2.1.3 Nucleotides nucleic acids Flashcards
draw and label the structure of a nucleotide, make sure they are combines to te corrects carbons :D
https://docs.google.com/document/d/1YAqlrSiS9YOn4vkAJhGgEGGAk9AOO-pf1GieocY6v4M/edit?usp=sharing
what is the structure of DNA
Anti parallel backbones
complimentary bases
What are the purines?
Adenine and Guanine
what are the Pyrimidines?
Thymine and cytosine
How many bonds does each nucleotide base pair have?
Adenine + Thymine = 2 bonds
Guanine + Cytosine = 3 bonds
what is a codon?
A triplet base on mRNA that codes for an Amino acid
What is a mutation?
A random change to genetic material
-can alter the structure/number of chromasomes
What is a gene mutation?
A gene mutation is a change in DNA
- DNA is stable, though spontaneous mutations can occur during DNA replication
- Can also happen in mitosis
what are the 2 main classses of mutation?
- substitution mutation:one base replaces another
- insertion or deletion mutation: parts of the DNA are shifted/ replaced and can have ,major effects on the organism
what does it mean if DNA is degenerate?
amino acids in the DNA can be coded for by different combinations of triplet bases
What are the 3 types of substitution mutations?
1) Nonsense
2) Silent
3) Missence
what are the differences between DNA and RNA?
- RNA uses Uracil instead of thymine
- RNA is a single strand
What is mRNA
- Mae in the nucleus and is small enough to fit through the nuclear pores
- Contains a copy of the DNA that codes for a protein/polypeptide that will be synthesised at a ribosome
- uses uracil instead of thymine and is single stranded
what is tRNA?
- Singular stranded, however folds into a clover shape
- Contains an Anticodon that is hydrogen bonded to it
What are the 3 points where gene expression is controlled?
- Transcription
- Post-transcription
- translation
What is the process of Transcription?
-DNA Helicase separates the 2 strands of DNA by breaking H-Bonds
-RNA polymerase moves along one of the DNA strands causing nucleotides to
join with complementary bases
-Adenine joins with uracil instead of thymine
-As RNA polymerase moves along, the DNA strands joins behind it
How does the RNA plymerase know when to binf?
There is a promotor region in the DNA, asweel as a terminating region, to that specific sections can be transcribed
what is a transcription factor?
short non-coding areas that combine with specific lengths of DNA that activates or inhibits the transcription of genes
What are some molecules that can switch genes on and off?
Hormones, e.g. Oestrogen
what are introns?
A section of a gene thst does not code for an Amino acid
what are exons?
A section of a gene that codes for an amio acid
How are Introns removed from pre-mRNA?
We use SPLICING
-this is when the introns are removed and the functional exons are joined together
