Question 1

What four elements make up 96% of biological matter?

Accepted Answer

Oxygen, carbon, hydrogen, and nitrogen comprise 96% of all biological matter in living organisms. These four elements form the foundation of life on Earth. The remaining 4% consists of calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium, which support vital biological functions.

Question 2

How is the periodic table organized?

Accepted Answer

The periodic table organizes elements by increasing atomic number into columns called groups and rows called periods. Elements in the same group share similar chemical properties, while elements in the same period are similar in size. The table displays each element's full name, chemical symbol, atomic number, and atomic weight.

Question 3

Why are trace elements important if they comprise less than 0.01% of the human body?

Accepted Answer

Trace elements, though present in tiny amounts, are critical for human health and survival. Iron, for example, binds oxygen in red blood cells for transport throughout the circulatory system. Deficiency in trace elements like iron causes serious conditions such as anemia, characterized by fatigue, weakness, and irregular heart rhythms.

Question 4

What role do metal ions play in cellular metabolism?

Accepted Answer

Metal ions including magnesium, manganese, copper, zinc, molybdenum, and potassium aid enzymes in catalyzing various metabolic reactions. These ions act as cofactors that enable enzymes to function properly and participate in biochemical processes. Understanding water organic molecules inorganic ions helps explain how these metal ions integrate into cellular chemistry.

Question 5

How do heavy metals like mercury affect living organisms?

Accepted Answer

Heavy metals such as mercury produce harmful symptoms even in small doses and can accumulate in organism tissues over time. Repeated exposure poses serious health risks, potentially causing death at higher concentrations. Heavy metal contaminants enter the food web through primary producers like plants before affecting higher trophic levels including humans.

Question 6

Why are calcium and iron specifically important in animals?

Accepted Answer

Calcium is essential for healthy growth and development of teeth and bones in animals. Iron plays a critical role in hemoglobin, the protein that carries oxygen molecules from the lungs to cells throughout the body. Both elements are vital for maintaining proper physiological function and preventing deficiency-related diseases.

Question 7

What information does the periodic table provide about each element?

Accepted Answer

Each square in the periodic table displays the element's full name, chemical symbol, atomic number, and atomic weight. The atomic number indicates the number of protons in the nucleus and provides information about the element's size. This standardized reference allows chemists and biologists to quickly access essential properties needed for understanding element behavior.

الجدول الدوري والعناصر العضوية