Ch. 4 - Biological molecules Flashcards
What are carbohydrates?
Substances that include sugars, starch and cellulose
What do carbohydrates contain?
Carbon, hydrogen, and oxygen
What’s the simplest carbohydrate?
Sugars
What are sugars?
The simplest carbohydrates, they’re small molecules and are soluble in water
What is glucose?
Glucose is a sugar which is used in respiration to release energy, dissolves in blood plasma (delivered to every cell)
What can glucose link to form?
Glycogen (in animals) and starch (in plants)
What is glycogen?
Contained in liver, liver keeps concentration of glucose constant, if too much glucose then glycogen formed, energy store
What is starch?
A carbohydrate that is used as an energy store in plant cells
How can you detect the presence of starch? What’s the colour change?
Iodine solution, from brown to blue-back
How can you detect sugars? What’s the colour change?
Benedict’s solution, from blue to orange-red if reducing sugars
What are fats and oils also known as?
Lipids
What is fat?
A lipid which is solid at room temperature
What is an oil?
A lipid which is liquid at room temperatures
What do fats and oils contain?
Carbon, hydrogen, and oxygen
What are fats made of?
Glycerol and fatty acids
What are fats used for?
To make cell membranes and as energy store
In mammals —> insulating layer
What do lipids dissolve in?
Not water, but in ethanol
How does emulsion work?
Food shaken with ethanol, fats dissolve, ethanol in tube containing water, tiny droplets of fats formed, milky appearance
What are proteins?
Molecules containing carbon hydrogen oxygen and nitrogen, sometimes sulfur as well
What are proteins made of?
Amino acids linked in different orders
What are examples of proteins?
- Enzymes
- Antibodies
- Haemoglobin
- Hair and fingernails made from protein KERATIN
How to test for proteins?
Biuret reagent, from blue to violet
What is DNA?
Material which makes up our genes
Where is DNA contained?
In nucleus
