Ribose

base

nucleoside

effect

A=T,C=G

(A T)/(C G) asymmetric ratio, indicating the distance of biological species' relationship

The DNA base composition of different tissues of the same organism is the same and does not change with changes in age, nutritional status, and environment.

Directionality

unique arrangement

antiparallel

AT two hydrogen bonds CG three hydrogen bonds

The average diameter is 2nm, the pitch is 3.4nm, the vertical distance between adjacent base pairs is 0.34nm, the angle between adjacent nucleotides is 36 degrees, and each helix is ​​10bp

The plane of the base is perpendicular to the longitudinal axis of the helix, and the plane of the sugar ring is parallel to the longitudinal axis.

DNA-binding proteins bind to the major groove

stabilizing factor

The right-hand helix has two structures, ADNA and BDNA.

Key Points: Plasmids

Chromosome: DNA and histones form nucleosomes, and the nucleosomes are connected by connecting DNA

nuclear genome

organelle genome

secondary structure

L type

Most of it exists in the nucleus, and a small part exists in the mitochondria and chloroplasts.

Most of it exists in the cytoplasm, and a small part exists in the mitochondria, chloroplasts, and nuclei.