Lec. 11 - Energy and Metabolism

Question 1

Explain what happens when a cell is placed in a hypotonic, hypertonic, and isotonic solution.

Answer 1

In hypotonic, water moves into the cell from surrounding solution, in hypertonic, water moves out of the cell toward the higher concentration of solutes outside, in isotonic, there is no net movement of water.

Question 2

Explain the difference between endocytosis, exocytosis, phagocytosis, and pinocytosis.

Answer 2

Endocytosis is when a cell takes in substances from the external environment by engulfing them into vesicles, exocytosis is when cells release substances from intracellular vesicles, phagocytosis is a specific type of endo. where cells engulf large solid particles. Pinocytosis is a type of endocytosis where cells take in small droplets of extracellular fluid.

Question 3

Explain symports, antiports, uniports.

Answer 3

Symports are membrane proteins that simultaneously transport two different molecules across the cell membrane, antiports are membrane proteins that transport two different molecules or ions across the cell membrane in opposite directions. Uniports are membrane proteins that transport a single type of molecule or ion across the cell membrane

Question 4

Explain the cellular importance of the Na+/K+ and how it relates to concentration gradients.

Answer 4

It actively transports sodium ions out of the cell and potassium ions into the cell against their respective concentration gradients.

Question 5

Describe energy and energy transformations.

Answer 5

There are 5 types of energy, mechanical, thermal, chemical, electrical, and nuclear. The first law of thermodynamics states that energy cannot be created or destroyed, only transformed, the second law of thermodynamics describes entropy which is the measure of disorder or randomness in a system.