Biology Homework Feedback

Question 1

Explain why structure of membrane is described as fluid-mosaic. (2)

Answer 1

• Fluid - Because molecules can freely move around
• Mosaic - Comprised of many different proteins, phospholipid and other molecules

Question 2

No organelles are visible in cytoplasm of RBC. Explain why. (1)

Answer 2

Cytoplasm of RBC filled with haemoglobin

Question 3

Before cell was examined, it was stained. This caused cell-surface membrane to appear as two dark lines. Explain why. (3)

Answer 3

1) Membrane has phospholipid bilayer membrane
2) Stain binds to phosphate
3) On inside and outside of membrane

Question 4

How does facilitated Diffusion work?

Answer 4

1) Facilitated diffusion is the passive process of transporting substances from high-low conc using carrier proteins
2) The carrier proteins are complementary to substrate

Question 5

Give two features of all prokaryotic cells that aren’t features of eukaryotic cells. (2)

Answer 5

1) loop of DNA
2) Murein cell wall