DNA, Protein Synthesis & Cell Division

DNA → RNA → protein → trait: DNA is transcribed into RNA, RNA is translated into protein, and proteins produce traits.

A pairs with T (2 hydrogen bonds); C pairs with G (3 hydrogen bonds).

A phosphate group, a deoxyribose sugar, and one nitrogen base (A, T, C, or G).

Each new double helix keeps one original strand and one newly built strand. Helicase unzips the helix and DNA polymerase builds the new strands.

RNA is single-stranded, uses ribose instead of deoxyribose, and uses uracil (U) instead of thymine (T).

In the nucleus, RNA polymerase reads a DNA template strand and builds a complementary mRNA strand (with U in place of T).

A codon is a group of three mRNA bases specifying one amino acid; the ribosome reads codons during translation while tRNA anticodons deliver matching amino acids.

A U G C C G U U A → Methionine (START), Proline, Leucine.

A substitution swaps one base (e.g., sickle-cell's A→T). An insertion or deletion causes a frameshift, scrambling every codon downstream — usually severe.

Prophase (chromosomes condense, envelope breaks down), Metaphase (chromosomes line up at the equator), Anaphase (sister chromatids pulled apart), Telophase (two nuclei re-form), followed by cytokinesis.