6.2 Role of chromosomes and DNA Flashcards
What is a chromosome?
a thread-like structure composed of DNA and proteins
What are chromosomes composed of?
DNA and protein (histones)
What is DNA and what does it stand for?
Deoxyribonucleic acid (DNA) contains four bases which form the major parts of the chromosome and containes coded genetic instructions
What are the 4 bases?
Adenine, Thymine, Cytosine, Guanine
What is a nucleosome?
A section of supercoiled DNA around
histones
when combined with other nucleosomes, it forms tightly compact DNA
What is a chromatin?
mass of genetic material composed of DNA and histones that condense to form chromosomes
What is the difference in shape of chromosomes between eukaryotic and prokaryotic cells?
Eukaryotic has linear while prokaryotic have circular
Why is DNA in prokaryotic cells less condensed?
They do not contain histones in the supercoiling process
What happens if DNA is not packaged properly?
-Will not physically fit in cell, loss of genetic info
-Cell will not be able to distribute DNA during cell division so daughter cells will not recieve correct genetic info
Why is it good to condense DNA?
It allows a lot of genetic info to be stored in the cell