4.6.1.5 DNA structure (SINGLE HT) Flashcards
DNA base pairs?
- A and T are complementary to each other
- C and G are complementary to each other
describe protein synthesis
- DNA strands separate
- one strand acts as a template
- mRNA nucleotides align by complementary base pairing and join together to form an mRNA strand - this is a template of the original DNA
- mRNA moves out of the nucleus and into the cytoplasm, and binds to the ribosome where it is read
- mRNA
- tRNA (carrier molecules) bring specific amino acids to the ribosome
- amino acids join together to form a protein
Which bases pair together?
AT and GC
What do the order of the bases in DNA detemermine?
The order of the amino acids that make up the protein
Which part of the nucleotide is the base attached to?
the sugar
When a protein in synthesised using DNA what carries the message to the ribosomes
template - mRNA
what molecule brings in specific amino acids according to the template to make a protein?
carrier molecules (tRNA)
When protein synthesis is complete what happens to the synthesised protein?
It folds up into a unique shape
What is a mutation?
A change in the base sequence of DNA
what effect can mutations in DNA have on proteins?
Some may have no effect, others may completely alter the protein e.g. an enzyme no longer fits its substrate
Which parts of the DNA molecule DO NOT code for proteins?
Non-coding sections
What role can these non-coding portions have?
They can switch genes on or off
What is mRNA?
a molecule that carries the DNA code to the ribosomes from the nucleus
When do mutations occur
randomly
When can mutation rate be increased?
exposure to UV, chemical carcinogens, radiation
