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118 Cards in this Set
- Front
- Back
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mitosis
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asexual reproduction/cloning. For growth, development and repair.
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cancer
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disruption of mitotic process. Uncontrolled cell growth.
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meiosis
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sexual reproduction
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what do meiosis and mitosis have in common?
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distribution of DNA onto two separate entities.
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What qualities are specific to mitosis?
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1) Keeps same # of chromosomes (diploid)
2) genetically identical daughter cells |
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What qualities are specific to meiosis?
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1) reduction of # of chromosomes to haploid
2) exchange paternal and maternal genetic material (diversity) |
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cytokinesis
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cell division
Not all mitotic processes result in cell division. |
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Interphase
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G1, S, G2
Results in 2 copies of chromosomes attached at the hip by centromere |
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histones
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form nucleosomes on which DNA ravels
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prophase
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-Chromatin condenses into chromosomes
-Copies (chromatids) still together at centromere. -Nuclear envelope dissolves -Nuclear spindle (tubulin) form anchored in animal cells only: by centrioles |
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homologous chromosomes
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1 from mom, 1 from dad
carry the same type (character) of information, but the content (trait) may be different (heterozygous) or the same (homozygous) |
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metaphase
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chromosomes line up in the equator of the cell, nuclear spindle fibers are attached to the centromere pulling the chromosomes to the center
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anaphase
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copies (called chromatids) separate and get pulled to opposing ends by tubulin hydrolysis
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telophase
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reversal of prophase.
Chromosomes decondense, nuclear envelope forms and spindles disappear |
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Go
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non-dividing cells are in this phase
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cell cycle controls
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cyclin
cyclin dependent protein kinase (cdk) |
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cyclin and cdk together
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bonded allosterically = maturation promotion factor (MPF)
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mutagen
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compounds, radiation, or viruses that change nucleotide sequence
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carcinogen
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mutagen which causes cancer
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causes of cancer
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heredity, organic chemicals, radiation, viruses, oncogene, nitrosamines
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nitrosamines
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blackened part of meats
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proto-onco genes
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healthy, control cell cycle
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onco genes
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mutated proto-onco genes --> deregulated cell cycle
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tumor suppressor genes
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when healthy, suppress cancer. When mutated, no cancer suppression.
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cancer cells
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have abnormal nuclei, cells round and look embryonic
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tyrosine kinases
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very important in cycle-stimulating pathway.
Ex. EGF, TNF, Ras protein |
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EGF
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epidermal growth factors
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TNF
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turmor necrosis factor
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Ras protein
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important in cell reproduction
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p53-protein
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inhibits cell cycle when active
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angiostatins
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used to make tumors smaller, starve blood supply
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meiosis of sperm
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stermatogonium --> spermatocyte --> meiosis I --> meiosis II --> 4 sperm
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meiosis of oocytes
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oogonium --> primary oocyte --> meiosis I (1st polar body, secondary oocyte) --> meiosis II --> ovum and 3 polar bodies
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what happens in each phase of meiosis?
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interphase: DNA replication
meiosis I: homologous separate (same type) meiosis II: sister chromatids separate (identical) |
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genomic aberrations
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result from nondisjunction in anaphase I or II --> polyploidy or aneuploidy
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polyploidy
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missing or extra whole set of chromosomes.
often leads to new species. |
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aneuploidy
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extra chromosome or missing chromosome
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trisomy 21 or 22
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down syndrome
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XO
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Turner syndrome
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XYY
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Jacob's syndrome - results in lower IQ
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chromosomal aberrations
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a change in a PIECE of a chromosome: deletion, duplication, translocation, or inversion.
defective crossing over. Meiosis I only. |
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dihybrid problems
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more than one character on different chromosomes. Organisms differ in two traits.
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law of segregation
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when any individual produces gametes, the copies of a gene separate so that each gamete recieves only one copy
--> inheritable unit (allele) are separate from each other |
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law of independent assortment
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characters not linked on the same chromosome get randomly distributed in anaphase
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types of inheritance patterns
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dominant (A,B), recessive (a,i), incomplete inheritance (C^A,C^a), codominance (AB)
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polygenic traits
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more than one allele/gene involved in phenotype (eg. skin color, eye color)
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epistasis
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one set of alleles rules the expression of another
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pleiotropy
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one gene determines many different phenotypes (eg. male determining factor on the y chromosome)
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sex linked genes
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X chromosome is very large - lots of genes
write X^N, X^n |
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hollandric gene
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on Y chromosome
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population
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the smallest unit of evolution.
a group of individuals of one species living in same place at same time. |
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equation for allele frequencies
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p + q = 1
p^2 + 2pq + q^2 = 1 |
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if no evolution occurs in an allele...
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no change in the allele frequency over time
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causes of evolution (4)
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1) gene flow
2) genetic drift 3) mutation 4) natural selection |
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bonds btwn nitrogenous bases of nucleotides in DNA, RNA
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hydrogen bonds
DNA: Adenine - Thymine (2 bonds) Cytosine - Guanine (3 bonds) RNA: Adenine - Uracil (2 bonds) Cytosine - Guanine (3 bonds) |
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3 components of a nucleotide
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phosphate + deoxyribose + nitrogenous base
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gene
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a nucleotide sequence (sense strand) encoding the amino acid sequence of a polypeptide or regulatory RNA strand
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histone proteins
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conserved through evolution
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nucleosome
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DNA coiled around histones
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heterochromatin
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non-active DNA (info locked up) on periphery of nucleus
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euchromatin
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active DNA (info accessible) in center of nucleus
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antiparallel
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one strand of DNA is 5` to 3`. The complementary is 3` to 5`.
