CHAPTER 4

Question 1

Describe how surface area-to-volume ratios change in size. How is this important to bacteria?

Answer 1

As size increases the surface area -to-volume ratio decreases. This is important to bacteria because bacteria need to stay small in order to expose more surface area to exchange materials with their environment; the surface area volume needs to stay large.

Question 2

Compare prokaryotic and eukaryotic cells.

Answer 2

Prokaryotic cells
- most primitive (found ~3.5 BYA)
- microscopic, lack most organelles
- unicellular
- DNA is not contained in a nucleus
ex: bacteria and archaea -> extremophiles

Eukaryotic cells
- larger, more complex (found ~2.1 BYA)
- many types of organelles
- DNA is in a membrane-bound nucleus

Question 3

Compare animal and plant cell structure. What 3 structures are only found in plant cells?

Answer 3

1. cell wall - made of cellulose for structural support
2. chloroplast - site of photosynthesis
3. central vacuole - stores water, nutrients, waste, etc

Question 4

Describe the structure and function of a plasma membrane. Know how to diagram

Answer 4

Structure: Surrounds all cells
Function: it’s semipermeable
- letting some things in, but not others
- has a phospholipid bilayer + some proteins embedded in it