1.3- nucleotides

Question 1

what is a nucleotide

Answer 1

-single unit (monomer)
-can combine by condensation reactions to form long chains called nucleic acids
-best known nucleic acid is DNA

Question 2

what are nucleic acids

Answer 2

e.g. DNA and RNA
-polymers, their monomers are nucleotides composed of;
a pentose sugar
an organic nitrogeneous base
a phosphate group

Question 3

what is a mononucleotide of DNA made up of (structure)

Answer 3

-deoxyribose pentose sugar
-organic nitrogenous base
-phosphate group

Question 4

names of 2 types of bases

Answer 4

-pyrimidines
-purines

Question 5

what is a pyrimidine

Answer 5

-smaller base type, contain a single ringed structure
thymine
uracil
cytosine

Question 6

what is a purine

Answer 6

-larger bases, contain a double ringed structure
adenine
guanine

Question 7

what is gout

Answer 7

-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

Question 8

the structure of ATP

Answer 8

-adenine base (double ringed as it is a purine)
-3 phosphate groups
-sugar

Question 9

definition of energy

Answer 9

-the ability to do work

Question 10

why do we need energy

Answer 10

-metabolism
-movement
-active transport
-maintenance, repair and cell division
-substance production
-body temp maintenance

-ATP allows these all to happen

Question 11

the ATP cycle

Answer 11

-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

Question 12

enzymes used in DNA replication (3)

Answer 12

1. 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

Question 13

stages of transcription

Answer 13

-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

Question 14

stages of translation

Answer 14

-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

Question 15

DNA vs RNA

Answer 15

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

Question 16

mRNA

Answer 16

-matches with the template strand, and is a copy of the coding strand with U replacing T