BIO Set #2 - Short Answer / Essay questions for Exam Flashcards
Cell Membranes Photosynthesis Cell Respiration
Two theories of cellular evolution.
- Endosymbiotic Theory: This theory proposes that eukaryotic cells evolved from prokaryotic cells through a symbiotic relationship. Smaller prokaryotic cells (like mitochondria and chloroplasts) were engulfed by larger prokaryotic cells and eventually became essential organelles.
- Autogenous Theory: This theory suggests that eukaryotic cells evolved gradually from a single prokaryotic ancestor. Internal compartments within the cell gradually developed to form organelles over time.
Differences between prokaryotic and eukaryotic cells.
Eukaryotes are a type of cell that has a well-defined nucleus present inside a nuclear envelope. They form large and complex organisms and have the presence of cell organelles.
Endomembrane system (in and out of the cell).
The endomembrane system is a network of interconnected organelles within a eukaryotic cell that works together to synthesize, modify, package, and transport proteins and lipids. It includes:
Organelles inside the cell:
Nuclear envelope: A double membrane that surrounds the nucleus, regulating the passage of molecules between the nucleus and cytoplasm.
Rough (ER) Endoplasmic reticulum : A network of membrane-bound sacs and tubules involved in protein synthesis (rough ER) and lipid synthesis (smooth ER).
Transport vesicles
Golgi apparatus: A stack of flattened sacs that modifies, sorts, and packages proteins and lipids for transport within or out of the cell.
Secretory Vesicles: Small, membrane-bound sacs that transport materials throughout the cell.
Lysosomes: Organelles containing digestive enzymes that break down cellular waste and debris.
Plasma membrane: The outermost membrane that surrounds the cell, controlling the movement of molecules in and out of the cell.
Exocytosis: The process by which materials are transported out of the cell by fusing with the plasma membrane.
Endocytosis: The process by which materials are taken into the cell by engulfing them with the plasma membrane.
Nuclear Envelope → Rough Endoplasmic Reticulum (ER) → Transport vesicles → Golgi Apparatus → Secretory Vesicles → Plasma membrane (or lysosomes or vacuoles)
What makes chloroplast and mitochondria unique?
Chloroplasts and mitochondria are unique organelles because they have their own DNA and ribosomes, allowing them to replicate independently of the cell. This suggests that they were once free-living prokaryotes that were engulfed by a larger cell and formed a symbiotic relationship.
Chloroplasts: These organelles are found in plant cells and are responsible for photosynthesis, converting sunlight into energy.
Mitochondria: Found in most eukaryotic cells, they are involved in cellular respiration, breaking down nutrients to produce energy.
C4 and CAM plants and their adaptations for photorespiration.
C4 plants have a special way of fixing carbon dioxide (CO2) in their leaves. They do this in two different parts of the leaf, which helps to keep CO2 levels high and oxygen levels low. This makes photosynthesis more efficient.
CAM plants are like night owls! They open their tiny pores (stomata) at night to take in CO2. During the day, they close their stomata to save water, but they still use the CO2 they stored at night to do photosynthesis.
Alcohol and Lactic acid fermentation.
Alcohol Fermentation: Converts sugar into alcohol and CO2 (e.g., yeast in bread, beer).
Lactic Acid Fermentation: Converts sugar into lactic acid (e.g., bacteria in yogurt, muscles during exercise).
Alcohol Fermentation is primarily carried out by yeast and certain bacteria. In this process, glucose is broken down into ethanol (alcohol) and carbon dioxide. This reaction is essential for the production of alcoholic beverages like beer and wine. Additionally, the carbon dioxide produced during alcohol fermentation is responsible for the rising of bread dough.
Lactic Acid Fermentation is another common type of fermentation. It occurs in bacteria, which are used in the production of yogurt and sauerkraut. Additionally, human muscle cells can undergo lactic acid fermentation during intense exercise when oxygen supply is limited. In this process, glucose is converted into lactic acid. While lactic acid can cause muscle soreness, it provides a temporary source of energy.
Both alcohol and lactic acid fermentation are important for various organisms and industries. They allow for the production of food and beverages, and they help organisms to survive in environments with limited oxygen availability.
Hypotonic, Hypertonic and Isotonic solutions and reactions to cells.
If a cell is placed in a hypertonic solution, water will leave the cell, and the cell will shrink. In an isotonic environment, there is no net water movement, so there is no change in the size of the cell. When a cell is placed in a hypotonic environment, water will enter the cell, and the cell will swell.
ATP production between cell types.
ATP is made via a process called cellular respiration that occurs in the mitochondria of a cell. Mitochondria are tiny subunits within a cell that specialize in extracting energy from the foods we eat and converting it into ATP.
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Differences between and influences of photosynthesis and cellular respiration.
Photosynthesis and cellular respiration are two essential processes that are interconnected.
Photosynthesis occurs in plants and some other organisms with chlorophyll. It uses sunlight, water, and carbon dioxide to produce glucose (sugar) and oxygen. This process is essential for life on Earth as it provides the food and oxygen necessary for most organisms.
Cellular respiration occurs in all living cells. It breaks down glucose and other organic molecules to produce energy (ATP). This process requires oxygen and releases carbon dioxide as a waste product.
The relationship between the two processes is cyclical:
Photosynthesis: Produces glucose and oxygen
Cellular respiration: Uses glucose and oxygen to produce energy, releasing carbon dioxide
Photosynthesis: Uses carbon dioxide produced by cellular respiration to produce more glucose
In essence, photosynthesis creates the food and oxygen needed for life, while cellular respiration breaks down that food to provide the energy needed for cellular activities.
