dna and mitotic cycle Flashcards
semi-conservative replication
each time DNA is replicated half of the original molecule is kept in each new molecules
steps of DNA replication
1 unwinding, dna helices breaking hydrogen bonds
2 dna polymerase for copying process adding nucleotides
3 leading strand replicated continuously in 3’ to 5’
lagging strand replicated discontinuously in 5’ to 3’ direction In short sections making Okazaki fragments
nucleotides are joined by
phosphodiester bonds
what phase does dna replication occur in
s phase
rna polymerase is used in
transcription
what are Okazaki fragments joined by
DNA ligase
purines
double ring structure
adenine
guanine
semi conservative replication is good because
it ensure genetic continuity between generations
lagging strand
runs in the 5’ to 3’ direction
transcription
1 rna polymerase attaches to start of gene and unwinds gene
2 template/transcribes strand is copied
3 nucleotides approach and hydrogen bond with complementary bases +phosphodiester bonds to growing mrna hydrogen broken
mana leaves through nuclear pore
translation
tuna transfer amino acids to ribosome anticodon on tRNA complementry to codon
modifying mrna
rna processing
rna splicing removes introns and exons joined together
introns help dna regulate activity of genes
alternative splicing
results in different Mrnas ebbing made from original primary transcript meaning. that one gene can code for several proteins or diff forms of same protein
gene mutation
change in sequence of bases can result in different sequence of amino acid
chromosome mutation
Chromosome structure mutations are alterations that affect whole chromosomes and whole genes rather than just individual nucleotides. These mutations result from errors in cell division that cause a section of a chromosome to break off, be duplicated or move onto another chromosome.
stop codons
UAG, UAA, UGA
start codon
AUG amino acid methionine
2 things in early prophase
nuclear envelope breaks down
chromosome condense
2 things in late prophase
chromosomes migrate to opposite poles of cell
spindle fibres from
2 things in metaphase
chromosomes line up along equator
spindle fibres attach to kinetochores
kinetochore
protein structure found at centromere where microtubules attach
3 things in anaphase
chromatids separate
spindle fibres attach to centrosome
poles of cell move apart
3 things in telophase
chromosomes begin to uncoil
nuclear envelope reforms
spindles disappear
telomere
a repetitive sequence of DNA at the end of a chromosome that protects genes from the chromosome shortening at each cell division
oncogene
mutated gene that has the potential to cause cancer.
transcription
genetic code on DNA is copied into mRNA;
double helix of DNA unwinds (in region to be copied); complementary nucleotides line up along coding strand of DNA; A to U and C to G;
assemble together to make a complementary strand of mRNA; under influence of RNA polymerase;
mRNA unzips from DNA template and passes to ribosomes;
translation
