The molecular level of life. Chemical composition of the cell
Answers are for parents and teachers.
1
Choose four microelements and write the role of each in the organism.
For example: iodine – thyroid hormones; fluorine – tooth enamel; cobalt – vitamin B12; zinc – part of insulin and some enzymes.
2
Why is life considered impossible without water? Give three properties of water.
Water is a universal solvent (polar molecule), transports substances, has a high heat capacity (due to hydrogen bonds), and most reactions occur in an aqueous medium.
3
A cell sample of 400 mg is 75% water. What is the mass of water in mg? (Number only.)
300
4
Draw and explain a scheme showing how a polymer (starch or a protein) forms from monomers.
For example, a chain glucose – glucose – glucose ... forms starch, with one water molecule released at each link; in a protein, amino acids are joined by peptide bonds.