① Two reverse parallel deoxynucleotide chains are hovered into a double helix structure.

②Outer side: Deoxyribose and phosphoric acid alternately connect to form the basic skeleton. Inner: consists of base pairs connected by hydrogen bonds.

③There are certain rules for base pairing: A = T; G ​​≡ C. (Base complementary pairing principle)

① Stability: The order of alternating deoxyribose and phosphoric acid in DNA molecules remains stable

② Diversity: The arrangement order of base pairs in DNA molecules is diverse (main), the number of bases and the proportion of bases are different.

③Specificity: Each DNA in a DNA molecule has its own specific base pair arrangement order

Genes are genetically effective DNA fragments

① Can copy itself;

②The structure is relatively stable;

③Storage genetic information;

④Able to control traits.

Diversity, specificity and stability.

Material: E. coli

Method: Isotope Tracer

Place: Cell nucleus

Basic conditions

process

in principle

significance

(1) Experimental process and conclusions of transformation of pneumococcal pneumoniae

(2) Process and conclusions of bacteriophage infecting bacterial experiments

(1) The genetic material of certain viruses is RNA

(2) The genetic material of most organisms is DNA

1. Proposer: Crick

2. Content: Genetic information can flow from DNA to DNA, that is, the self-replication of DNA; it can also flow from DNA to RNA, and then to proteins, that is, the transcription and translation of genetic information. However, genetic information cannot flow from protein to protein, nor from protein to DNA or RNA. The two pathways of genetic information flowing from RNA to RNA and from RNA to DNA are complementary to the central law.

(1) Indirect control: control the metabolic process by controlling the synthesis of enzymes, and then control the properties of organisms; such as albinism, etc.

(2) Direct control: Direct control of biological traits by controlling protein structure. Such as cystic fibrosis, sickle cell anemia, etc. [Note] Multigene factors of organism traits: genes and genes; genes and gene products; and environment have complex interactions, and jointly finely regulate organism traits.

Constituent elements: C, H, O, N, P

Basic unit: Ribonucleotides (4 types)

Structure: generally single-stranded

It is a DNA fragment with genetic effects, mainly on the chromosome.

1. Transcription:

2. Translation

3. Calculation related to gene expression:

4. Password

Vertical Deepening: Exploration of Genetic Materials → The Essence of Genes → Function of Genes

Horizontal association: Structure determines function

Chemistry: Chemical composition, chemical bonds, enzymatic reactions, ATP energy supply of DNA

Physics: isotope labeling, density gradient centrifugation, spatial configuration of DNA double helix

Genes are DNA fragments, not all DNA fragments are genes

Genes are arranged linearly on chromosomes

Two strands of parent DNA molecules are used as templates to synthesize progeny DNA strands

One strand in the progeny DNA molecule is the parent strand, and one strand is the progeny strand

Template: DNA strand vs mRNA raw materials: ribonucleotide vs amino acid

Product: mRNA/tRNA/rRNA vs polypeptide chain; location: eukaryotic nucleus/prokaryotic nucleophiles vs ribosomes

Direction of genetic information transmission: DNA → DNA, DNA → RNA → RNA → protein, RNA → RNA, RNA → DNA

Retrotranscription occurs only in retroviruses

Helicase (replication only), DNA polymerase (replication) vs RNA polymerase (transcription, both decoylation function)

Position: mRNA vs tRNA; quantity: 64 vs 61

eukaryotic "transcription first and then translation" vs prokaryotic "translation while transcribing"

DNA double helix structure stability → Ensure stable storage of genetic information

Codon degeneration → Reduce the effect of gene mutations on protein synthesis

Verify that "the genetic material of a certain RNA virus is RNA"

Reasons for the radioactivity of the supernatant of ³²P in phage infection experiment

The reason why "heavy belt, medium belt, light belt" appeared in the third generation in DNA semi-reserved replication experiment

How to distinguish between phosphoric acid, deoxyribose and bases

Determine base pair type: A-T contains 2 hydrogen bonds, G-C contains 3 hydrogen bonds

Identify "replication fork", "maternal strand", "child strand", and "RNA primers"

Positioning "ribosome", "anticodon of tRNA", "start codon", "stop codon"