Unit #1: Study Review Questions Flashcards
What characteristics do all living organisms (on earth) have in common?
Reproducing Made of cells Heredity Metabolism Species can evolve
In the year 2030 you are assigned to lead an expedition to look for life on Jupiter’s moon Europa. What will you look for,
and how will you decide if it is alive?
Reproducing Made of cells Heredity Metabolism Species can evolve
What is the difference between a hypothesis and a theory?
Hypothesis: A possible answer regarding an observation; answer proposed in a scientific investigation
Must be falsifiable : hypothesis can be supported or it cannot be supported by the data
Theory: hypothesis that has been repeatedly tested over time and supported by experimental data
Equivalent to a law: Cell theory Theory of evolution by natural selection Law of gravity 99.9% sure its correct
Please explain the five steps to designing an experiment.
State a hypothesis Make predictions Experiment (include controls) Result and Interpretation Controls
- Observations only for the scientific method
- Provides data that either supports or does not support the hypothesis
Who was the first to propose that evolution explains the fossil record?
Jean Baptiste Lamarck
How did Lamarck propose that evolution occurs?
Theory of evolution by acquired characteristics
Organisms evolved as they strive for perfection by acquiring characteristics passes to the offspring
If u lose a arm in battle ur kid won’t have an arm
1809
What contribution did Lyell make to Darwin’s theory of evolution?
Lyell: change happens gradually
Geologist: studied rock formations
Said earth is extremely old
By the bible its 4000 years but lyell said no no no no its billions of years old
Way in which soil is deposited
Fossil evidence
What contribution did Malthus make to Darwin’s theory of evolution?
Malthus
Population biologists
Populations grow exponentially in size but food is limited
Competition for food & stuff
Nature controls population size through death
What evidence lead Darwin to propose his theory?
1859: Darwin published theory of evolution by natural selection
“Survival of the Fittest”
Fit: individual is best adapted to its environment
Evidence:
- biogeography (similarities of areas in the world with similar climates)
- Fossils evidence
- Comparative anatomy
- Embryology
- Works of lyell, malthus, & lamarck
- Vestigial structures
- Artificial breeding: selecting mom and dad
What are the two parts of darwins theory?
Variability in population, some individuals are fit and some are not
Heredity: Genes can be transferred to the next generation
What are the five key assumptions of darwins theory?
Organisms produce more offspring than will survive and reproduce
Variation among individuals
Survivors are more adapted/fit (superior) in certain characteristics
Characteristics are heritable
There has been lots of time
Why is heredity a key element in Darwin’s theory of evolution by natural selection?
Heredity PROVIDES A MECHANISM
Heredity is the ability to copy genetic information and pass it on to their offspring
Why is evolution the main unifying theme of biology?
Evolution explains WHY
Embryos look the same and stuff
Why is Darwin’s theory of evolution such a key turning point in the history of biology?
Biology changed from description/observation (“stamp collecting”) to use of scientific method
Evolution became the main unifying theme of biology
Why do biologists need to know a lot of chemistry?
Explains why metabolism happens
Life is made out of chemicals
Life converts nutrients into biochemicals by chemical reactions
Life is chemistry with a purpose
To understand life, must understand chemistry
What is an atom and what are atoms made of?
Smallest particle matter with unique physical and chemical properties
Consists of protons, neutrons, and electrons
What is an element?
What defines the element?
Substance made out of one type of atom
{Atoms have the same atomic number
***atomic number defines the element***}
#6 carbon
#2 helium
What is the difference between atomic mass and atomic number?
Atomic number: Tell u the # of protons and electrons
Atomic mass: number of protons and neutrons
of neutrons = atomic mass - atomic number
Why is the atomic number important?
Determines the number of electrons, therefore the chemical and physical properties of an element
{Reactivity of an element is determined by the number of electrons in the outermost (valence) shell of the atom}
What are isotopes?
Different forms of the same element that differ in atomic mass
Same atomic #
Same e- and p+
Different neutrons
Do the charges vary: between isotopes
No there will be no charge
What is radioactive decay, and why is it useful?
Emission of particles from unstable isotopes; involves the release of energy as nucleus decays
Used for: dating, medicine for diagnosing
What is the difference between a cation and an anion?
Cation: ion with a positive charge
CATS HAVE POSSSS
Anion: ion with a negative charge
What is the difference between oxidation and reduction?
If one atoms gives up an electron, another atom has to take it
Oxidation: (gave electron away) - loss of electron
Reduction: (received) the electron - gain of electron
has to happen at same time
Redox reaction
Leo goes ger
Why are redox reactions important for living organisms?
When electrons move, they take their energy with them; REDOX REACTIONS ARE USED FOR ENERGY TRANSFER
If an atom or molecule is reduced it gains energy
What is an ion?
atom with a charge; give or take an electron to get a charge
Proton # does not equal the electron number
Which molecule is most reduced and has the most energy?
The more reduced a molecule is, the more energy it has
CH4
What is the difference between an orbital and an electron energy level?
How many electrons do orbitals have?
Shapes?
Electron energy level = shell
*This can be made up of one or more orbitals
Orbital = the probable location of an electron: each orbital can have 0, 1, or 2 electrons
*Orbitals have distinct shapes
What is the valence shell?
