シャドーイング練習: Glycolysis - 動画で英語スピーキングを学ぶ

練習モードを選ぶ

各モードは全画面の練習ルームで開きます。

170 文

文が短すぎたり長すぎる場合は、Editをタップして調整してください。

Welcome back to the high -yield biochemistry series.

This is brought to you by Dirty Medicine.

In today's video, we're going to continue our discussion about the biochemical pathways and talk about glycolysis.

Glycolysis is typically the first biochemical pathway that you learn when you're learning about biochemistry, and it's because of that that it's extremely high -yield.

It shows up on exams all of the time.

Now, when you're learning about glycolysis, as you'll see me mention throughout this video, it's really important to remember the bigger picture.

And when I say that, I'm referring to things like what is the function or the role of glycolysis?

What are we taking as a reactant and turning into a product?

And what are the regulatory mechanisms in terms of feedback?

So what makes this go forward?

What inhibits this?

And what is the rate limiting enzyme?

Just like all of the biochemistry videos that I've created, you need to know the rate -limiting enzyme and the regulatory mechanisms.

So we're talking about things like inhibitors, etc. So let's start with a quick overview of glycolysis.

Glycolysis is an irreversible biochemical reaction that occurs in the cytoplasm.

The net equation for glycolysis is that you start with glucose, and the goal is to take that glucose and turn it into pyruvate,

where it can downstream take multiple pathways through that pyruvate pathway

and preferentially usually this goes into the citric acid cycle

but here's the net equation you've you start with glucose

and you add two phosphates two adps and two nads

and what you get out of

that is two 2 pyruvates plus 2 ATPs plus 2 NADH plus 2 hydrogens plus 2 waters.

But if you wanted to just think very simply about what glycolysis is doing,

it's taking glucose and breaking that glucose down into storable products that the body can use in other biochemical pathways.

So now that we've understood the overview of glycolysis, let's just get into the meat and potatoes here.

We're going to talk about the pathway.

You need to understand the pathway, and I'm going to pay very special attention to the regulatory mechanisms of this pathway and the rate -limiting enzyme.

So you start with glucose, right?

Any person takes a bite of a cheeseburger, eats a french fry, drinks a milkshake, and they've got a bunch of carbohydrate in their body.

And that carbohydrate is composed usually of glucose.

And if it's not of glucose, then the other types of sugars will get turned into glucose so

that glycolysis can utilize

it the first step is glucose will get turned into glucose

6 -phosphate glucose 6 -phosphate will get turned into fructose

6 -phosphate fructose 6 -phosphate will get turned into fructose 1 -6 -bisphosphate

and now you've got like multiple steps

that are going to happen there's going to be four

or five more reactions in this pathway and you'll end up with phosphoenolpyruvate which will get turned into pyruvate.

And going from glucose down to pyruvate is the entire glycolysis pathway.

So when you get to pyruvate you're basically finished with glycolysis.

Now let's talk about the important enzymes that you need to know.

So the first step that converts glucose to glucose 6 -phosphate, there's actually two different enzymes

that can be used depending on the circumstances of the glucose concentration and where in the body we're talking about.

So those two enzymes are glucokinase and hexokinase.

So to be perfectly clear, either glucokinase or hexokinase can convert glucose to glucose 6 -phosphate.

And what you'll need to know for test day that's really high yield is to understand under

which circumstances both of these enzymes might be used.

So for glucokinase, this enzyme has a low affinity and a high

Km, Just remember the reciprocal relationship between affinity and Km.

The higher the Km, the lower the enzyme has an affinity for its substrate.

So glucokinase has a low affinity for glucose.

It typically doesn't want to go and grab glucose.

And the reason for this is because glucokinase acts as a glucose sensor.

It's present in the liver and the pancreatic beta cells, and it's only used when glucose is at high concentrations.

So basically what you should think of glucokinase as is an emergency enzyme that is acting as a glucose sensor.

And it's really not grabbing glucose because instead of grabbing glucose and breaking it down through glycolysis,

what it's doing is it's sensing glucose and it's going, okay, let's test how much glucose is over here.

uh that's okay we're not going to jump in yet um hexokinase you go first

so hexokinase on the other hand that is a high affinity enzyme

which means it has a low km and

because it has high affinity for its substrate hexokinase is the one that's constantly going to be latching onto glucose

and converting it to glucose 6 -phosphate and sending it down the glycolysis pathway

and the reason for that is because hexokinase is the enzyme that's used to operate the basal glucose metabolism.

So constantly throughout your body in all of your tissues, you have this enzyme hexokinase that's just keeping a basal level of glucose metabolism present.

It's trying to make sure that your glucose level is adequate throughout the body in all of the tissues.

