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27 Cards in this Set
- Front
- Back
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Explain the Genetic Basis of Gene Expression (5) |
- Gene expression is regulated by proteins that bind to specific base sequences in DNA - Non-coding regions of DNA are the binding sites for these proteins: - Promoters: attachment points for RNA Polymerase - Enchanters: attachment points for Activator Proteins (increase rate of transcription) - Silencers: attachment points for Repressor Proteins (block/reduce rate of transcription) |
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Environment of Organism influencing Expression of Genes (4) |
Some genes are dependent on outside Temperature: - Human hair/skin impacted by exposure to sunlight & higher temperatures - Pigments in fur of Himalayan rabbits regulated by temperature (Gene C active between 15-25C - gene produces black pigments at nose, feet, and ears [the colder extremities] to absorb more light) |
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Environment of Cell influencing Expression of Genes (6) |
Embryonic Development: - Only a small number of genes determine body patterns at this stage - Their expression is determined by molecules called morphogens (regulate factors which manage transcription production) - Morphogens diffuse from a concentrated source (different embryonic cells get different concentrations of morphogen) - Result = activation/inhibition of different genes in different cells (determines length of fingers, where nose is on face, and other specifics about body structure) |
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Define Epigenetics and Factors within it (4) |
Epigenetics:
The branch of genetics concerned w/ heritable changes NOT caused by DNA Epigenetic Tags: - Methylation (addition of methyl groups to DNA; Binds DNA more tightly to histones & inhibits transcription) - Acetylation (addition of acetyl groups to histones (H1, also DNA too); Binds DNA more loosely to histones & promotes transcription) |
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Environment influencing Heritable changes in Epigenetic Factors (5) |
Example: Rat pups and nurturing - GR gene produces proteins which help rat relax after stressful events - In newborn rat pups, methyl molecules are attached to the gene (from birth), silencing it. - Licking/grooming from mother causes the methyl groups to detach, activating the gene - Extent at which the mother rat nurtures the rat pup effects its characteristics |
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Explain the Process of Transcription (5 - one has two extra facts) |
1) RNA Polymerase binds to the promoter sequence (intron DNA) 2) Operator region of DNA regulates transcription and can inhibit it (silencer) by binding to a repressor protein (preventing the RNA Polymerase from moving/synthesizing mRNA) 3) RNA Polymerase separates the DNA strand & synthesizes a RNA copy (antisense to the DNA) - Moves in a 5' to 3' direction - Covalently bonds ribonucleoside triphosphates 4) Once the mRNA is synthesized, the RNA Polymerase & mRNA detach from the DNA Transcription all occurs within the nucleus |
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Define Pre-mature mRNA (3) |
Pre-mature mRNA: mRNA which still has non-coding sections of a gene (introns). - To become mature needs to remove its introns (post transcriptional modification) - Eukaryotes only |
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Explain mRNA Splicing (3) |
1) Pre-mature mRNA forms splicesomes (complexes assembled from small nuclear RNA [snRNA] and proteins) 2) The splicesomes cause introns to form loops, joining the exons together 3) The introns are then seperated from the mRNA and broken down back into nucleotides to be reused |
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How can splicing increase the number of different proteins an organism can produce? |
Splicing can happen multiple different ways w/ the same gene
- Particular exons can be included/excluded from mature mRNA - Each protein produced w/ alternate splicing will have a diff. function This means that multiple proteins can be produced from the same gene (ex. The IgM gene produces different immunoglobulins (antibodies) to fight different pathogens |
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Explain the metabolism of lactose in E.Coli (3) |
1) When no lactose is present, repressor proteins bind to the operator and prevent the RNA Polymerase to bind to the promoter 2) When lactase is present, it binds to the repressor proteins and changes the active site of the protein, meaning that it cannot bind to the operator. 3) The RNA Polymerase then is allowed to transcribe the proteins involved in lactose metabolism (lactase) |
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Define Chromatin and the Different Types (3) |
Chromatin: A complex of DNA, protein, and RNA. Forms chromosomes. - Heterochromatin: Tightly packed chromatin which can't be transcribed (because of methylation) - Euchromatin: Loosely packed chromatin which can be transcribed (because of acetylation) |
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Describe the structure of a Ribosome (5) |
Large Subunit: - Has the binding sites for tRNA (E-P-A) - Catalyzes the peptide bonds between AAs Small Subunit: - Has the binding sites for mRNA |
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Explain the binding sites of the Ribosome's large subunit (4) |
E site: exit site; where tRNA leaves the ribosome P site: where tRNA holds the growing polypeptide A site: where tRNA (carrying AAs) binds to first in the ribosome (since a maximum of two tRNAs can be bound at the same time, the tRNA at the E site will always be released) |
