dna and cell cycle
TRANSCRIPT
Cells•Smallest unit of life. •Able to carry out all functions of life.
Cell Theory• All living organisms are made of one or more
cells.• All cells come from other cells.
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The Cell Cycle
•series of changes a cell undergoes from the time it forms until the time it divides• stages • interphase• mitosis• cytoplasmic division
Stages of Interphase
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• Cell grows, maintains routine functions• Cell replicates genetic material and synthesizes new organelles to prepare for division
• G1: 1st growth stage. Cell matures and carries out it’s assigned function. May last indefinitely.• S: Genes are copied• G2: 2nd growth stage. Membranes, cytosol, and organelle numbers increase.
Mitosis
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2 identical daughter cellsExact replicas of the parent cellGrowth, Repair, Replacement
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Genes• DNA- molecule that carries
genetic information• Chromosome- DNA plus
associated proteins• Gene – segment of DNA
that codes for one protein• Genome – complete set of
genes
1 gene = 1 protein
DNA and the Cell Cycle
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Genes
Gene – segment of DNA that codes for one protein1 gene = 1 protein
Genome – complete set of genesGenetic Code – method used to translate a sequence of nucleotides of DNA into a sequence of amino acids
What is the difference between a gene, DNA, and a chromosome?
Protein Synthesis
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1) Transcription: DNA copied to mRNA in nucleus
2) Translation: mRNA copied to protein at ribosomes• Codon: mRNA triplet• Anticodon: tRNA triplet
DNA mRNA protein
DNA vs RNA DNA RNAdouble stranded single stranded Deoxyribose RiboseA,C,T,G A,C,U,GMust stay in nucleus Can leave nucleus1 type 3 types
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RNA MoleculesMessenger RNA (mRNA) -
• delivers genetic information from nucleus to the cytoplasm• single polynucleotide chain• formed beside a strand of DNA• RNA nucleotides are complementary to DNA nucleotides
(exception – no thymine in RNA; replaced with uracil) • making of mRNA (copying of DNA) is transcription
Transfer RNA (tRNA) -• carries amino acids to mRNA• carries anticodon to mRNA• translates a codon of mRNA into an amino acid
Ribosomal RNA (rRNA) –• provides structure and enzyme activity for ribosomes
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TranscriptionRNA polymerase copies DNA mRNAActive strandComplementary strand
Transcription
TranscriptionmRNA is a mirror image of the active strand, except T is now U
mRNA Leaves Nucleus
Translation•On the ribosome•mRNA codon matches to tRNA anticodon•tRNA carries amino acid
TranslationmRNA Protein
Protein Chain•Where did the original DNA go?•Where did the mRNA go?•Where did the tRNA go?•Where did the ribosome go?•Where did the amino acids go?•Where does the protein go?
Genetic Code64 codons20 amino acidsRedundancy