Theme 2D Flashcards
what are mutations
changes to nucleic acid sequence
are mutations inherited or not
both (inherited = germline, not = somatic)
what is the progenitor cell
where the mutation occurrs, all other daughter cells will express the mutation
what is base substitution
single nucleotide change
what is insertion
one or more base pairs added in sequence during DNA replication
what is deletion
one or more base pairs skipped during DNA replication
can mutations occur in introns, exons, telomeres, or centromeres
yes
what are spontaneous mutations
naturally occurring mutations, mainly caused by DNA replication errors
what are induced mutations caused by
mutagens that cause mutations at a much higher rate than spontaneous mutagens, they can replace or alter a base so it mispairs, or damage a base so it can’t pair correctly
what happens if a mutation occurs on the exon of a gene
there may be impacts on the encoded polypeptide
missense mutation
codon change causes change in an amino acid
nonsense mutation
sense codon change into a stop codon
silent mutation
codon change does no change amino acid due to degeneracy of the genetic code
frameshift mutation
insertion or deletion of a small number of base pairs that alter the reading frame
which type of mutation would have the most effect on the function of the polypeptide
depends on location
deletion (large scale chromosomal mutation)
loss of gene
duplication/amplification
increasing dosage of genes
translocation
interchanged genetic parts form non homologous chromosomes
inversion
reversing orientation of a segment of the chromosome
wild type allele
form of gene most found in nature or the standard laboratory stain of a model organism
loss of function alleles (lof)
mutations that reduce/eliminate gene function/expression
gain of function allele (gof)
mutations that enhance gene function/expression
what is the cell cycle
an ordered set of processes by which one cell grows and divides into two daughter cells
what happenes in G1 and G2
synthesis of proteins, RNA, metabolites, (not DNA)
what happens in S phase
DNA replication
what happens in M phase
mitosis
what are homologous chromosomes
maternal and paternal pair of the same chromosome
siste chromatids
identical copies of a chromosome, created during DNA replication and joined at the cenromere
prophase
(2n) duplicated chromosomes condense and evoke visible w/ sister chromatids, nuclear envelope breaks down, centrioles move apart and form mitotic spindles
metaphase
(2n) chromosomes are aligned at equator (metaphase plate) and are attached to opposite poles under tension
anaphase
(4n) sister chromatids and centromeres separate to the poles (8 chromosomes), centrosomes move further apart
telophase
(4n) chromosomes clustered at opposite pole and decondensing, cytoplasm begins to divide by furrowing (cytokinesis)
what is recombination
exchange of sections of non sister chromatids (in homologous pairs) by crossing over (during prophase I)
after mitosis I, what is the ploidy of each cell
haploid, but the chromosomes are replicated
are the sister chromatids split after meiosis I
no
when do centromeres and sister chromatids separate in meiosis
anaphase II
at the end of meiosis, how many daughter cells are there and what is their ploidy
4 non-identical haploid cells
