BIO 202 Unit 3 terms Flashcards
G1 phase
longest phase; when the cell is growing and metabolically active
S phase
when DNA synthesis (replication) takes place
G2 phase
cells prepare for cell division
M phase
cell division (mitosis or meiosis) occurs as well as cytokinesis
helicase
separates the two parental strands
single-strand binding proteins (SSBPs)
keep the separated parental strands from rejoining
topoisomerase
keeps the DNA strand that is not yet separated from coiling up
primase
RNA polymerase that creates RNA primer on the lagging strand
DNA pol III
synthesizes the leading strand; replaces RNA primer with DNA on the lagging strand
DNA pol I
extends the Okazaki fragment on the lagging strand
DNA ligase
zips the DNA back up
in which direction is DNA synthesized?
5’-3’ where new pieces are added onto the 3’ end
chromosome
a piece of a genome
gene
a specific region of a chromosome where the sequences of bases in that region contain the information to make a unique RNA
genome
the entire genetic information of a cell in the sequences of bases in DNA
homolog/homologous chromosomes
same in shape or size, but have slightly different alleles
alleles
alternate versions of a gene
karyotype
number and types of chromosomes in a cell
chromatid
a double-stranded DNA copy of a replicated chromosome
sister chromatids
identical pieces of a replicated chromosome that are attached to each other; when separated they become individual chromosomes
diploid cells
2n; have two of each chromosome type
haploid cells
n; have one of each chromosome type
what is the difference between homologous chromosomes/pairs and sister chromatids?
homologous pairs are not identical; sister chromatids are identical
independent assortment
alleles of different genes don’t stay together when gametes form
