In pea plants, green pod color (G) is dominant to yellow pod color (g). A cross was done between a plant with green pods and a plant with yellow pods. Of the resulting offspring, 50% had green pods and 50% had yellow pods. Which of the following were the genotypes of both parent plants?

A. Both endocrine and exocrine glands produce secretions that affect target cells, but the way they deliver these secretions to the target cells is different. Endocrine glands release hormones directly into the bloodstream, which then travel to the target cells, while exocrine glands secrete their products into ducts that lead directly to the target areas.

B. Nerve innervation refers to the supply of nerves to a particular part of the body or organ.

While nerve innervation can influence the activity of glands, it is not the primary distinguishing feature between endocrine and exocrine glands.

C. The biochemical nature of the secretions can vary widely among different glands, but this is not the main characteristic that differentiates endocrine from exocrine glands. Both can produce a variety of biochemical substances, including enzymes, hormones, and other compounds.

D. This is the key difference between endocrine and exocrine glands. Endocrine glands are ductless and release their hormones directly into the bloodstream, allowing them to be transported throughout the body. In contrast, exocrine glands have ducts through which they release their secretions to the surface of an organ or tissue, or to the outside of the body.

A. Methane molecule (CH4) consists of one carbon atom forming four covalent bonds with four hydrogen atoms.

B. Ammonia molecule (NH3) involves one nitrogen atom forming three covalent bonds with three hydrogen atoms.

C. Chlorine molecule (Cl2) is made up of two chlorine atoms sharing a single covalent bond between them.

D. Water molecule (H2O) has one oxygen atom forming two covalent bonds with two hydrogen atoms.

A. The alveoli are the tiny air sacs within the lungs where the exchange of oxygen and carbon dioxide takes place. In diseases like emphysema, the walls between the alveoli can be damaged, leading to fewer and larger air sacs instead of many tiny ones. This reduces the surface area for gas exchange, making it difficult for the body to get the oxygen it needs.

B. The trachea, or windpipe, is the main airway that leads to the lungs. While it is not directly involved in the gas exchange process, it does play a crucial role in providing a clear path for air to reach the respiratory structures deeper within the lungs.

C. The primary bronchi are the two main branches from the trachea that lead into each lung.

They are large airways that begin the process of directing air to the lungs' smaller passages but are not the sites of gas exchange.

D. The secondary bronchi, also known as lobar bronchi, are divisions of the primary bronchi that enter each lobe of the lungs. Like the primary bronchi, they are part of the airway system that conducts air to and from the gas exchange surfaces but are not themselves involved in the exchange of gases.

A. Skeletal muscles are not autorhythmic; this term refers to the ability to generate a rhythmical electrical impulse without the need for nervous stimulation, which is a characteristic of cardiac muscles.

B. Cardiac muscles contain intercalated discs, which are unique structural formations that allow for the rapid transmission of electrical impulses between cardiac cells. This feature is not found in skeletal muscles, which are composed of individual muscle fibers that are controlled voluntarily.

C. Cardiac muscles are involuntary, meaning they function without conscious control, which is necessary for the continuous pumping action of the heart. In contrast, skeletal muscles are under voluntary control, allowing for movement of the body in response to conscious decisions.

D. Skeletal muscles are not found in the viscera; they are attached to bones and are responsible for body movements. Cardiac muscles, on the other hand, are located in the heart, which is not in the cranium but in the thoracic cavity. The term 'viscera' refers to the internal organs in the main cavities of the body, especially those in the abdomen, not the cranium.

A. Potassium, with an atomic number of 19, has one electron in its outermost shell. This makes it more likely to lose that electron to achieve a stable electron configuration, resulting in a positively charged ion or cation.

B. Oxygen, with an atomic number of 8, has six electrons in its outer shell. It is more likely to gain two electrons to fill its outer shell and become an anion, not a cation.

C. Helium, with an atomic number of 2, has a full outer shell of electrons, making it very stable and unlikely to form ions under normal conditions.

D. Fluorine, with an atomic number of 9, has seven electrons in its outer shell. It tends to gain one electron to complete its outer shell and become an anion, not a cation.

A. A pivot joint allows for rotational movement around a single axis. An example of a pivot joint is the atlantoaxial joint in the neck, which allows for the rotation of the head.

B. A hinge joint permits movement in one plane, much like the opening and closing of a door.

C. The elbow and knee joints are classic examples of hinge joints, allowing for flexion and extension.

D. Gliding joints, also known as plane joints, allow for sliding movements in multiple directions within a plane. These are found in areas like the carpals of the wrist, where small bones slide against each other to allow for a range of movements.

