Genetic information is stored in DNA. An RNA transcript can be made and transported into the cytoplasm, where it translated into proteins. RNA comes in three forms: messenger (mRNA), ribosomal (rRNA), and transfer (tRNA). Transcription takes place in three parts: initiation, elongation, and termination. Translation builds an amino acid sequence based on the genetic code. Start and end points are indicated using codons. Silent mutations can occur where the same proteins are translated even though the genetic code has changed as redundancy is built into the genetic code. The second type is missense mutation, where a different amino acid will be added to a protein chain based on the genetic mutation. Nonsense mutations form a stop codon. Natural errors, chemicals, excessive sunlight, and radiation can all cause mutations.
consist of nucleic acid enclosed in a protein capsid. Some viruses
are covered by an envelope derived from the host cell membrane.
cannot reproduce independently. To reproduce, they must infect a
host cell and use the host cell's machinery to produce viral
nucleic acids and proteins.
may reproduce either via the lytic cycle or the lysogenic cycle.
the lytic cycle, the virus attaches to the host cell and then
injects its genetic material. A viral enzyme degrades the host DNA
and the host cell's machinery is used to synthesize viral nucleic
acids and proteins. The phage self-assemble and the bacterial cell
is lysed to release the newly produced phage.
the lysogenic cycle, phage DNA integrates into the bacterial genome
and is replicated along with the bacterial DNA. An environmental
cue, such as UV light, can trigger the phage to be excised from host
DNA and enter the lytic cycle.
sense RNA viruses contain RNA that can be translated directly into a
protein. Negative sense RNA viruses contain RNA that serves as a
template for the synthesis of mRNA.
synthesize complementary DNA (cDNA) from an RNA template using the
enzyme reverse transcriptase. HIV is a retrovirus.
Viral Structure and Genetics
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.
The book and CD package include two full length practice exams that are presented with all questions answered and explained. The author also presents detailed reviews of all test topics and includes multiple-choice and free-response questions with answers at the end of each topic's chapter.
This book includes a review of the AP Biology exam format and scoring, proven strategies for answering multiple-choice questions, and hints for tackling the essay questions. The practice tests include answers and explanations and there is also proven test-taking strategies for both the multiple choice and essay parts.