PRINCIPLES OF BIOLOGY I - BIOL101
COURSE EVALUATION ASSIGNMENT
Name _RACELL EVANS
Answers all the questions below; answer each question in complete sentences. Pay attention to
the weight of each questions.
1. What is the precise role of oxygen in respiration? (2 Marks)
Oxygen serves as the final electron acceptor in the electron transport chain during
aerobic respiration. It combines with electrons and hydrogen ions to form water,
allowing the chain to continue functioning and producing ATP.
2. The rate of uptake of oxygen increases immediately exercise starts. How is the supply of
oxygen from outside the body to the cells increased during exercise? (3 Marks)
During exercise, the breathing rate and depth increase, which enhances oxygen intake in the
lungs. Simultaneously, the heart rate increases, pumping more oxygenated blood to tissues.
Blood vessels also dilate (vasodilation) in active muscles to allow more efficient oxygen delivery
to cells.
3. What does lactic acid level in the blood continue to rise after exercise when anaerobic
respiration has ceased?(2 Marks)
After exercise, lactic acid continues to be released into the blood as it is transported from
muscles to the liver. There, it is gradually converted back to glucose in a process called the Cori
cycle. This delayed processing causes the lactic acid levels to remain elevated for a short time
after exercise.
4. Describe the function of the mitochondria. Name four chemical substances which are
involve in respiration which would enter the mitochiondrion from the cytoplasm and
four which would leave. (12 Marks)
Mitochondria are known as the "powerhouses" of the cell because they generate ATP through
aerobic respiration. They house the Krebs cycle and the electron transport chain, essential for
energy production.
Entering the mitochondrion:
Pyruvate
