substance prepared from killed or weakened microorganisms that is introduced
into the body to produce immunity
What type of bacteria is able to cause disease?
Virulent Bacteria
What is a bacteriophage?
A virus that infects bacteria
What is DNA and what is it made up of?
A long molecule made of subunits called nucleotides that are linked together
What are the three parts of a nucleotide?
A phosphate group, a five-carbon sugar molecule, and a nitrogenous base
Whatis DNA and what is it made up of?
Deoxyribose
What two parts of a nucleotide is the same for each nucleotide ina molecule of DNA?
The sugar molecule and the phosphate group
What are the four different types of DNA nitrogenous bases?
adenine
guanine
thymine
cytosine
Adenine and guanine belong to what class of organic molecules?
Purines
Thymine and Cytosine are what type of class that has a single ring of carbon and nitrogen atoms?
Pyrimidines
What two scientists took X-ray diffraction photographs of the DNA molecule that suggested DNA resembled a tightly coiled helix?
Wilkins and Franklin
Watson and Cook used X-ray diffraction photographs to do what?
Build a model of DNA with a double helix configuration
How is the DNA double helix consisting of alternating sugar and phosphate units of purines and pyrimidines held together with?
Hydrogen bonds
Why is a pyrimidine always paired with a purine?
Because that is how they form the hydrogen bond that holds them together and keeps an equal diameter of the DNA
Which purines bond with which pyrimidines?
Adenine bonds with Thymine
Cytosine bonds with Guanine
The process of synthesizing a new strand of DNA is called what?
DNA replication
The point at which the double helix separates is called what?
Replication fork
What is formed when the helicase begins separating the two strands in the middle of the DNA?
Replication Bubble
At the replication fork ensymes known as ___________ move along each strand of DNA adding nucleotides to exposed bases following the basic-pairing rules.
DNA polymerase
Eukaryotic organisms usually have many replication forks that begin in the midle andmove in what direction? What do they create?
Both directions, replication bubbles
What are genes frequently interrupted by?
Introns which are long segments of nucleotides that have no coding information
What are the nucleotide segments that code for amino acids called?