Figure 1. The bacteriophage virion. (a) Electron micrograph of a phage virion negatively stained with uranyl acetate. The head is about 63 nm in diameter. (b) Diagram of the virion with the locations of the structural components indicated by gene name. Larger gene names indicate more molecules of the encoded protein are present; parentheses indicate gene products which are likely (but not yet proven) to be virion components; asterisks indicate covalently modified proteins.

Figure 2. Map of the bacteriophage chromosome. The linear virion chromosome is shown with a scale in kilobase pairs (kbp) below. Rectangles above indicate known genes; with yellow ones transcribed rightward and green ones leftward. Important sites (e.g. P, promoters; t, terminators) on the DNA are indicated below the genes, and arrows below the kbp scale indicate the transcripts made from the chromosome: brown, made only in a lysogen; black, made in lysogen and pre-early conditions; orange, pre-early; blue, early; green, late; purple, made in response to high CII levels; grey, made in response to DNA replication.

Figure 3. Lambda's lysis–lysogeny decision. The cII gene protein plays a central role in the lysis–lysogeny decision. Yellow circles represent phage-encoded functions and green circles represent host functions. Red arrows indicate positive effects and blue lines indicate negative effects. Question marks indicate areas of mechanistic uncertainties.