U1M1 p2 slides Flashcards
Origins of Life
Matter is composed of _______.
elements.
What is the technical definition of a cell?
self-replicating chemical systems that communicate with each other and the environment.
protons are charged ________.
positively
electrons are charged ________.
negatively
what are the subatomic particles?
- protons
- electrons
- neutrons
where are protons located in an atom?
the nucleus, aka the core of the atom
How did the first life evolve?
four stages.
- The abiotic synthesis of small organic molecules, such as amino acids and nitrogenous bases
- The joining of these small molecules into polymers, such as proteins and nucleic acids.
- The packaging of these molecules into “protocells,” droplets with membranes that maintained an internal chemistry different from that of their surroundings.
- The origin of self- replicating molecules that eventually made inheritance possible
What is the smallest unit of matter that still retains the properties of an element?
an atom
where are neutrons located in an atom?
the nucleus, aka the core of the atom
neutrons are charged __________.
neutrally.
where are electrons located in an atom?
in clouds surrounding the nucleus. Picture the moon orbiting the planet, electrons would be like the moon(s).
in levels called electron shells.
What is the atomic number?
number of protons in an atom
what is the mass number of an atom?
number of protons + neutrons
different mass numbers between atoms of the same element means what?
different isotopes of the same element.
What are isotopes?
- atoms of the same element with different mass numbers.
- they have the same number of protons always, but number of neutrons changes
- share almost the same chemical properties but differ in physical properties
- stable isotopes do not emit raditation, unstable isotopes do emit radiation
what makes an isotope stable/unstable?
stable isotopes have equal numbers of protons and neutrons.
unstable isotopes have more neutrons than protons. This means their internal forces are unbalanced and the nucleus has an excess of internal energy.
What subatomic particle is involved in chemical activity?
electrons
which electron shell has the lowest energy level?
the innermost shell
which electron shell has the highest energy level?
the outermost shell
In an atom, energy is lost when …
an electron moves to a shell closer to the nucleus
In an atom, energy is absorbed when …
an electron moves to a shell further from the nucleus
reactivity in an atom arises from …
the presence of unpaired electrons in one or more orbitals of the valence shell
What are covalent bonds?
two atoms share one or more outer-shell electrons.
In biology, what is the strongest kind of bond?
covalent bonds
What are ionic bonds?
attractions between ions of opposite charge.
results in a gain or loss of electrons.
not sharing electrons, instead it’s giving/taking electrons.
In chemistry, what are the strongest bonds?
Ionic bonds
What are vander waals interactions?
What are hydrogen bonds?
when hydrogen has a slightly positive charge from being part of a stronger polar bond, a weak bond (hydrogen bond) forms between that positive ish hydrogen and the slightly negative end of another polar molecule.
The tendency of an atom to attract shared electrons is called ________.
electronegativity
what is electronegativity?
the tendency of an atom to attract shared electrons.
Why are the strongest bonds different between chemistry and biology?
Because ionic bonds (strongest in chem) are much weaker in the presence of water. In biology, most reactions and bonds are in the presence of water, making covalent bonds the strongest.
Some atoms have different electronegativities. Rank the four elements human bodies are mostly composed of in order of highest to lowest electronegativities.
O > N > C ≈ H
What is a non polar bond?
when atoms have equal electronegativity
what is a polar bond?
when atoms have different electronegativities, causing one side of the molecule to be more negative than the other
What is the electronegativity like in molecules where all atoms are the same element?
all have the same electronegativity
When hydrogen is part of a polar bond, it has a partial ______ charge.
positive
what is the bond where there is a gain or loss of electrons?
ionic
what is the bond where electrons are shared
covalent
what is the bond that happens because of polarity in molecules
hydrogen
what is an ion?
an atom or molecule with an electrical charge from gain/loss of electrons.
what is the solvent of life? why?
water
the versatility from the polarity of its molecules.
how does water dissolve a solute?
water molecules will surround charged solutes, with positive end of water facing negative solutes and vice versa.
what is the more positive end of water molecules?
the side with the hydrogen atoms
what is the mroe negative end of water molecules?
the side with the oxygen atom - opposite the hydrogen atoms
What element is the basis of life?
carbon
how many bonds can carbon form?
four
what is one of the simplest organic compounds?
Methane (CH4)
a carbon skeleton is a chain of carbon atoms that can vary in …
- length
- branching
- bond position
- presence of rings
what are structural isomers?
molecules with the same atoms, except with branching is different places, different shapes.
what are cis-trans isomers?
cis isomers are molecules with functional groups on the same side of the molecule. trans isomers are molecules with the functional groups on opposite sides of the molecule.
what are enantiomers?
molecules that are mirror images of each other. cannot get the same molecule by rotating or repositioning in any way.
what is this functional group called?
- OH
hydroxyl
what are isomers?
compounds with the same formula but different structural arrangements
what is this functional group called?
- COOH
= O - C - OH
Carboxyl
what is this functional group called?
> C = O
Carbonyl
what is this functional group called?
- NH2
- H - N - H
amino
what is this functional group called?
- CH3
H
-
- C - H
-
H
Methyl
what is this functional group called?
- SH
sulfhydryl
what is this functional group called?
- OPO3 ^2-
O
= - O - P - O^-
-
O^-
Phosphate
What is the formula of this functional group? - hydroxyl
- OH
What is the formula of this functional group? - carbonyl
> C=O
What is the formula of this functional group? - carboxyl
- COOH
What is the formula of this functional group? - amino
-NH2
What is the formula of this functional group? - sulfhydryl
-SH
What is the formula of this functional group? - methyl
- CH3
What is the formula of this functional group? - phosphate
-OPO3 ^2-
