Introduction To Cell Biology

Question 1

What are the three principles of cell theory?

Answer 1

1. All living things are composed of cells (or cell products)
2. The cell is the smallest unit of life
3. Cells only arise from pre-existing cells

Question 2

What are the three caveats to the cell theory?

Answer 2

Striated muscle fibers, aseptate fungal hyphae, giant algae

Question 3

How do striated muscle fibers challenge the cell theory?

Answer 3

Muscle cells have multiple nuclei despite being surrounded by a single, continuous plasma membrane
-Challenges the idea that cells always function as autonomous units

Question 4

How do aseptate fungal hyphae challenge the cell theory?

Answer 4

-Fungi may have filamentous structures called hyphae, which are separated into cells by internal walls called septa
-Some fungi are not partitioned by septa and hence have a continuous cytoplasm along the length of the hyphae
-Challenges the idea that living structures are composed of discrete cells

Question 5

How does giant algae challenge the cell theory?

Answer 5

Certain species of unicellular algae may grow to very large sizes (e.g. Acetabularia may exceed 7 cm in length)
-Challenges the idea that larger organisms are always made of many microscopic cells

Question 6

What are the 7 basic functions of life?

Answer 6

Metabolism, sensitivity, reproduction, homeostasis, excretion, nutrition, growth

Question 7

What are paramecia?

Answer 7

Paramecia are surrounded by small hairs called cilia which allow it to move
Paramecia engulf food via a specialised membranous feeding groove called a cytostome

Question 8

What are scenedesmus?

Answer 8

Scenedesmus exchange gases and other essential materials via diffusion
Chlorophyll pigments allow organic molecules to be produced via photosynthesis

Question 9

What are emergent properties?

Answer 9

Emergent properties arise when the interaction of individual components produce new functions