Macromolecules of living cells

Cell physiology란 세포가 정상적으로 작용하기 위해 작동하는 물리적인 활동을 말한다. 소화작용, 혈액순환 뿐만 아니라 근육축소운동까지도 포함된다. 이런 다양한 물리적인 활동을 위해 우리몸은 각각 다른세포가 다른 기능을 하기위해 모양까지도 정교하게 디자인 되어있다.

The chemical components of a cell:

1. water:

  • Good solvent
  • chemical reaction
  • water pressure in vacuoles(plant) keeps the cell turgid
  • high thermal capacity – it can absorb a lot of heat without its temperature rising to levels which damage the proteins in the protoplasm. (물은 섭씨 100도나 되어야 끓을수 있는 물질이다. 그런 성질때문에 더운 날씨에도 잘 끓지않기때문에 단백질이 잘 상하지 않게된다. 하지만 0도에서 얼기때문에 영하로 내려가는 날씨에는 동상에 걸리거나, 식물들이 얼어죽게 된다.)

2. Protein: Polymers

When small organic molecules (monomers) are joined together – huge macromolecules (polymers) are formed when small organic molecules (monomers) are joined together – huge macromolecules (polymers) are formed.

  • Carbohydrates consist of monosaccharide
  • lipids consist of fatty acids
  • proteins consist of amino acids
  • nucleic acids consist of  nucleotides
  • protein has C,H,N,O,S in its molecule
  • most abundant macromolecule in the cell
  • structural, transport, hormonal functions
  • proteins very diverse in living organisms
  • 20 dif. amino acids in all living things
  • amino acids are linked together by a peptide bond
  • Enzymes accelerate chemical reactions in cells. Enzyme은 자신은 소모되지 않고 세포안의 화학작용이 빨리 진행되게 도와주는 단백질이다. 하지만 높은 온도나, 맞지 않는 pH에서는 denature가 되어버린다.
  • Denaturation = Shape of the molecules alter, and proteins loose its original properties. Proteins form enzymes and many of the structures in the cell, so if they are denatured the enzymes and the cell structures will stop working and the cell will die.

3. Carbohydrates

  • Simple, soluble sugars or complex materials like starch and cellulose.
  • all carbohydrates contain carbon, hydrogen and oxygen only
  • commonly occurring simple sugar is glucose
  • Monosaccharides = single carbon ring
  • Disaccharides = two carbon rings in their molecules
  • Polysaccharides = many glucose molecules are joined together, the carbohydrates. Not readily  soluble in water. eg) glycogen, starch, cellulose

4. Salts (ions)

  • salts are present in cells in the form of their ions eg. sodium ions, chloride ions
  • ions take part in and influence many chemical reactions in the cell.
  • involved in determining how much water enters or leaves the cell.
  • calcium, potassium, and sodium ions are particularly important in chemical changes related to electrical activities of a cell.
  • Important for responding to stimuli or conducting nerve impulses.
  • a shortage or excess of ions in the cells upsets their physiology and affects the normal functioning of the whole organism.

5. Vitamins

  • plants can make their own vitamins
  • animal cells have to be supplied with vitamins ready made.
  • play a part in chemical reactions in the cell
  • eg. transfer energy from one compound to another

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