JAN MOCK IMPROVEMENTS

Question 1

What are microvilli and how do they increase the rate of absorption?

Answer 1

-highly folded cell-surface membrane
-increase the surface area for diffusion/increase the surface area for carrier proteins

Question 2

Structures in a bacterium:

Answer 2

RNA
Cell wall
Capsule

Question 3

How can you monitor temperature?

Answer 3

TAKE READINGS using a thermometer

Question 4

Give ways a student can ensure they produce a correct biological drawing.

Answer 4

-include a scale bar or magnification of image
-do not shade in any structures
-draw parts to the same scale
-draw only outline of tissues

Question 5

Describe how humans breathe in and out

Answer 5

Breathing in:
-diaphragm contracts and diaphragm flattens
-external intercostal muscles contract and ribcage pulled up
-causing volume of the thoracic cavity to decrease and the pressure to increase
Breathing out:
-diaphragm relaxes and diaphragm moves up
-external intercostal muscles relax and ribcage moves down
-causing volume decrease in the thoracic cavity and pressure increase

Question 6

Describe the processes involved in the absorption and transport of digested lipid molecules from the ileum into lymph vessels

Answer 6

-the micelles contain bile salts and fatty acids
-brings fatty acids to the cell
-fatty acids absorbed by diffusion
-triglycerides reformed in the smooth endoplasmic reticulum
-triglycerides move in vesicles to Golgi apparatus where they are modified
-triglycerides associate with cholesterol and lipoproteins to form chylomicrons
-chylomicrons transported in vesicles to cell-surface membrane and leave via exocytosis
-absorbed into lacteals

Question 7

Why would an ELISA test for antibodies be falsely negative if a person is tested within 2 weeks of being infected by a bacterium?

Answer 7

-no antibodies produced during first 2 weeks
-only primary response/by plasma cells

Question 8

People with coeliac disease have damaged microvilli. Explain why they therefore have low concentrations of amino acids in their blood.

Answer 8

-reduced surface area
-less absorption

-cell membranes damaged
-fewer carrier proteins

Question 9

Explain why it is important to control experimental variables.

Answer 9

So results can be compared