Atomic Structure and Bonding Quiz

The atomic number of an element is the number of protons in its nucleus, which determines the element's identity. Atomic mass, on the other hand, is the total number of protons and neutrons in the nucleus. For example, carbon (C) has an atomic number of 6, meaning it has 6 protons. Its atomic mass is 12, indicating it has 6 protons and 6 neutrons.

An ion is an atom that has gained or lost electrons, resulting in a net electrical charge. Ions are formed when atoms either gain or lose electrons to achieve a stable electron configuration in their outermost shell. For example, a sodium atom (Na) can lose one electron to become a sodium ion (Na+), which has a positive charge.

Covalent bonding occurs when two or more atoms share electrons to achieve a stable electron configuration. In contrast, ionic bonding involves the transfer of electrons from one atom to another, creating ions with opposite charges that attract each other.

<p>Dehydration synthesis is a chemical reaction where a water molecule is removed during the formation of a bond between two molecules. In this process, a hydrogen atom is removed from one molecule and a hydroxyl group (OH) is removed from another molecule, forming water. For example, two monosaccharides can combine to form a disaccharide through dehydration synthesis, releasing a water molecule.</p> Signup and view all the answers

<p>Water's properties, such as its high specific heat, its ability to act as a solvent, and its cohesive and adhesive properties, are essential for life. Its high specific heat allows it to regulate temperatures, while its solvent properties enable transport of nutrients and waste. Cohesion and adhesion properties are crucial in processes like transpiration in plants.</p> Signup and view all the answers

<p>Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen, typically with a hydrogen-to-oxygen ratio of 2:1. They are classified as monosaccharides (simple sugars), disaccharides, and polysaccharides. Monosaccharides like glucose and fructose are single sugar units, while disaccharides like sucrose are formed from two monosaccharides. Polysaccharides, such as starch and cellulose, are complex carbohydrates composed of many monosaccharide units linked together.</p> Signup and view all the answers

<p>Isotopes of an element differ in the number of neutrons they contain, leading to variations in their atomic mass. For example, carbon-12, carbon-13, and carbon-14 are isotopes of carbon, each containing 6 protons but differing in their number of neutrons: 6, 7, and 8, respectively.</p> Signup and view all the answers

<p>Covalent bonds involve the sharing of electrons between atoms, while ionic bonds involve the transfer of electrons from one atom to another. In covalent bonding, sharing electrons allows atoms to achieve a stable electron configuration by filling their outermost shells. In ionic bonding, the transfer of electrons creates ions with opposite charges that attract each other, forming a stable compound.</p> Signup and view all the answers

<p>Deoxyribose lacks an oxygen atom on the 2' carbon of the sugar ring, while ribose has it.</p> Signup and view all the answers

<p>A monosaccharide is a single sugar unit, while a disaccharide is formed by the bonding of two monosaccharides.</p> Signup and view all the answers

<p>NADH is an electron carrier that is produced in glycolysis and the Krebs cycle. It carries electrons to the electron transport chain where it is used to produce ATP.</p> Signup and view all the answers

<p>Starch serves as a storage form of energy for plants.</p> Signup and view all the answers

<p>Autotrophs are organisms that can produce their own food from inorganic sources, typically using sunlight or chemical energy. Plants are an example of autotrophs. Heterotrophs are organisms that must consume other organisms for food. Animals such as lions are an example of heterotrophs.</p> Signup and view all the answers

<p>Lipids are nonpolar molecules, while water is polar. Due to this difference in polarity, they do not mix.</p> Signup and view all the answers

<p>Glycerol, a three-carbon alcohol, and three fatty acid chains.</p> Signup and view all the answers

<p>Decomposers break down dead organisms and waste products, returning nutrients to the soil and making them available to producers. Decomposers play a crucial role in nutrient cycling, ensuring that nutrients are not lost from the ecosystem.</p> Signup and view all the answers

<p>A food chain is a linear sequence of organisms in which each organism is consumed by the next. For example, grass - grasshopper - frog - snake. A food web is a more complex representation of feeding relationships in an ecosystem, showing interconnected food chains. For example, a food web might include interactions between multiple types of plants, herbivores, and carnivores, with each organism potentially having multiple prey and predators.</p> Signup and view all the answers

<p>Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have at least one double bond.</p> Signup and view all the answers

<p>Carbon, hydrogen, oxygen, and nitrogen.</p> Signup and view all the answers

<p>The energy transfer between trophic levels is not 100% efficient. Some energy is lost as heat during metabolic processes, and some energy is never consumed as some parts of the organism can be indigestible. This results in only about 10% of the energy available being transferred from one trophic level to the next.</p> Signup and view all the answers

<p>Amino acids</p> Signup and view all the answers

<p>Nitrogen fixation is the process by which atmospheric nitrogen gas is converted into ammonia, a form that can be used by plants. This process is carried out by certain types of bacteria that convert nitrogen gas into ammonia, making nitrogen available to living organisms.</p> Signup and view all the answers

