DNA, RNA, Gene Expression, and the Central Dogma of Molecular Biology

4 months ago

In this video, I explain the central dogma of molecular biology, which states that genetic information flows from DNA to RNA, and from RNA to protein, but never in reverse—from protein back to RNA or DNA. DNA (Deoxyribonucleic acid) contains hereditary genetic information, which can be transcribed into RNA (Ribonucleic acid). This RNA may either function as non-coding RNA or be translated into a protein, which ultimately influences an organism's physical traits.

Time stamps:

DNA carries genetic hereditary information: 0:16
Diagram of 2 spiral DNA strands: 2:22
Gene is a unit of heredity that corresponds to a region of DNA: 2:37
Diagram of a typical prokaryotic cell: 3:46
Genotype is complete assemblage of genes. Phenotype is the outward expression of genes: 4:50
Gene expression is process by which a gene is used to produced a functional end product (protein or non-coding RNA): 5:40
Central dogma of molecular biology: DNA makes RNA, and RNA makes protein: 7:15
98% of human DNA is non-coding, which don't serve as patterns for protein sequences: 9:53
C-value enigma: Genome size and amount of non-coding DNA do not correlate to organism complexity: 12:02
Messenger RNA (mRNA) are created using DNA strands as a template in transcription: 14:39
- mRNA specify sequence of amino acids in proteins during translation: 14:58
- Transfer RNA (tRNA) is an adaptor RNA molecule that links mRNA and the amino acid sequence of proteins: 16:08
Recent research shows gene expression involving multiple different proteins being translated from a single RNA transcript: 18:36
All steps of gene expression can be regulated: 21:46
RNA splicing involves removing introns (non-coding regions of RNA) to join together exons (coding regions) of precursor mRNA (pre-mRNA) into mature messenger RNA (mRNA): 22:09
- Small nuclear ribonucleoproteins (snRNPs) form a spliceosome to splice pre-mRNA: 26:41
Post-transcriptional modification processes an RNA primary transcript into a mature, functional RNA molecule: 27:43
Ribozymes catalyze RNA splicing, similar to the action of protein enzymes: 29:00
Post-translational modification (PTM) is the modification of proteins following protein biosynthesis from RNA: 29:50
Regulation of gene expression controls timing, location, and amount of protein or ncRNA: 32:44
Extended central dogma of molecular biology: 33:03
Reverse transcriptase (RT) is an enzyme used to generate complementary DNA (cDNA) from an RNA template, a process called reverse transcription: 35:31
Positive sense corresponds to DNA or RNA strand that corresponds directly to synthesizing protein, negative if it can't synthesize protein: 35:51
- Sometimes coding strand and template strand terms are used, but the coding / sense strand need not always contain code for a protein since ncRNA may be transcribed: 39:38
Diagram of coding and template strands during transcription: 42:44
Negative sense RNA is sometimes called antisense RNA: 45:45