Cell Transport
Define active transport. Mention the gradient.
A type of transport that uses energy to move molecules across the membrane. Goes AGAINST the concentration gradient.
Define chromosome.
Define enzymes.
Proteins that speed up biochemical reactions by lowering the activation energy.
Define ATP.
An energy carrying molecule that carries/stores energy for cell functions.
Define trophic levels.
The levels of nourishment in a food chain.
What is a positive feedback loop? Give an example.
Give ALL phases of the CELL CYCLE. This includes both interphase and mitosis.
G1 phase, S phase, G2 phase, Prophase, Metaphase, Anaphase, Telophase, Cytokinesis
What is the difference between an endothermic reaction and an exothermic reaction?
An endothermic reaction absorbs energy, while an exothermic reaction releases energy.
Which group of molecules in ATP get modified to generate energy for cell functions?
The 3 phosphate groups of ATP. Specifically, the bond between the 2nd and 3rd phosphate breaks to generate energy.
Consider a food chain consisting of phytoplankton -> shrimp -> large fish -> shark. In this food chain, what trophic level is large fish in?
Secondary consumer.
How does the cell membrane help maintain homeostasis? Name and define the property that allows this to happen.
The cell membrane allows transportation of key molecules in and out of the cell, to properly address cellular responses. The cell membrane is selectively permeable, which means that it can decide what goes in and out of the cell using properties of the molecule being transported.
What happens during the anaphase of mitosis?
Reactants that have a combined energy of 500 J creates products that have a combined energy of 750 J. What type of a reaction occurred?
Since there is more energy present in products than present in reactants, an endothermic reaction most likely occurred.
True or False : Overall, the ATP-ADP cycle is an endothermic process. Explain your answer.
False. While the ATP-ADP cycle does involve an endothermic reaction, the overall process is exothermic. This is because the energy released from the exothermic reaction of the cycle is much greater than the energy absorbed from the endothermic reaction of the cycle.
An owl consumes a mouse that contains 345 J of energy. Is it reasonable to assume that the owl obtained 345 J of energy from consuming the mouse? Explain your answer.
No. As energy flows through trophic levels, only 10% of the energy consumed becomes available for usage. Therefore, the owl would only be able to use 34.5 J of energy from consuming the mouse.
What would happen to a freshwater fish that suddenly got placed in seawater? Explain the mechanism of what would happen.
Freshwater fish are unable to live in seawater because seawater is hypertonic relative to their body. This would mean that water would flow quickly out of the fish's body, and the fish would quickly die of dehydration.
Why are some cancers seen as "harmless"? Are they really harmless?
There are two types of cancer cells, benign and malignant. Cancers caused by benign tumors are seen as noncancerous. This is because benign tumors grow slowly compared to malignant tumors, and do not stray from their origin. As such, benign tumors are usually not problematic to deal with. They are "harmless".
Platinum is a catalyst for the reaction that converts a toxic gas, carbon monoxide, to something less harmful, carbon dioxide. A scientist decides to grab more platinum plates to make sure that the reactions remain continuous. Why is this a silly thing to do?
Catalysts do not take part in the actual reaction. This means that catalysts do not get used up in the reaction, and they don't need to be replaced. They can theoretically be used over and over again in the chemical reaction.
Name the macromolecules that our body breaks down for energy in order from most prioritized to least prioritized. Is there a macromolecule that our body will never break down? Why is that?
Carbohydrates -> Lipids -> Proteins. Our body will never break down nucleic acids. This is because our DNA is made up of nucleic acid, and it would be detrimental to our body for us to break down our DNA.
List the 4 types of heterotrophs, and describe what they consume for energy.
Herbivores -> plants
Carnivores -> meat
Omnivores -> both plants and meat
Decomposers -> dead materials
The human body has receptors that regulate the pH of our blood. A sick individual goes to the hospital and gets notified that there are problems with his blood regulation. It has been found that the individual's blood pH is regulated by a positive feedback loop. What is wrong with this? What needs to change? Explain your answer.
The human body is very sensitive to pH, and it needs to be maintained around a specific range for our body to function properly. A positive feedback loop amplifies responses. If a response triggered the pH level to move out of the range, a positive feedback loop would further move it away from the optimal range. Therefore, pH needs to be regulated by a negative feedback loop, which would attempt to negate the response that would move the pH level out of its range.
The problem most likely occurred during the S phase of the cell cycle, where the number of chromosomes did not duplicate properly. The mechanism that should have checked for and stopped this problem is checkpoints. In the case that the cell somehow bypassed the checkpoint, the body should have detected that there exists an abnormal cell. The cell should have gone through apoptosis, which is programmed cell death of abnormal cells.
Enzyme is an example of factors that influence the rate of reactions. What are the other four factors that influence the rate of reactions? List all 5, and describe HOW they affect the rate of reaction.
Temperature -> increase in temperature indicates increase in heat energy, which would cause molecules to collide more resulting in more reactions happening. Increase in rate of reaction.
pH -> enzymes work at very specific pH levels, and need to stay within a certain range to remain functional. Rate of reaction will decrease when enzyme is out of range.
Substrate concentration -> more substrate means more molecules, which will increase chance of molecules colliding with each other. This means reactions will happen more frequently. Increases rate of reaction.
Catalyst -> Like enzymes, catalysts lower the activation energy needed for reactions to occur. This means reactions will have an easier time happening. Increases rate of reaction.
Competitive Inhibitor -> An inhibitor (not the substrate that we want) binds to the active site of the enzyme. Since the substrate that we want is unable to bind to the enzyme, the enzyme is not active. Decreases rate of reaction.
An athlete consumes a bulk of carbohydrates 10 seconds before intense physical activity. They quickly realize that they don't have as much energy as they thought they would have to continue the physical activity. Why would this be the case? (think about what source of energy our cell functions mainly use)
It takes time for metabolic reactions to complete. To add on to the problem, our body does not directly use the energy from food as a source of energy for our cell functions. Our body uses the energy released from breaking ATP. This is why the process takes time, and the athlete should have consumed the carbohydrates long before the physical activity.
On a particular food web, an owl is at the top of the food web. This means that it is not consumed by anything. Later, you find out off a Google search that owls get consumed by eagles and hawks. You bring this to attention with your teacher, and claim that the food web was incorrect, as owls are consumed. Is this a reasonable claim? Explain your answer.
Much like how certain organisms can be classified as part of multiple trophic levels depending on what food chain is being discussed, the extent of a food web depends on its scope. For that particular food web, the owl was definitely the apex predator of the food web, but that is not necessarily true in a different context. No, it is not reasonable to say the food web was incorrect, as it differs based on context.