What is metabolism?
Q: What is metabolism?
A: Metabolism is the chemical reactions which keep us alive. It happens in the cells of living organisms and is catalyzed by enzymes. Metabolism allows organisms to grow, reproduce, maintain their structures, and respond to their environments. The word ‘metabolism’ can also refer to digestion and the transport of substances into and between different cells.
Q: How is metabolism divided?
A: Metabolism is usually divided into two categories: Catabolism breaks down organic matter and harvests energy by way of cellular respiration; Anabolism uses energy to build molecules such as proteins and nucleic acids.
Q: What are metabolic pathways?
A: The chemical reactions of metabolism are organized into metabolic pathways, or cycles, like the Krebs cycle. One chemical is transformed through a series of steps into another chemical by a series of enzymes.
Q: How does an organism's metabolic system decide what it finds nutritious or poisonous?
A: The metabolic system of an organism decides which substances it finds nutritious and which poisonous. For example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals.
Q: What influences how much food an organism needs?
A: The speed of metabolism, called the metabolic rate, influences how much food an organism will need, and how it is able to get that food.
Q: Why do all organisms have similar metabolic pathways?
A: All organisms have similar metabolic pathways due to their early appearance in the evolution of life, kept because they are efficient for survival purposes.
