Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
The Cell is the basic structural and functional unit of all living organisms, first discovered by Robert Hooke in .
The Cell Membrane (Plasma Membrane) is a thin, delicate, and semi-permeable outer layer that regulates the entry and exit of substances.
The Cell Wall is a rigid outer layer found only in plant cells, primarily composed of , providing shape and protection.
The Nucleus is the 'brain' of the cell, containing genetic material in the form of (Deoxyribonucleic acid) and (Ribonucleic acid).
Cytoplasm is a jelly-like substance where various organelles like mitochondria, ribosomes, and vacuoles are embedded.
Mitochondria are known as the 'Powerhouse of the cell' because they release energy in the form of (Adenosine Triphosphate) through cellular respiration.
Vacuoles are large and permanent in plant cells (providing turgidity), while they are small and temporary or absent in animal cells.
Plastids are organelles found only in plant cells; Chloroplasts contain the green pigment used for photosynthesis.
Centrosomes are present only in animal cells and assist in cell division.
📐Formulae
💡Examples
Problem 1:
A student observes a cell under a microscope and notices a thick outer boundary and a large central empty space. Identify the cell type and the specific structures observed.
Solution:
The cell is a Plant Cell. The thick boundary is the Cell Wall and the large space is a Vacuole.
Explanation:
Animal cells lack a cell wall and typically have many small vacuoles rather than one large central vacuole.
Problem 2:
Explain the chemical process occurring in the Mitochondria using scientific notation.
Solution:
Explanation:
Mitochondria oxidize glucose () in the presence of oxygen () to release carbon dioxide (), water (), and energy for cellular activities.
Problem 3:
Why are Chloroplasts absent in animal cells?
Solution:
Animal cells are heterotrophic and do not perform photosynthesis.
Explanation:
Chloroplasts contain , which is required to convert and into glucose (). Since animals consume food rather than synthesizing it from sunlight, they do not require plastids.