But if hexokinase becomes overwhelmed because suddenly there's a massive influx of glucose, that is when hexokinase turns to glucokinase and says,

glucose, I know you usually have a low affinity, but I really need some help now because the glucose concentration is high.

So if you think about it, that's the reason that glucokinase is only found in the liver and the pancreatic beta cells,

because it does a very specific regulatory job where it's only acting when the blood glucose levels are super, super high.

When that concentration reaches some critical point, that's when glucokinase in the liver and the pancreatic beta cells jumps in to save hexokinase.

So the takeaway from this slide is that both glucokinase

and hexokinase are enzymes that catalyze that conversion from glucose to glucose 6 -phosphate.

The only difference is that hexokinase is kind of there all of the time, making a basal level of glucose, and glucokinase jumps in in emergencies.

But understand the differences between those two enzymes that I've put in the gray boxes.

They are extremely high yield and probably will show up on your test.

So here's where we are.

We've talked about the enzymes in the first step.

The enzyme that converts fructose 6 -phosphate to fructose 1 ,6 -bisphosphate is the rate -limiting enzyme of glycolysis,

and that's phosphofructokinase 1.

Sometimes you'll hear this referred to as PFK1.

So PFK1, or phosphofructokinase 1, is the rate -limiting enzyme, and it converts fructose 6 -phosphate to fructose 1 ,6 -bisphosphate.

Now, I told you at the start of this video

that the very important thing to keep in mind for USMLE and Comlex is the regulatory mechanisms.

And what I mean when I say regulatory mechanisms are what inhibits this pathway and what promotes this pathway.

And we're going to talk about that for the first time right here.

And because phosphofructokinase 1 is the rate -limiting enzyme,

it's really high yield to understand what inhibits phosphofructokinase 1 and what promotes phosphofructokinase 1.

And that's what you see here.

So ATP and citrate will inhibit the rate -limiting enzyme PFK1,

but AMP will promote the rate -limiting enzyme of PFK1.

And this should be somewhat intuitive to you.

So think about what glycolysis is doing.

The role of glycolysis is to take glucose, convert it to pyruvate and ATP,

and then let that pyruvate enter one of many different pathways, but usually the citric acid cycle where you'll then create citrate.

So if you think about that,

the question becomes, what would this pathway want to do if it already had ATP and therefore didn't need to make it,

or if it already had citrate and therefore didn't need to make pyruvate, which would then go to citrate.

And that's why ATP and citrate inhibit PFK1, because if you have ATP and you already have citrate, then you don't need to do glycolysis.

So the presence of those products will inhibit the rate -limiting enzyme, and therefore glycolysis won't occur.

100

Now, likewise, think about AMP.

101

If you have AMP, which is monophosphate, only one, you don't have ATP.

102

And therefore, if you don't have ATP, you want to do glycolysis.

103

So in the presence of AMP, which is to say in a situation where you don't have ATP,

104

AMP will promote PFK1 and will therefore promote glycolysis.

105

So anytime you're not really sure about how the regulatory mechanisms are working, think about this intuitively.

106

Ask yourself on test say, well, would glycolysis happen if there was AMP?

107

Would glycolysis happen if there was citrate?

108

It should make sense to you if you understand what the big picture role of these pathways are.

109

So that's what promotes and inhibits PFK1.

110

Now I need to pause for a second and tell you about this little nuance of glycolysis.

111

So fructose 6 -phosphate can go to fructose 1 ,6 -bisphosphate as you see on this slide.

112

But additionally, there's sort of a side step that occurs, a pivot if you will.

113

Fructose 6 -phosphate can also become fructose 2 ,6 -bisphosphate.

114

And if fructose 6 -phosphate will become fructose 2 ,6 -bisphosphate,

115

the enzyme that catalyzes this conversion is phosphofructokinase 2, PFK2.

116

So very similarly named, of course, to the rate limiting enzyme that we just talked about, but instead of 1, it's 2.

117

So when this happens, you create fructose 2 ,6 -bisphosphate.

118

And interestingly, that fructose 2 ,6 -bisphosphate will promote PFK1.

119

So the goal when the body does this is to make glycolysis happen faster.

120

Now the question then becomes what is promoting or inhibiting phosphofructokinase 2 or PFK2?

121

And that's really simple.

122

So it's going to be inhibited by glucagon and it's going to be promoted by insulin.

123

So think about it.

124

If fructose 2 ,6 -bisphosphate makes glycolysis happen faster.

125

And in glycolysis, you're breaking down glucose.

126

It makes sense that insulin will promote PFK2 because in the presence of glucose,

127

the body's going to secrete insulin and the body's telling anything that any cell that has a glycolysis pathway occurring, it's like, yo, take that glucose,

128

break it down, please get this out of the system.

129

And that's insulin's role.

130

The opposite of that is glucagon.

