Topic 4 - Genes Flashcards
(22 cards)
What’s the role of histones?
To organise and condense the DNA tightly so that it fits into the nucleus and helps ensure the DNA doesn’t take as much space.
What’s a chromatin?
The tightly coiled combination of DNA and proteins, that makes up the chromatids
What are sister chromatids?
The two chromatids that make up the double structure of the chromosome
Why is it important that the sister chromatids are identical?
During cell division, one chromatid goes into one daughter cell and one goes to the other daughter cell during mitosis, ensuring that the daughter cells are genetically identical.
What is the definition of a gene?
It’s a base sequence of DNA that codes for the amino acid sequence of a polypeptide chain and for a functional RNA.
What’s is the definition of locus?
Fixed position a gene occupies on a particular DNA molecule.
Compare Prokaryotic DNA with Eukaryotic DNA.
Prokaryotic DNA is short and circular whilst eukaryotic DNA is long and linear.
Prokaryotic DNA isn’t associated with proteins whilst eukaryotic DNA is, called histones.
What eukaryotic cellular organelles contain DNA which are similar to Prokaryotic DNA?
Mitochondria and Chloroplast as they have DNA that are short and circular, which aren’t associated with proteins.
Describe the structure of DNA.
Deoxyribose sugar
Phosphate group
Nitrogenous bases (Adenine, Thymine, Guanine, Cytosine)
Define a Triplet code.
A sequence of 3 DNA bases which codes for a specific amino acid.
Define Genome.
The full set of genes in a cell
Define a proteome.
The full range of proteins which a cell is able to produce
What is the genetic code?
It’s universal, non-overlapping, degenerate
Define universal.
The same base triplet codes for the same amino acids in all organisms
Define non-overlapping.
Each base is part of 1 triplet so each triples is only read once.
Define degenerate.
An amino acid can be coded by more than 1 base triplet.
What is a non-coding base sequence?
DNA that doesn’t code for amino acids.
What is the non-coding base sequence within the gene?
Introns
What is the non-coding base sequence between the genes?
Non-coding multiple repeats.
What are non-coding multiple repeats?
The same base sequence repeated many times.
What are introns?
Base sequence of a gene that doesn’t code for amino acids.
What are exons?
Base sequence of a gene that codes for a sequence of amino acids.
