DNA - The Universal Molecule of Life
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Created by:
maestro12 on September 22, 2010
Subjects:
transcription, translation, protein synthesis, dna replication, mutations
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34 terms
Terms | Definitions |
|---|---|
 TRANSCRIPTION | Generates a single stranded mRNA molecule that is identical in sequence with once of the strands of the DNA double helix. |
| mRNA | Single stranded identical copy of one strand of DNA. Contains Uracil instead of Thymine. |
| INTRONS | Nucleotide sequences that are removed before the mRNA leaves the nucleus; not involved in translation. |
| EXONS | Nucleotide sequence of pre-mRNA that are not removed in the nuclues and ultimately make up mRNA that is translated at the ribosomes to form proteins. |
| pre-mRNA | mRNA before it leaves the nucleus. Has not had the introns removed yet. |
| TRANSLATION | The process by which a ribosome assembles amino acids in a partiucular sequence to synthesus a specific polypeptide coded for by the mRNA. |
| RIBOSOMES | Are made of two sub-units, one small one large. Assembled in the nuclus from rRNA and proteins. |
| tRNA | Transfers amino acids to the ribosomes. Exist free-floating within the cytoplasm. Have anti-codons which are complementary to the mRNA codons. |
| GENE REGULATION | Cells do not express all of the genes in its genome at the same time, even when expressed there are controls on how fasr the gene is transcribed and translated. |
| REGULATOR GENE | A gene that codes for the production of a repressor protein. |
| REPRESSOR PROTEIN | A proteing coded for by a regulator gene that binds to an operator gene which inhibits the transcription of the structural gene. |
| OPERATORS | A region of DNA situated around the promoter that interacts with a specific repressor. When bound to the repressor, it prevents the transcription of the structural gene. |
| MUTATION | A change to DNA and genetic information. Can be spontaneous or induced. |
| SOMATIC MUTATIONS | Occur in somatic cells are NON-HERITABLE |
| GERM LINE MUTATIONS | Occur in germ line cells or gametes. Are HERITABLE. |
| CHROMOSOME MUTATIONS | Result of chnages to overall structure of chromosomes. |
| GENE MUTATIONS | Result of chemical changes in individual genes. May occur in the process of DNA replication. |
| POINT MUTATIONS | A change to a single nucleotide base. |
| SUBSTITUTIONS | When one base is subsituted for another. Can be: - Neutral - no effect on the amino acid produced - Codes for a different amino acid but a functional protein is still produced - Codes for a different amino acid but the resulting protein is non-functional. |
| INVERSION | When two or more nucleotides reverse eg: GAG to AGG - changes the amino acid produced. |
| INSERTION | The sddition of one or more nucleotides in a gene mutation. Is a frameshift mutation. |
| DELETION | The deletion of a whole amino acid with no change to subsequent ones. Or the deletion of one nucleotide which will cause a frameshift mutation and will affect all subsequent bases. |
| CHROMOSOME MUTATIONS | ... |
| DELETIONS | When a section of chromosome breaks off, taking all the genetic information that it contains with it. |
| INVERSION | When the chromosome breaks and the peice rotates 180 degrees and joins again. Thus reversing the normal sequence of genes. |
| TRANSLOCATIONS | When a section of one chromosome breaks off and attaches to another one. The individual still contains the same genetic information, just in a different place. |
| DUPLICATIONS | When a section of a chromosome replicates so that it repeats a set of genes. |
| ANEUPLOIDY | When the chromosome number is more/less than that of a normal diploid/haploid cell. Results in the addition/loss of chromosomes. |
| NON-DISJUNCTION | When two homologous chromosomes, instead of seperating, go into the same cell. |
| TRISOMY | A condition where an individual has 3 of one chromosome (eg: down syndrome - trisomy of chromosome 21) |
| POLYPLOIDY | Half the gametes have two of each type of chromosome and the other half have none. Lethal in humans, but very common in plants. |
| TRIPLOID | A diploid gamete fuses with a normal gamete resulting in the child having 3 of each chromosome |
| TETRAPLOID | Two diploid gametes fuse to create a child with four of each chromosome. |
| MUTAGENS | Speed up the rate of mutation. Can include: - X-Rays, UV light, Colchicine, Cyclamate, Mustard Gas, Nitrous Acid, Acridine orange. |
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