<p>A niche is the role that an organism plays in an ecosystem, including its habitat, food sources, and interactions with other species. The niche of a deer in a forest might be a herbivore that feeds on plants, provides food for predators like wolves, and helps to disperse seeds through its droppings.</p> Signup and view all the answers

<p>Animal proteins typically contain all 20 essential amino acids, while plant proteins often lack one or more essential amino acids.</p> Signup and view all the answers

<p>Carboxyl groups make the amino acid acidic.</p> Signup and view all the answers

<p>An example of a mutualistic relationship is between bees and flowering plants. Bees pollinate flowers by gathering nectar, transferring pollen from one flower to another. This benefits the plants by allowing them to reproduce, and the bees benefit by obtaining food in the form of nectar.</p> Signup and view all the answers

<p>Carbon, hydrogen, oxygen, nitrogen, and phosphorus.</p> Signup and view all the answers

<p>A nucleotide is a monomer, the building block of a nucleic acid, while a nucleic acid is a polymer composed of many nucleotides linked together.</p> Signup and view all the answers

<p>Enzymes act as biological catalysts, speeding up the rate of chemical reactions within living organisms.</p> Signup and view all the answers

<p>Enzymes provide an alternative reaction pathway with a lower activation energy barrier, making it easier for the reaction to occur.</p> Signup and view all the answers

<p>The independent variable is the factor that is manipulated or changed by the experimenter, while the dependent variable is the factor that is measured or observed in response to the independent variable.</p> Signup and view all the answers

<p>The rough endoplasmic reticulum is responsible for modifying and transporting proteins synthesized by ribosomes attached to its surface.</p> Signup and view all the answers

<p>Lysosomes are organelles that break down old or damaged cellular components, such as organelles and macromolecules, for recycling and energy production.</p> Signup and view all the answers

<p>Simple diffusion involves the passive movement of small, uncharged molecules across the cell membrane down their concentration gradient. Facilitated diffusion requires specific protein channels to transport larger molecules across the membrane, still following the concentration gradient.</p> Signup and view all the answers

<p>ATP provides the energy needed to move molecules against their concentration gradient during active transport. This process requires energy because it doesn't rely on a concentration gradient, but rather actively pushes molecules across the membrane.</p> Signup and view all the answers

<p>A hypertonic solution has a higher solute concentration than the cell, causing water to move out of the cell and potentially causing it to shrink. An isotonic solution has the same solute concentration as the cell, resulting in no net movement of water. A hypotonic solution has a lower solute concentration than the cell, causing water to move into the cell, potentially causing it to swell or burst.</p> Signup and view all the answers

<p>The light-dependent reactions capture light energy and convert it into chemical energy in the form of ATP and NADPH. These reactions occur in the thylakoid membranes within the chloroplast's grana.</p> Signup and view all the answers

<p>Chlorophyll is the primary pigment in plants that absorbs light energy, primarily red and blue wavelengths, for photosynthesis. It reflects green light, giving plants their characteristic color.</p> Signup and view all the answers

<p>The Calvin cycle, also known as the dark reactions, use the energy from ATP and NADPH generated in the light-dependent reactions to convert carbon dioxide into glucose, the primary energy source for plants.</p> Signup and view all the answers

<p>Glycolysis is the initial step in both aerobic and anaerobic respiration, breaking down glucose into pyruvate. Aerobic respiration requires oxygen and continues with the Krebs cycle and electron transport chain, ultimately producing a much higher amount of ATP. Anaerobic respiration occurs in the absence of oxygen and uses fermentation to regenerate NAD+ for further glycolysis, yielding a limited amount of ATP.</p> Signup and view all the answers

<p>NAD+ is a coenzyme that acts as an electron carrier in cellular respiration. It accepts electrons during glycolysis and the Krebs cycle, becoming NADH, which is used to generate ATP during the electron transport chain.</p> Signup and view all the answers

<p>Fermentation is essential in anaerobic respiration because it regenerates NAD+ from NADH. This regeneration is necessary for glycolysis to continue producing a small amount of ATP in the absence of oxygen.</p> Signup and view all the answers

<p>Alcoholic fermentation, typically carried out by bacteria, yeast, and some fungi, produces ethanol and carbon dioxide as byproducts. Lactic acid fermentation, occurring in some bacteria and animals, produces lactic acid as a byproduct.</p> Signup and view all the answers

<p>The cell membrane regulates the passage of substances into and out of the cell. It acts as a barrier, controlling what enters and exits the cell's internal environment.</p> Signup and view all the answers

<p>The cell membrane is called a fluid mosaic because it is composed of various components, including phospholipids, proteins, and carbohydrates, that are constantly moving and interacting. It's like a mosaic because it is made up of various pieces.</p> Signup and view all the answers

<p>Channel proteins provide a passage for specific molecules to move across the membrane passively, following their concentration gradient. Transport proteins use energy, typically ATP, to actively move molecules against their concentration gradient.</p> Signup and view all the answers