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Cell Biology and Physiology Fundamentals
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Cell Biology and Physiology Fundamentals
Cell Biology and Physiology Fundamentals
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Question
What are the primary structural differences between eukaryotic and prokaryotic cells?
Answer
Eukaryotic cells contain their genetic material enclosed in a nucleus and have membrane-bound organelles. Prokaryotic cells (like bacteria) are much smaller and their genetic material is not enclosed in a nucleus.
Question
What occurs during the three main stages of the cell cycle including mitosis?
Answer
First, the cell grows and increases sub-cellular structures while DNA replicates. Second, mitosis occurs where one set of chromosomes is pulled to each end of the cell and the nucleus divides. Finally, the cytoplasm and cell membranes divide.
Question
How do embryonic stem cells differ from adult stem cells in terms of potency?
Answer
Embryonic stem cells can be cloned and made to differentiate into most different types of human cells. Adult stem cells (like those in bone marrow) can only form many, but not all, types of cells such as blood cells.
Question
What are the three main factors that affect the rate of diffusion across a membrane?
Answer
The rate of diffusion is affected by the difference in concentrations (concentration gradient), the temperature, and the surface area of the membrane.
Question
How does osmosis differ from active transport in terms of energy requirements?
Answer
Osmosis is a passive process that does not require energy, moving water from a dilute to a concentrated solution. Active transport requires energy from respiration to move substances against a concentration gradient.
Question
What is the 'lock and key' theory of enzyme action?
Answer
The 'lock and key' theory states that an enzyme has a specifically shaped active site. Only a substrate with a complementary shape can fit into the active site to react and form products.
Question
What are the reagents and positive color changes for testing sugars and starch?
Answer
For sugars, use Benedict's solution and heat; a positive result turns from blue to brick-red. For starch, use iodine solution; a positive result turns from orange-brown to blue-black.
Question
What are the roles of bile in the digestive system?
Answer
Bile is alkaline to neutralize hydrochloric acid from the stomach. It also emulsifies fat to form small droplets which increases the surface area for the enzyme lipase to work on.
Question
How do the structures of arteries and veins relate to their functions?
Answer
Arteries have thick walls containing muscle and elastic fibers to withstand high pressure. Veins have thinner walls and valves to prevent the backflow of blood at lower pressure.
Question
What is the balanced chemical equation for photosynthesis?
Answer
The balanced equation is: \(6CO_2 + 6H_2O \xrightarrow{\text{light}} C_6H_{12}O_6 + 6O_2\)
Question
How does aerobic respiration differ from anaerobic respiration in humans?
Answer
Aerobic respiration uses oxygen and produces carbon dioxide and water, releasing a large amount of energy. Anaerobic respiration occurs without oxygen, produces lactic acid, and releases much less energy.
Question
What is the role of the immune system in defending against pathogens?
Answer
The immune system defends via phagocytosis (engulfing pathogens), antibody production (to target specific pathogens), and antitoxin production (to neutralize toxins).