BIOL 1030H Study Guide - Final Guide: Coiled Coil, Spindle Apparatus, Polymerase Chain Reaction
3 May 2018
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Cell Division
●Prokaryotes divide by binary fission
1. The circular bacterial DNA molecule is attached by proteins to the inner membrane (red)
2. DNA replication begins at a specific location and proceeds bidirectionally around the
circle
3. The newly synthesized DNA molecule is also attached to the inner membrane, near the
attachment site of the initial molecule
4. As replication proceeds, the cell elongates symmetrically around the midpoint, separating
the DNA attachment sites
5. Cell division begins with the synthesis of new membrane and wall material at the
midpoint
6. Continued synthesis complete the constriction and separates the daughter cells.
Cell Division
●Mitotic cell division is the process by which a single cell divides into two cells that,
except for rare mutation, are genetically identical to the parent cell
1. Prophase: Chromosomes condense. Centrosomes radiate microtubules and migrate to
opposite poles.
2. Prometaphase: Spindles attach to kinetochores on chromosomes.
3. Metaphase: Chromosomes align in centre of cell
4. Anaphase: Sister chromatids (individual chromosomes when the centromere splits)
separate and travel to opposite poles
5. Telophase and Cytokinesis: Nuclear envelope re-forms, chromosomes condense, and
the cytoplasm divides.
Mitosis
1. Prophase: Chromosomes condense. Centrosomes radiate microtubules and migrate to
opposite poles
2. Prometaphase: Microtubules of the mitotic spindle attach to chromosomes.
3. Metaphase: Chromosomes align in center of cell.
4. Anaphase: Sister chromatids (which become individual chromosomes when the
centromere splits) separate and travel to opposite poles.
5. Telophase: Nuclear envelope re-forms and chromosomes decondense.
Meiosis and Sexual Reproduction
●Meiosis is the basis for sexual reproduction
●Produces gametes in multicellular organisms
●Gametes are haploid
●Fuse during fertilization, creating diploid cell- Zygote
Chromatin
1. DNA duplex 2 nm in diameter
2. Nucleosome fiber 10 nm in diameter
3. Chromatin fiber 30 nm in diameter
4. Coiled chromatin fiber 300 nm in diameter
5. Coiled coil 700 nm in diameter
6. Condensed chromatid 1400 nm in diameter
DNA Replication
●During replication, the two strands of the parental duplex separate
●Each parental strand serves as a template for the synthesis of a new daughter strand, using
the base-pairing rules of A with T and G with C
●The bases are paired in the parental duplex, either A-T or G-C
DNA Synthesis and RNA Primers
●RNA primase lays down an RNA primer
●DNA polymerase extends the RNA primer.
PCR: Polymerase Chain Reaction
●Denaturation
○A solution containing double-stranded DNA (the template duplex) is heated to
separate the DNA into two individual strands.
●Annealing
○When the solution is cooled, the two primers anneal to their complementary
sequence on the strands of the template duplex.
●Extension
○DNA polymerase synthesizes new DNA strands (complementary to the template
duplex strands) by extending primers in a 5 to 3 direction.
Sanger Sequencing- The Sequence
●After the interrupted daughter strands are separated by size, a trace of the fluorescent tags
reveals the identities of the successive dideoxyribonucleotides that terminate strand
elongation, and allows the template sequence to be deduced.
●Once the daughter strand sequence is known the sequence of the template strand can be
determined.
Document Summary
Mitotic cell division is the process by which a single cell divides into two cells that, except for rare mutation, are genetically identical to the parent cell opposite poles: prophase: chromosomes condense. Meiosis is the basis for sexual reproduction. Fuse during fertilization, creating diploid cell- zygote. Chromatin: dna duplex 2 nm in diameter, nucleosome fiber 10 nm in diameter, chromatin fiber 30 nm in diameter, coiled chromatin fiber 300 nm in diameter, coiled coil 700 nm in diameter, condensed chromatid 1400 nm in diameter. During replication, the two strands of the parental duplex separate. Each parental strand serves as a template for the synthesis of a new daughter strand, using the base-pairing rules of a with t and g with c. The bases are paired in the parental duplex, either a-t or g-c. Rna primase lays down an rna primer. A solution containing double-stranded dna (the template duplex) is heated to separate the dna into two individual strands.
