AS Science OCR Unit 2 Module 3

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Roles of Proteins in cells?
Channels in membranes, structural molecules, hormones, antibodies, enzymes.
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What is a primary structure?
A sequence of amino acids, maintained by peptide links – covalent bonds
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What is a tertiary structure?
The way in which the whole protein is folded into a complex 3-D shape. Maintained by hydrogen bonds, ionic bonds (between charged amino acid groups) and disulphide bridge (between cystine amino acids)
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What is a space filled model of a protein?
Shows the space taken up by atoms in a molecule, shows tertiary structure well.
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What is the ribbon model of a protein?
Shows the protein chain as a ribbon without showing any individual atoms. Shows secondary structure well.
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What is an enzyme?
A biological catalyst that enables reactions to occur in cells with a lower activation energy.
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Why is it important enzymes have a tertiary structure?
So that only one type of substrate will bind to the active site, and a tertiary structure allows a more complex active site
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What is the lock and key model?
Substrate molecule fits into the active site and bonds to it, Energy released by bonds made causes active site change shape &/or bonds to break in the substrate, substrate reacts to form product molecules.
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How does pH affect enzyme action?
Concentration of H+ ions in solution affects the charges on the side groups in the active site. Has an optimum pH at which charge pattern is just right to maintain the shape of the active site
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How does temperature affect enzyme action?
Increased temperature causes the reaction to occur faster but above the optimum temperature bonds break and the active site denatures
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how does Enzyme concentration affect enzyme action?
Increases rate of reaction
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How does substrate concentration affect enzyme action?
Increases the rate, but at high levels of concentration active sites become saturated meaning all active sites become full and no longer has an effect on the rate
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How does a Competitive inhibitor affect enzyme action?
Binds to active site blocking it, not allowing the substrate to enter.
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How does a noncompetitive inhibitor affect enzyme action?
Bonds elsewhere on the enzyme that causes the active site to change shape
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Roles of enzymes in respiration?
Enzymes in cells breakdown glucose and carbon dioxide and water at the same time ATP is form from ADP
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Role of enzymes in photosynthesis?
Enzymes build up glucose from carbon dioxide and water at the same time break down ATP and ADP to release energy
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Role of enzymes in protein synthesis?
Enzymes are required to help form the peptide link to join amino acids together.
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Structural features of DNA?
Two strands of nucleotides, each strand consists of a sugar phosphate backbone with a base bonded to each sugar molecule, two strands twisted around form a double helix, strand is bonded together by bases that hydrogen bond each other
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What are nucleotides made of?
A sugar molecule, base molecule, a phosphate group
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How is the DNA replicated?
...
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What is Transcription?
...
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What is a codon?
A sequence of three bases which specifies a particular amino acid in a protein.
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What is tRNA?
...
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What is Translation?
...
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How is genetic modification carried out by plasmid?
A small circular piece of DNA, taken from bacterium, infects plant cells and in doing so incorporate its genes into the plant genome
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How is genetic modification carried out by virus?
Infects plant similarly to plasmids
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How genetic modification is carried out by micro particle?
Gene is attached to a minute particles of inert substance e.g. gold. And injected into the nucleus of target cells
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Other cards in this set

Card 2

Front

What is a primary structure?

Back

A sequence of amino acids, maintained by peptide links – covalent bonds

Card 3

Front

What is a tertiary structure?

Back

Preview of the front of card 3

Card 4

Front

What is a space filled model of a protein?

Back

Preview of the front of card 4

Card 5

Front

What is the ribbon model of a protein?

Back

Preview of the front of card 5
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