They are all made of protein.

它們都是由蛋白質構成的。

In this video we're going to discuss the structure and uses of protein molecules.

在本視頻中，我們將討論蛋白質分子的結構和用途。

Proteins are long chain molecules made of strings of amino acids joined together.

蛋白質是由氨基酸串聯而成的長鏈分子。

All amino acids are compounds with a similar basic structure.

所有氨基酸都是具有相似基本結構的化合物。

They have an amino group, a carboxyl group and a side chain or R group that is specific to each amino acid.

每種氨基酸都有一個氨基、一個羧基和一個側鏈或 R 基。

There are 20 different amino acids.

有 20 種不同的氨基酸。

All of the different proteins are made from these 20 amino acids.

所有不同的蛋白質都是由這 20 種氨基酸組成的。

The variation in proteins is caused by the order of amino acids, the chain length and by folding the chain in distinct ways.

蛋白質的變化是由氨基酸的順序、鏈的長度以及以不同方式摺疊鏈造成的。

As part of a balanced diet, roughly how much of it do you think should be protein?

作為平衡膳食的一部分，您認為蛋白質應占多少比例？

About 14%.

約 14%。

Sources of protein in our diets include meat, fish, eggs, cheese, beans and nuts.

我們飲食中的蛋白質來源包括肉、魚、蛋、奶酪、豆類和堅果。

But did you know that proteins are large molecules, too large for our bodies to absorb?

但是您知道嗎，蛋白質是大分子，我們的身體無法吸收。

That's why enzymes in our digestive system break down proteins into amino acids which are small enough to pass from our digestive system into our blood to be assimilated by the body.

這就是為什麼我們消化系統中的酶會將蛋白質分解成氨基酸，而氨基酸又足夠小，可以從消化系統進入血液被人體吸收。

When we absorb these amino acids they are then built back up into proteins and sulphate solution and sodium hydroxide solution.

當我們吸收這些氨基酸後，它們又會被重新生成蛋白質、硫酸鹽溶液和氫氧化鈉溶液。

These two liquids together may be called biuret solution which is a pale blue liquid.

這兩種液體合在一起可稱為生物雷特溶液，它是一種淡藍色的液體。

To begin the first experiment, first make a solution of the food sample by dissolving it in some water.

開始第一個實驗時，首先將食物樣品溶解在水中，製成溶液。

You may need to grind this up first with a pestle and mortar.

您可能需要先用杵和研缽將其磨碎。

Next, add a few drops of sodium hydroxide solution to your food solution.

然後，在食物溶液中滴入幾滴氫氧化鈉溶液。

Then a few drops of copper sulphate solution.

然後滴幾滴硫酸銅溶液。

If the solution turns lilac or purple, the food contains protein.

如果溶液變成淡紫色或紫色，說明食物中含有蛋白質。

If the food solution remains blue, no protein is present.

如果食物溶液保持藍色，說明沒有蛋白質。

But how does our body build proteins from amino acids?

但是，我們的身體是如何利用氨基酸製造蛋白質的呢？

Our DNA acts as a set of instructions for how to build proteins.

我們的 DNA 是如何構建蛋白質的一系列指令。

Each individual's DNA is made of people.

每個人的 DNA 都是由人組成的。

For example, hair color and eye color.

例如，頭髮的顏色和眼睛的顏色。

A change in the DNA called a mutation can lead to a protein with a different structure being produced.

DNA 的改變被稱為突變，可導致產生結構不同的蛋白質。

This can lead to albinism for example.

例如，這會導致白化病。

To learn more about mutations you can watch this video.

要了解有關基因突變的更多資訊，請觀看這段視頻。

So what are proteins used for in the body?

那麼，蛋白質在人體內有什麼用呢？

The answer is they are used in thousands of ways.

答案是它們有成千上萬種用途。

Our hair, nails, skin and muscles are all examples of structures made of protein.

我們的頭髮、指甲、皮膚和肌肉都是由蛋白質構成的結構。

Many hormones including insulin are made of protein.

包括胰島素在內的許多激素都是由蛋白質構成的。

Antibodies made by white blood cells to protect us from diseases are also made of protein.

白細胞製造的抗體也是由蛋白質組成的，可以保護我們免受疾病的侵襲。

Enzymes, biological catalysts found inside our body are made of enzymes in this video.

在本視頻中，酶是我們體內的生物催化劑，由酶製成。

And last but not least, proteins are also used to move some substances across cell membranes in active transport.

最後但並非最不重要的一點是，蛋白質還用於在主動運輸中將某些物質運過細胞膜。

For example, to absorb glucose in the small intestine.

例如，在小腸中吸收葡萄糖。

So now you can see just how important proteins are.

現在你可以看到蛋白質有多麼重要了吧。

If you liked the video give it a thumbs up.

如果您喜歡這段視頻，請豎起大拇指。

Please like and share our videos and don't forget to subscribe.

請喜歡並分享我們的視頻，別忘了訂閱。

If you have any questions that you can help with, just comment below.

如果您有任何問題需要幫助，請在下面留言。

Why not check out our other videos as well.

不妨也看看我們的其他視頻。

Until next time, bye for now!

下次再會，再見！