ch 3 Flashcards
genome
one copy of all DNA of an organism
how many genomes do bacteria have
1 million nucleotide base pairs
how many genomes do humans have
3 billion nucleotide base pairs
does genome size equal organism complexity
no
chromosomes
DNA stored in the nucleus as chromosomes
how many unique chromosomes are in humans
23
define histones
protein DNA is wrapped around
multiple DNA-wrapped histones form _____-
coils
define chromatin
DNA and protein together
how many types of histone proteins are there
5
define nucleosome
one set of histones with DNA wrapped around
8 histones make 1 nucleosome
2 copies of H2A, H2B, H3, & H4
which histone is not used to make a nucleosome
H1
what does the H1 histone do
lie outside nucleosome and clamp DNA to it
not considered part of the nucleosome
define heterochromatin
condensed chromatin
inactive DNA
define euchromatin
decondensed chromatin
active DNA
function of chromatin remodeling complexes
control chromatin compaction
what are the 3 main types of DNA sequences
genes
intergenic regions
telomeres
define genes
distinct DNA segments that can be transcribed
transcription process overview
1.) DNA of gene is opened
2.) RNA nucleotides are added based on DNA
3.) RNA molecule complementary to DNA is formed
translation process overview
1.) mRNA is used as instructions to make a protein
2.) amino acids are linked together for polypeptide chains
3.) sequence of amino acids is determined by RNA sequence
define ncRNA
noncoding RNAs
don’t make protein
define mRNA
protein-coding genes
define promoter
DNA sequence just before gene
helps begin transcription
define terminator sequence
DNA sequence at end of gene
stops transcription
parts of a gene
promoter
transcribed portion
terminator sequence
define intergenic regions
DNA regions between genes
not used to make RNA
define junk DNA
intergenic and noncoding DNA
not actually junk lol
define telomeres
ends of chromosomes
forms closed loop
