Topic 9: Introduction to DNA Flashcards
what does DNA stand for
deoxyribonucleic acid
where is dna found
in nucleus
what is dna
chromosomes or genes
how many chromosomes do we have
23 pairs of chromosomes
46 chromosomes
what is dna also known as
chromatin
hetero - darker
euchro - lighter
how is dna structured
in a double helix
where are genes
in nucleus
which do genes code for
proteins
where are proteins made
cytoplasm
how are proteins made
dna -> rna -> proteins
what is the human genome
320 million letters of code (base pairs)
the code that makes us who we are
used to understand diseases
how long is dna
2 metres
how big is a nucelus
6 micrometers
what is the width of the double helix
2 nanometeres
how big is a eukayrotic cell
15 micrometers
what is the first level of dna packaging (BASIC UNIT)
2 bits of dna is looped around a histone core (made of 8 proteins, 146 base pairs) which forms a nucleosome (beads on a string)
what is the second level of dna packaging
solenoid
30nm fibres
what is heterochromatin
tightly packed solenoid 30nm fibres
what is euchromatin
beads on a string (basic unit)
where are the genes expressed
euchromatin
as dna is more accessible in comparison to solenoid fibres (not in heterchromatin)
what is a chromsome
condensed = solenoid loops tightly packed
when unwound = beads on string
when completely unwound = dna double helix
what are genes
sections of dna
carry the code for proteins
they have a chromosomal location
how many genes do humans have
25000
what is a genome
the entire DNA sequence of a species
made of 24 chromosomes (22 = autosomoal, 2= sex, XX - female, XY - male)
what cell doesnt have dna
red blood cell - no nucleus