131

Glucagon's putting the brakes on this pathway and saying, yo, chill, we need to reverse this and make energy available because blood glucose is low.

132

So think about it, guys.

133

Insulin will promote PFK2 because it will make fructose 2 ,6 -bisphosphate, which feeds back to PFK1 and makes this happen faster.

134

But in another situation, glucagon will inhibit PFK2 because PFK2 would normally make fructose 2 ,6 -bisphosphate,

135

which would feed back to PFK1 and make this process happen faster.

136

So again, understanding the big picture about what glycolysis is actually doing helps you understand the regulatory mechanisms

137

that you need to memorize for your test.

138

So the takeaway from this slide is that PFK2 inhibited by glucagon and promoted by insulin.

139

The last enzyme that we need to talk about is the enzyme that converts phosphoenolpyruvate to pyruvate, the last step of glycolysis.

140

That enzyme is pyruvate kinase.

141

And just like PFK1, this is going to be inhibited by ATP and citrate for the same exact reasons.

142

And those reasons are, again, glycolysis wants to create ATP.

143

Glycolysis wants to make pyruvate, which can then become citrate in the TCA cycle.

144

So therefore, if you already have ATP or you already have citrate, what's the point?

145

You don't need to do glycolysis.

146

So the presence of those products will inhibit the enzymes that usually make glycolysis work.

147

So guys, that's it for glycolysis.

148

And you're probably sitting there starting to have a panic attack thinking about, whoa, dirty.

149

What about all the other enzymes?

150

Don't worry about the other enzymes.

151

This is what you need to know for USMLE and Comlex.

152

You need to know the enzymes I put in these slides, the regulatory mechanisms that I put in these slides,

153

and understand the difference between glucokinase and hexokinase that we discussed at the beginning of this video.

154

All of the other intermediary steps, you don't need to know them.

155

You really don't.

156

They're not going to show up on your test unless you're taking a college level or intro to biochemistry course.

157

You really don't need to know them.

158

If you do want to know them for completeness sake, I would encourage you to go online, look at some diagrams, memorize some enzymes.

159

But this is what you need to know to answer 99 % of the questions that will show up on USMLE,

160

Comlex, your question banks, your practice tests, et cetera.

161

So again, and I cannot stress this enough because it's the biggest theme for all of biochemistry.

162

Know the rate limiting enzyme, know the regulatory mechanisms.

163

And if you get stuck on test day about what's inhibiting or what's promoting, ask yourself, what's the goal of this pathway?

164

And therefore, what do I think might happen?

165

That's it.

166

If you liked this video, drop me a like or a comment in the comment section.

167

Please remember to check my Patreon page.

168

You can click

169

that link in the description of any of my videos sign up to send a secure monthly donation

170

and support the channel love you good luck

アプリをダウンロード

流暢に話すために必要なすべて

AI発音採点文ごとに採点

IPA練習すべての音をマスター

単語学習自分の単語帳を作る

単語ゲーム遊びながら覚える

QRをスキャン

Download on theApp Store Get it onGoogle Play

同じチャンネル

FOR YOU

このレッスンの語彙とスピーキングのポイント

繰り返し出てくる語は次のとおりです：glucose, glycolysis, enzyme, pathway, fructose。この動画には、シャドーイング用の文が170文、単語が2233語あります。音声の長さは14:16です。話す速さは1分あたり約156語で、日常会話に近い自然なペースです。英語の頻出3,000語に含まれる単語は76%だけなので、語彙は難しめです。

この動画の重要語彙

動画に出てくる覚えておきたい単語15語を、発音と意味つきで紹介します。

単語	発音	意味
glucose 名詞	/ˈɡluː.kəʊz/	ブドウ糖, 葡萄糖
enzyme 名詞	/ˈɛn.zaɪm/	酵素
mechanism 名詞	/ˈmɛk.ə.nɪ.zəm/	仕組み, 機構
affinity 名詞	/əˈfɪnɪti/	アフィニティ, 親和性
slide 名詞	/ˈslaɪ̯d/	滑り台
yield 動詞	/jiːld/	もたらす
insulin 名詞	/ˈɪnsəlɪn/	インスリン, インシュリン
occur 動詞	/əˈkɜː/	起こる, 起る
concentration 名詞	/ˌkɑn.sənˈtɹeɪ.ʃən/	集中, 集中力
beta 名詞	/ˈbeɪtə/	ベータ
acid 名詞	/ˈæsɪd/	酸
refer 動詞	/ɹɪˈfɜː/	問い合わせる
tissue 名詞	/ˈtɪʃ.(j)u/	織物
conversion 名詞	/kənˈvɝʒən/	改宗
overview 名詞	/ˈoʊ.vɚˌvjuː/	概要

繰り返し練習したい文

動画に出てくる短く完結した文です。日常会話でそのまま使えます。

What are we taking as a reactant and turning into a product?
We're going to talk about the pathway.
We've talked about the enzymes in the first step.
You don't need to do glycolysis.
You really don't need to know them.

