Biology

• The breakdown of glucose during glycolysis produces two molecules of pyruvate.
• Reproduction in plants and animals is a process by which they produce offspring, with two main forms being sexual and asexual reproduction.
• Skin color and adult height are examples of polygenic characteristics in humans.
• In sexual reproduction, an organism combines the genetic information from each of its parents and is genetically unique.
• Each polygenic characteristic has multiple phenotypes.
• In asexual reproduction, one parent copies itself from a genetically identical offspring.
• Nutrition refers to the activities of obtaining raw materials from the environment and transporting them into their cells, with all the elements and compounds taken in by living things being called nutrients.
• Plants are considered autotrophs because they can produce their own food and do not depend on others for their source of nutrition.
• Animals are considered heterotrophs because they cannot produce their own food and mainly depend on other organisms to survive.
• Plants are capable of using light as the energy source in the synthesis of food from inorganic matter, a process known as photoautotrophy.
• Chemosynthesis is the process by which food is made by bacteria or other living things using chemicals as the energy source, typically in the absence of sunlight.
• Giant tube worms are an example of organisms that use chemosynthesis.
• Saprophytes feed, absorb or grow on decaying organic matter, an example of which is Mucor and dead organisms.
• Holozoic nutrition involves the consumption of solid and liquid food.
• Parasitic organisms live on other organisms, relating to or having the habit of a parasite, examples of which include Fungi and viruses.
• The Law of Independent Assortment states that different genes and their alleles are inherited independently within sexually reproducing organisms.
• Many genes have multiple (more than two) alleles.
• An example is ABO blood type in humans, where there are three common alleles for the gene that controls this characteristic: the allele for type A is codominant with the allele for type B, and both alleles are dominant to the allele for type O, resulting in the possible phenotypes of type A, B, AB, and O.
• As a result, each characteristic was inherited independently of the other characteristics.
• If the genes are on nonhomologous chromosomes, they may be recombined in various ways because of independent assortment.
• If the genes are located close together on the same chromosome, they are likely to be inherited together.
• This resulted in just two possible phenotypes for each characteristic.
• Genetic variation is also introduced by random fertilization of the gametes.
• If the alleles are different, the individual is heterozygous.
• Codominance occurs when both alleles are expressed equally in the phenotype of the heterozygote.
• For these reasons, the inheritance of polygenic characteristics is very complicated.
• Such characteristics may have many possible phenotypes.
• Incomplete Dominance occurs when the dominant allele is not completely dominant and expression of the dominant allele is influenced by the recessive allele, resulting in an intermediate phenotype.
• The genes may be on the same chromosome or on nonhomologous chromosomes.
• During meiosis, chromosomes are separated into multiple gametes.
• Polygenic characteristics are controlled by more than one gene, and each gene may have two or more alleles.
• An allele is one of two or more versions of a gene.
• Non-Median Inheritance refers to the inheritance of characteristics that is not as simple as it is for the characteristics that Mendel studied in pea plants.
• If the two alleles are the same, the individual is homozygous for that gene.
• Each characteristic Mendel investigated was controlled by one gene with two possible alleles, one of which was completely dominant to the other.
• Each characteristic Mendel studied was also controlled by a gene on a different (non-homologous) chromosome.
• In meiosis I, crossing over during prophase and independent assortment during anaphase creates sets of chromosomes with new combinations of alleles.
• However, it is possible that they will be separated by crossing-over during meiosis, in which case they may be inherited independently of one another.
• Independent assortment produces new combinations of alleles.
• An individual inherits two alleles for each gene, one from each parent.