Unit 1: DNA & The Genome - Key Area 1: Structure of DNA Flashcards
define ‘genome’
an organisms complete set of DNA including all of its genes
what is a function of DNA?
stores genetic information in a sequence of bases which determines an organisms genotype and structure of proteins
what does the base sequence of DNA form?
genetic code
name the repeating units that make up a molecule of DNA
nucleotides
what are the components of a nucleotide
phosphate, deoxyribose sugar and base
what bonds different nucleotides together in a strand and describe them?
strong chemical bonds. Forms between the phosphate group of one nucleotide and carbon 3 of a sugar on another
what type of bonds are between bases
weak hydrogen bonds
what shape does DNA form?
a double helix
why are DNA strands described to be anti-parallel?
because they run in opposite directions making them antiparallel, the left strands runs from 5’ end to 3’ end while the right strand runs from 3’ to 5’ end.
what end does the deoxyribose sugar occur?
3’ end
what end does the phosphate occur?
5’ end
describe the base pairing rule
Adenine to Thymine
Cytosine to Guanine
what are the types of eukaryotes?
plant, fungal and animal cells
what is a special eukaryote that contains plasmids?
yeast cell
what is a sugar-phosphate backbone?
strongly bonded strand of DNA
what does prokaryotic refer to?
refers to the domain of life characterised by cells with no discrete nucleus
what does eukaryotic refer to?
refers to a domain of life characterised by cells with a discrete nucleus
Cell organelles in which the aerobic stages of respiration occur
mitochondria
Organelle in which the chemical reactions of photosynthesis occur
chloroplast
Structure that contains the genetic material of an organism encoded into DNA
chromosome
define ‘plasmid’
a small circular piece of DNA
organisms which lack a membrane bound nucleus
prokaryotes
what are the type of prokaryotes?
bacteria cell
where is DNA found in prokaryotes?
in the cytoplasm of the cell
organisms which have a membrane bound nucleus that stores genetic material
eukaryotes
what is the name of the protein packaged in linear chromosomes?
histone
describe the structure of a prokaryote cell
> prokaryote cells have circular chromosomal DNA which is contained in the cytoplasm as plasmids
don’t have a nucleus
there is no DNA in organelles as prokaryote cells like bacteria don’t have any organelles.
describe the structure of a eukaryote cell
> eukaryote cells have a nucleus present
linear chromosomes that are tightly coiled and packaged with the protein histone is contained in the nucleus
there are only plasmids present in some yeast cells but absent in plant and animal cells
there is circular chromosomes found in mitochondria
there is circular chromosomes found in chloroplasts
