# Tutor profile: Bethany A.

## Questions

### Subject: Organic Chemistry

Lipids are made from fatty acids and is _____ because of the single bonds.

Saturated. I always think of fats that are saturated as being able to tightly pack together, because they are made up of all single bonds. Since the chains are able to tightly pack to one another, it makes sense that saturated fats are typically solids. Unsaturated fats have double bond(s), which cause bending and limit the rotation of the molecule. Thus, unsaturated fats cannot pack of closely together and are typically liquid at room temperature.

### Subject: DAT

Which of the following structures is responsible for the release of calcium ions?

Calcium ions are crucial for muscle contraction to happen. Without the release of calcium, the myosin head is not able to bind to the actin at the binding sites. Calcium binds and removes troponin from the myosin-binding sites on the actin. The axon terminal closest to a muscle fiber releases acetylcholine (a neurotransmitter), which then leads the sarcoplasmic reticulum to release calcium into the muscle cell, which permits muscle contraction to happen.

### Subject: Calculus

Find the derivative of f(x) = 6x^3-9x+4

Answer: 18x^2-9 Explanation: You would multiple the 6 in front of the x^3 by the power of the exponent which is 3 and that is how you would get the 18. You would then minus 1 from the exponent to get the 2. For the second term or -9x, you would multiple the power of the exponent again, which in this case is 1 by the coefficient out in from, which is -9 to get -9 and you would minus 1 from the power of the exponent, which in this case is equal to 1, so in this case, it becomes 1-1 or 0. The derivative of a constant, like 4 is 0.

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