Nukleotida dan struktur DNA
Diperkenalkan| English | Makna |
|---|---|
| nucleotide/ˈnjuːklɪɒtaɪd/ | nukleotida |
| nucleic acid/njuːˈklɪɪk ˈæsɪd/ | asam nukleat |
| double helix/ˈdʌbl ˈhiːlɪks/ | heliks ganda |
| purine/ˈpjʊəriːn/ | purin |
| pyrimidine/ˈpɪrɪmɪdiːn/ | pirimidin |
| deoxyribose/diːˈɒksɪrɪbəʊs/ | deoksiribosa |
| phosphodiester bond/ˈfɒsfəʊdɪstə bɒnd/ | ikatan fosfodiester |
| antiparallel/ˌæntɪˈpærəlel/ | antiparalel |
| complementary base pairing/ˌkɒmplɪˈmentəri beɪs ˈpeərɪŋ/ | pasangan basa komplementer |
Nucleotides 核苷酸 and DNA
- DNA and RNA are nucleic acids 核酸 — polymers of small units called nucleotides.
- The same building block also powers the cell as ATP.
- DNA's famous shape, the double helix 双螺旋, comes from how its bases pair up.
Nucleotides and bases
- Each nucleotide has three parts: a phosphate, a 5-carbon sugar, and a base.
- ATP is a nucleotide with the base adenine, the sugar ribose, and three phosphates — breaking off the last one releases energy.
- Five bases, in two groups:
- purines 嘌呤 (double ring): adenine (A), guanine (G).
- pyrimidines 嘧啶 (single ring): cytosine (C), thymine (T), uracil (U).
Purines (A, G) have a double ring; pyrimidines (C, T, U) have a single ring
A space-filling model of the DNA double helix, showing its twisted-ladder shape
Satu nukleotida tunggal terdiri dari:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Setiap nukleotida memiliki tiga bagian: gugus fosfat, gula pentosa, dan basa nitrogen.
ATP melepaskan energi untuk sel ketika:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
ATP memiliki tiga fosfat; memutus fosfat terminal melepaskan energi.
The DNA backbone
- DNA is two strands twisted into a double helix.
- Each strand has a backbone of alternating deoxyribose 脱氧核糖 sugar and phosphate, joined by phosphodiester bonds 磷酸二酯键.
- The two strands run in opposite directions — they are antiparallel 反平行 (one 5′→3′, the other 3′→5′).
A nucleotide and ATP
Jelajahi tangga DNA
Ketuk setiap bagian heliks ganda — dua tulang punggung antiparalel dengan pasangan basa komplementer sebagai anak tangga.
Dua untai DNA disebut antiparalel karena mereka:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Antiparalel berarti untai-untai mengarah ke arah berlawanan: 5′→3′ pada satu, 3′→5′ pada yang lain.
Complementary base pairing 碱基互补配对
- The strands are held together by their bases in the middle, paired exactly:
- A pairs with T — 2 hydrogen bonds.
- C pairs with G — 3 hydrogen bonds (so C–G is harder to separate).
Cocokkan setiap kelompok basa dengan deskripsinya.
Difficulty 2/5 · 140 coins + a small bonus on first completion today
Purin (cincin ganda) selalu berpasangan dengan pirimidin (cincin tunggal): A–T dan C–G.
Dalam DNA, A selalu berpasangan dengan T, dan C selalu berpasangan dengan ______.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Pasangan basa komplementer: A–T (2 ikatan hidrogen) dan C–G (3 ikatan hidrogen).
Sampel DNA mengandung 30% adenin. Karena A berpasangan dengan T, berapa persentase timin?
Difficulty 2/5 · 140 coins + a small bonus on first completion today
A selalu berpasangan dengan T, jadi %A = %T. Dengan 30% adenin terdapat 30% timin (meninggalkan 40% dibagi antara C dan G).
Pasangan basa C–G memiliki 3 ikatan hidrogen, sehingga lebih sulit dipisahkan daripada pasangan A–T.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
C–G diikat oleh 3 ikatan hidrogen dan A–T hanya oleh 2, sehingga DNA dengan lebih banyak C–G lebih stabil.
You've got it
- nucleotide = phosphate + sugar + base; ATP = adenine + ribose + 3 phosphates (energy)
- purines (A, G, double ring) vs pyrimidines (C, T, U, single ring)
- DNA = double helix; backbone = deoxyribose + phosphate (phosphodiester bonds); strands antiparallel
- A–T (2 H-bonds), C–G (3 H-bonds) — complementary base pairing