The outermost shell of electrons
Why do valence electrons determine the chemical properties of an element?
The number of electrons in the valence shell can be used to predict the type of reaction that will occur
Why do elements whose atomic numbers differ by eight have similar chemical properties?
What is this called?
These elements have the same number of electrons in their valence shell, so they will behave the same way
This is called the octet rule
How many electrons does each shell hold?
first = 2 e- second = 8 e- third = 8 e-
Why is helium chemically inert?
2 its outermost shell is full
The reason why atoms react with each other is to fill their outermost shell
Why is bromine very reactive?
#30 outermost shell with 7 electrons
Needs one more electron, so will it take one electron
Bromine will be reduced and develop a negative charge
What groups develop what charges?
group 5, 6, and 7 are negative
group 1, 2, and 3 are positive
What is the difference between an ionic and a covalent chemical bond?
Ionic bond results from a transfer of electrons from one atom to another
Opposites attract
Attraction between these ions is the ionic bond
Na+ Cl- : cation anion
Covalent bond is due to atoms sharing electrons
How are covalent bond represented?
solid line
Which bond is stronger and contains more energy?
covalent
What sorts of bonds do you expect lithium (3) to form?
ionic
What sorts of bonds do you expect phosphorus (15) to form?
covalent
What bond will form if an atom wants to gain or lose 1 or 2 electrons?
ionic bond
What bond will form if an atom has a valence shell that is half full?
covalent bond
Why are weak bonds important for living organisms?
Weak bonds are easily made and easily broken; makes it possible to rearrange things quickly
Ex. molecular zippers
What sorts of weak bonds are commonly found inside living organisms?
Ionic bonds in solutions
hydrogen bonds
Van Der Waals bonds
Hydrophobic interactions
What is a hydrogen bond?
ATTRACTION due to partial charges on atoms that result from the unequal distribution of electrons in the atom the molecule will have a partially positive side and a partially negative side
Where do electron go on water?
Electrons drawn to oxygen in the middle so its partially negative on oxygen side
What happens with hydrogen bonded molecules that have a partially positive end and a partially negative end?
they are polar
What are Van Der Waals interactions?
Atom with partial charges are attracted to atoms with the opposite partial charge
Molecules will position themselves at optimum distance
When molecules get too close, electrons will repel the molecules away from each other
*****important in protein folding
Why do Van Der Waal interactions occur?
because of the transient polarity of electrically neutral molecules
What are four factors which influence the rates of chemical reactions?
- Temperature: as temperature increases rate of reaction increases
- As concentration of reactants increases rate of reaction increases
* In biological systems, we use substrate instead of reactant - As concentration of product increases, rate of reaction decreases
- If catalyst (enzyme) is present, reaction rate increases
What are the most abundant elements in living organisms?
SPONCH
Sulfur Phosphorus Oxygen Nitrogen Carbon Hydrogen
Why is SPONCH the most abundant?
These elements can form covalently bonded molecules; most useful
What is the difference between a macronutrient and a micronutrient?
Macronutrient - element required in large amounts by living organisms
SPONCH
Micronutrients - element required in small amounts by living organisms
Ca. Fe.
What is the difference between an organic and an inorganic molecule?
Organic: molecule that contains reduced C
Inorganic: not reduced C
C-H → reduced carbon
Attached to hydrogen = organic
CO2 → inorganic
C6H12O6 organic
What is the fundamental reason for all the remarkable properties of water?
what are some properties?
Properties of water are due to hydrogen bonds between water molecules.
Each water molecule has 4 hydrogen bonds to other water molecules
Water is a polar molecule; charged molecule; hydrophilic (likes water)
What is the difference between cohesion and adhesion?
capillary action → adhesion and cohesion
Cohesion: water clings to water
*dripping faucet
Adhesion: water clinging to hydrophilic molecules or water clinging to polar molecules
*water droplets clinging to web
Why does water have such high specific heat and such high heat of vaporization?
Energy / Heat added to water must first be used to break H-bonds
Then H2O molecules can move faster as more heat is applied until they vaporize
H2O resists temperature change
Why should you use deodorants rather than anti-perspirants?
Sweating cools the body
As water evaporates it takes heat away from the body
Why does ice float?
When H2O goes from liquid → solid …
H2O molecules are further apart then in liquid form
Solid water is less dense than liquid water
Why is water such a good solvent?
For polar molecules: H2O will get between other molecules and separate them causing them to make a solution
Why are ionic bonds weaker in water?
Ions are separated
Water between ions which weakens the bonds
Oxygen bonds to positive and hydrogen bonds to negative to break it up
What is the difference between the mean and the median?
Mean = average
Median = control value when the data are in increasing order
Why is the median often used instead of the mean?
Median is a better measure of central tendency
What is the standard deviation, and how does it differ from the variance?
Tells us the degree to which each value deviates from the mean
SD = Square root of Variance
What is a statistical test, and what are they used for?
Used to analyze data
when testing a hypothesis…observed data is compared to expected data
Chi squared
T test
What is the difference between a solute and solvent?
Solute: that which is dissolved (iced tea mix)
Solvent: that which you are dissolving in (water)
solute is dissolved in solvent
