BIO.B. Cell Growth and Reproduction
Topic Summary for Sexual Reproduction:
There are two main reasons why cells divide:
Information “overload”: The larger a cell gets, the more demands it places on its DNA. Eventually, the cell’s DNA cannot meet the cell’s needs.
Exchange of materials: Cells take in nutrients and eliminate wastes through the cell membrane.
• The larger a cell’s volume, the more materials it needs to function and the more waste it creates.
• A cell’s volume increases at a faster rate than its surface area. As a cell grows, its surface-area-to-volume ratio becomes too small.
• The larger a cell gets, the harder it is for enough materials to move across its cell membrane.
Cell division solves the information overload and materials exchange problems.
Cell division is part of both types of reproduction:
Asexual reproduction:
• produces genetically identical organisms.
• occurs in many single-celled organisms and in some multicellular organisms.
• allows rapid reproduction of organisms in favorable environments.
Sexual Reproduction:
• produces organisms with genetic information from both parents.
• occurs in most animals and plants and in many single-celled organisms.
• increases genetic diversity, which aids species survival in changing environments.
Topic Summary for Sexual Reproduction:
There are two main reasons why cells divide:
Information “overload”: The larger a cell gets, the more demands it places on its DNA. Eventually, the cell’s DNA cannot meet the cell’s needs.
Exchange of materials: Cells take in nutrients and eliminate wastes through the cell membrane.
• The larger a cell’s volume, the more materials it needs to function and the more waste it creates.
• A cell’s volume increases at a faster rate than its surface area. As a cell grows, its surface-area-to-volume ratio becomes too small.
• The larger a cell gets, the harder it is for enough materials to move across its cell membrane.
Cell division solves the information overload and materials exchange problems.
Cell division is part of both types of reproduction:
Asexual reproduction:
• produces genetically identical organisms.
• occurs in many single-celled organisms and in some multicellular organisms.
• allows rapid reproduction of organisms in favorable environments.
Sexual Reproduction:
• produces organisms with genetic information from both parents.
• occurs in most animals and plants and in many single-celled organisms.
• increases genetic diversity, which aids species survival in changing environments.