Which of the following scientists is credited with contributing to the cell theory by proposing that all cells come from pre-existing cells?

A. Matthias Schleiden

B. Theodor Schwann

C. Rudolf Virchow

D. Robert Hooke

Which characteristic is common between Amoeba and Paramecium?

A. Shape

B. Mode of nutrition

C. Presence of cilia

D. Method of reproduction

Why is the surface area to volume ratio a limiting factor for cell size?

A. It limits nutrient uptake

B. It affects cell communication

C. It influences the rate of diffusion

D. It determines the number of organelles

Which level of cellular hierarchy is directly above organelles?

A. Cells

B. Tissues

C. Organs

D. Organ systems

During embryonic development, what role do transcription factors play?

A. Nutrient supply

B. Cell differentiation

C. Cell division

D. Energy production

a) Discuss the contributions of Schleiden and Schwann to the development of the cell theory and explain why their contributions were significant to the field of biology. [4]

b) In relation to the cell theory, explain how the work of Rudolf Virchow provided further understanding of the origin of cells. [2]

a) Explain the concept of surface area to volume ratio and discuss its implications on the limitations of cell size. [3]

b) Provide an example of a unicellular organism and describe how it obtains nutrients and adapts to its environment. [3]

a) Discuss the role of transcription factors in embryonic development and how they contribute to cell differentiation and the formation of various tissues and organs. [4]

b) Briefly outline the ethical considerations associated with the use of embryonic stem cells in research and medicine. [2]

a) Define pluripotency and explain the significance of pluripotent cells in embryonic development. [3]

b) Differentiate between embryonic and adult stem cells in terms of their potential and applications in medicine. [4]

c) Evaluate the importance of intercellular communication and specialisation in the context of cellular hierarchy. [3]

a) Describe the characteristics and mode of reproduction in Paramecium. [3]

b) Elaborate on how the surface area to volume ratio affects the adaptability and functioning of cells, such as Paramecium, in their environment. [4]

c) Discuss the three principles of cell theory and explain how they are illustrated by the characteristics of unicellular organisms like Paramecium. [3]