Physio Lecture Exam #35-70

The correct answer is "More negatively charged on the outside surface." An electrical gradient for membrane potential exists across a cell membrane because there is a difference in the distribution of charged ions on the inside and outside surfaces of the membrane. The inside surface of the membrane is more negatively charged compared to the outside surface. This difference in charge creates an electrical gradient that contributes to the membrane potential.

The mass number of an atom is determined by the sum of its protons and neutrons. In this case, the atom of oxygen has 8 protons and 8 neutrons, resulting in a mass number of 16. The number of electrons does not affect the mass number.

Anabolic reactions refer to the process of synthesizing larger molecules from smaller ones, which is exactly what synthesis reactions entail. These reactions involve the combination of two or more substances to form a more complex product. Therefore, the correct answer is "Synthesis reactions."

When the sodium pump is used to drive the secondary active transport of a substance in the same direction that the sodium is moving, it is called symport or co-transport. In this process, both sodium ions and the substance being transported are moved across the cell membrane in the same direction, utilizing the energy generated by the sodium pump. This allows for the efficient uptake of nutrients or other molecules into the cell.

Steroids are classified as lipids because they are a type of fat molecule. Lipids are hydrophobic and insoluble in water, and steroids share these characteristics. Steroids are composed of four interconnected carbon rings, and they play important roles in various biological processes, such as regulating cell signaling, inflammation, and metabolism.

The electron shell nearest to the electron holds a maximum of 2 electrons because the first shell, also known as the K shell, can hold a maximum of 2 electrons. This is based on the principle that the first shell consists of only one subshell, which is the s subshell, and the s subshell can accommodate a maximum of 2 electrons.

Solution B is hypertonic to Solution A because it has a higher concentration of NaCl dissolved in water. Hypertonic solutions have a higher solute concentration compared to the surrounding solution, causing water to move out of Solution A and into Solution B through osmosis. This results in Solution B having a higher osmotic pressure than Solution A.

In endochondral bone formation, the original pattern for the bone is made of hyaline cartilage. This process involves the replacement of cartilage with bone during embryonic development and growth. Initially, a cartilage model is formed, which serves as a template for bone formation. Osteoblasts then replace the cartilage with bone tissue, resulting in the formation of the bone. Hyaline cartilage is an important component in this process as it provides the initial structure and shape for the bone to form.

Pure water is considered to be neutral on the pH scale because it has a pH value of 7. The pH scale measures the acidity or alkalinity of a substance, with values below 7 indicating acidity, values above 7 indicating alkalinity, and a value of 7 indicating neutrality. Pure water has an equal concentration of hydrogen ions (H+) and hydroxide ions (OH-), resulting in a balanced pH level.

Denaturing of a protein refers to the disruption of its structure, leading to the loss of its biological function. This can occur due to various factors such as heat, pH changes, or exposure to chemicals. When a protein is denatured, its native conformation is altered, causing it to lose its ability to perform its specific biological function. This can have significant consequences in biological systems, as proteins play crucial roles in various cellular processes. Therefore, the correct answer is loss of biological function.

Active transport is the correct answer because it is the process by which cells move substances against their concentration gradient, from an area of lower concentration to an area of higher concentration. In this case, sodium ions are being moved out of the cell against their concentration gradient, from an area of lower concentration in the cytoplasm to an area of higher concentration outside the cell. This requires the use of energy in the form of ATP, making it an active process.

Osteoclasts are cells that destroy bone matrix. They are responsible for the process of bone resorption, where they break down and remove old or damaged bone tissue. Osteocytes are mature bone cells that are involved in maintaining bone health and regulating mineral levels. Osteoblasts, on the other hand, are responsible for the formation of new bone tissue. However, in this case, the question specifically asks for the cells that destroy bone matrix, and that is the function of osteoclasts.

Inorganic bases are substances that release hydroxide ions (OH-) in water. These hydroxide ions then react with hydrogen ions (H+) to form water molecules. Additionally, inorganic bases also release cations, which are positively charged ions. Therefore, the correct answer is "One or more hydroxide ions and one or more cations."

Atoms of different elements are distinguished by the number of protons in their nucleus. The number of protons determines the atomic number of an element, which is unique to each element. Therefore, the correct answer is "Protons in the nucleus."

When an atom becomes a cation, it means that it loses electrons from its outermost electron shell. Cations are formed when atoms have a positive charge, which occurs when they have more protons than electrons. By giving up electrons, the atom loses negative charges and becomes positively charged, resulting in the formation of a cation.

The pH scale measures the concentration of hydrogen ions in a solution. pH stands for "potential of hydrogen" and it is a logarithmic scale that ranges from 0 to 14. A pH of 7 is considered neutral, pH values below 7 indicate acidity (higher concentration of hydrogen ions), and pH values above 7 indicate alkalinity (lower concentration of hydrogen ions). Therefore, the correct answer is hydrogen ion concentration.

