lecture 3 part 2 Flashcards
non covalent bonds`
keep atoms close together without sharing electrons
what are biologically important non covalent bonds
-hydrogen bonds
-ionic bonds
-van der waals forces (occur due to hydrophobic interactions)
are non covalent bonds individually weaker than covalent bonds
yes
what are hydorgen bonds and ionic bonds due to
due to the attraction of opposite charges
where do hydorgen bonds exists
exist between two atoms with opposite partial charges
-water is not required but it frequently forms hydrogen bonds)
-the partial charge is on a hydrogen atom
-partial negative charge is usually on a N or O atom
what do hydrogen bonds give water
its special properties important for life
-surface tension (cohesive forces)
can water form hydrogen bonds with other polar molecules
yes
-glucose
-ammonia
hydroxyl group
OH
Hydrogen bonds are a type of _____ _______ bond and are due to the attractions of _______ charges (no sharing electrons)
non covalent; opposite
ionic bonds
hold together two ions with opposite charges (number of protons doe snot equal number of electrons)
ionic bonds in different environments
they are strong in dry environments and weak in aqueous environemnts
-in many aq solutions ionic bonds dissocoaute (why salt dissolves in water)
water forms ________ _____ around ions
hydration shell
-several water moleqs surround the ion
-opp charges on water oriented towards the ion
uncharged polar molecules and ions interact well with ______ and are called ________ molecules
water; hydrophillic
ions often ______ in water but they dont form __ ______ with water
dissolve; Hydrogen bonds
do no polar molecules interact well with water and what are they called
no and they are called hydrophobic molecules
what do non polar molecules do in water
they group together in water because water molecules for H bonds with on another
hydrophobic interactions
association of non polar molecules (or non polar regions w/in a molecule)
-lessens interactions with water and other polar moleqs (or polar regions w/in moleq)
van der waals forces
weak attractive forces between adjacent moleqs due to transient fluctuations in electrical charges
what type of force stabilizes hydrophobic interactions
wan der waals forces
do avn der waals forces initiate hydrophobic interactions
no hydrophobic interactions do
what are critical for the 3D structure of many macromolecules
non covalent bonding
what type of bond stabilizes the double stranded DNA struvture
hydorgen bonds
non covalent bonds are necessary for what
proteins to be in their correct 3D shape (so they can function properly)
structure determines what
fucntion
what can stabilize the loop structure in protein
non covalent bond
what are important for intermolecular interactions
non polar covalent bonds
intermolecular interactions is between ____ moleqs
2
exampels of intermolecular interactions
-hormone binding to receptor
-body binding to pathogen
-enzyme binding to substance
-transcription factor binding to DNA to regulate gene expression
what are some non covalent bonds important points
-individually much weaker than covalent bonds (because they don’t share e-)
-collectively exhibit strength in proportion to their numbers
-changes in environment conditions can cause them to break and molecules to denature or dissociate
what can disrupt non covalent bond
higher than optimum temperatures
what happens to non covalent bonds in higher than optimum temps
cause the molecules to denature (unfold) or dissociate
-proteins
-nucleic acids
-lipids with hydrophobic tails
what can disrupt hydorgen and ionic bonding
salt concentration and pH
