Table of Contents
Do different cell types have different sets of genes?
A cell typically expresses only a fraction of its genes, and the different types of cells in multicellular organisms arise because different sets of genes are expressed. Moreover, cells can change the pattern of genes they express in response to changes in their environment, such as signals from other cells.
Why do all cells have the same genes?
Almost all of the cells in your body share the same DNA as was found in that first cell*. The answer lies with what DNA is and how it works. Your DNA contains all of the information needed for making you. This information is stored in the over 20,000 human genes found in almost all your cells.
Does every chromosome have the same DNA?
Each chromosome is, if fact, an enormous DNA molecule. There are 22 homologous pairs and two sex chromosomes (the X and Y chromosomes). One chromosome in each pair is inherited from one’s mother and one from one’s father. Each chromosome is a single molecule of DNA.
Why are different types of cells have different genes?
If the cells didn’t stop growing, this growth would cause cancer. So when everything is working OK, each cell type only reads the genes it needs. That way it only makes the proteins it needs too. That is how cell types can be so different even though they have the same set of genes.
How are embryonic stem cells derived from humans?
Embryonic stem cells are derived from human embryos, which are destroyed to obtain the cells. The destruction of human embryos is an ethical problem. And, the DNA in an embryonic stem cell would differ from the DNA of the person being treated, which could result in immune problems or rejected of tissue.
Why are cells different from other cells in the body?
These cells are different because they use the same set of genes differently. So even though each of our cells has the same 20,000 or so genes, each cell can select which ones it wants to “turn on” and which ones it wants to keep “turned off”.
What are the different types of stem cells?
They include the embryonic stem cells of the embryo, fetal stem cells of the fetus, and adult stem cells in the adult. One type of adult stem cell is the epithelial stem cell, which gives rise to the keratinocytes in the multiple layers of epithelial cells in the epidermis of skin.