Question

Metabolic reactions take place (a) In vitro (b) In vivo (c) both (a) and (b) (d) only in unicellular organisms

Short answer

The correct answer is (c) both (a) and (b). Metabolic reactions can take place both 'in vitro' and 'in vivo'.

Step-by-step solution

Understand the Given Options

Firstly, review the meanings of 'in vitro', 'in vivo' and 'unicellular organisms'. 'In vitro' refers to processes that take place in a laboratory environment or in an artificial setting, whereas 'in vivo' refers to processes that take place inside an organism. 'Unicellular organisms' are those that only consist of a single cell.

Evaluate Each Option Individually

Consider each option individually in the context of metabolic reactions. (a) In vitro: Metabolic reactions can and do often take place in a laboratory setting for certain experiments. (b) In vivo: Metabolic reactions naturally take place inside the bodies of living organisms as a part of their life processes. (d) Only in unicellular organisms: This is not accurate since metabolic reactions also occur in multicellular organisms.

Determine the Correct Option

After evaluating each option, it is clear that metabolic reactions can occur both 'in vitro' and 'in vivo', making option (c) 'both (a) and (b)' the correct answer.

Key concepts

In Vivo

The term "in vivo" refers to metabolic reactions or processes that occur within a living organism. This is essential for maintaining life, as metabolic reactions drive the vital functions in living beings.
These reactions include various biochemical processes such as digestion, respiration, and cellular energy production. Metabolic processes are tightly regulated to ensure homeostasis—the stable internal conditions necessary for survival.
In vivo studies provide insights into how these reactions function within the complex environment of a living organism, reflecting realistic physiological conditions.

In Vitro

"In vitro" means "in glass." This term describes experiments conducted outside of a living organism, often in a controlled laboratory environment like a petri dish or test tube.
Scientists use in vitro methods to study cellular and molecular biology in a simplified setting, which allows for precise control over variables.
These studies are critical for understanding specific metabolic pathways without the complexities present in a whole organism. Although in vitro conditions can't replicate all aspects of a living system, they are invaluable for preliminary experiments prior to in vivo testing.

Unicellular Organisms

Unicellular organisms are life forms that consist of a single cell, such as bacteria, archaea, and some algae and fungi.
Despite their simplicity compared to multicellular organisms, they carry out all necessary life functions within that one cell, including metabolic reactions.
These organisms are fascinating because they highlight the fundamental biochemical processes required for life, such as DNA replication, energy production, and waste elimination, all functioning within a single cell structure.

• Examples include bacteria like Escherichia coli and yeast.
• They often serve as models in laboratory research due to their simplicity and rapid growth rates.

Multicellular Organisms

Multicellular organisms are composed of many cells, often organized into tissues and organs. This complex structure allows for specialization, where different cells perform specific functions.
These organisms include humans, animals, and plants, and they evolved from unicellular ancestors. Metabolic reactions in multicellular organisms are often coordinated across various types of cells to maintain entire-body systems.
The specialization in multicellular organisms allows them to adapt and function efficiently within diverse environments, showcasing the diversity of life processes, including metabolism, growth, and response to stimuli.