Pku (phenylketonuria) is an autosomal recessive disease, in which the synthesis of amino acid tyrosine from phenylalanine is blocked. as a result, an excess of phenylalanine gets converted into phenylketones, which appear in the urine. in severe conditions it may also result in damage to the brain. the gene responsible for this is p, whereas the gene p is responsible for normal synthesis of tyrosine. in a small population of brazilian natives, the frequency of gene p, responsible for this disease, is 0.3. what must be the frequency of people who are heterozygous for this disease? ( p + q = 1, p2 + 2pq + q2 = 1) a) .56 b) .35 c) .42

Elements and compounds are pure substances that cannot be broken down physically into a simpler substance. a physical change doesn’t break the bonds between atoms of a substance or form new ones. compounds can be broken down by a chemical change. a chemical change breaks chemical bonds and/or forms new ones between atoms of a substance. what simple substance would a compound break into? the basic elements that make it up! for example, if you passed a very strong electric current through water you’d break the chemical bonds in water and be left with oxygen and hydrogen. which of the following is an example of a chemical change? a separating water into different glasses b breaking frozen ice cubes with a hammer c running an electric current through water d boiling water to evaporate it on a stove

What would happen to the nutrients in an ecosystem if decomposers, such as bacteria, didn’t exist there?

For each of the following, decide whether the statement describes photosynthesis, cellular respiration, or both. releases energy in the form of atp. stores energy in glucose molecules. performed by producers. performed by consumers.