5 Steps to a 5 AP Biology, 2014-2015 Edition

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Molecular Genetics

IN THIS CHAPTER

Summary:This chapter describes the various processes in cells that take DNA

from gene to protein: replication, transcription, posttranscriptional modifica-

tion, and translation. It also discusses the regulation of these processes

before concluding with a discussion about viruses, bacteria, and genetic

engineering.

Key Ideas

✪DNA: adenine-thymine, cytosine-guanine—arranged in a double helix.

✪RNA: adenine-uracil, cytosine-guanine—single stranded.

✪DNA replication occurs during the S-phase in a semi-conservative fashion

and in a 5’ to 3’ direction.

✪Types of DNA replication mutations: frameshift, missense, nonsense.

✪Transcription: mRNA is formed from a DNA template.

✪Translation: process by which mRNA specified sequence of amino acids is

lined up on a ribosome for protein synthesis.

✪Operons act as on-off switches for transcription—allow for production of

genes only when needed.

✪Types of genetic recombination: transformation, transduction, and conjugation.

Introduction

Genetics has implications for all of biology. We begin our study of this subject with an

introduction to DNA and RNA, followed by a description of the various processes in cells

that take DNA from gene to protein: replication, transcription, posttranscriptional modi-

fication, translation, and the regulation of all these processes. The genetics of viruses and

bacteria follows, and the chapter concludes with a discussion of genetic engineering.

CHAPTER

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KEY IDEA

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