Chapter 6:DNA structure and replication Flashcards
What does DNA stand for?
Deoxyribonucleic Acid
What is a gene?
Genetic material is carried and stored in coded in genes, one section of DNA and can be switched off on and by other genes
What does expressed mean?
A gene switched on
Where is DNA found in Eukaryotes?
Nucleus, chloroplasts and mitochondria
What is chromatin?
DNA in a non-dividing cell which only appears grainy and undefined under a microscope
What happens to chromatin when a cell prepares to divide?
Condenses by coiling up and thickens allowing individual chromosomes to be seen
What is a chromosome?
One molecule of DNA with its associated proteins
How is DNA displayed?
Double stranded molecule
What is an unduplicated chromosome?
A long double helix molecule coiled around a histone protein
What is a histone?
A protein that DNA winds around in eukaryotic cells
What are sister chromatids?
Two identical copies of a single chromosomes, formed by replication and connected by centromere
What is a centromere?
A waist like construction in a chromosome required for the movement of chromosomes during cell division
What shape do sister chromatids and centromeres form?
X shape
When are chromosomes visible?
Prior to division stage and after replication has occurred
What are homologous chromosomes?
pair of chromosomes that have the same size, shape and genes at the same location
Where do the chromosomes come from in homologous chromosomes pairs?
One is inherited from each parent