January Mock

Question 1

How does Glucose/amino acids absorption

Answer 1

1) Sodium removed from the epithelial cell by active transport via sodium-potassium carrier protein.
2) into the blood
3) maintaining low conc of sodium in epithelial cells.
4) Glucose moves in with sodium (into epithelial cell).
5) via carrier protein (co-transport).
6) Glucose moves into blood.
7) by facilitated diffusion

Question 2

Describe structure + explain how this aids function. (Absorption)

Answer 2

Walls are folded into villi= increase S.A for faster absorption
walls are 1 cell thick = short diffusion distance for faster absorption
Epithelial cells have microvilli = increase S.A for faster absorption.
Many capillaries = Rich blood supply maintains diffusion gradient.
Muscle in villi = maintain diffusion gradient by moving contents of lumen.

Question 3

Describe how DNA is replicated?

Answer 3

1) strands separate/ hydrogen bonds break
2) DNA helicase is involved.
3) both strands act as templates.
4) free nucleotides attracted.
5) H bonds reform
6) complementary/ specific base pairing/ AT+ GC
7) DNA polymerase joins nucleotides via phosphodiester bonds
8) semi-conservative replication and one new strand,