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32 Cards in this Set
- Front
- Back
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________: DNA replicates in the cells, never leaving the nucleus. When complete, a new double stranded molecule identical to the original is formed. |
DNA replication |
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What is the role of the proteins involved in DNA replication? |
One protein unwinds the double helix, one holds the strands apart, and others perform different distinct functions. |
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_________: Crucial enzyme that travels along the single DNA strand, adding the correct nucleotides to the free end of the new strand. Also performs proofreading and checks for mutations. |
DNA polymerase |
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________: Mutation where one base pair is replaced by another; also called missense mutation. |
Base pair substitution |
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_______: Insertion or deletion of one or more base pairs to the DNA molecule. |
Frame shift mutation |
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Where does protein synthesis take place? |
Cytoplasm |
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________: Process by which RNA is synthesized from a DNA template. |
Transcription |
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What is the function of RNA polymerase during transcription? |
RNA polymerase binds to a promoter site on the DNA. Then pulls a portion of the DNA strands apart from one another, allowing unattached DNA bases to be exposed. This one DNA strand provides the template for the sequence of mRNA nucleotides. |
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Transcription continues until a ______ _____ is reached. |
Termination sequence |
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After the termination sequence is reached, what happens? |
The RNA polymerases detaches from DNA, and the transcribed RNA is freed to move out of the nucleus and into the cytoplasm |
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________: Process by which RNA directs the synthesis of a polypeptide. |
Translation |
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Anticodon |
dksaf |
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Describe the process of translation. |
-tRNA has site for attachment of an amino acide (opposite side of tRNA is three nucleotides called the anticodon) -tRNA brings specific amino acids (encoded by each mRNA codon) into place at the ribosome site. -As the amino acids are brought into the proper sequence, they are joined together by peptide bonds to form long strands called polypeptides -Translation creates chain of amino acids in specific order that creates a unique protein |
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T/F: Several polypeptide chains may be needed to make a complete protein molecule. |
TRUE |
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_______: Creates chain of amino acids in a specific order that creates a unique protein. |
Translation |
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Why are transcription and translation important? |
Because of cell function! -Most cells produce effects on body through use of proteins. -Each cell has a particular set of genes that is turned on so that it produces its specific proteins.
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"Each cell has a particular set of genes that is turned on so that it produces its specific proteins".
Explain how beta cells in the pancreas illustrate the above statement. |
Beta cells in the pancreas produce insulin- No other cells in the body do that; they have that particular genetic code turned on. As the cells replicate, they reproduce that exact pattern of DNA, which is then transcribed to mRNA, which is translated to a protein, which then produces the hormone. |
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What are the four phases of protein conformation? |
Primary Secondary Tertiary Quaternary |
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Describe the primary protein conformation. |
-Simply an amino acid chain. -Sequence of a chain of amino acids -"Stringing together of amino acids" |
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Describe the secondary protein conformation. |
-Amino acid chain folded into a pleated sheet or helix (DNA!) -Hydrogen bonding of the peptide backbone causes the amino acids to fold into a repeating pattern. |
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Describe the tertiary protein conformation. |
-Pleated sheet or helix folded into hydrophillic or hydrophobic molecule -Three-dimensional folding pattern of a protein due to side chain interactions -Folded in (exposes positive charge) vs. folded out (exposes negative charge) |
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Describe the quaternary protein conformation. |
-Two or more tertiary structures combine to form a functional protein -Protein consisting of more than one amino acid chain -Two or more of the amino acid chains have been folded and oriented, then stick together. -Hemoglobin is an example |
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Proteins are made from what? |
A chain of amino acids (polypeptides) |
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There are _____ types of amino acids in proteins. |
20 types |
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T/F: Each type of protein has a unique sequence of amino acids. |
TRUE |
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T/F: Proteins are major workhorses of the cell. |
TRUE |
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Proteins facilitate transport across membranes by serving as ______, ______, and _____. |
Receptors Enzymes Transporters
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Describe the functional and structural roles proteins play in cell, organ, and organ system function. |
1. Recognition and binding units (receptors) for substances moving in and out of the cell. 2. Pores or transport channels for various electrically charged particles (ions/electrolytes) and specific carriers for amino acids. 3. Specific enzymes that drive active pumps and promote concentration of ions (K+) within the cell, while keeping concentration of other ions (Na+) below concentrations in extracellular environment. 4. Cell surface markers (ex: glycoproteins) that identify a cell to its neighbor. 5. Cell adhesion molecues (CAMs)- Allow cells to hook together and form attachments to the cytoskeleton to maintain cellular shape. 6. Catalysts of chemical reactions 7. Energy transduction: Membrane proteins are key components in converting chemical energy into electrical energy.
***OVERALL: Proteins govern communication between cells through enzymatic, transport, and recognition-receptor functions in cell physiology. |
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Describe a ligand gated ion channel. |
-Proteins make up the channel and are embedded in the membrane -They have a channel and receptor site -Essentially have to be open or closed at any given time. |
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Describe a G-protein coupled receptor. |
-Second messenger system -Protein embedded in the cell- Goes through lipid bilayer 7 times -GDP --> GTP which binds to a plasma protein; Then creates a secondary message response -cAMP and calcium are both prevalent examples |
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Describe an enzyme-linked receptor. |
-Specific ligand binds to BOTH proteins at the SAME TIME, bringing the two proteins together that cause a reaction to phosphorylate different proteins; Reactions then trigger a signal. -Also called "catalytic receptors" -Extracellular side binds ligand; Intracellular side acts as an enzyme!!! -In summary: Enzyme linked receptors essentially turn an extracellular chemical signal into enzyme activity inside the cell. -Regulates gene transcription and primarily CELL GROWTH. |
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Describe an intracellular receptor. |
-Has to be lipophillic -Inside the cell, they connect with a receptor -Happens in the cytosol or nucleus -Whole complex can bind to the DNA and trigger more protein production -Ex: Steroid hormones |
