Term
|
Definition
| Viruses require a host cell in order to make new viruses. Bacteriophages are viruses that infect only certain kinds of bacteria. The material injected into the bacteria was unknown to scientists in the 1950's and spurred research over hereditary genetic material. |
|
|
Term
|
Definition
| A nucleotide is a nitrogenous base attached to a phosphate group and a five-carbon sugar. The four nucleotides are categorized as pyridimines- thymine and cytosine- and purines- adenines and guanines. These make up DNA and are the building blocks for nucleic acids. |
|
|
Term
|
Definition
| A beam from an x-ray is directed at a molecule and is scattered in a pattern that can be caught on film. The pattern consists on dots and streaks. This machine was used to view DNA, Rosalind Franklin was the first to use the machine to view DNA that occurs in living cells. Franklin was able to discover DNA's relative shape and width. |
|
|
Term
|
Definition
| Adenine pairs with thymine. Guanine pairs with cytosine. Bases are held together with hydrogen bonds. |
|
|
Term
|
Definition
| The molecule inherited is duplicated before a cell divides, this takes place during interphase in the cell cycle. The DNA strand is unzipped and each half of the strand is twisted together into a double helix with a new compliment strand. |
|
|
Term
|
Definition
| An enzyme that unzips hydrogen bonds between nucleotides. When they are unzipped the DNA strands unwind and cannot wind back together. |
|
|
Term
|
Definition
| This speeds up(catalyzes) the formation of two new strands of DNA from the stockpile of free nucleotides in the cell. They also speed up the hydrogen bonding of the parent strand and the complementary strand in a 5' to 3' direction. |
|
|
Term
|
Definition
| This enzyme is like glue and seals the stretches between nucleotides into a continuous strand. The parent strand wings with its compliment and two new DNA double helixes are formed. |
|
|
Term
| DNA Proofreading mechanisms |
|
Definition
| These repair most errors in replication and strand breaks. There are many different kinds of proofreading mechanisms that fix base pairings and other problems. |
|
|
Term
|
Definition
| Some mismatches get past proofreading mechanisms and cause the backbone of the double helix to break and bond differently. A repair enzyme mends some changes, they recognize problems, cut them out and sometimes replace it with the correct nucleotide(s). |
|
|
Term
|
Definition
| About every 75 pregnancies the dividing embryo inside the mother duplicates and grows separately as identical twins. Scientists clone embryos by stimulating a split in the ball of cells. Once done successfully it is implanted in a surrogate mother. |
|
|
Term
|
Definition
| Scientists take a cell(unfertilized egg), strip it of its nucleus and replace it with a young embryo. Both embryos are identical twins. |
|
|
Term
|
Definition
| She discovered an improved form of x-ray diffraction that allowed her to see DNA better than anyone before her. Her discovery was the long, thin shape of DNA. Watson and Crick would not have been able to finish their research without her data. |
|
|
