Fill in phases of cell cycle
most cells that will no longer divide
mitotic spindle begin to form
chromosomes become visible
kinetochore-microtubule interactions move chromosomes to midline
chromosomes line up at central plate
sister chromosome separate and chromosomes move apart
nuclear membranes form around separated chromosomes
cell plate forms or cleavage furrow pinches cells apart
Probabilities of Genotype (example)
AAbb X AaBb
AaBB X AaBb
AABbcc X aabbCC
AaBbCc X AaBbcc
Blood Groups of Man who could not be the father
no groups exonerated
A or O
A or O
B or O
Steps of transcription
Transcription factors bind to promoter and facilitate the binding of RNA polymerase II, forming a transcription initiation complex; RNA polymerase II separates DNA strands and RNA synthesis begins at the start point.
RNA polymerase II moves along the DNA strand, connecting RNA nucleotides that have paired to the DNA template to the 3' end of the growing RNA strand
After polymerase transcribes past a polyadenylation signal sequence, the pre-mRNA is cut a released.
Phases of cell cycle
90% of cell cycle; growth and DNA replication
Chromosome consists of a long thin chromatin fiber made of DNA and associated proteins; growth and metabolic activities occur.
Synthesis of DNA. Chromosome is duplicated; two exact copies (sister chromatids) are produced and held together tightly at their centromeres and by cohesions along with their length; growth and metabolic activities continue.
Growth and metabolism continue
Cell division occurs
The sister chromatids, held together by sister chromatid cohesion, become coiled and tightly condensed.
Kinetochore fibers from opposite ends of the mitotic spindle attach to the kinetochores of the sister chromatids; the chromosomes move towards midline.
The centromere of the chromosome is aligned at the metaphase plate along with the centromeres of the other chromosomes.
Cohesins are cleaved and the sister chromatids separate (now considered individual chromosomes) and move to opposite poles of the cell.
Chromatin fiber of the chromosome uncoils and is surrounded by reforming nuclear membrane.
Processes of transcription and translation
nucleus (cytoplasm in prokaryotes)
cytoplasm; ribosomes can be free or attached to ER
RNA nucleotides, DNA template strand, RNA polymerase, transcription factors
amino acids, tRNA, mRNA, ribosomes, ATP, GTP, enzymes, initiation, elongation, and release factors.
RNA polymerase, spliceosomes
aminoacytl-tRNA synthetase, ribosomal enzymes (ribozymes)
Control- start and stop
transcription factors locate promoter region with TATA box and start point, polyadenylation signal sequence to stop
initiation factors, initiation sequence (AUG), stop codons, release factor
primary transcript (pre-mRNA)
RNA processing: 5' cap and poly-A tail, splicing of pre-mRNA, introns removed by spliceosomes.
spontaneous folding, disulfide bridges, signal peptide removed, cleaving, quaternary structure, modification with sugars, etc.
Key events of meiosis
Chromosome duplication; sister chromatids attached at centromere and by sister chromatids cohesion along their lengths.
Chromosomes condense. Synapsis of homologous pairs (held by synaptonemal complex); crossing over (exchange of corresponding DNA segments) is evident at chiasmata.
Homologous pairs line up independently at metaphase plate (orientation of maternal and paternal homologs is random).
Homologous pairs of chromosomes separate and homologs move toward opposite poles; sister chromosomes remain attached at centromere.
Haploid set of chromosomes, each consisting of 2 sister chromatids, aligns at metaphase plate; sister chromatids not identical due to crossing over.
Sister chromatids separate and move to opposite poles as individual chromosomes.
Levels of metaphase chromosome packing
1. Nucleosomes (10-nm fiber of nucleosomes and linker DNA)
2. 30-nm fiber
3. Looped domains (300-nm fiber)
4. coiling and folding of looped domains into highly condenses metaphase chromosome.
DNA sequence info
Types of DNA
Exons or rRNA/t-RNA coding
Protein and RNA coding sequences
noncoding sequences with genes
enhancers, promoters, and other such sequences
Transposable elements and related sequences
multiple copies of mostly movable sequences
family of short sequences related to transposable elements
retrotransposons found in introns of most genes
Unique noncoding DNA
gene fragments and psuedogenes
multiple copies of large sequences
Simple sequence DNA
DNA centromeres and telomeres, also STRs