Amoebae move by growing an extension of their bodies in the direction of movement and then flowing into it. This extension is called a pseudopod because when it's fully extended it resembles a limb, despite being only an extension of the amoeba's plasma membrane.Know More
An amoeba is a single-celled protist and therefore lacks true limbs. Moving through a medium without the flagellum of other protists requires a special mechanism for shifting the contents of the amoeba's body. It accomplishes this by extruding a section of its protective outer layer, the plasma membrane, and creating a small mass that is farther along in the direction of movement than the main body of the amoeba. The contents of the amoeba's body, mostly cytoplasm and various organelles along with the amoeba's nucleus, then flow through the pseudopod and into the amoeba's new location.
The amoeba's movement is not just mechanical. The directed flow of cytoplasm within the amoeba's body depends on changes to the viscosity of the cellular fluids. This factor is tightly controlled by special proteins that, when activated, change the consistency of the amoeba's cytoplasm from thin and viscid to gelatinous. This chemical change renders the fluid at the end of the pseudopod relatively firm and allows the thinner cytoplasm of the amoeba's body to flow after it.Learn More
The two types of nucleic acids are deoxyribonucleic acid, or DNA, and ribonucleic acid, or RNA. DNA can be found in most living organisms and is found in the nucleus of living cells. RNA converts genetic information found in genes into amino acid sequences.Full Answer >
DNA replicates to make copies of itself. This is an indispensable process that allows cells to divide for a living organism to grow or reproduce. Each new cell needs a DNA copy, which serves as instructions on how to function as a cell.Full Answer >
Gregor Mendel learned through studies with pea plants that factors, now known as genes, are what determine biological inheritance. When he bred the plants, he noticed that the flower's color was never a blend of the parent plants' colors but rather a solid shade.Full Answer >
When two genes segregate independently, it is called independent assortment. Gregor Mendel, a European monk who studied heredity, identified this process in 1865 while he was investigating multiple generations of pea plants.Full Answer >