1.1 Introduction to cells

Question 1

What 3 points does the cell theory state?

Answer 1

1. All living things are composed of cells.
2. Cells are the smallest functional unit of life.
3. New cells arise from pre-existing cells.

Question 2

What are the three exceptions to the cell theory?

Answer 2

1. Giant Algae: one multi-nucleated cell that grows to a large size without separate cells.
2. Striated Muscle Fibres: large multi-nucleated fibre formed from fusion of muscle stem cells
3. Fungal Hyphae: Aseptate hyphae that do not contain cross walls.

Question 3

What are the 7 functions of life?

Answer 3

Metabolism
Reproduction
Homeostasis
Growth
Response
Excretion
Nutrition

Question 4

Large surface area to volume ratio is achieved when…

Answer 4

the cell gets smaller

making diffusion of nutrients and waste materials more effective

Question 5

What are stem cells?

Answer 5

Unspecialized cells that have potency ( ability to differentiate into a range of specialized cells) and self renewal (ability to divide without specializing).

Question 6

Categories of Stem Cells

Answer 6

Totipotent- can differentiate into all types of cells
Pluripotent- can differentiate into majority of cell types (embryonic stem cells)
Multipotent- can differentiate into a limited number of related cell types (adult stem cells)

Question 7

Use of stem cells in leukaemia

Answer 7

ASCs used to replace mutated and destroyed stem cells in bone marrow killed by chemotherapy

Question 8

Use of stem cells in Stargardt’s Disease

Answer 8

ESCs injected to replace degenerated retinal cells to restore vision

Question 9

When can stem cells be used?

Answer 9

• produce regenerated tissue for skin grafts
• healing diseases where type of cell is lost (type 1 diabetes)
• possibility of being used to grow organs
• renewable source of cells for scientific studies and tests