HighFour Biology Category C: Grades 9 – 10 Round 6 Monday, February 29, 2016 The use of calculator is not required. Answer #1: Explanation: Answer #2: Explanation: Answer #3: Explanation: Answer #4: Explanation: binary fission Binary fission literally means "division in half". Contrary to sexual reproduction, wherein the cells generated contain mixed genetic material from the parent cells, binary fission results to two daughter cells having identical genetic information. The cell will first replicate its genetic material and subsequently divide into two nearly equal sized daughter cells. homeostasis Homeostasis is the property of organisms to keep a relatively stable internal environment. This is usually achieved by employing various metabolic processes (e.g. sweating) that balance the effect of the outside environment. autotrophs Generally, all life forms can be classified as either autotrophs or heterotrophs. Autotrophs are organisms that have the ability to produce organic matter from inorganic substances, such as minerals and gases. They are usually at the bottom of the food chain, followed by heterotroph herbivores. peroxisomes Peroxisomes are spherical cell compartments that use oxygen to decompose fatty acids into smaller molecules that can be used for cellular respiration. Although this process produces toxic hydrogen peroxide, other enzymes in the peroxisomes can neutralize it and convert it to water. Cellular damages from different enzymes are avoided through compartmentalization. HighFour Biology Category C: Grades 9 – 10 Round 6 Monday, February 29, 2016 The use of calculator is not required. Answer #5: Explanation: Answer #6: Explanation: Answer #7: Explanation: Answer#8: Explanation:
actin filaments There are three structures that compose the cytoskeleton: microtubules or tubulin polymers, microfilaments or actin filaments, and intermediate filaments. Actin, which polymerizes to form microfilaments, is the most abundant protein in most eukaryotic cells. Systema Naturae Systema Naturae features the major works of Carl Linnaeus, wherein he consistently used binomial nomenclature to name and classify thousands of species, both plants and animals. The full translated title of the 10th edition (1758) is "System of nature through the three kingdoms of nature, according to classes, orders, genera and species, with characters, differences, synonyms, places". Bluid Mosaic Model/ Mosaic Model In 1972, the fluid mosaic model was proposed by scientists S.J. Singer and G. Nicolson. Membrane proteins reside in the phospholipid bilayer with their hydrophilic regions sticking out at the surface. Protein contact will be maximized while maintaining a non-­‐aqueous environment internally. clumped dispersion There are three main types of population dispersion: clumped, uniform, and random. Clumped dispersion is the tendency of animals to stay in their habitats or travel to other places in groups or packs. This may be a strategy to protect themselves against their predators or to maximize the available natural resources. HighFour Biology Category C: Grades 9 – 10 Round 6 Monday, February 29, 2016 The use of calculator is not required. Answer #9: Explanation: Answer#10: Explanation: Answer #11: Explanation: Answer #12: Explanation: plasmodesmata Plasmodesmata are microscopic channels that serve as bridges linking cells to each other, efficiently facilitating communication and allowing transport of certain molecules. The constriction and the dilation of the openings at the ends of the plasmodesmata affect the passage of nutrients, and the growth and development of plants. brackish water/briny water Brackish water is the term used to refer to water that has a salinity range in between those of seawater and freshwater. It may result from the mixing of seawater with fresh water, as in estuaries, or it may be present in brackish fossil aquifers. The world's largest lake containing brackish water is the Caspian Sea. Jean Baptiste Lamarck Jean Baptiste Lamarck was a French biologist who proposed the principles of "use and disuse" and "inheritance of acquired characteristics" in 1809. iteroparity There are two reproductive strategies employed by organisms: semelparity and iteroparity. Semelparity involves a one-­‐shot pattern of big-­‐bang reproduction while iteroparity involves repeated reproduction. Iteroparity allows the parents to provide and nurture their offsprings better. HighFour Biology Category C: Grades 9 – 10 Round 6 Monday, February 29, 2016 The use of calculator is not required. Answer #13: Explanation: Answer #14: Explanation: Answer #15: Explanation: Answer #16: Explanation: benthic zone Benthic zone is the bottom of all aquatic biomes. It is made up of sand and organic and inorganic sediments. The organisms that reside in this region feed on dead organic matter called detritus. detritivores / decomposers The detritivores or decomposers is a group of heterotrophs that connect consumers with the primary producers in a food chain. After feeding off detritus or the remains of consumers, they play a critical role in recycling chemical elements for the benefit of primary producers. Detritivores are usually prokaryotes and fungi. keystone species Sea otters are keystone species. Their presence has an effect on the community regardless of their abundance. commensalism Commensalism is a type of symbiotic relationship wherein an individual benefits from the relationship without benefiting or harming the other party. From the example, the barnacle benefits and receives transportation from the whale, without giving something in return. HighFour Biology Category C: Grades 9 – 10 Round 6 Monday, February 29, 2016 The use of calculator is not required. Answer #17: Explanation: Answer #18: Explanation: Answer #19: Explanation: Answer #20: Explanation: radioactive dating The most common variety of radioactive dating is carbon dating. It involves the measurement of the amount of radiocarbon or C-­‐14 left from a dead organism. When an organism is alive, it acquires a steady amount of C-­‐14. When it dies, the level of C-­‐14 decreases due to radioactive decay. The older the sample is, the less C-­‐14 there is to be detected. nucleoid The nucleoid is an irregularly shaped region within a prokaryotic cell which contains all genetic information. Although it is not membrane-­‐bound, it is visibly distinct by transmission microscopy or nucleic acid staining techniques. oviparous There are three possible types of animal development after fertilization. Oviparous species lay eggs that hatch outside the mother's body. Examples of this species include most fish, amphibians, reptiles, insects, and arachnids. mycorrhizae Mycorrhizae refers to a symbiotic association composed of the fungus and the roots of a vascular plant. The fungus colonizes the host plant's roots intracellularly or extracellularly. The interaction is considered to be mutualistic, but can also be weakly pathogenic depending on the species.