Physiologists investigate how the diving reflex in Weddell seals (Leptonychotes weddellii) affects blood flow to different organs and tissues during deep dives to conserve oxygen. The table below shows the average rate of blood flow to these parts when resting at the surface and during a deep dive:
| Organ / Tissue | Rate of blood flow at Surface (mL min−1\text{mL min}^{-1}mL min−1) | Rate of blood flow during Deep Dive (mL min−1\text{mL min}^{-1}mL min−1) |
|---|---|---|
| Brain | 350 | 350 |
| Heart muscle | 200 | 200 |
| Skeletal muscles | 1550 | 120 |
| Kidneys & Digestive organs | 1600 | 50 |
| Other tissues | 800 | 80 |
| Total | 4500 | 800 |
By how many times has the total blood flow decreased during a deep dive? Give your answer to the nearest whole number.
Explain the changes in blood flow rate to the skeletal muscles and the kidneys & digestive organs during a deep dive.
82 exam-style questions on OCR GCSE Biology 2.1 Supplying the cell, covering 2.1.1 Transport across cell membranes, 2.1.2 Mitosis and the cell cycle, 2.1.3 Importance of cell differentiation, and 2.1.4 Stem cells. Each one has a worked solution and a mark scheme showing where the marks go.