1.1 Introduction to cells

Question 1

Define differentiation:

Answer 1

Differentiation involves the expression of certain genes and not others.

Question 2

What properties of Stem cells make them useful to us:

Answer 2

They are pluripotent. They are undifferentiated cells. Because of this they can be used to repair damaged tissues.

Question 3

What are expressed/unexpressed genes known as?

Answer 3

Expressed genes are known as Euchromatin. Unexpressed genes are known as heterochromatin.

Question 4

What is the Cause, Effect, and Final result of Stargardt’s molecular dystrophy?

Answer 4

The cause is a recessive mutation on the ABCA4 gene. The effect is the degeneration of photoreceptors on the retina. The final result is blindness.

Question 5

What is the significance of SA to Volume ratio in Cells?

Answer 5

It limits cell size.

Question 6

How does SA to volume ratio limit cell size?

Answer 6

As cells increase in their size, their SA to volume ratio decreases. This is significant, as, at a low ratio, substances needed for the processes of life do not enter the cells quickly enough, and hence metabolism cannot be sustained. Furthermore, the waste products of metabolism do not diffuse out of the cell quickly enough, leading to a toxic build-up that can kill the cell. Shorter diffusion distances, easier to generate concentration gradient.

Question 7

What are some exceptions to the Traditional cell theory?

Answer 7

Aseptate fungal hyphae- the hyphae of this fungus is not compartmentalized.
RBC’s- they do not have a nucleus
Giant Algae- Challenge the idea that large organisms must be multicellular.
Striated muscle cells- challenge the idea that cells have only one one nucleus.