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DNA and RNA polymerases can only facilitate the dehydration reaction in which direction?
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The 5` to 3` direction.
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helicase
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binds to origin of replication + unwinds DNA
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topoisomerase
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binds downstream and prevents overwinding
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single strand binding proteins
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prevents DNA strands from reannealing (attaching to each other again). Stabilizes unwinding.
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primase
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binds w/ an RNA primer, which allows polymerase III to bind.
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DNA polymerase III
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replaces primers w/ RNA.
Nucleotides are complementary binding and form covalent bonds. |
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leading strand
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nucleotides (triple phosphorylated) attached in a 5` to 3` direction.
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lagging strand
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polymerase works backward, but also in 5` to 3` direction, forming okazaki fragments.
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ligase
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binds okazaki fragments together
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DNA polymerase I
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substitutes out primer for DNA
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central dogma
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DNA --> RNA --> polypeptide
Info -----------------> function |
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transcription
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DNA --> RNA (nucleotide sequence)
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translation
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RNA --> polypeptide (nucleotide sequence --> amino acid sequence)
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Alu sequences
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10% of DNA. repetitive DNA that does not code for proteins.
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transposons
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"cut out" and reattached. A form of jumping genes.
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retrotransposons
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made of RNA. reverse transcriptase transcribes into DNA, which is inserted into the genome.
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gene
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encodes the information (nucleotide sequence) to produce a polypeptide (amino acid sequence) or a regulatory compound (RNA)
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sense strand
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complementary to the antisense/nonsense strand (which is transcribed into mRNA). Polypeptide sequence can be directly inferred from this strand.
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antisense/nonsense strand
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codes for the RNA that is translated into proteins
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nitrogenous bases of RNA
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Uracil
Adenine Cytosine Guanine |
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codon
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codes for 1 amino acid. 3 nucleotides.
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RNA processing
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eukaryotes have processing, prokaryotes don't
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RNA polymerase II
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binds to TATA box in promoter.
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transcription initiation complex
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RNA polymerase II w/ several transcription factors (eg. steroid/hormone receptor complex) and an enhanser (for upstream) binded to the promoter.
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RNA polymerase
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separates hydrogen bonds from bases and complements the sense strand w/ RNA nucleotides
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transcription ends when...
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terminator sequence is reached
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extra step in eukaryotes after transcription
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transcription gives pre-mRNA, which must be processed to produce mRNA
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processing of pre-mRNA
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happens in nucleus.
-5` end cap attached -poly-A tail attached to 3` end -introns spliced out and exons linked together |
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5` end cap
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used for binding to ribosomes
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poly-A tail
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-attached to 3` end.
-encodes the # of polypeptides to be produced -AAAAA: w/ each copy snips off an A = 5 copies |
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splicosomes
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splice introns out of pre-mRNA, link exons together
can lead to alternative splicing |
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consequence of splicing of pre-mRNA
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same informational space + same info in many different polypeptide domains
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how does mRNA get to ribosomes? What does it do there?
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goes through nuclear pores (controlled) to the ribosomes for translation
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southern blotting
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DNA-DNA hybridization
puts DNA on nitrocellulose paper to be used as court evidence |
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where does translation occur
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at a ribosome
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codon
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on mRNA. 3 nucleotides, but only usually 2 are read to code for each amino acid.
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anti-codon
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on tRNA.
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start codon
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AUG --> methionine
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codon at distal end
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ACC
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tRNA synthase
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mathes up anticodon w/ one binding site and amino acid at other end (binding site)
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steps in translation
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initiation, elongation, termination
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sites on rRNA
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exit, polypeptide, attachment
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initiation
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1) mRNA binds to ribosome in the p-site
2) initiator tRNA w/ anticodon UAC and methionine binds to p-site 3) large subunit moves on top to close ribosome --> translation/initiation complex is complete |
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elongation
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1) next tRNA w/ amino acid moves into the a-site
2) anticodon/codon bind and the multienzyme/ribosomal RNA of the ribosome facilitate dehydration rxn btwn polypeptide chain on p-site + amino acid on a-site to form a peptide bond. 3) Ribosome moves 1 codon downstream --> peptide chain moves from a-site to p-site 4) empty tRNA leaves at e-site (can be reused after being loaded again) |
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termination
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1) stop codon is reached (no matching tRNA)
2) released factors bind to the a-site on stop codons 3)complex disintegrates into: ribosomal subunits, tRNA, releasing factors, finished polypeptide chain |
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stop codons
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UAG, UAA, AUGA
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chaparonins
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multienzyme complexes giving ideal environment to fold an enzyme a certain way
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when all A's on the poly-A tail are gone:
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mRNA disintegrates into its nucleotides
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polysomes
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several ribosomes translating an mRNA at the same time
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which polypeptides are synthesized into the rough ER?
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polypeptides destined for exocytosis or as integral proteins in the membranes
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signal peptide mechanism
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1) mRNA contains a nucleotide sequence which codes a signal peptide
2) signal peptide binds to a signal recognition particle forming a signal-recognition-particle complex 3) SRP-complex binds to SPR-receptor protein embedded in ER membrane 4) results in peptide chain (growing) to penetrate through a pore into the ER. 5) signal peptide gets removed when done |
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point mutations
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single nucleotide polymorphisms (SNPs)
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types of point mutations
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missence, consense, frameshift, 3-bp deletion
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missence mutation
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changes one amino acid
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consense mutation
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early stop codon
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frameshift mutation
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deletion, cause extensive missense
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