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Describe the structure of a RNA molecule and specific parts of it (3) |
RNA (specifically mRNA) is made of codons (triplets of nucleotide bases which code for a particular protein) Start Codon: The codon (AUG) the coding region always starts with (the AA associated to it is Methionine) Stop Codon: The last codon (UAA, UAG, or UGA) if the coding region which terminates translation. Doesn't add a AA but releases the polypeptide. |
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What does "degenerate" mean? (2) |
Degenerate: (in terms of the genetic code) when multiple different codons code for the same AA - There are 64 different codons and 20 different AAs |
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Explain the Process of Translation |
Initiation: 1) mRNA binds to a small subunit ribosome 2) The large subunit binds to the small subunit 3) The ribosome moves along the mRNA (5' to 3') until it reaches the start codon (AUG) 4) A tRNA w/ the complementary codon (UAC) and Methionine attached to it bind to the P site Elongation 5) A 2nd tRNA (w/ an AA and complementary to the 2nd codon on the mRNA) binds to the A site 6) As a consequence for catalyzing the new peptide bond (via condensation) the AA at the P site detaches from the tRNA and is transferred to the AA of the A site 7) Ribosome moves one codon (5' to 3') - tRNA of the P site moves to the E site and is released - tRNA of the A site moves to the P site 8) Another tRNA (w/ AA and complementary to the following mRNA codon) binds to the A site 9) The ribosome continues to move and catalyses new peptide bonds on the arriving AAs until the ribosome reaches the stop codon Termination 10) At the stop codon, a release protein factor attaches to the A site (NOT a tRNA) 11) The polypeptide chain is released 12) The ribosome complex disassembles to be reused (mRNA is also broken down & reused in transcription) (Translation happens in the cytoplasm) |
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Compare / Contrast Proteins made by Free and Bound Ribosomes (7) |
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Distinguish between Protein Synthesis in Prokaryotes and Eukaryotes (4) |
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Define: - Secondary Structure - Tertiary Structure - Quaternary Structure |
- Sequence & number of AA in the polypeptide - Alpha helices and Beta pleated sheets formed - 3D shape of polypeptides formed via further folding of the AA sequence - Multiple polypeptide chains and/or prosthetic groups |
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Define Prosthetic Groups (2) |
Prosthetic Groups: An inorganic compound involved in a protein (ex. heme group in hemoglobin) |
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Compare how the various protein structures are formed (4) |
- Primary: covalent bonds between adjacent AAs - Secondary: H-bonds (between non-adjacent AAs & carboxyl groups) - Tertiary: interactions of R-groups (H-bonds, ionic bonds, disulphide bridges & hydrophobic/hydrophilic interactions) - Quaternary: interactions of polypeptides/prosthetic groups (conjugated proteins) |
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Explain the purposes of the various protein structures (doesn't include Quaternary) (3) |
- Primary: controls all following levels of structure (b/c it is the sequence) - Secondary: provides structural stability - Tertiary: Important at times for the function of proteins (enzymes and active sites) |
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Similarities between Protein structures (4) |
- All are made of polypeptide (AA) chains - Both Secondary and Quaternary can be/are Fibrous proteins - Both Tertiary and Quaternary can be/are Globular proteins - All start as primary structures |
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Describe the structure of tRNA (5) |
"Clover-leaf Structure" (there are three loops) - Single chain of RNA - Acceptor loop: (ACC) 3' end; where AA attaches - Bases within the left/right loop aren't paired - The bottom loop (anticodon loop) has the anticodon which is antisense to a codon on mRNA |
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Define Bioinformatics and computers' importance to it (3) |
Bioinformatics: A interdisciplinary field of science (related to multi-branches of knowledge) which collects & analyzes complex & large amounts of data. - Calculations, relies on computers, study/process biological data (genetics/genomics), combines computer science, stats, math, and reasoning Computers analyze the molecular structure of structures like ribosomes/tRNA and make calculations. These calculations would take weeks/months without computers. |
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Explain how tRNA is activated (4) |
- The enzyme Amino-acyl tRNA synthetase binds the AA to ATP, forming an activated AA - The AA is then transferred to the Acceptor loop (3' end) and releases the now ADP molecule - The tRNA is now "charged" meaning it can be used for translation - The energy in the bond linking tRNA & AA will later be used to form the peptide bond of the AA chain |
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What is the purpose of Transcription and Translation? (3) |
The two process work together to create a polypeptide (which becomes a protein). - Proteins carry many essential functions in the cell (the homeostatic environment of the body) which makes their creation so important. (enzymes maintain metabolism which maintains homeostasis) |
