Chem Review Flashcards
what are all living things composed of
all living things are composed of molecules specifically arranged to perform specific functions (making and breaking organic molecules)
what are the organic molecules
lipids
nucleic acids
carbs
proteins
where is the highest density of mitochondria located
brain and muscle
is plastic organic
plastic isn’t organic even though it’s mostly carbon
what are organisms composed of
organisms are composed of matter which is anything that takes up space and has mass
what is matter composed of
elements, which cannot be broken down into simpler materials by ordinary chemical reactions
what are the 5 main elements in the human body
hydrogen
calcium
carbon
nitrogen
oxygen
what is each element made up of
atoms composed of neutrons, protons and electrons
what is the atomic number equal to
number of protons
what is the mass number equal to
number of protons + number of neutrons
what are the number of electrons equal to
the number of electrons usually equals the number of protons resulting in a net charge of 0
what are isotopes
atoms of the same element with different mass numbers (same # of protons but diff # of neutrons)
how are molecules formed
when 2 or more atoms are held together by covalent bonds
what are compounds
combination of elements in a specific
what does the behaviour of an atom depend on
valence shell (# of electrons in outermost shell)
what are chemical bonds
attractive forces that govern the interaction of atoms and molecules
what are strong bonds
Strong bonds involve atoms giving up or acquiring electrons in
order to complete each other’s outer shell
2 types of strong bonds
covalent bond
ionic bond
what is a covalent bond
when two atoms share one or more pairs of electrons they form a covalent bond
what is polarity
polarity depends on the difference in electronegativity of the two atoms in question
what are non polar covalent bonds
a non polar covalent bond is a bond between 2 atoms that have similar electronegativities ( the electrons are shared equally between them)
what is electronegavity
the measure of an atom’s attraction for shared
electrons in covalent bonds, the more electronegative an atom is, the
more strongly it pulls shared electrons toward itself.
what do lipids primarily consist of
carbon and hydrogen covalent
bonds (making lipids
primarily nonpolar molecules)
what are polar covalent bonds
occurs between two atoms that do not have the same electronegativities (atom with higher electronegativity will pull the shared electrons closer to it)
what is an ionic bond
ionic bond formation involves complete transfer of an electrons (results in the formation of ions)
what is an ion
an atom or a molecule with 1 or
more units of electrical charge
what is a cation
a positively charged ion
what is an anion
a negatively charged ion
how do ions fit into biology
neuronal action potential
muscle contraction
what usually affects the strength of ionic bonds
in water (ionic bonds are weaker in this state)
which has the highest ionic character
nonpolar covalent bonding
polar covalent bonding
ionic bonding
how do lipids identify
lipids as a class belong to non polar covalent bonding group, chemically do not react with anything that has a partial charge, does not react with water
what are the characteristics of weak chemical bonds
- allow molecules to interact
- adhering molecules briefly when they collide with each other
- provide stability within large molecules (proteins, DNA)
what are the 3 types of weak chemical bonds
hydrogen bonding
london dispersion
ionic bonds in water
what are hydrogen bonds
tend to form between an atom with a partial negative charge and a hydrogen atom that is covalently bonded to a very electronegative element (O or N)
why are hydrogen bonds important
these bonds are important
in living organisms due to the
high prevalence of water molecules in our cells and tissues
are hydrogen bonds mostly weak or strong
- hydrogen bonds are individually weak
- collectively hydrogen bonds can be very strong when they are present in large numbers (DNA)
are van der waals mostly weak or strong
Individually, these interactions are
weak, but if molecules are close
enough and occur simultaneously, they can become very powerful
how are london dispersion forces related to biology
forces are between stacked bases in DNA molecule is important in keeping DNA structure
