MCAT Biological and Biochemical Foundations Practice Test 2

The electron transport chain, which is embedded in the mitochondrial membrane, exists primarily to generate new molecules of ATP for use by the cell. This is accomplished by a positive gradient of H+ ions that are formed outside the membrane which then pass back through a specialized channel known as ATP synthase. The energy created from this phosphorylates an ATP to an ATP, known as oxidative phosphorylation. The mechanism by which H+ returns to the inside of the mitochondria is known as what?

A common heart defect in humans is a ventricular septal defect, in which there is a hole in the septum between the right and left ventricles. If a patient were to have this defect, which of the following statements is correct?

A patient comes into the hospital after being bit by a dog who he stated was “acting crazy”. The wound is open and bleeding. Animal control captured the dog and said that it was foaming at the mouth and extremely aggressive. Suspecting a rabies infection, the patient is given a serum that contains rabies antibodies that were grown inside a horse. This is an example of what kind of immunity?

The descending loop of Henle of the nephron of the kidney is permeable to which of the following substances?

The hypothalamus controls the stress response of the body by releasing CRF, which leads to eventual release of cortisol, the body’s stress hormone, systemically. This trigger is eventually suppressed by which mechanism?

Pregnancy tests are extremely sensitive and function by detecting levels of B-hCG, or human chorionic gonadotropin, in urine. This hormone is secreted by what tissue, and what is its function?

A scientist using mouse models to determine the response of blood hormones to large levels of glucose in the body discovers a new hormone not previously described. According to his data, this hormone is found both inside and out of cells when carrying out its function, increase the amount of nucleic acid in the cell while functioning, and are derived from a structure containing four hydroxycarbon rings. This will likely be categorized as which type of hormone?

A scientist, using electrodes, is stimulating a group of neurons in the hypothalamus and recording their membrane potential changes. She observes a sharp rise in membrane potential when she first stimulates them, the difference of 100mV. When she tries another stimulation immediately after the first, there is no response. However, when she increase the amount of voltage she supplies to the second shock, she observes a similar response to the first. What time period of stimulation would the second shock be characterized in regards to membrane potential?

In a genetic test of a newborn, a rare genetic disorder is found that has X-linked recessive transmission. Which of the following statements is likely true regarding the pedigree of this disorder?