Have you heard of DNA? Every living organism has DNA. It is a little bit like an instruction manual which tells living things how to grow and even decides how they look. This week we're going to extract DNA from a kiwi fruit. Make sure that a grown-up helps you with this experiment.
What you will need:
Some tall narrow glasses
(champagne flutes work well)
to act as test tubes
Salt
Rubbing alcohol (you can buy this at a chemist)
Water
Dish detergent
A kiwi fruit
A coffee filter
A measuring jug
A kettle
Bamboo skewers
A bowl and a spoon (or a pestle and mortar)
A knife
Two jars
1.Put the rubbing alcohol in the freezer to chill it.
2.Peel the kiwi fruit. Chop it into small pieces.
3.Put the kiwi fruit into the bowl and mash it up until it is pulp.
4.In a jar place 100ml of tap water. Add half a teaspoon of salt and two-thirds a tablespoon of dish detergent. Stir very gently. You want to avoid making any bubbles. When the salt is dissolved you have made an extraction buffer.
5.Carefully add the extraction buffer to the kiwi and mash up the mixture. You want to extract as much DNA as possible, but you have to be careful not to make bubbles. The more you pulp the mixture, the more DNA you will get.
6.Pour the pulp into a jar.
7.Now comes the tricky part. You need to make an incubator. Boil some water. Ask a grown-up to help you put some of the boiling water into the measuring jug. Then ask him or her to add the same amount of tap water. You want the water to sit around the jar with the pulp in it, so how much you use will depend on the size of the jar. The water tempurature should be around 60°C.
8.Leave the pulp incubating for 15 minutes. You can use this time to wash up the spoon and bowl and tidy up your workspace.
1. DNA n.
脫氧核糖核酸 (tuo1 yang3 he2 tang2 he2 suan1)
2. organism n.
有機體 (you3 ji1 ti3)
3. extract v.t./v.i.
提煉 (ti2 lian4)
4. test tube n.
試管 (shi4 guan3)
5. rubbing alcohol n.
外用酒精 (wai4 yong4 jiu3 jing1)
6. mash v.t.
搗成糊狀 (dao3 cheng2 hu2 zhuang4)
7. pulp n.
糊狀物質 (hu2 zhuang4 wu4 zhi2)
8. extraction buffer n. phr.
提取緩衝液 (ti2 qu2 huan3 chong1 yi4)
9. incubator n.
培養器 (pei2 yang3 qi4)
10. spongy adj.
海綿狀的 (hai3 mian2 zhuang4 de5)
11. spool v.t.
纏繞 (chan2 rao4)
12. lipid n.
脂質 (zhi1 zhi2)
13. protein n.
蛋白質 (dan4 bai2 zhi2)
14. enzyme n.
酵素 (xiao4 su4)
9.Place a coffee filter in the neck of a clean, dry jar. Spoon a bit of the pulp into the filter. Slowly add all the pulp. You'll have to be patient as this can be a little slow. At the end you will have a jar of fluid and filter paper full of pulp. Throw the filter and the pulp away.
10.You should have enough fluid to make several samples. Pour some fluid into your "test tube" until it is a third full.
11.Ask a grown-up to help you with the ice-cold alcohol. Put about 100ml into the measuring cup. Very slowly pour the alcohol down the side of your test tube. You want the alcohol to sit on top of the fluid, making a second layer. Use about the same amount of alcohol as kiwi fluid.
12.Set the test tube down. Watch carefully. A white spongy substance should be forming above the kiwi fluid at the bottom of the alcohol layer. This is DNA!
13.After a few minutes you can use the bamboo skewer to spool in the DNA, but be very gentle. When you think you have enough you can pull it out of the tube. It's safe to play with it, but don't eat it!
(CATHERINE THOMAS, STAFF WRITER)
你聽過DNA（脫氧核糖核酸）嗎？所有生物都有DNA，它有點像是一本會指導生物如何成長，甚至決定他們外觀的使用說明書。本週我們要從奇異果中提煉DNA，務必請一位大人從旁協助你做這個實驗。
所需材料︰
數個細長的杯子（香檳杯效果最好）當作試管用
鹽巴
外用酒精（可在藥局買到）
水
洗碗精
一顆奇異果
一張咖啡濾紙
一個量杯
一個水壺
竹籤
一個碗和一支湯匙（或搗研缽和杵）
一把刀
兩個瓶子
1.將外用酒精放到冰庫冷凍。
2.將奇異果去皮，切成小塊。
3.將奇異果放入碗中搗成泥。
4.將一個瓶子裝入一百毫升的自來水，再加入半茶匙的鹽和三分之二湯匙的洗碗精，非常輕地攪拌，避免弄出任何泡泡。待鹽完全溶解後，「提取緩衝液」就完成了。
5.小心地將提取緩衝液加到奇異果中，並搗拌混合物，雖然希望提取愈多DNA愈好，但是要小心別搗出泡泡，你搗得愈細就會得到愈多DNA。
6.將搗好的混合物倒入一個瓶子中。
7.接下來的步驟比較難處理，你得做出一個「培養器」。煮沸一些水，然後請一個大人幫你將沸水裝入量杯中，再請她或他在量杯中倒入等量的自來水，因為裝有果泥的瓶子要置放在量杯的自來水中，所以可以以瓶子的大小來衡量所需的水量，水溫應在攝氏六十度左右。
8.將培養器靜置十五分鐘，你可以利用這段時間清洗碗和湯匙，並整理工作區域。
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