Life at the Cellular level Flashcards
Prokaryote characteristics
lack nuclear membrane
no mitochondria
no membrane bound structures
Eukaryote characteristics
human cells
multi cellular animals and plants
nucleus with membrane
membrane bound structures
Multuipotent
cells that can differentiate into many cell types
pluripotent
all cell types of the body
types of tissues
epithelial
connective
nervous
muscular
Adherens junctions
link actin filaments
Desmosomes
link keratin filaments
ER and Golgi apparatus
membrane bound
rough ER has ribosomes attached to it
they coordinate protein modifications and transport
smooth ER is used mainly to breakdown compounds
Lysosomes
used to separate enzymes from the rest of the cell
99% of you are the elements…
H, O, N and C
Functional groups define
biomolecular function
Nucleic acids
polymers of nucleotide monomers
Retrovir
A nucleotide analogue
analogue of THYMINE nucleotide found in DNA
Polysaccharides
polymers of sugar monomers linked by GLYCOSIDIC BONDS
d-Glucose is deemed a reducing sugar because
the linear form has an aldehyde group which can be oxidised
if it is oxidised then the other reactant would be reduced - so the glucose would be termed a ‘reducing sugar’
entropy
gauge of randomness or chaos within a closed system
enthalpy
heat released to surroundings
A spontaneous process must decrease ……. and/or increase ……….
enthalpy (H)
entropy (S)
delta G
change in gibbs free energy
𐤃G =
𐤃H - T 𐤃S
Spontaneous reactions only occur if 𐤃G is…
-ve
so if the reaction releases energy
Normal biological processes require more order… so have …… 𐤃G
+ve
Free energy flows between …….. and ………. processes allowing them to occur
catabolic and anabolic
Enzymes function to…
selectively alter the rate of particular parts of metabolic pathways
Glucose releases its potential energy by
heat
ATP–> ADP releases…
Free energy
which is harnessed to drive thermodynamically unfavourable reactions
Anabolic reactions
thermodynamically unfavourable reactions proceed
Catabolic
coupling allows for thermodynamically favourable reactions to proceed
Glucose releases its potential energy when it is
degraded
intermediate step produces PEP
PEP
acts as an intermediate for a reaction that goes on to produce ATP during PEP to Pyruvate conversion
𐤃G for PEP to Pyruvate
-31.4 kJ/mol
H atoms are utilised as an
energy source
eg - palmitate has loads of H atoms - so is rich in energy
Hydrolysis (ATP –> ADP) will
decrease in free energy
Condensation (ADP–> ATP)
requires free energy
Water is polar/non-polar
POLAR
O is more electronegative than H so it…
attracts the electrons of the covalent bonds towards it
Polarity allows for
hydrogen bonding
H bonds are the strongest when the 3 atoms involved lie
in a straight line
Molecules that form hydrogen bonds are
water soluble
eg sugars
alcohols
aldehydes
ketones
oxygen and carbon dioxide have no POLARITY which makes then poorly
water soluble
Charged Molecules
the water forms ‘screens’ around each ion - keeping the NaCl
in solution once dissolved
Charged (polar) molecules are
hydrophilic
Uncharged (non-polar) molecules are
hydrophobic
Only the lipids at the …. force the ordering of water
edge of the cluster of lipids
hydrophobic lipids are transported in the blood in a
chylomicron
water has a neutral pH because what are equal?
H and OH
Strong acids
dissociate fully
weak acids only
partially dissociate
acids are proton
donors
bases are proton
acceptors
a proton donor and a proton acceptor together make up a
conjugate acid-base pair
The stronger the acid the greater its tendency to
lose a proton (and vice versa)
The tendency for any acid to lose a proton and form its conjugate base is defined as the
equilibrium constant (Keq)
or
dissociation constant (Ka)
Kw
ion production of water
Henderson Hasselbalch equation
relates the acid dissociation equation to the buffering of a weak acid/conjugate base
If blood did not have a biocarbonate buffer system - then pH would
fluctuate wildly as cellular products of acids would cause drops in blood pH
normal blood pH is
7.4
