DNA, genes and chromosomes Flashcards
What is a gene?
A gene is a section of DNA containing coded information for the forming of polypeptides and functional RNA
What is locus?
Locus is the location of where you find a particular gene
What is an allele?
A different form of a gene
What is a chromosome?
A chromosome is tightly coiled DNA, a way that DNA is stored
How many chromosomes are in the human body?
There are 46 chromosomes in the human body, in 23 pairs
What are homologous pairs?
Homologous pairs are chromosomes that have identical genes, but may have different alleles
What is the 23rd pair of chromosomes
The 23rd pair of chromosomes is the sex chromosomes (X and Y), therefore it is never numbered
How is DNA stored in eukaryotic cells?
DNA is stored in the nucleus. The DNA is tightly wound around histone proteins. This forms nucleosomes.
How is DNA stored in prokaryotic cells?
DNA molecules are shorter and circular so they are not protein bound, instead they supercoil to fit inside the cell.
What two organelles in eukaryotic cells contain their own DNA?
The mitochondria and chloroplasts
How is DNA in chloroplasts and mitochondria similar to prokaryotic cells?
Their DNA is shorter and circular like prokaryotic cell DNA. It is also not protein bound like prokaryotic cells
What is the function of a histone protein?
A histone protein assists in the tight coiling of DNA to fit chromosomes into the nucleus
What shape are chromosomes in eukaryotic cells compared to the shape of chromosomes in prokaryotic cells?
Chromosomes are linear in shape in eukaryotic cells compared to prokaryotic cells short and circular shape
Describe the DNA found in prokaryotic cells, mitochondria and chloroplasts
DNA is short and circular and is not protein bound (not wound around histones).
