cells Flashcards
what is the largest organelle
nucleus
what is the function of the nucleus
contains chromosomes which carry genetic material which control the cell activities
what is the function of the cell surface membrane
forms boundary between cytoplasm of cell and the outside
partially permeable so determines what can go in and out of cell(selectively permable)
what is a gene
a section of DNA that determines a particular feature
what are proteins that DNA coils around
histone proteins
what is the function of DNA polymerase
assembles new strands of DNA from nucleotides
where does protein synthesis take place
cytoplasm of cell
what are the differences between DNA and RNA
DNA is a double helix RNA is a single strand
DNA contains the sugar deoxyribose RNA contains ribose
RNA contains the base uracil instead of thymine
what are the 2 stages of prt synthesis
transcription and translation
describe the process of transcription
happens in the nucleus
in a chromosome part of the DNA helix unwinds and unzips so the 2 strands separate exposing the bases along the template strand
DNA forms framework and mRNA is formed
building blocks of mRNA are RNA nucleotides
they line up according to the complementary base pair rule
mRNA leaves nucleus and moves in to cytoplasm through the pores of the nuclear membrane
DNA helix then zips up again
describe the process of translation
takes place at ribosome
first tRNA binds to bind at mRNA does so at start codon
another tRNA brings an anticodon which binds with next codon on mRNA
bonds form between first and second amino acid process is ongoing forming a polypeptide
at end of chain is stop codon
what is a mutation and what types of mutations can occur
random change in DNA of cell
duplication: nucleotide is inserted twice
deletion: nucleotide is missed out
substitution: diff nucleotide is used
inversion: sequence of bases in a triplet is reversed
