https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/dna-and-rna-structure/v/dna-deoxyribonucleic-acid 2023-06-06T10:35:22.92767095Z DNA DNA, or deoxyribonucleic acid, is the molecular basis for inheritance, discovered in the mid-1800s and understood in 1953 with the double helix structure. Composed of a sugar-phosphate backbone and base pairs (adenine-thymine, guanine-cytosine), DNA stores genetic information, replicates, and expresses traits. The human genome contains 6 billion base pairs across 46 chromosomes, making it a compact and efficient information storage system. Sal Khan video https://cdn.kastatic.org/googleusercontent/N-FD1seHs-vdXACc6Ug4MuC44TkW3_s9SQcxTbnTpvAsX9wVNZXctud872V8KvhGq_fRRDQjDIVNX55fJrm1WiMGGw DNA DNA, or deoxyribonucleic acid, is the molecular basis for inheritance, discovered in the mid-1800s and understood in 1953 with the double helix structure. Composed of a sugar-phosphate backbone and base pairs (adenine-thymine, guanine-cytosine), DNA stores genetic information, replicates, and expresses traits. The human genome contains 6 billion base pairs across 46 chromosomes, making it a compact and efficient information storage system. https://cdn.kastatic.org/ka-youtube-converted/AmOO4j0E408.mp4/AmOO4j0E408.mp4 782 DNA and RNA https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/dna-and-rna-structure/v/molecular-structure-of-dna 2023-12-04T19:02:25.924542584Z Molecular structure of DNA DNA, short for deoxyribonucleic acid, consists of nucleotides forming a double helix structure. Nucleotides contain a phosphate group, deoxyribose sugar, and a nitrogenous base. The bases, adenine, thymine, cytosine, and guanine, pair up through hydrogen bonds, creating the rungs of the DNA ladder. Sal Khan video https://cdn.kastatic.org/googleusercontent/8CAJsW9lm5PD2iqAOUcaBs0SdH5kHWd9vp0hQQZSfvR0266sVqQL_LcDa7DaTO9bZfE8uC8NPZkcrCvMSBiwdedR Molecular structure of DNA DNA, short for deoxyribonucleic acid, consists of nucleotides forming a double helix structure. Nucleotides contain a phosphate group, deoxyribose sugar, and a nitrogenous base. The bases, adenine, thymine, cytosine, and guanine, pair up through hydrogen bonds, creating the rungs of the DNA ladder. https://cdn.kastatic.org/ka-youtube-converted/L677-Fl0joY.mp4/L677-Fl0joY.mp4 781 DNA and RNA https://www.khanacademy.org/science/ap-biology/chemistry-of-life/nucleic-acids-ap/v/antiparallel-structure-of-dna-strands 2023-12-04T19:02:25.924542584Z Antiparallel structure of DNA strands DNA structure consists of two strands, each with a backbone of alternating phosphate and sugar groups. These strands are linked by complementary nitrogenous bases, forming a ladder-like structure. The strands are antiparallel, meaning they run in opposite directions, which is crucial for DNA replication. Sal Khan video https://cdn.kastatic.org/googleusercontent/jlVOYhrBGzFF4uavk6HLPEFezcJ4JuLlY5qyQV1xEBLQZkR_bUVOk-7iIDFFKzmKmfe1iWYRUsI8ZF4LX2aIjL_r Antiparallel structure of DNA strands DNA structure consists of two strands, each with a backbone of alternating phosphate and sugar groups. These strands are linked by complementary nitrogenous bases, forming a ladder-like structure. The strands are antiparallel, meaning they run in opposite directions, which is crucial for DNA replication. https://cdn.kastatic.org/ka-youtube-converted/0CQ5ls3Uc2Q.mp4/0CQ5ls3Uc2Q.mp4 597 DNA and RNA https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/dna-and-rna-structure/v/molecular-structure-of-rna 2023-06-22T09:32:02.370557018Z Molecular structure of RNA DNA and RNA have different sugar backbones: deoxyribose for DNA and ribose for RNA. Notably, RNA has uracil instead of thymine as a nitrogenous base. RNA plays various roles in cells, including messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), and microRNA, and it is a vital part of processes such as transcription, translation, and cellular functions. Sal Khan video https://cdn.kastatic.org/googleusercontent/h1FObigLo5Ws6DQyI0rvscZJD8U2s8Ob78wh75lDvw2DSbV8myer4FbWdbzDvRKmeRTN7Wv_zWj0s6SYj0S4COM Molecular structure of RNA DNA and RNA have different sugar backbones: deoxyribose for DNA and ribose for RNA. Notably, RNA has uracil instead of thymine as a nitrogenous base. RNA plays various roles in cells, including messenger RNA (mRNA), transfer RNA (tRNA), ribosomal RNA (rRNA), and microRNA, and it is a vital part of processes such as transcription, translation, and cellular functions. https://cdn.kastatic.org/ka-youtube-converted/jUUJSOM1ihU.mp4/jUUJSOM1ihU.mp4 690 DNA and RNA https://www.khanacademy.org/science/ap-biology/gene-expression-and-regulation/dna-and-rna-structure/e/dna-and-rna-structure 2025-11-24T21:00:40.80360556Z DNA and RNA structure Test your knowledge of DNA and RNA structure! Megan Cohn exercise https://www.khanacademy.org/science/hs-bio/x230b3ff252126bb6:gene-expression-and-regulation/x230b3ff252126bb6:untitled-348/a/rna-structure-and-function 2026-03-18T10:10:31.931963487Z RNA structure and function Learn about the structure of RNA and the many functions that RNA carries out in the cell. article https://www.khanacademy.org/science/grade-11-biology-snc-aligned/x58c107ba92d3f0b2:introduction-to-molecular-biology/x58c107ba92d3f0b2:dna-and-rna/a/types-of-rna 2024-09-13T19:15:03.436689889Z Types of RNA This article summarizes the different types of RNA, including more well-known RNA like tRNA and ribosomal RNA, and less-known RNA like siRNA that also contribute to cell function. article https://www.khanacademy.org/science/10th-grade-melcs/x1cfbe2e54160ac98:3rd-quarter/x1cfbe2e54160ac98:heredity/v/central-dogma-of-molecular-biology-2 2023-08-11T20:27:11.407186761Z Central dogma of molecular biology Discover the central dogma of molecular biology, the fundamental process that decodes our genetic information. Learn how DNA replicates itself, how DNA is transcribed into RNA, and how RNA is translated into proteins. Learn about the roles of nucleic acids and amino acids in this process. video https://cdn.kastatic.org/googleusercontent/I_A-0Ww41Xli4P8fYgFfXkHLJXpL0ZHRjUDZUBhf9WnJ5XhvfvIXk2Ob8vM7Zu3Uxhj5XYs2efnM_LlzE3_EpjTT Central dogma of molecular biology Discover the central dogma of molecular biology, the fundamental process that decodes our genetic information. Learn how DNA replicates itself, how DNA is transcribed into RNA, and how RNA is translated into proteins. Learn about the roles of nucleic acids and amino acids in this process. https://cdn.kastatic.org/ka-youtube-converted/KIvBn6gfRgY.mp4/KIvBn6gfRgY.mp4 262 DNA and RNA https://www.khanacademy.org/science/shs-biology-2/x2ea931c66bba6acd:3rd-quarter/x2ea931c66bba6acd:lesson-3-genetics-central-dogma/e/central-dogma 2021-04-29T07:59:51Z Central dogma Test your knowledge on the central dogma of biology! Ashley exercise