この動画の文法

話し手がよく使っている文型を、動画の実際の表現とともに紹介します。

文型	動画での表現
受動態 be + 過去分詞 — 誰がするかより、何が起きるかに焦点を当てる	is brought · is composed · is only found
現在完了形 have/has + 過去分詞 — 過去の出来事が今も関係している	I've created · we've understood · I've put
関係詞節 who / which + 節 — 人や物について情報を加える	phosphoenolpyruvate which will · AMP, which is · pyruvate, which can

注意したい発音

話し手はdon't, you're, we'reなど、短縮形や弱形を41回使っています。聞こえたとおりの短い形で発音しましょう。

「sh」と「zh」の音: concentration /ˌkɑn.sənˈtɹeɪ.ʃən/, tissue /ˈtɪʃ.(j)u/, conversion /kənˈvɝʒən/, equation /ɪˈkweɪ.ʒən/, donation /doʊˈneɪʃən/
長い単語（アクセントの位置に注意）: regulatory /ˈɹɛɡ.jʊ.lə.t(ɔː.)ɹi/, mechanism /ˈmɛk.ə.nɪ.zəm/, affinity /əˈfɪnɪti/, concentration /ˌkɑn.sənˈtɹeɪ.ʃən/, metabolism /məˈtæb.əˌlɪz.əm/

日本語話者が苦手な音：

/r/ と /l/ の区別 — /l/ は舌先を歯茎につけ、/r/ はどこにもつけない: regulatory /ˈɹɛɡ.jʊ.lə.t(ɔː.)ɹi/, irreversible /ˌɪr.ɪˈvɝ.sə.bəl/, preferentially /ˈpɹɛf.ɜː(ɹ)ˌɛn.ʃə.li/, reciprocal /ɹɪˈsɪpɹək(ə)l/
/v/ — /b/ にならないように、上の歯を下唇に当てる: convert /kənˈvɝt/, conversion /kənˈvɝʒən/, overview /ˈoʊ.vɚˌvjuː/, reverse /ɹɪˈvɝs/, intuitive /ɪnˈtjuːɪtɪv/
/f/ — 「フ」ではなく、上の歯と下唇で出す: affinity /əˈfɪnɪti/, refer /ɹɪˈfɜː/, feedback /ˈfiːdˌbæk/, influx /ˈɪnˌflʌks/, fructose /ˈfɹʌk.toʊs/

この動画での練習方法

まず声を出さずに動画を最後まで聞き、知らない単語をメモします。
まず0.75倍速で一文ずつシャドーイングし、慣れてきたら通常の速度に戻します。
自分の声を録音して元の音声と比べます。glucose, enzyme, mechanismなどの単語に特に注意しましょう。

シャドーイングとは？英語上達に効果的な理由

シャドーイング（Shadowing）は、もともとプロの通訳者養成プログラムで開発された言語学習法で、多言語習得者として知られるDr. Alexander Arguelles によって広く普及されました。方法はシンプルですが非常に効果的：ネイティブスピーカーの英語を聞きながら、1〜2秒の遅延で声に出してすぐに繰り返す——まるで「影（shadow）」のように話者を追いかけます。文法ドリルや受動的なリスニングと異なり、シャドーイングは脳と口の筋肉が同時にリアルタイムで英語を処理・再現することを強制します。研究により、発音精度、抑揚、リズム、連音、リスニング力、そして会話の流暢さが大幅に向上することが確認されています。IELTSスピーキング対策や自然な英語コミュニケーションを目指す方に特におすすめです。

シャドーイングのやり方: ステップ別の完全ガイドを読む →

シャドーイング練習: Glycolysis - 動画で英語スピーキングを学ぶ

練習モードを選ぶ

アプリをダウンロード

同じチャンネル

Retinal Artery Occlusion vs. Retinal Vein Occlusion

Pyruvate Pathways & Metabolism

Embryology of the Nervous System

Lymphoma

おすすめ動画

Cell Biology | Cell Structure & Function

Introduction to HPLC - Lecture 1: HPLC Basics

Go’s Big Mistake

Creatine: is there truth behind the hype?

Lecture 12: Retina, Part 2: Retinal vascular occlusions

Faces of Chemistry: Organic solar cells (BASF) - Video 2 (14+)

Homeostasis - How Your Body Keeps its Balance - Physiology Series

Pharmaceutical Industry Overview | Pharma and Biotech: Distinctions | Understanding Pharmaceuticals

Diodes Explained - The basics how diodes work working principle pn junction

Antimycobacterials | Anti-TB Drugs

Petroleum - 06 - Drilling Fluid Laboratory