Microbiology Basics

Transformation

• A process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria.

Bacteriophage

• A kind of virus that infects bacteria.
• Infects bacterial cells, sticks to the surface, and injects its genetic information.
• The viral genes make many new bacteriophages, which destroy the bacterium.

DNA

• Stands for Deoxyribonucleic acid.
• Main jobs: store information, copying information, and transforming information.
• Made up of nucleotides, which are the building blocks of nucleic acids.
• Nucleotides are composed of three basic parts: a 5-carbon sugar called deoxyribose, a phosphate group, and a nitrogenous base.

Nucleotides

• There are 4 different types of nucleotides: Adenine, Guanine, Cytosine, and Thymine.
• These nitrogenous bases pair with each other in a specific manner: Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G).

Chargaff's Rule

• A rule that states the percentages of Adenine and Thymine bases are almost equal in any sample of DNA.
• The same is true for Guanine and Cytosine.
• Observed that A=T and G=C in DNA samples from diverse organisms.

Franklin's X-Rays

• Showed that the X-ray pictures of DNA strands are twisted around each other, forming a helix shape.
• Suggested that the nitrogenous bases are near the center of the DNA molecule.

Double Helix Structure

• Held together by hydrogen bonds, which are fairly weak bonds.
• The two strands of DNA run in opposite directions, forming an antiparallel arrangement.

Replication

• The process of copying DNA prior to cell division.
• Involves the unwinding of the double helix, and the formation of new strands.
• DNA polymerase is the main enzyme involved, joining individual nucleotides to make new strands of DNA.

Enzymes in DNA Replication

• Pull apart a molecule of DNA, breaking the hydrogen bonds between base pairs.
• Unwind the 2 strands.
• DNA polymerase produces the sugar-phosphate bonds that join nucleotides together to form the new strands.

Test your understanding of microbial concepts, including bacterial transformation and bacteriophages. Learn about the process of gene transfer and viral infection in bacteria.