Relate the significance of biomolecules (carbohydrate and lipid) to life.
Biomolecules are elementary building blocks exist in organism and they assist the vital biological process for life.
significance of carbohydrates and lipid 👇🏻
Carbohydrate 🥐
Carbohydrate with the formula of Cx(H2O)y and it can be classified into simple carbohydrate (monosaccharides) and complex carbohydrates (disaccharides and polysaccharides).
1. Monosaccharides
- Monosaccharides is the source of energy for energy as it is the substrate needed during respiration.
- Monosaccharides give turgidity to plant cell as well as permit the opening and closure of stomata through the exertion of osmotic pressure.
👆🏻These are the example of monosaccharides - glucose, fructose and galactose.
2. Disaccharides
- Maltose - act as respiratory substrate during respiration to generate energy.
- Lactose - act as respiratory substrate during respiration to generate energy and serve as the carbohydrate source during suckling as it present in mammalian milk.
- sucrose - act as respiratory substrate during respiration to generate energy and form of carbohydrate that transport throughout the plant.
- Disaccharides give turgidity to plant cell as well as permit the open and closure of stomata through the exertion of osmotic pressure.
👆🏻These are the example of disaccharides - sucrose, lactose and maltose.
3. Polysaccharides
- Starch - storage form of carbohydrate in plant.
- Glycogen - storage form of carbohydrate in animal.
- Cellulose - the main component of the plant cell wall.
👆🏻This is the example of polysaccharides - starch.
Lipid 🥩
Lipid is a non-polar and hydrophobic organic compound that mainly consist of carbon, hydrogen and oxygen.
Lipid can be classified into triglycerides, phospholipids and steroids.
1. Triglycerides
- Triglycerides can be act as the energy storage in organism due to its insolubility. Herein, a huge amount of triglycerides can be stored without the affection towards water potential of cells.
- Triglycerides can be a source of metabolic water in the circumstance of limit external source of water.
- Triglycerides can provide protection towards organism. Fat surrounding internal organs acting as the shock absorber.
- Triglycerides have the function of insulator of heat. As fat is a poor heat conductor that a layer of fat underneath skin can provide warmth to organism.
- Triglycerides can provide buoyancy towards organism. Fat is less dense than water that it assist organism to float e.g. blubber in aquatic life.
👆🏻This is the structure of triglycerides.
2. Phospholipid
- Phospholipid is the main component of cell membrane.
- Phospholipid assist the transportation of hydrophobic substance in hydrophilic condition through enclosing them in micelles.
👆🏻This is the structure of phospholipid.
3. Steroid
- Cholesterol, sex hormones and vitamin D are steroid needed in organism.
- Cholesterol present in animal cell membrane that regulate the fluidity of cell membrane as well as prevent the leakage of polar molecules.
👆🏻These are the structure and example of steroid.
In HKDSE Biology examination, you will be asked question on why carbohydrates and lipids are important towards life ❗️ ❕
That's the end of this topic 👏🏻
References
- Thomas, B. & Chris, H. (2013) Hong Kong DSE Biology Critical Guide. Yellowreef Limited.
- Libretexts. (2019, June 15). 1. 10: Carbohydrates. Retrieved from https://bio.libretexts.org/Bookshelves/Introductory_and_General_Biology/Book:_Introductory_Biology_(CK-12)/1:_Introduction_to_Biology/1._10:_Carbohydrates
- Thompson, T. E. (2020, February 21). Lipid. Retrieved from https://www.britannica.com/science/lipid