Question

a zebra cell is just about to replicate its dna. what will happen first? all of the cells dna attaches to proteins. the dna folds over itself to create a dense chromosome. the dna unravels to make two strands. rna attaches to dna.

Explanation:

DNA replication is a process where the DNA molecule makes a copy of itself. The first step in DNA replication is the unwinding of the double - helix structure of DNA. This unwinding is carried out by an enzyme called helicase. When the DNA unwinds, it separates into two single strands. These two strands then serve as templates for the synthesis of new complementary strands.

• Option 1: DNA attaching to proteins is not the first step in replication. DNA is already associated with proteins (histones etc.) in the chromatin structure.
• Option 2: Folding to create a dense chromosome is not the first step in replication. Chromosome condensation occurs at a later stage in cell division (not at the very start of DNA replication).
• Option 3: Unraveling to make two strands is correct as the first step in DNA replication is the unwinding of the double - stranded DNA.
• Option 4: RNA attaching to DNA (like in transcription or priming for replication) occurs after the DNA has unwound.

Answer:

The DNA unravels to make two strands.