DNA/genes/chromosomes Flashcards
How is DNA stored differently in Eukaryotes vs Prokaryotes? [7]
EUKARYOTIC DNA
- long
- linear
- associated with proteins called histones
- tightly coiled into chromosomes
PROKARYOTIC DNA
- short
- circular
- not associated with proteins/histones
Which two organelles in eukaryotic cells have their own DNA?
Mitochondria
Chloroplasts
Describe the DNA contained within mitochondria and chloroplasts [4]
- Similar to prokaryotic DNA
- short
- circular
- not associated with proteins/histones
What is the difference between a haploid and diploid cell?
Haploid - half the number of chromosomes (23)
Diploid - full set of chromosomes (46)
What is a gene? [4]
Sequence of DNA bases that codes for:
- The amino acid sequence of a polypeptide
- A functional RNA (e.g. rRNA and tRNA)
A gene occupies a fixed position, called a locus, on a particular DNA molecule
Describe the nature of the genetic code [4]
- Sequence of DNA triplets (made of 3 bases) codes for the sequence of amino acids
- Universal > The same specific DNA base triplets code for the same amino acids in all living organisms
- Non-overlapping > each individual base can only be used once in a single triplet
- Degenerate > The same amino acid can be coded for by more than one base triplet sequence
In eukaryotes much of the DNA doesn’t code for polypeptides, why? [2]
- Between genes > Non-coding multiple repeats
- Within genes > Only exons code for amino acid sequences, which are separated by non-coding sequences, called introns
Define a Genome
The complete set of genes in a cell (including those in the mitochondria + chloroplasts)
Define a Proteome
The full range of proteins that a cell/genome is able to produce
Define an Allele
different version of the same gene (resulting in different presented characteristics)
What is a homologous pair of chromosomes?
same size chromosomes with same genes, but different alleles
