BIO 105 Exam #1 Questions And Answers

What are the characteristics of life? - ANS 1. Life is organized. 2. Life requires materials + energy. 3. Life needs to maintain homeostasis. 4. Respond to stimuli. What are the different levels of life? - ANS 1. Atom. 2. Molecule. 3. Cell. 4. Tissue. 5. Organ. 6. Organ System. 7. Organism. 8. Population. 9. Community. 10. Ecosystem. 11. Biosphere. Which category has the most organisms? - ANS Kingdom has the most organisms. What are the domains of life and where do humans fall in the domains? - ANS Bacteria, Archaea, and Eukarya. We fall into the Eukarya domain. Which domains have cells with no nucleus? - ANS Archaea and bacteria have cells with no nucleus. What are cells with no nucleus called? - ANS Prokaryotic cells. What does emergent properties mean? Give an example. - ANS The whole has characteristics that do not emerge in any of its component parts. An example would be that an organ has no purpose outside of the body but when working together with other organs, maintains life. What is the simplest level of life that can be considered alive? - ANS The simplest level of life that can be considered alive is the cell. What are two internal environments that are maintained very carefully in homeostasis? Why are these two maintained within such close parameters? - ANS Blood pressure and body temperature have to be maintained in close parameters in order to show what is normal fluctuations and what is abnormal. Can plants move? How or when do they move? - ANS Plants do move. They move in response to a stimulus. This may be touch or towards the sun. What is it called when plants move toward the sun? - ANS Phototropism or heliotropism. What is it called when plants move in response to touch? - ANS Thigmotropism. What did Dr. Barry Marshall have to do to prove bacteria causes ulcers and not stress? - ANS Dr. Barry had to identify a bacteria found near patient's ulcers and isolate the bacteria in a pure culture. Afterwards, a contaminated substance was given to animals. When that didn't work, Dr. Barry Marshall ingested the bacteria and confirmed the hypothesis. Properties of atoms and subatomic particles, which have a charge, where are each of the subatomic particles located in the atom? - ANS The subatomic particles are protons, neutrons, and electrons. Protons are positively charged, electrons are negatively charged, and neutrons are neutral. Protons and neutrons are found in the nucleus and electrons are found circling around the nucleus. How are ionic bonds formed and give an example? - ANS An atom donates or takes on electrons. Table salt (sodium chloride) because both elements have a charge. How are covalent bonds formed and give an example? - ANS Atoms share electrons. Water (H20) because both hydrogen and oxygen share electrons. How are hydrogen bonds formed and give an example? - ANS Hydrogen bonds form between a hydrogen in covalent bonds and negatively charged atoms. They are found in DNA strands, the Hydrogen is weak but stabilizes DNA. If you know the number of protons in an element, what other information do you also know? - ANS Atomic number & number of electrons bc atoms in the periodic table are neutral. How are radioactive isotopes used in medicine? Why are they so useful? - ANS Radioactive isotopes are used in X-Rays and radiation. They are useful because they image body organs/tissue and kill cancer cells. If an element has high electronegativity, what does it attract? - ANS Electrons. What are the properties of water? Why are these properties so useful in bio? - ANS Liquid water at room temp, liquid water doesn't change temp easily, high heat of vaporization, less dense frozen than liquid, molecules cling together, solvent of polar molecules. These properties are so useful because they make life possible. What kind of bonds are responsible for water's special properties? - ANS Hydrogen bonds. Why is water polar? Explain. - ANS Water is polar because the two hydrogens have a positive charge and the oxygen having a negative charge. When you are able to add 30 drops of water on a penny-what property of water is being demonstrated? - ANS Internal cohesion. Can you name a bodily function where hydrolysis is used everyday? - ANS Digestion of food where water breaks down compounds to be easily absorbed. Acids and bases and buffers-where in the body is it very important to keep almost neutral pH? - ANS The blood is very important to keep neutral because it needs to be able to be in good condition to fight off illness. Examples of acid, basic, and neutral pH values. - ANS Acidic: Stomach Acid & Vinegar. Neutral: Pure Water. Basic: Ammonia & Household Bleach. Where is one place in the body where the pH is not near neutral? - ANS Stomach because of stomach acid. What is the relationship between the numbers in the pH scale? - ANS The numbers are in a factor of 10.