Lecture 1 Biological molecules Flashcards
What are the types of chemical bonds?
Covalent bond
covalent bonds - share a pair of electrons between two atoms
What is an ionic bond?
is an electrostatic attraction bwtween full positive and negative charges on ions
What are van der waals interactions?
interactions between partial positive and partial negative regions of different molecules
What is a hydrogen bond?
can be formed when hydrogen atom that is covalently bonded to a highly electronegative atom (O2, N) is partially stripped of its electrons by that atom, allowing a transient bond to form with a highly electronegative atom on a nearby molecule
chemical reactions consist of what?
breaking of some bonds between atoms and the formation of others
without the lose of materisal
Breaking bonds requires what?
energy
The formation of new bonds does what?
releases energy
Water molecules are what?
uncharged and polar and can form hydrogen bonds with other water molecules
What explains waters unusual behaviour?
uncharged, polar, can form hydrogen bonds with other water molecules
Why are water molecules cohesive?
due to their hydrogen bonds
water has a high heat capacity due to what?
hydrogen bonds
water has a high boliling point due to what?
hydrogen bonds
Water molecules will associate with what?
other uncharged molecules that have polar covalent bonds and with the full charges on ions
Hydrogen bonds in ice and water
In water the hydrogen bonds form and break constantly
In ice the hydrogen bonds are stable due to lower thermal energy
If a molecule cannot be superimposed on its mirror image it is what?
is said to have chiral properties
An organic molecule is chiral if it has what?
At least one carbon atom bonded to four different groups (an asymmetric carbon). the two mirror image fors are called enantiomers
What areenantiomers
two mirror image forms
Most molecules in cells are what?
chiral
Organic molecules are molecules containing what?
carbon
since carbon atoms can for covalent bonds there is what?
a huge variety of carbon skeleton possibilities
Much of the reactivity and functionality of organic molecules in cells arise from what?
from the functional groups they contain
