1308-Homework 1

Name: Tavy Musselman Biol 1308-Homework #1 List four characteristics of living things and give an example to illustrate each. (8 pnt) Living organisms must be able to: Collect/ use materials and energy to sustain themselves Maintain the organized complexity of their being: organs, systems, and processes Sense and respond to internal and external stimuli Grow, reproduce and evolve as a population A plant needs water, minerals, light and heat to grow and survive. It collects these materials and energy through the processes of cohesion, adhesion, and photosynthesis. Lifeforms, both singular and multicellular, are complex organisms in which multiple organs and systems operate to process the materials and energy necessary to keep them viable. To keep life going, these systems and processes must remain stable and work together like cogs in a machine. The brain is supported by the blood that the heart pumps, the heart by the brain’s electrical signals to its musculature to keep the heart beating … and the organism alive. Like a plant, or another photosynthetic organism like plankton, without the necessary organelles in its cell structure, such as the chloroplasts in plant cells, it would not be able to respond to the external stimuli of the sun. Animal instincts, based on sense of smell, hearing, sight and sound, necessary to the survival of both predator and prey, would not be possible without the organs that alert each organism through chemical and electrical signals that are triggered from each sense. To maintain the presence of life, not only must the processes, complexity, and sense/response to stimuli be present, but each organism must maintain its population to survive by: growing, reproducing, and evolving as a population. One lifeform cannot reproduce (unless in the case of a unicellular organism’s ability to reproduce asexually), nor produce enough change to evolve on its own. In a unicellular organism, it grows by enlarging its cells by absorbing materials and energy until it gets large enough to split apart into separate cells through asexual reproduction. The parent cell’s genes are a carbon copy to that of the resulting cells, unless an error/mutation occurs during the copying process. This error is then copied into further generations of cells, thus resulting in evolution. What is the difference between covalent and ionic bonds? (2pnt) Covalent bonds share electrons, while ionic bonds take or give electrons. What type of bonding exists between the slight positive charge of a hydrogen atom and the slight negative charge of a nearby oxygen atom? (1 pnt) A hydrogen bond forms between hydrogen and oxygen atoms. How does a base differ from an acid? (1 pnt) A base contains more hydroxide than hydrogen, when dissolved in water, the hydroxide ionizes/combines to/with hydrogen to neutralize/stabilize the solution. What happens when hydrochloric acid (HCl) dissociates in pure water? (1 pnt) Hydrochloric acid will release Hydrogen atoms, breaking the bonds in the molecule. HCl H++Cl- If sulfur has an atomic number of 16, how many covalent bonds can it form with other atoms? (1 pnt) Sulfur has the capacity to hold 8 electrons in its outer shell, however, in most cases it holds 6. To gain a full outer shell it can share electrons with 2 other atoms. In which kingdom does a multicellular, eukaryotic, photosynthetic organism belong? (1 pnt) A multicellular, eukaryotic and photosynthetic organism belongs to the Plantae kingdom. Define biodiversity. (1 pnt) Bio-life Diversity-variety Therefore, the term biodiversity refers to the variety of life, within a given area or on earth as a whole. Describe at least two cellular-level differences between a photosynthetic prokaryote and a plant. (4 pnt) Eukaryotic organisms like plants have membrane-bound organelles (structures that carry out specific functions), such as chloroplasts, while prokaryotes do not. Though prokaryotic organisms do not have membrane-bound organelles, prokaryotic photosynthetic organisms have infoldings of the plasma membrane for chlorophyll attachment and photosynthesis, with photosynthetic reactions occurring in the cytoplasm.