CET Biology 2

Marine teleosts (bony fish) excrete trimethylamine oxide (TMAO) as a nitrogenous waste product to help maintain osmotic balance in their saline environment.

Thyroxine is the hormone responsible for triggering metamorphosis in amphibians. If it is prevented from reaching the blood, the tadpole will not undergo metamorphosis, leading to a postponement of the process.

The formation of the fertilization membrane (cortical reaction) is a defense mechanism that prevents polyspermy, ensuring that only one sperm fertilizes the egg.

Freshwater fish are ammonotelic, meaning they excrete ammonia as their primary nitrogenous waste. Ammonia is highly toxic but water-soluble, and freshwater fish have ample water to dilute and excrete it.

Uric acid is excreted as a semi-solid paste, which requires very little water. This is an evolutionary adaptation for birds to conserve body water, especially during embryonic development in eggs.

The placenta acts as a temporary endocrine gland, secreting hormones such as human chorionic gonadotropin (HCG), progesterone, and estrogen, which are essential for maintaining pregnancy.

Glucose is filtered into the kidney tubules but is normally reabsorbed into the blood. The difference in concentration between blood entering and leaving the kidney is primarily due to the metabolic consumption of glucose by kidney cells to power active transport processes.

All living cells require a medium for gas exchange, which is typically a moist surface. Option B is false because some animals use diffusion directly; C is false because many animals use skin or tracheae; D is false because some organisms are anaerobic.

 Foramen of magendie is found in medulla oblongata. It drains cerebrospinal fluid (CSF) from the fourth ventricle into the cisterna magna.

 Hypothyroidism in adulthood leads to myxoedema. Myxoedema refers to deposition of mucopolysaccharides in the dermis, which results in swelling of the affected area.

During an action potential, the resting membrane potential is negative. Upon stimulation, depolarization makes the interior positive, followed by repolarization, which returns the membrane to a negative potential.

The Foramen of Monro (interventricular foramen) is the specific channel connecting the lateral ventricles to the third ventricle in the brain.

Forced breathing (hyperventilation) lowers the partial pressure of CO2 in the blood. Since CO2 is the primary chemical stimulus for the respiratory center, its reduction leads to a temporary cessation of breathing (apnea) until levels rise again.

Tidal volume is defined as the volume of air inspired or expired during a normal, quiet breath.

Pepsin is a gastric enzyme that functions optimally in the highly acidic environment of the stomach, which typically has a pH between 1.5 and 2.0.

In an allergic reaction, mast cells release histamines, which cause vasodilation and increased capillary permeability, leading to the inflammatory response.

The liver is the primary metabolic organ responsible for detoxifying harmful substances, drugs, and metabolic waste products in the human body.

The corpus luteum is a temporary endocrine structure formed in the ovary after ovulation, often referred to as the yellow body due to its appearance.

Human chorionic gonadotropin (hCG) is a hormone produced by the placenta after implantation, and its presence in urine is the basis for pregnancy tests.

The respiratory rhythm center, which controls the basic rate of breathing, is located in the medulla oblongata of the brainstem.

The brain, spinal cord, pituitary gland, and pineal gland are all derived from the ectoderm during embryonic development.

The organ of Corti, located within the cochlea of the inner ear, contains the hair cells that act as sensory receptors for sound.

Acetylcholine, nor-adrenaline, and dopamine are well-known neurotransmitters used in the nervous system to transmit signals across synapses.

The adrenal medulla is controlled directly by the sympathetic nervous system, whereas the adrenal cortex is regulated by ACTH from the pituitary gland.

Testosterone is a steroid hormone from the androgen group and is found in humans and other vertebrates. In humans and other mammals, testosterone is secreted primarily by the testicles of males and, to a lesser extent, the ovaries of females.

Hydra has a diffuse nerve net that allows it to respond to stimuli, but it lacks a centralized brain or ganglion cluster.

A tendon is a fibrous connective tissue that attaches muscle to bone, enabling movement.

Distilled water is hypotonic to the cytoplasm of red blood cells. Water enters the cells via osmosis, causing them to swell and eventually burst (hemolysis).

Absorption rates of monosaccharides differ; galactose and glucose are absorbed via active transport (SGLT1), with galactose typically showing the fastest rate of absorption in the small intestine.

Presbyopia is the age-related loss of the eye's ability to focus on near objects due to the hardening of the lens.

A conditioned reflex is a learned response, such as Pavlov's dog salivating at the smell or sound associated with food, unlike innate reflexes.

Cholecystokinin stimulates the gall bladder (a-3), Erythropoietin stimulates bone marrow (b-1), and Enterogastrone inhibits the stomach (c-2).

Cerebrospinal fluid is secreted by the choroid plexus, a network of blood vessels located in the ventricles of the brain.

The acrosome of the sperm, which contains enzymes for penetrating the egg, is formed from the Golgi apparatus during spermiogenesis.

The oxygen dissociation curve shifts to the right (Bohr effect) when hemoglobin's affinity for oxygen decreases. This occurs in conditions of high CO2 concentration, low pH, high temperature, and increased levels of 2,3-DPG.