LACL 2 Flashcards
how many elements are used for living organisms out of 90 natural elements?
10 elements
what are the 10 elements?
carbon, oxygen, nitrogen, hydrogen, potassium, sodium, calcium, phosphorous, sulphur, chloride
how many trace elements (metals) are needed in smaller quantities?
e.g. magnesium, zinc, iron, etc.
why is 99% of our body made from HONC (hydrogen, oxygen, nitrogen and carbon)?
because lightest molecules can make the strongest covalent bonds, with C being the most versatile
why is C particularly versatile?
because it can form single, double and triple bonds
what is the configuration?
fixed arrangement of atoms in a molecule (e.g. C=C is a very rigid confirmation)
what are trans and cis molecules?
trans= atoms are found on a different side of the double bond molecule cins= atoms are found on the same side of the double bond molecule
how can you interconvert between a trans and cis molecule?
by breaking and reforming double bonds
can a double bond twist and rotate?
no; in order to change a molecule from one to the other, it needs to be reacted
in which process is configuration particularly important?
in absorption of light by rhodopsin in rod cells
what light sensitive protein which sits in disc inside rod cells, has both cis and trans isomers?
Rhodopsin
what happens to rhodopsin isomers when light reaches it?
energy from the light causes the bonds to break and rearrange itself and enzymes then act on molecules, change its shape and stimulate the function (slow reaction to turn trans to cis and vice versa)
what are two forms of chiral (asymmetrical) centres?
- laevo (left hadned)
2. dextro (right handed)
which form of a chiral centre do enzymes only recognise?
L-amino acids only (not D-amino acids)
what is conformation?
precise arrangement of atoms in a molecule
which bonds can rotate freely without having to break and re-form them?
C-C bonds
what are 5 chemical reactions of life?
- redox reactions
- making and breaking C-C bonds
- internal rearrangements (making and taking out things)
- group transfers
- condensation and hydrolysis reactions (for polymer formation etc.)
how many hydrogen atoms/ protons are usually transferred from one molecule to the next?
2 (lost/gained)
what is an example in glycolysis where rearrangement of a molecule occurs?
from G6P to F6P
what is an example in glycolysis where a phosphate group is transferred?
F6P becomes F-1,6-BP
fructose-1,6-biphosphate
what does the transfer of a group produce?
a molecule with a higher energy
what process are subunits of proteins, polysaccharides and nucleic acids made from and what are they broken by?
made by condensation and broken by hydrolysis
what 3 types of filament is the cytoskeleton made from?
- microtubule (largest)
- intermediate tubules
- actin filaments
what are 2 kinds of bases in nucleic acids?
- pyrimidines
2. purines
what are pyrimidines?
flat, single rings (like cytosine, thymine, uracil (CTU)
what are purines?
flat, double rings (like adenine, guanine) AG= PURE AGONY
what is a nucleoside?
nucleotide without the phosphate group
what can be used in antiviral drugs to prevent infection, such as in HIV patients who use ZDV?
Nucleotide analogues
what is ZDV (zidovudine) in HIV patients an analogue of?
thymine nucleotide
what does reverse transcriptase create?
viral DNA
Starch and glycogen are both polymers of what type of glucose?
D-glucose (reducing agent)
why is D-glucose a reducing agent?
the linear form of it (not cyclic) has an aldehyde group which can be oxidised
what is the name for the end monomer in a chain?
reducing end
what structures are liquid lipids?
kink structures
what are single and double bonds in terms of saturation?
single bonds: saturated
double bonds: unsaturated
what are 2 types of lipids?
- triacylglycerides (triglycerides)
2. phospholipids
what are properties of triacylglycerides?
- storage lipids
- non-polar
- 3 fatty acids linked to a glycerol
- can be broken down to make energy
what are properties of phospholipids?
- have a phosphate group attached to its glycerol head and has 2 fatty acid tails
- polar
- hydrophobic tails and hydrohpillic heads
