1.3- nucleotides Flashcards
what is a nucleotide
-single unit (monomer)
-can combine by condensation reactions to form long chains called nucleic acids
-best known nucleic acid is DNA
what are nucleic acids
e.g. DNA and RNA
-polymers, their monomers are nucleotides composed of;
a pentose sugar
an organic nitrogeneous base
a phosphate group
what is a mononucleotide of DNA made up of (structure)
-deoxyribose pentose sugar
-organic nitrogenous base
-phosphate group
names of 2 types of bases
-pyrimidines
-purines
what is a pyrimidine
-smaller base type, contain a single ringed structure
thymine
uracil
cytosine
what is a purine
-larger bases, contain a double ringed structure
adenine
guanine
what is gout
-in the liver, excess purines broken down into uric acid, which is then excreted in urine
-if your blood contains too much uric acid, may form crystals deposited in joints which are very painful
the structure of ATP
-adenine base (double ringed as it is a purine)
-3 phosphate groups
-sugar
definition of energy
-the ability to do work
why do we need energy
-metabolism
-movement
-active transport
-maintenance, repair and cell division
-substance production
-body temp maintenance
-ATP allows these all to happen
the ATP cycle
-ATP converted to ADP by hydrolysis (energy released) using ATPase
-ADP converted to ATP by condensation reaction using ATPsynthase which catalyses the synthesis of ATP
enzymes used in DNA replication (3)
- helicase- unzipping enzyme breaks through h bonds, taking 2 strands apart
2.DNA polymerase- replicates molecules to build new DNA strand
3.ligase- glue, puts strands together
stages of transcription
-happens in the nucleus
1.enzyme bind to a site before the code that is being transcribed
2.DNA helicase breaks h bonds+ DNA unzips
3.mRNA nucleotides move in and pair with their complementary base pair (U replaces T)
4.RNA polymerase joins the mRNA nucleotides to form one strand of mRNA held by phosphodiester bonds
5. mRNA leaves the nucleus via a nuclear pore and enters cytoplasm for translation
stages of translation
-happens in cytoplasm
1.mRNA attaches to the ribosome at a start codon
2.tRNA is attached to a specific amino acid
3.anticodon binds to mRNA
4.peptide bond forms between each amino acid
5. process finishes at stop codon
DNA vs RNA
D-deoxyribonucleic acid
-antiparallel structure
-5’ end and 3’ hydroxyl end
-long molecule
-constant distance between strands as purine paired with pyrimidine
R-ribonucleic acid
-no thymine, instead uracil
-formed in cytoplasm, needed for photosynthesis
-shorter molecule
-single stranded