Phagocytosis is the process by which solid particles are engulfed into a vesicle and brought inside a cell. It is a form of endocytosis where the cell membrane surrounds and engulfs the particles, forming a vesicle. This process is commonly observed in immune cells called phagocytes, which engulf and destroy pathogens or foreign particles. Exocytosis, on the other hand, is the opposite process where vesicles fuse with the cell membrane to release their contents outside the cell. Pinocytosis is a similar process to phagocytosis, but it involves the engulfment of fluid or dissolved substances. Filtration is a process where substances are separated based on size or other properties using a filter.

The correct answer is that the cell will undergo cremation because the extracellular solution has a higher osmotic pressure. When the red blood cells are placed in a solution with a higher concentration of NaCl, water will move out of the cells in an attempt to equalize the osmotic pressure. This will cause the cells to shrink and eventually undergo cremation, or cell death.

In receptor-mediated endocytosis, the molecule that binds to the receptor is called a ligand. Ligands are typically small molecules or proteins that specifically bind to receptors on the cell surface. This binding triggers the internalization of the ligand-receptor complex into the cell, forming an endosome. The ligand-receptor interaction is crucial for the selective uptake of specific molecules into the cell through receptor-mediated endocytosis. Therefore, in this process, the molecule that binds to the receptor is referred to as a ligand.

During endochondral bone formation, the primary center of ossification forms in the diaphysis. The diaphysis is the shaft or main portion of a long bone. In endochondral ossification, bone tissue replaces cartilage tissue. The process starts with the formation of a primary center of ossification in the diaphysis, where bone cells called osteoblasts begin to lay down bone tissue. This primary center then expands towards the epiphyses, the rounded ends of the bone. Therefore, the correct answer is diaphysis.

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When glucose is broken down in the presence of oxygen, it undergoes a process called aerobic respiration. During this process, glucose is completely broken down into carbon dioxide and water. This occurs in the mitochondria of cells and is the most efficient way for cells to produce energy. The carbon dioxide produced is released as a waste product, while water is used by the body for various metabolic processes.

H2CO3 is the correct answer because it is known as carbonic acid. It is formed when carbon dioxide dissolves in water, and it is a weak acid that can release hydrogen ions in a solution. Ca2(PO4)2, NaOH, and KCl are not acids. Ca2(PO4)2 is a calcium phosphate compound, NaOH is sodium hydroxide, and KCl is potassium chloride. These compounds are either salts or bases, but not acids.

Facilitated diffusion is the process in which solutes move down a concentration gradient with the help of transport proteins embedded in the cell membrane. These proteins act as channels or carriers, allowing specific molecules to pass through the membrane. Unlike active transport, facilitated diffusion does not require energy input from the cell. It is a passive process that relies on the concentration difference between the inside and outside of the cell. Therefore, facilitated diffusion is the correct answer because it describes the movement of solutes down a concentration gradient through transport proteins.

Pinocytosis is the process by which cells engulf liquid particles. It is a form of endocytosis, where the cell membrane invaginates to form a vesicle that surrounds and internalizes the liquid particles. This process is passive, meaning it does not require energy input from the cell. Pinocytosis allows cells to take in fluid and dissolved substances from their surroundings, which can be important for nutrient uptake and waste removal.

Na+ is the principal cation in extracellular fluid because it is the most abundant positively charged ion found outside the cells. It plays a crucial role in maintaining fluid balance, regulating blood pressure, transmitting nerve impulses, and supporting muscle contractions. Na+ is actively pumped out of cells and into the extracellular fluid, creating an electrochemical gradient that allows for various physiological processes to occur. Additionally, Na+ is often paired with Cl- to form the salt NaCl, which is important for maintaining osmotic balance and facilitating the movement of water across cell membranes.

Inorganic acids, when dissolved in water, dissociate into one or more hydrogen ions (H+) and one or more anions. This is because inorganic acids are substances that release hydrogen ions when dissolved in water, leading to the formation of positively charged hydrogen ions and negatively charged anions. Therefore, the correct answer is "One or more hydrogen ions and one or more anions."

Water is a good solvent for ionic compounds because it contains polar covalent bonds. These polar covalent bonds create a partial positive charge on the hydrogen atoms and a partial negative charge on the oxygen atom. When an ionic compound is dissolved in water, the positive ions are attracted to the partial negative charge on the oxygen atom, while the negative ions are attracted to the partial positive charge on the hydrogen atoms. This electrical attraction between the polar water molecules and the ions helps to separate the ions and dissolve the ionic compound in water.

Facilitated diffusion is the correct answer because it involves the use of carrier molecules to transport substances across the cell membrane. Unlike simple diffusion, which occurs directly through the lipid bilayer, facilitated diffusion relies on specific proteins called carrier molecules or transporters to facilitate the movement of molecules that are too large or polar to pass through the membrane on their own. These carrier molecules bind to the specific substance being transported and undergo a conformational change to transport it across the membrane. Therefore, facilitated diffusion is the process that requires carrier molecules for transport across the cell membrane.

The selective permeability of a cell membrane is determined by various factors, including the lipid solubility of a substance, the electrical charge of the molecule, and the site of the molecule crossing the membrane. However, the total number of phospholipid molecules in the membrane does not directly affect the selective permeability. The number of phospholipids may affect the overall structure and fluidity of the membrane, but it does not play a direct role in determining which substances can cross the membrane.