth of cancerous cells that migrate or, in other words, metastasize to other organs. And really, the malignant tumors are the ones that are the most dangerous because they can create a tumor in one area of the body. But then they can migrate or metastasized to a completely different organ within the body and also cause health complications in that other organ. Now, benign tumors are the second type of tumor, and these are not cancerous. This is an overgrowth of cells that are not cancer cells, and they do not migrate, so they do not metastasize. Instead, the benign tumors are going to remain at the same site, and benign tumors are or can be can cause health complications. But they're not nearly as dangerous as the malignant tumors are. And so now below in our image notice. Over here on the far left, we're showing you malignant tumors, and over here on the far right, we're showing you the benign tumors. And so again, the malignant tumors are cancerous. And so the benign tumors over here on this side are non cancerous cells. Now, the malignant tumors that are cancers there actually non caps, elated and the benign tumors over here they actually are caps elated. And the capsule is just this, uh, basically structure of tissue that can surround and capsule ate the cells basically containing them in their same area. Now the malignant tumors tend to be very fast growing. They divide very, very fast since they are cancerous cells, whereas the benign tumors arm or slow growing, and then in terms of metastasizing or migrating to other areas of the body. Of course, malignant tumors are characterized by the migration or the metastases, so this is of course, going to be yes, they do metastasize, whereas the benign tumors On the other hand, in terms of do They metastasize, the answer to this would be no, they do not metastasize and partially because they are capsule aid. And so this year concludes our introduction to cancer and the difference between malignant tumors and benign tumors. And in our next lesson, video will get to talk a little bit more about cancer by talking about specific genes that control the cell cycle. So I'll see you all in that video.

The difference between benign and malignant tumors is:

a) Malignant tumors do not spread to other sites.

b) Benign tumors have not lost growth control.

c)  Benign tumors have not spread to other sites.

d)  Malignant tumors have not lost growth or control.


Types of Genes Regulating Cell Growth

Play a video:
Was this helpful?
In this video, we're going to introduce two types of genes that regulate cell growth. And so, in a healthy and normal cell that is not cancerous and is not part of the tumor, this healthy normal cell is going to have two types of genes that regulate cell growth. And we've got these two labeled down below number one and number two. And so the first type of gene that's going to regulate cell growth in a healthy, normal cell is a proto oncogene. And so a proto oncogene is going to be a gene that provides signals that promotes appropriate cell division. And so because it's promoting appropriate cell division, proto oncogene is pretty much acting like the green light for cell division. And so it's going to allow cell division to proceed. Now, the second type of gene that regulates cell growth is a tumor suppressor jean. And so the tumor suppressor gene, as its name implies, is going to do pretty much the opposite of the proto oncogene. It's going to provide signals to not promote but inhibit cell division, so it's basically acting like the red light for cell division to inhibit cell division and to slow it down. Now, a protein called P 53 is an example of a protein that serves as a tumor suppressor gene. And so if we take a look at our image down below, over here on the left hand side, notice we're showing you a proto oncogene and how it pretty much acts like the cell division gas pedal. It pretty much promotes cell division, so it acts like the green light for cell division to allow cell division to proceed normally and appropriately. And then over here on the right hand side, notice, we're showing you the tumor suppressor gene, which is pretty much acting like the cell division breaks or the brakes to cell division or the red light for cell division that slows down or inhibit cell division. And so again, within a healthy and normal cell, there are both proto oncogene, and there are tumor suppressor genes that will either promote or inhibit cell division appropriately so that cell division will proceed appropriately. However, although proto oncogenes and tumor suppressor genes are normal and healthy genes found a normal and healthy cells, they are susceptible to mutations and mutations in either of these types of jeans and either proto oncogenes or tumor suppressor genes can lead to the development of cancer uncontrollable cell division. And so again, although proto oncogenes are essential. Although proto oncogenes are essential and healthy genes that promote cell division appropriately again, they are susceptible to mutations that congenital wait. Uncle jeans and Anca genes are different than proto oncogenes. Proto oncogenes are healthy and normal genes that are needed and required to promote appropriate cell division. However, aka genes are mutated proto oncogenes. And so that's exactly how we're defining oncogene down below. They are mutated jean that is going to promote unrestrained cell growth. Essentially, it's going to promote cancer. And so this year concludes our introduction to the two types of genes that regulate cell growth. Proto oncogene, zand, tumor suppressor genes and how they are normal, healthy genes that are required to regulate cell division and how they're both susceptible to mutations that can lead to the development of cancer. And so this year concludes this video, and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video

Which of the following processes do normal proto-oncogenes typically exhibit?

a)    They normally suppress tumor growth.

b)    They enhance tumor growth.

c)    They stimulate normal cell growth and division.

d)    They are underexpressed in cancer cells.


When activated by signals in the cell, Protein X can stop cells from growing and dividing into new cells. What type of gene codes for Protein X?

a) Oncogene.

b) Tumor-suppressor gene.

c) Protein kinase gene.

d) Protein Vesicle gene.

e) Proto-oncogene.