Biology Chapter 2 Flashcards
Matter
- Matter: Anything that occupies space and has mass. Exists in three forms:
- Solids, liquids, gas
Explain the significance of trace elements to human health
The 14 trace elements exist in very small amounts in organisms, but the organisms can’t survive without them (for example, without iodine, the thyroid doesn’t function)
Describe the relative size, location, and electrical charge of protons, neutrons, and electrons within an atom
- Protons: positively charged, same size as neutrons, located in the nucleus
- Neutrons: neutral charge, same size as protons, located in the nucleus
- Electrons: negatively charged, much smaller than protons and neutrons, exist in a cloud outside the nucleus
Atomic Number
The number of protons in an atom (determines the element)
Mass number
Sum of protons plus neutrons, determines mass of the atom
Mass
Measure of the amount of matter in an object
Define an isotope and explain how isotopes are used in biological research and medicine
- An isotope is an alternate mass form of an element (same number of protons and electrons but different number of neutrons)
- Isotopes can be used to determine the fate of atoms in living organisms by measuring half life
Explain how the location of electrons determines the chemical properties of an atom
The number of atoms in the outermost shell determines the chemical properties of an atom because it determines how an atom reacts to other atoms.
Describe the structure of water and explain how its shape makes water a polar molecule
- Water molecules have two positively charged hyrdogen atoms at one end and a negatively charged oxygen atom at the other.
- Water molecules are polar molecules because opposite ends of the molecule have opposite charges.
Write the chemical formula for the creation of water from hydrogen and oxygen. Identify the reactants and the products of this reaction.
- 2H2+ O2 –> 2H2O
- Reactants: Hydrogen and Oxygen
- Product: Water
Describe the four life-supporting properties of water. Describe an example of how each property affects some form of life.
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Cohesion: water molecules stick together because of their hydrogen bond
- Important to water transport in plants
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Temperature Moderation: water gains and loses heat very slowly
- The giant supply of water on earth keeps the planet from having drastic temperature swings.
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Ice Floating: When water freezes, the molecules move apart and it becomes less dense than water, so it floats
- If ice did not float, bodies of water would freeze solid and life would not be able to survive
- Solvent: Water dissolves other molecules
Describe the relationship between aerobic exercise and brain size
Increased exercise reduces the amount that brains shrink with age
Distinguish between the chemical properties of acids, bases, and neutral solutions. Explain how buffers stabilize the pH of acidic and basic solutions.
- Acids: release H+ to a solution
- Bases: accepts and removes H+ from a solution
- Unfinished: look up buffers when book arrives
Describe the potential impact of rising levels of carbon dioxide on the pH of the ocean
Rising levels of carbon dioxide could potentially lead to increased acidification of the ocean
Explain why the search for extraterrestrial life centers on the search for water
Because life would probably need water to act as a solvent to enable chemical reactions and transport materials.
