Explanation:
Glycine is the smallest amino acid and its flexibility allows it to fit well in the middle of an alpha helix. However, proline has a rigid structure due to its cyclic side chain, which disrupts the regular folding pattern of an alpha helix. Therefore, glycine and proline are the least likely amino acids to occur in the middle of an alpha-helical protein structure.
Explanation:
The thalamus is a central processing center in the brain that receives sensory information from all senses except olfaction (smell). It relays this information to the appropriate regions of the cerebral cortex for further processing. The thalamus is embryonically derived from the diencephalon.
Explanation:
Chylomicrons are responsible for transporting dietary triacylglycerols (triglycerides) from the intestine to various tissues in the body. Very low-density lipoproteins (VLDL) are responsible for transporting endogenous triacylglycerols synthesized by the liver to peripheral tissues. Therefore, chylomicrons and VLDL are the lipoproteins most responsible for carrying and transporting triacylglycerols in the body.
Explanation:
In mice, embryos are typically transferred back to the uterus at the 8-cell stage. At this stage, the embryo has undergone several cell divisions and consists of eight cells. This stage is optimal for transferring embryos back to the uterus because it allows for successful implantation and further development.
Explanation:
Prolactinomas are pituitary tumors that cause excessive production of prolactin. Dopamine acts as an inhibitory neurotransmitter in the hypothalamus and plays a role in regulating prolactin secretion from the pituitary gland. Therefore, prescribing dopamine agonists can help control the release of prolactin and alleviate symptoms associated with prolactinoma, such as headaches and double vision.
Explanation:
Damage to the Cupula would disrupt the fish's ability to sense angular acceleration and changes in water movement, which are crucial for maintaining proper orientation within a school of fish.
Explanation:
Elastic fibers in the tunica media of arteries allow them to stretch and recoil, accommodating the pulsatile flow of blood from the heart and helping maintain blood pressure. Veins, on the other hand, have thinner walls and do not require as much elasticity to handle blood flow, so elastic fibers are less abundant in their tunica media.
Explanation:
Oranges are a good source of vitamin D, which is essential for bone health and can help improve the condition of rickets.
Explanation:
The iris is the colored part of the eye that contains smooth muscle fibers. It controls the size of the pupil, which regulates the amount of light entering the eye. Contraction of the iris muscles constricts the pupil in bright light conditions to reduce the amount of light entering the eye, while relaxation of these muscles dilates the pupil in dim light conditions to allow more light to enter. Therefore, the iris plays a crucial role in adjusting to changes in ambient light levels and maintaining optimal visual acuity.
Explanation:
Alpha-ketoglutarate is an important intermediate in the Krebs cycle, which is involved in the synthesis of several amino acids, including glutamate. Glutamate serves as a precursor for the synthesis of several other amino acids, including arginine, glycine, phenylalanine, and tyrosine. However, histidine is synthesized from other precursors and does not directly require alpha-ketoglutarate for its synthesis. Therefore, if alpha-ketoglutarate levels are low, histidine production is less likely to be affected compared to the other amino acids listed.
Explanation:
Treatment with a calcium ionophore disrupts calcium signaling, which is essential for sperm-egg fusion. Without proper calcium signaling, successful fertilization is unlikely to occur. Therefore, this condition would result in unsuccessful fertilization.
