A patient is admitted to the hospital after a traumatic injury to her adrenal cortex. Which of the following hormones is most likely to be present at normal levels?

There are two models for the operation of the Golgi apparatus in eukaryotic cells. As it is difficult to visualize the operation of cells at the molecular level in real time, scientists typically rely on static electron micrographs to see the morphology of organelles. As a result, the dynamic operation of these organelles can sometimes be unclear.

Cisternal Maturation Hypothesis

In the cisternal maturation hypothesis, the cisternae of the Golgi apparatus evolve. Proteins leave the endoplasmic reticulum, and enter the cis-Golgi. The cisterna of the cis-Golgi then matures, with its enzymatic contents and internal environment changing as it becomes the medial-Golgi, and, eventually, the trans-Golgi.

In this model, the proteins never physically leave their membrane-bound cisternae during their transit across the Golgi. Instead, the entire unit of contents remains within the evolving cisternae.

Vesicular Transport Hypothesis

In contrast to the cisternal maturation hypothesis, the vesicular transport hypothesis posits that the cis-, medial-, and trans-Golgi cisternae are more static structures. Instead of evolving around their contents, the contents are physically shuttled via vesicular intermediates from each cisterna to the next.

In the case of vesicular transport, vesicles are shuttled along microtubules. Motor proteins facilitate this movement, with unique proteins being used for each direction of movement along a microtubule.

Which of the following is most likely to take place in the Golgi apparatus?

A scientist is working with a new species of insect and is specifically observing the inheritance of two traits: eye color and antennae shape. Eye colors come in red (dominant) and white (recessive), and antennae come in long shapes (dominant) and short shapes (recessive). He performs a dihybrid cross between two insects heterozygous for both traits and observes a ratio of 3:1 (red eyes and long antennae: white eyes short antennae). Which of the following explanations most likely explains the observed ratio?

The common precursor for all blood and immune cells, including red blood cells and lymphocytes, is found in what part of the body?

Which of the following is not a function of the human gastrointestinal system?

What role does calcium play during muscle contraction?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the loss of tolerance to self antigens leading to the presence of high autoantibody titers. There are several underlying causes behind SLE, one of which is a dysregulation in the clearance of apoptotic cells, which can lead to secondary necrosis. This leads to the leakage of danger signals which contributes to the loss of peripheral tolerance and chronic inflammation.

A deficiency in the clearance of apoptotic cells can be attributed to which immune cell type?

Passage:

This has seemed a fatal objection to the chromosome view, but it may not be so, as Spillman has argued, so long as it has not yet been shown that all of the dominant characters may be present at the same time. But even admitting this possible way of eluding the objection, the other point raised above concerning the absence of groupings of characters in Mendelian inheritance seems a fatal objection to the chromosome theory, so long as that theory attempts to locate each character in a special chromosome. We shall have occasion to return to this point later.

In recent years most workers in Mendelian inheritance have adopted a new method of formulating their theory. Characters that Mendelize are no longer allelomorphic to each other, but each character has for its pair the absence of that character. This is the presence and absence theory. We can apply this hypothesis to the chromosome theory. For examples, let us assume a new variety or race arises by the loss of a character from that chromosome that has heretofore carried it. The chromosome still remains in existence, since it may carry many other characters besides the one that was lost, and it becomes in the hybrid the mate of the one still retaining that character. If now separation occurs, two classes of germ-cells result, one with and the other without the character; and the observed numerical proportions follow. There is nothing in this assumption that meets with any greater difficulty on the chromosome separation hypothesis than on the earlier view of paired allelomorphs, but it meets with the same difficulties, and as an assumption is neither more nor less in accord with the postulated mechanism.

Excerpt from Morgan, T. H. 1910. Chromosomes and heredity. The American Naturalist, 44:449–496.

Asssume that in a particular studied species of rodents, coat color is an autosomally-inherited trait, with black fur being the dominant phenotype and white fur being the recessive phenotype. In an experiment, a mouse with black fur mates with a mouse with a mouse with white fur. The resultant 26 offspring mice all have grey fur color. Which of the following genetic principles is best demonstrated by this result?

Both the sympathetic and the parasympathetic nervous systems are essential for homeostasis and for survival. For example, when we are trying to run away from a threat, the sympathetic nervous system is in full effect to allow us to escape from danger. However, when there is no obvious threat, the parasympathetic nervous system tends to be more in control.

There are similarities and differences between the sympathetic and the parasympathetic nervous systems. In preganglionic nerve fibers, both the sympathetic and the parasympathetic nervous system utilize the neurotransmitter acetylcholine. Closer to the target organ, the parasympathetic nervous system remains dependent on acetylcholine whereas norepinephrine and epinephrine are the predominant neurotransmitters utilized by the sympathetic nervous system.

When norepinephrine and epinephrine bind to their receptors, different effects are carried out based on the type of receptor, affinity, and location of the receptor. For example, epinephrine has a higher affinity for the beta-2 receptor. When epinephrine binds to the beta-2 receptor, common effects include vasodilation and bronchodilation. Norepinephrine has a stronger affinity for the alpha-1, alpha-2 and beta-1 receptors. When norepinephrine binds to its receptor, common effects on the body include vasoconstriction (alpha-1), increased heart rate (beta-1) and uterine contraction (alpha-1).

When a patient has a severe allergic reaction, a common prescribed drug is epinephrine. Which of the follow best explains the effects of epinephrine on a patient experiencing a severe allergic reaction?

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the loss of tolerance to self antigens leading to the presence of high autoantibody titers. There are several underlying causes behind SLE, one of which is a dysregulation in the clearance of apoptotic cells, which can lead to secondary necrosis. This leads to the leakage of danger signals which contributes to the loss of peripheral tolerance and chronic inflammation.

A deficiency in the clearance of apoptotic cells can be attributed to which immune cell type?