Name: suspensions, sedimentation, and colloids
Uploaded: 2023-06-23T15:38:43.000Z
Duration: 1 min 17 s
Channel: JoVE

콜로이드와 현탁액은 물리적으로 혼합된 두 개 이상의 성분의 이질적인 혼합물입니다.
콜로이드에서 용질 입자의 크기는 1에서 1000 나노미터 사이이며, 개별적으로 보이지 않을 정도로 작습니다. 그러나 이러한 용질 입자는 빛을 산란시켜 콜로이드를 반투명하거나 불투명하게 보이게 할 수 있습니다. 그들은 용액에 무기한 남아 있으며 침전되지 않습니다.
살아있는 세포 내부의 반유체 물질인 사이토졸(Cytosol)은 그 안에 흩어져 있는 수많은 단백질과 대사 산물 때문에 콜로이드입니다.
대조적으로, 현탁액에는 일반적으로 10000나노미터 이상의 큰 입자가 포함되어 있으며 종종 육안으로 볼 수 있습니다.
방해받지 않고 방치하면 이러한 입자는 퇴적물로 가라앉습니다.
혈액은 서스펜션의 예입니다. 갓 채취한 혈액을 얼마 동안 방해받지 않고 방치하면 적혈구가 용기 바닥에 가라앉습니다. 혈장이라고 하는 상부 액체 부분은 작은 용질과 더 큰 혈장 단백질을 포함하는 콜로이드의 용액입니다.

콜로이드 및 현탁액

놀고 있는 아이들은 종종 진흙과 물, 밀가루와 물의 혼합물이나 템페라 페인트로 알려진 고체 안료를 물에 녹인 현탁액을 만듭니다. 이러한 현탁액은 육안으로 보이거나 돋보기로 볼 수 있는 비교적 큰 입자로 구성된 이질적인 혼합물입니다. 그것들은 흐리고, 부유 입자들은 혼합 후에 가라앉습니다. 현탁액에 부유된 입자는 일정 시간 혼합한 후에 침전됩니다. 현탁액에서 입자가 분리되는 것을 침전이라고 합니다. 침강 속도를 확인하기 위한 혈액 검사는 시험관의 적혈구가 설정된 시간 동안 혈액의 물이 많은 부분(혈장이라고 함)에서 얼마나 빨리 침전되는지를 측정합니다. 건강한 신체에서는 혈액 세포의 급속한 침전이 일반적으로 발생하지 않습니다. 하지만 특정 질병의 측면에서는 혈액 세포가 서로 뭉치는 현상이 발생할 수 있으며, 이러한 무거운 혈액 세포 덩어리는 일반 혈액 세포보다 더 빨리 시험관 바닥에 가라앉습니다. 콜로이드(또는 콜로이드 분산액)라고 불리는 또 다른 종류의 혼합물은 현탁액과 용액의 중간 특성을 나타냅니다. 콜로이드의 입자는 대부분의 단순 분자보다 큽니다. 그러나 콜로이드 입자는 매우 작아서, 방치해도 가라앉지 않습니다. 콜로이드의 입자는 빛을 산란시킬 만큼 충분히 큽니다. 틴들 효과(Tyndall effect)라고 불리는 현상; 이것이 바로 서치라이트 광선과 같이 콜로이드 혼합물이 흐리거나 불투명하게 나타나는 이유입니다. 구름도 콜로이드 혼합물입니다. 그것들은 분자보다 훨씬 크지만 가라앉지 않을 만큼 작은 물방울로 구성되어 있습니다. 일부 콜로이드는 액체에서 고체(겔) 상태로 가역적으로 변형될 수 있는 졸-겔 변형을 겪는 특성을 가지고 있습니다. 예를 들어, 젤라틴 제품은 냉장 보관하면 응고되어 젤을 형성하고, 가열하면 다시 액화될 수 있습니다. 살아있는 세포의 액체인 세포질의 졸-겔 특성은 세포 분열이나 세포 모양 변화와 같은 많은 세포 활동에 필수적입니다. 상대적으로 적은 양으로 존재하는 콜로이드 용액의 미립자 성분을 분산상이라고 합니다. 미립자가 분포되어 있는 물질이나 용액을 분산매라고 합니다. 
이 문서는 <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/2-4-inorganic-compounds-essential-to-human-functioning">Openstax, Anatomy and Physiology 2e, Section 2.4: Inorganic Compounds Essential to Human Functioning</a> and <a href="https://openstax.org/books/chemistry-2e/pages/11-5-colloids">Openstax, Chemistry 2e, Section 11.5: Colloids</a>.

놀고 있는 아이들은 종종 진흙과 물, 밀가루와 물의 혼합물 또는 템페라로 알려진 물에 있는 고체 안료의 현탁액과 같은 현탁액을 만듭니다.

Education

교육

JoVE Core

Anatomy and Physiology

해부학 및 생리학

Unit 1

제1단원

Fundamentals of Chemistry

화학의 기초

KEY TERMS AND CONCEPTS

주요 용어 및 개념

Colloids and Suspensions

suspensions, sedimentation, and colloids

Suspensions and colloids are two common kinds of mixtures seen in everyday life. Mud and water, flour and water, and tempera paint are suspensions. These mixtures are heterogeneous, which means their particles are not spread out evenly. The particles are relatively large and can be seen with the naked eye or a magnifying glass.

Suspension particles make mixtures cloudy, and they settle out after mixing. The settling of particles in a suspension is called sedimentation. A blood test can measure the rate of sedimentation by showing how fast red blood cells settle out of plasma, the watery part of blood, in a test tube over time. Rapid sedimentation is not usual in a healthy body, but some diseases can cause blood cells to clump together and sink faster than normal cells.

Colloids, also called colloidal dispersions, sit between suspensions and solutions. Their particles are larger than most simple molecules, but they are small enough that they do not settle out when left standing. Colloidal particles are still large enough to scatter light. This is known as the Tyndall effect, and it makes colloids look cloudy or opaque, like a beam from a searchlight.

Clouds are another example of a colloid. They contain water droplets that are bigger than molecules, but still small enough to stay suspended in the air. Some colloids can also change from a fluid sol to a solid gel and back again. Gelatin is one example. It forms a gel when chilled and can become liquid again when heated. The sol-gel behavior of cytosol, the fluid inside living cells, is important for cell division and for changes in cell shape.

In a colloid, the dispersed phase is the particulate part present in smaller amount. The dispersion medium is the substance that carries the particles throughout the mixture. These terms help describe how colloids are organized and why they behave differently from suspensions and solutions.

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key terms and concepts

Learn how suspensions settle, how sedimentation works, and why colloids stay cloudy without settling. Explore real examples like blood, clouds, and gelatin.

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Suspensions, Sedimentation, and Colloids

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