2.3 nucleic acids Flashcards
what is a gene?
a length of DNA that codes for a polypeptide or length of RNA
why do you add ethanol when extracting DNA?
so the DNA forms a precipitate
why do you add pineapple juice when extracting DNA?
- a source of protease enzymes
they break down the proteins associated with the DNA is the nuclei
why do you add salt when extracting DNA?
To break down the hyrodgen bonds between the DNA and water molecules
why do you add washing-up liquid when extracting DNA?
to break down the cell membrane
why do you grind your sample when extracting DNA?
to break down the cell walls
What are mutations?
a change in the genetic code, leading to a change in the structure of the protein
what elements make up nucleic acids?
- Hydrogen
- Carbon
- Oxygen
- Nitrogen
- Phosphorus
What is a codon?
a triplet of bases on mRNA
What is an anticodon?
a triplet of bases on tRNA
What is a base triplet?
a triplet of bases on DNA
Why is DNA universal?
almost all living organisms have the same genetic code
why is DNA degenerate?
each amino acid has more than 1 codon
why is DNA non-overlapping?
each base is only part of one codon
what is the structure of DNA?
- 2 polynucleotide chains
- antiparallel
- long
what bond joins the phosphate group and pentose sugar in a nucleotide molecule?
a phosphodiester bond
How many hydrogen bond do adenine and thymine make?
2
how many hydrogen bonds do cytosine and guanine make?
3
what is a nucleotide?
a molecules consisting of a
- pentose sugar
- phosphate group
- nitrogenous base
what are pyrimidine bases?
Cytosine
Uracil
Thymine
what are purine bases?
Adenine
Guanine
What are the 3 theories for DNA replication?
- conservative
- semi-conservative
- dispersive
How does DNA replicate in prokaryotes?
a bubble sprouts from the DNA loop, causing the loop to unwind and unzip. The complementary nuclotides join to the expose nuclotides. Eventually the whole loop is copied.
what is semi- conservative repliacation?
- where the DNA produces is made from 1 original chain and 1 newly synthesised chain
how is DNA organised in prokaryotic cells?
DNA is found in a loop in the cytoplasm.
Where is DNA found in eukaryotic cells?
- nucleus
- mitochondria
- chloroplats
What sugar is found in DNA?
deoxyribose
what bases are found in DNA?
thymine
adenine
guanine
cytosine
what bases are found in RNA?
uracil
adenine
guanine
cytosine
what sugar is found in RNA?
ribose
what are the types of RNA?
mRNA
tRNA
rRNA
What is the process of transcription?
1- the gene unwinds and unzips
2- hydrogen bonds between the complementary bases are broken by DNA helicase
3- DNA polymerase catalyses the formation of phosphodiester bonds between nucleotides to form RNA
4- a complementary length of RNA is produced
5- the mRNA passes out of the nucleus to the ribosomes
what is the proces of tanslation?
1- mRNA attatches itself to the ribosomes, tRNA molecules carry amino acids to the ribosomes
2- tRNA moleculw=e with an anticodon attatches itself to a codon on the mRNA
3- a second tRNA molecules attatches itslef to the next codon
4- rRNA catalyses the formation of peptide bonds between the two amino acids
5- this process continues until it reaches a STOP codon on the mRNA
what base is found in ATP?
adenine
how many phosphate groups are on ATP?
3
what sugar is found in ATP?
ribose
What are the components of ATP?
- ribose
- 3 phosphate groups
- adenine.