The hip joint is a ball-and-socket joint, which is characterized by a spherical end of one bone fitting into a cup-like depression of another bone. This structure allows for a wide range of motion, including flexion, extension, abduction, adduction, and rotation. The hip joint, specifically, is formed by the articulation of the head of the femur and the acetabulum of the pelvis. It is designed for stability and weight-bearing, making it one of the most stable joints in the human body. This type of joint is also found in the shoulder, where the humerus fits into the glenoid fossa of the scapula.

A. The myocardium, is the thick, muscular middle layer of the heart's walls and is responsible for the pumping action of the heart due to its contractile cardiomyocytes.

B. The pericardium is the fibrous sac that encloses the heart providing protection and anchoring the heart within the thoracic cavity.

C. The epicardium is the outermost layer of the heart wall, also known as the visceral layer of the serous pericardium, and it provides an additional layer of protection and contains the blood vessels and nerves that supply the heart tissue.

D. The endocardium is the thin inner lining of the heart chambers and also forms the surface of the valves. It is comprised of endothelial cells and a layer of subendocardial connective tissue, which is continuous with the connective tissue of the myocardium. This layer is essential for providing a smooth lining for the chambers of the heart and the heart valves, ensuring efficient blood flow and minimizing turbulence within the heart.

A. Neuron cell axons are typically found in the white matter of the brain, as they are the long, slender projections of neurons that transmit electrical impulses away from the neuron's cell body to other neurons, muscles, or glands.

B. The meninges are the protective membranes that cover the brain and spinal cord, not the grey matter itself. They consist of three layers: the dura mater, arachnoid mater, and pia mater, which work together to protect the central nervous system and contain cerebrospinal fluid.

C. The corpus callosum is a thick band of nerve fibers that divides the cerebrum into left and right hemispheres and facilitates communication between the two sides of the brain. It is part of the white matter, not the grey matter.

D. Neuron cell bodies, also known as somas, are the parts of the neuron that contain the nucleus and most of the cytoplasm. They are responsible for maintaining the life of the neuron and are primarily located in the grey matter of the brain and spinal cord, where they process information received from the body's sensory systems or other neurons. Grey matter is a crucial component of the central nervous system and is primarily composed of neuronal cell bodies, neuropil, glial cells, synapses, and capillaries.

A. Blood pumped from the heart first enters arterioles that then merge to form arteries that deliver blood to the organ. This statement is incorrect because the flow of blood from the heart starts in the arteries, not arterioles, and arterioles do not merge to form arteries but rather are smaller branches of arteries.

B. Blood pumped from the heart first enters arteries that then narrow to form veins that deliver blood to the organ. This statement is incorrect as veins do not deliver blood to organs; veins carry blood back to the heart.

C. Blood pumped from the heart first enters arteries that then narrow to form arterioles that deliver blood to capillaries of the organ. This statement is correct. The blood leaves the heart through the arteries, which branch into smaller arterioles. The arterioles further branch into capillaries, where the exchange of gases and nutrients occurs within the tissues of the organ.

D. Blood pumped from the heart first enters veins that then narrow to form venules that deliver blood to arteries of the organ. This statement is incorrect because veins and venules are part of the return pathway to the heart, not the outbound pathway to the organs, and they do not deliver blood to arteries.

A. The cell membrane, also known as the plasma membrane, is a common structure found in both prokaryotic and eukaryotic cells. It is a phospholipid bilayer that encloses the cell, providing a barrier to control the movement of substances in and out of the cell, thus maintaining homeostasis. It also plays a role in cell communication and signaling due to the presence of various proteins and carbohydrates on its surface.

B. The Golgi apparatus is an organelle found only in eukaryotic cells. It is involved in modifying, sorting, and packaging proteins and lipids for secretion or for use within the cell. It is part of the endomembrane system and works closely with the rough endoplasmic reticulum.

C. The endoplasmic reticulum (ER) is another organelle that is exclusive to eukaryotic cells.

It comes in two forms: rough ER, which is studded with ribosomes and is involved in protein synthesis, and smooth ER, which is involved in lipid synthesis and detoxification processes.

D. Chloroplasts are specialized organelles found in the cells of plants and some algae, which are eukaryotes. They are the site of photosynthesis, where light energy is converted into chemical energy in the form of glucose. Chloroplasts contain their own DNA and are part of the group of organelles known as plastids.