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23 Cards in this Set
- Front
- Back
What is a mononucleotide? |
A mononucleotide is a type of biological molecule. It's made from a pentose sugar (has 5 carbon atoms), a nitrogen containing organic base and a phosphate group. |
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What is the sugar in DNA? |
The pentose sugar in a DNA mononucleotide is called deoxyribose. Each DNA mononucleotide has the same sugar and phosphate group. The base cam vary though. The four bases are Adenine, Thymine, Cytosine and Guanine. |
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What is the sugar in RNA? |
RNA contains mononucleotides with a ribose sugar. It has a phosphate group and one of four different bases. These bases are Adenine, Uracil, Cytosine and Guanine. |
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How are polynucleotides formed from mononucleotides? |
A polynucleotide is a polymer of mononucleotides. Both DNA and RNA mononucleotides form polynucleotides. They are joined through condensation reactions between the phosphate of one mononucleotide and the sugar group of another. DNA is made of two polynucleotide strands, RNA has just one. |
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What is the structure of DNA? |
Two DNA polynucleotide strands bond together by hydrogen bonding between bases. Each base has a complementary base partner. Adenine pairs with Thymine and Cytosine bonds with Guanine. Two polynucleotide strands twist to form the DNA double helix. |
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How is the genetic code non-overlapping? |
In the genetic code, each base triplet is read in sequence, separate from the triplet before it and after it. The base triplets don't share their bases, thus it is non-overlapping. |
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How is the genetic code degenerate? |
There are more possible combinations of triplets than there are amino acids (20 amino acids but 64 triplets). This means that some amino acids are coded for by more than one base triplet. Tyrosine can be coded by UAU or UAC. |
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What is a gene? |
A gene is a sequence of mononucleotide bases on a DNA molecule that codes for the sequence of amino acids in a polypeptide. The sequence of amino acids in a polypeptide chain form the primary structure of a protein. |
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What is the general structure of an amino acid? |
Amino acids have the general structure of a carboxyl group, an amine group (-NH2) and a carbon containing R group. The difference between the amino acids are the R group. |
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How are polypeptides formed? |
Amino acids are linked together by condensation reactions to form polypeptides. A molecule of water is released during the reaction. The bonds are called peptide bonds. |
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What are the primary and secondary structures of a protein? |
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What is the tertiary structure of a protein? |
The coiled or folded chain of amino acids is often coiled and folded further. More bonds form between the different parts of the chain.
For proteins made from a single polypeptide chain, the tertiary structure forms the final 3D structure. |
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What bonds are present in the tertiary structure of a protein? |
Ionic Bonds - attractions between negative and opposite charges on different parts of the molecule. Disulphide bridges - When two molecules of cysteine come close together, the sulphur atom in one bonds to the sulphur in the other, Hydrophobic and hydrophobic interactions - hydrophobic groups clump together, meaning hydrophilic groups are more likely to be pushed outside, which affects how the proteins fold up. |
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What is the quaternary structure of a protein? |
Proteins that are made of several different polypeptide bonds are held together by bonds. The quaternary structure is the way these chains are assembled together. For proteins made from more than one chain (insulin, collagen etc.) the quaternary structure is the final 3D structure. |
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What are globular proteins? |
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What are fibrous proteins? |
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How do enzyme properties relate to their tertiary structure? |
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Why are enzymes said to be biological catalysts? |
Look in topic 2 text book. |
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What was the first model to explain enzymes? |
The lock and key model states the substrate fits into the enzyme the same way the key fits into a lock. |
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What is the 'induced fit' model? |
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How do enzymes affect rate of reaction? |
These factors reduce the activation energy so the reaction happens faster. |
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How does enzyme concentration affect rate of reaction? |
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How does substrate concentration affect rate of reaction? |
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