쉐도잉 연습: Parts of the Eukaryotic Cell - 영상으로 영어 말하기 배우기

All cells

have a few things in common, including the cell membrane.

Cell membranes and all membrane-bound organelles are made up almost entirely of lipids.

Lipids are a broad category of fatty macromolecules, which include oils, waxes, triglycerides, and phospholipids.

Phospholipids are the major component of cell membranes and membrane-bound organelles.

Triglycerides are fats and oils, also known as saturated and unsaturated fats.

Waxes, like your earwax, are protective, lubricating substances.

And sterols, like cholesterol or steroids, are used for cell wall integrity and for making hormones.

So let's look at the cell membrane up close and see some of those lipids in action.

The cell membrane is made mostly of phospholipids, which form a double layer called the phospholipid bilayer.

The round heads of the phospholipids are polar and hydrophilic, which means that they are water-loving.

The tails are nonpolar or hydrophobic, which means they are water-fearing.

This is why they form a bilayer, which keeps the polar heads in the water and the nonpolar tails away from it.

Another lipid, cholesterol, is a key part of the cell membrane, keeping it together while still allowing the proteins to move around.

There are three basic types of membrane proteins as well.

Recognition proteins, which tell the cell who it is and where it is.

Receptor proteins, which can pick up signals.

And transport proteins, which can move chemicals in and out of the cell.

Those three proteins are also integral proteins because they're integrated into the lipid bilayer.

This pink-colored protein that's on the edge of the membrane is called a peripheral protein, just like your peripheral vision is at the edge of your vision, peripheral proteins on the edge of the membrane.

The proteins all create a speckled mosaic appearance on the membrane, but they aren't locked into one place.

They can move around through the phospholipids.

Because of this, we say the cell membrane is a fluid mosaic.

The mitochondria are sometimes called the powerhouse of the cell.

They transfer energy from organic molecules into ATP, which powers almost all reactions in the cell.

Because mitochondria are the energy producers, you can expect to find more mitochondria in cells that do more work, like muscle cells.

The mitochondria has an outer and an inner membrane.

The inner membrane is bunched and folded, and the folds are called cristae.

Inside the cristae, and between the inner and outer membrane, is a fluid called the matrix.

Because mitochondria are small and also have their own DNA, some scientists think that mitochondria may have developed from prokaryotes like bacteria.

Ribosomes are small structures that are responsible for building protein.

They have no membrane like other organelles and are just made of protein and RNA.

You can find ribosomes on the rough ER or floating around in the cytoplasm.

The endoplasmic reticulum is a transportation highway which has two parts, rough and smooth.

The rough ER produces phospholipids in proteins and is covered in ribosomes.

The smooth ER produces lipids, such as cholesterol.

You can tell it apart from the rough ER because it has no ribosomes on it and it's more tubular than flat.

The Golgi apparatus, which is also known as the Golgi body, modifies many cellular products that it receives from the endoplasmic reticulum,

and it prepares them for export to other regions of the cell or out of the cell entirely.

You can tell the Golgi apparatus from the ER

because it doesn't have ribosomes on it and it's further away from the nucleus.

Lysosomes are vesicles that are made from the Golgi apparatus that contain digestive enzymes.

These enzymes will help break down unwanted substances.

The cytoskeleton is a network of tubes and filaments that give shape and structure to the cell, just like your bones give your body shape and structure.

Centrioles are short cylinders of microtubules that exist in pairs

and are used in animal cells to organize microtubules during cell division so that the chromosomes will divide evenly.

This cell image has a flagella, which is a long whip-like tail for motion, but it doesn't have any cilia.

Cilia are smaller versions of flagella and they can be used for propulsion

or as a way to increase surface area for things like absorbing food in your intestines.

The nucleus contains the DNA, but it's actually made of three more specific parts.

The nuclear membrane is a double membrane that has little pores

that provide passageways for RNA and other materials to go in and out, but the pores aren't big enough for the DNA to move out.

Inside the nucleus is the DNA in the form of a thread-like material called chromatin.

has the instructions for the structure and function of the organism.

The nucleolus is the dense, round area in the nucleus, where the DNA is concentrated to build ribosomes.

So those are the parts of the eukaryotic cell that most have in common.

Next time we'll look at special parts that the plant cells have in addition to these.

Thank you.

쉐도잉이란? 영어 실력을 빠르게 키우는 과학적 방법

쉐도잉(Shadowing)은 원래 전문 통역사 훈련을 위해 개발된 언어 학습 기법으로, 다언어 학자인 Dr. Alexander Arguelles에 의해 대중화된 방법입니다. 핵심 원리는 간단하지만 매우 강력합니다: 원어민의 영어를 들으면서 1~2초의 짧은 지연으로 즉시 소리 내어 따라 말하는 것——마치 '그림자(shadow)'처럼 화자를 따라가는 것입니다. 문법 공부나 수동적인 청취와 달리, 쉐도잉은 뇌와 입 근육이 동시에 실시간으로 영어를 처리하고 재현하도록 훈련합니다. 연구에 따르면 이 방법은 발음 정확도, 억양, 리듬, 연음, 청취력, 말하기 유창성을 크게 향상시킵니다. IELTS 스피킹 준비와 자연스러운 영어 소통을 원하는 분들에게 특히 효과적입니다.

쉐도잉 연습: Parts of the Eukaryotic Cell - 영상으로 영어 말하기 배우기

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