test 6 Flashcards
cell division and classical genetics
What is the central dogma of molecular biology?
theory that DNA stays in the nucleus but needs to direct activities into the cytoplasm, therefore it only flows in one direction, DNA is responsible for the building of proteins, Replication (DNA → DNA) -> Transcription (DNA → RNA) -> Translation (RNA → Protein)
What is DNA made of? Why is it important to life?
double helix shaped polymer, consists of nucleotide monomers with a sugar-phosphate backbone, important as it serves as the instructions for protein- building that supports life functions- develop, survive, reproduce
complimentary paired nucleotides
adenine (A) + thymine (T) and cytosine (C) + guanine (G)
what does a karyotype show
a display of the chromies of a cell, which can be used to identify chromie abnormalities
chromosome
condensed chromatin passed from parent to offspring
sister chromatid
a chromosome and its duplicate joined at the centromere
centromere
where sister chromatids link together
karyotype + down syndrome
third chromie is present in one of the 23 homologous pairs, making 47 total chromies
cell cycle
interphase (90%) and mitosis + cytokinesis (~10%)
stages of mitosis- nuclear division
- interphase 2. prophase 3. metaphase 4. anaphase 5. telophase 6. cytokinesis
interphase
centriole pair replicates & DNA replicates to create duplicated chromies, starts w/ 4 chromies + 8 tids
interphase stages
G1= growth 1 (centriole pair replicates, S= synthesis (DNA replicates), G2= growth 2 (nuclear membrane + nucleolus still intact)
prophase
centriole pairs begins to migrate to opposite poles, nuclear membrane begins to dissolve, spindle fibers begin to form between centriole pairs, duplicated chromosomes begin to condense, nucleolus begins to disappear
metaphase
centriole pairs are fully migrated to opposite poles, spindle apparatus (mitotic spindle) is fully formed, chromies in middle of cell, nuclear membrane dissolved, chromies most condense
anaphase
away, spindle fibers pull the sister chromatids apart at the centromere and drag them to opposite poles, cell elongates (ovoid-egg shaped)
telophase
pinching in (cleavage furrow), nuclear membranes begin to reform, spindle apparatus disassembled, chromies begin to decondense, nucleolus begins to reform
cytokinesis
2 daughter cells- 4 chromies each 0 tids, no spindle fibers, chromies decondensed + lengthened, nucleolus & nuclear membrane formed
what is the purpose of each cell checkpoint? what is checked?
to determine if the cell can continue, contents of cell are reviewed to assess for DNA damage or phase being incomplete
how does a cancer cell differ from a healthy cell
cancer cells do not regulate the cell cycle like normal, they divide excessively and invade other tissues of the body
What is the difference between a proto-oncogene and a tumor suppressor gene?
A proto-oncogene is a normal gene that can turn into an oncogene, which promotes cell growth. A tumor suppressor gene is a normal gene that inhibits cell growth and division, preventing cancer development
how does the cell prepare for mitosis/meiosis
they begin with diploid parent cells & chromies that were duplicated during the S phase of interphase (chromies duplicated)
what is the fxn of mitosis for a cell and where does it occur
produces 2 genetically identical diploid somatic daughter cells from somatic (body) cells, bone marrow, neurons, rbc, skin cells, 46 chromies