Topic 4 - DNA, genes & chromosomes Flashcards
How is DNA arranged in an eukaryotic cell?
1) DNA is found in linear chromosomes.
2) Associated with histones (proteins).
3) DNA molecules are very long.
How is DNA arranged in a prokaryotic cell?
1) DNA molecules are short and circular.
2) Not associated with proteins.
3) DNA molecule are joined in a complete circle with no ‘free ends’.
How is DNA arranged in the mitochondria and chloroplast?
1) Short.
2) Circular.
3) Not associated with protein (like in prokaryotes)
What are introns?
Sections of genes that don’t code for amino acids.
What are exons?
Coding sections of genes.
What is a gene?
A base sequence of DNA that codes for the amino acid sequence of a polypeptide or a functional RNA molecule.
What do genes determine?
The genes in a DNA molecule control protein structure as they determine the exact sequence in which the amino acids join together.
What is a locus?
Locus is the specific actual location of the gene on a region of a chromosome.
What is a triplet?
A sequence of three bases on a DNA molecule, coding for one amino acid.
How is genetic code universal?
The genetic code is the same for all organisms.
How is genetic code non-overlapping?
Each base in the sequence is only read once.
How is genetic code degenerate?
Each amino acid is coded for by more than one triplet.
What are stopcodes?
Stopcodes are when three triplets don’t code for any amino acids and mark the end of the polypeptide chain.
