Unit 1 1 What are the characteristics of living things What are cells Order reproduction response to stimuli environment acquire convert energy growth and development regulate internal conditions evolutionary adaption Cells are the lowest level of organization that can perform all activities required for life 2 What is the alternative definition of life The alternative definition to life is anything that can evolve heritable characteristics that can be passed on to progeny cellular regulation metabolism not required virus 3 What is the relationship between structure and function Structure reflects function and vice versa 4 What is evolution What is a gene What is an allele Evolution change in an allele frequency in a population Gene sequence of DNA that codes for a trait Allele a form of a particular gene 5 Describe how evolution by natural selection occurs What 3 conditions are required for natural selection to occur Natural selection is the differential reproductive success among individuals because of environmental influences THREE requirements are variation among the population differences in success and inheritance of important traits 6 What are the different levels of biological organization Biosphere ecosystems communities populations organisms organs and organ systems tissues blood cells organelles nucleus molecules 7 What is an atom What are subatomic particles How are they charged An atom is the smallest particle that retains properties of the chemical elements and cannot be broken down by chemical reactions The subatomic particles that make it up are neutrons neutral charge protons positive charge and electrons negative charge 8 What is a molecule A compound An ion An isotope A molecule is two or more atoms held together by covalent bonds An ion is a charged atom A compound is a substance consisting of two or more different elements combined in a fixed ratio An isotope is a different form of an element with a different number of neutrons they behave the same in chemical reactions 9 What is electronegativity How does it affect whether covalent bonds are polar or non polar Electronegativity is an atom s attraction of the shared electrons in a covalent bond In a polar bond atoms have different electronegativities so electrons aren t shared equally In a nonpolar bond atoms have a similar electronegativity Nitrogen Oxygen are very electronegative and Carbon Hydrogen are somewhat electronegative 10 Explain hydrogen bonding How do hydrogen bonds occur How do hydrogen bonds affect DNA Hydrogen bonds are formed when a partial positive charge on a hydrogen atom that is covalently bonded to an electronegative atom allows the hydrogen to be attracted to a different electronegative atom nearby Hydrogen bonds hold together the two strands in a double helix of DNA stable attachment but weak enough to break with little energy wasted Hydrogen bonds are weaker than covalent bonds and are formed by electronegative charges 11 How do ionic bonds form How do covalent bonds form Ionic bonds form when cations and anions attract each other A covalent bond is the sharing of a pair of valence electrons by two atoms 12 What are hydrogen bonds How do they form in water A hydrogen bond is a type of weak bond that forms when the positive part of a hydrogen atom is attracted the partially negative part of a different atom 13 Describe and explain the properties of cohesion adhesion and surface tension How do cohesion and adhesion allow large drops of water to stand on a penny Cohesion hydrogen bonds hold water molecules together helps transport of water against gravity in plants Adhesion attraction between different substances i e water and plant cell walls Surface tension measure of how hard it is to break the surface of a liquid Water has a high surface tension due to hydrogen bonding between the molecules at the air water interface and to the water below 14 Explain how ice insulates water Is ice more or less dense than liquid water Why Ice is LESS DENSE than liquid water because of the structure of the atoms when they slow down Since ice floats on top of water it acts as a layer of insulation 15 What makes water a powerful solvent What is a hydration shell Water is a powerful solvent because of its polarity When a solute is being dissolved in an aqueous solution the partially positive H atoms surround the solute forming a shell and attach to make bonds with the atoms of the solute breaking them apart and making them part of the solution hydration shells A hydration shell is the sphere of water molecules around each dissolved ion 16 What is specific heat What results from the high specific heat of water Specific heat is the amount of energy required to increase the temperature of a substance High specific heat allows water to absorb and give off a lot of heat without much change in temperature 17 What are buffers and how do they work A buffer is a substance that minimizes the changes in the pH of a solution It does this by accepting hydrogen ions from the solution when there is excess and donating hydrogen ions when they have been depleted Example Carbonate Bicarbonate 18 What makes a solution acidic or basic How does the pH scale measure this A solution is acidic or basic depending on the amount of H and OH The more H the more acidic the more OH the more basic It s measured in scientific notation pH log H 19 What is meant by organic compounds What element is present in all organic molecules Compounds containing carbon are said to be organic Carbon is present in all of these molecules and most contain hydrogen in addition to carbon 20 What are hydrocarbons Are they polar or non polar Hydrocarbons are organic molecules that consist of only carbon and hydrogen They are non polar because both have little electronegativity 21 What are functional groups What affect can functional group variation have on organisms On the function of molecules Functional groups are a specific configuration of atoms commonly attached to the carbon skeleton of organic molecules and involved in chemical reactions A small variation such as estrogen and testosterone have dramatically different influences on animals All functional groups EXCEPT METHYL are hydrophilic so they are polar Hydroxyl OH alcohol Carbonyl C O ketone aldehyde Carboxyl COOH carboxylic acid organic acid Amino NH2 amine Sulfhydryl SH thiol Phosphate OPO3 Methyl CH3 methylated compound 2 organic phosphate 22 Bonds between which atoms cause polarity A bond
View Full Document
Unlocking...