DNA And Protein Synthesis P5 Flashcards
What is DNA made up of ?
Nucleotides
How many different nucleotides are there in DNA?
Four different types of DNA
What does each nucleotide consist of?
One sugar molecule, one phosphate group and one base.
Each DNA nucleotide consists of one sugar molecule, one phosphate group and one base.
Which of these is common to all DNA nucleotides?
Which of these varies?
The sugar and phosphate molecules are common to all DNA nucleotides.
The base varies.
What molecules form the backbone to the DNA strands?
Sugar and phosphate molecules in the nucleotide.
What does a base join to?
Sugar molecule
What are the four different bases found in a DNA molecule?
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
What does each base link to?
A base on the opposite strand in the helix.
What are the pairings for complimentary base pairing?
A always pairs up with T
C always pairs up with G
Proteins are polymers made up of what?
Amino acids
What decides the order of amino acids in a protein?
It is the order of bases in a gene that decides the order of amino acids in a protein.
What do the order of the base in a gene decide?
The order of amino acids in a protein.
How many bases code for each amino acid?
Each amino acid is coded for by a sequence of three bases in the gene called a triplet.
What amino acid does triplet AGG code for?
Arginine
What amino acid does triplet CTT code for?
Leucine
Where is DNA found?
In the cell nucleus.
Why can’t the DNA move out of the cell nucleus?
Because it’s really big
How does the cell get information from the DNA to the cell cytoplasm?
This is done using a molecule called messenger RNA (mRNA).
What is mRNA?
A polymer of nucleotides but shorter (than DNA) and only one strand.
What base does mRNA use instead of thymine(T)?
Uracil (U)
What does uracil (U) pair with?
Adenine (A)
Where are proteins synthesised?
In the cytoplasm
Describe how proteins are made (4 stages)
1 The DNA contains the gene for coding the protein.
2 In the nucleus, the two DNA strands unzip. The DNA is used as a template to make mRNA. Base pairing ensures the mRNA is complementary to the opposite DNA strand.
3 The mRNA molecule then moves out of the nucleus and into the cytoplasm, where it attaches to a ribosome.
4 Amino acids are then joined together in the correct order by the ribosomes, following the order of the triplets in the mRNA. This makes the protein coded for by the gene.
Explain how a gene codes for a protein. (2 marks)
Each triplet of bases in a gene code Doran amino acid (1 mark)
The order of triplets in a gene determines the order of amino acids in a protein (1 mark)
