1.1 DNA Structure Flashcards
What are the three molecules that make up a DNA nucleotide?
Deoxyribose sugar, phosphate, base.
What shape is a strand of DNA?
Antiparallel double-stranded helix.
Where is the phosphate group found in a DNA strand?
3’ and 5’ ends of each strand respectively.
What is the base pairing rule?
Adenine-Thymine and Guanine-Cytosine.
What bonds join the DNA nucleotides to form the sugar-phosphate backbone?
Covalent bonds.
What bonds join both DNA strands together?
Hydrogen bonds.
The genotype is determined by?
The sequence of bases.
What does the sequence of DNA form?
The genetic code.
How is the DNA organised in prokaryotes?
Prokaryotes have a single, circular chromosome and smaller circular plasmids.
Give an example of a prokaryote?
Bacterial cell.
True or false? Prokaryotes do not have a true membrane-bound nucleus.
True.
What do plasmids contain?
Additional genes.
How is the DNA organised in a eukaryotic cell?
All eukaryotes have linear chromosomes in their true membrane-bound nucleus.
How are linear chromosomes in the nucleus packaged?
They are tightly coiled and packaged with associated proteins called histones.
What type of chromosomes are found in chloroplasts and mitochondria?
Circular chromosomes.
What do the circular chromosomes in chloroplasts and mitochondria show?
That they were once individual prokaryotic organisms that were engulfed by early eukaryotic cells.
Why is a yeast cell unique?
It is a eukaryote that contains plasmids.
Give an example of a eukaryotic cell?
Fungi, plant or animal cells.
True or false? Eukaryotes do not have a true membrane-bound nucleus.
False.
What are the four bases found in DNA?
Adenine, cytosine, thymine and guanine
