2- Nucleic Acids Flashcards
DNA vs RNA (in terms of genetic info)=
DNA= holds genetic information RNA= transfers genetic information from nucleus to the rest of the cell
Ribosomes are formed from?
RNA & proteins
structure of nucleotide= (3)
1x pentose sugar, 1x nitrogen-containing base, 1x phosphate group
A condensation reaction between 2 nucleotides forms a __________ bond
phosphodiester
DNA nucleotide vs RNA nucleotide components
all have a phosphate group
- All have an organic base (RNA has U & DNA has T)
- DNA has deoxyribose sugar, RNA has ribose sugar
DNA vs RNA structure=
- DNA is composed of 2 nucleotide strands, RNA has 1
- RNA relatively short polynucleotide chain, DNA much longer
DNA structure=
- A double helix made up of 2 polynucleotide chains held together by H bonds
- consists of a sugar-phosphate backbone
- the strands run anti-parallel
How does the semi-conservative replication of DNA ensure genetic continuity
each strand of new DNA is made of ONE original polynucleotide strand & new complementary strand
Process of SCR (5)
- -DNA helicase binds to DNA &
breaks H bonds between 2
strands, unwinding & separating them - Free floating nucleotides form H bonds with complementary exposed bases
- each strand is used as a template
- DNA polymerase (via condensation reactions) joins adjacent nucleotides by forming phosphodiester bonds
- 2 new DNA strands are synthesised
Components of ATP=
1x adenine
1x ribose
3x phosphate group
Hydrolysis of ATP is catalysed by enzyme_________
ATP hydrolase
ATP hydrolysis can be used for: (2)
- energy coupling
(Hydrolysis of ATP can be coupled to other reactions within cells that need energy) - phosphorylation
(The Pi released in ATP hydrolysis can be used to phosphorylate other compounds)
ATP synthesis is catalysed by enzyme _________ during photosynthesis or respiration
ATP synthase
equation for ATP synthesis
ADP+ Pi (+energy) > ATP + H2O
Properties of water that make it a major component of cells= (5)
- metabolite
- high heat capacity
- large latent heat of vaporisation
- cohesive properties
- useful as a solvent
water & polarity
O atoms in water is slightly - charged
H atoms in water are slightly + charged
Polarity means a H atom on 1 molecule is attracted to the O atom on another water molecule
Latent heat of vaporisation=
amount of energy needed to change 1g of a liquid substance to gas
Why is water’s latent heat of vaporisation so large?
H bonding
why is water a good solvent?
- because ions and polar molecules can easily dissolve in it
- water is polar so the + end of the molecule attracts - ions & the - end attracts + ions
Water’s cohesive properties=
the strong attraction between H2O molecules, due to H bonds is called COHESION
Cohesion produces surface tension which can be beneficial
Benefit of High SHC in warm blooded animals=
heat can be more evenly dispersed in their bodies
what is water’s high SHC caused by ?
Hydrogen bonding
SHC=
amount of heat 1g of a substance must absorb or lose to change its temperature by 1 degree.
What are inorganic ions?
molecules that do NOT contain carbon
Important inorganic ions=
H+, Na+, Fe2+ & phosphate ions
Inorganic ions occur in _____ & ______ of organisms
cytoplasm, body fluids
Hydrogen ions (H+) and pH=
pH values represent the concentration of H+ in a solution
The more H+= the lower the pH
Iron ions (Fe2+) in haemoglobin=
iron ions are the central part of the haem group in haemoglobin, allowing blood cells to transport O2 & CO2.
Na+ in co-transport of glucose & AA
Transport of Na+ across cell membrane of cells in the intestine, allows the co-transport if glucose & AA
Phosphate ions as components of DNA & ATP
for DNA= Pi are essential part of sugar-phosphate backbone of DNA molecules.
for ATP= ATP can form ADP & release a phosphate ion + energy
for ADP= ADP can store energy by gaining a phosphate ion & taking in energy
