AP BIOLOGY

Detailed explanation-1: -Mitochondrial DNA replication is initiated at OH and proceeds unidirectionally to produce the full-length nascent H-strand.

Detailed explanation-2: -DNA replication begins at a single origin of replication, and the two replication forks assembled there proceed (at approximately 500–1000 nucleotides per second) in opposite directions until they meet up roughly halfway around the chromosome (Figure 5-30).

Detailed explanation-3: -The initiation of DNA replication occurs in two steps. First, a so-called initiator protein unwinds a short stretch of the DNA double helix. Then, a protein known as helicase attaches to and breaks apart the hydrogen bonds between the bases on the DNA strands, thereby pulling apart the two strands.

Detailed explanation-4: -The heavy strand (H-strand) is guanine rich, while the light strand (L-strand) is cytosine rich. The mtDNA control region (between nucleotide positions 16, 024–576) contains the origin of replication of the heavy strand, as well as the origin of transcription for both light and heavy strands.

Detailed explanation-5: -One strand of mtDNA is referred to as the heavy strand, and the other strand is referred to as the light strand. Transcription of the heavy strand produces 2 rRNAs, 12 mRNAs, and 14 tRNAs, whereas transcription of the light strand produces only 1 mRNA and 8 tRNAs.