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60 Cards in this Set
- Front
- Back
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What is the formula for glucose? |
C6H12O6 |
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Define Condensation Reaction |
The release of water from the joining of two molecules |
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Define Hydrolysis Reaction |
The splitting of two molecules from the addition of a water molecule |
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What is a glycosidic bond |
A weak bond formed between two monosaccharides, joined together through a condensation reaction |
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Describe Benedict's test for Reducing Sugars |
1. Add 2ml of the sample, in liquid form, into a test tube. 2. Add 2ml of Benedict's reagent into the test tube. 3. Heat up the mixture in a gently boiling water bath for 5 mins. 4. Observe the colour change. Blue- none Green- Very low Yellow- low Brown- medium Red- high |
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Glucose+Glucose= |
Maltose |
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Glucose+Galactose= |
Lactose |
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Glucose+Fructose= |
Sucrose |
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What is the test for non-reducing sugars? |
1. Add 2ml of the sample, in liquid form, into a test tube. 2. Add 2ml of Benedict's reagent into the test tube. 3. Heat up the mixture in a gently boiling water bath for 5 mins. 4. Observe the colour change. 5. Add another 2ml of food sample to 2ml of dilute HCl, and place in a gently boiling water bath for 5 mins. 6. Slowly add sodium hydrogen carbonate to neutralise the HCl. 7. Retest by adding another 2ml of Benedict's reagent to the test tube, in a gently boiling water bath for 5 mins. If a non-reducing sugar was present, the solution should turn orange/brown. |
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What is a polysaccharide |
A polymer of monosaccharides, formed through condensation reactions, and joined through glycosidic bonds. |
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Describe the test for Starch |
1. Place 2ml of sample in a test tube. 2. Add 2 drops of iodine solution and shake/stir. 3. If starch is present it will change into a black/blue colour. |
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Describe starch |
Energy store in plants Insoluble- doesn't affect water potential Large molecule- doesn't diffuse out of cell Compact- branched ends Forms alpha glucose when hydrolysed |
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What are the two polysaccharides of starch |
Amylose and Amylopectin |
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Describe Amylose |
Long, unbranched alpha-glucose chain, coiled structure so its more compact |
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Describe Amylopectin |
Long branched alpha-glucose chain, so enzymes can break it down simultaneously and quickly. |
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Describe Glycogen |
Energy store in animal cells-store of glucose Very compact Lots of side branching for rapid release of energy
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What is cellulose |
Formed when Beta glucose form hydrogen bonding and link together. Found in plants Forms micro-fibrils Usually provides structural support |
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What are the 4 roles of lipids |
Energy source Waterproofing Insulation Protection |
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What is a triglyceride |
3 fatty acids joined to a glycerol, through condensation reactions, held together by ester bonds |
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What is the reaction for the formation of triglycerides |
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What is a saturated lipid |
No double bonding between the carbon atoms in the fatty acid chain |
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What is a fatty acid with only 1 C=C bond called? |
Mono-unsaturated |
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Describe a phosphlipid |
A phosphate group head, attached to a glycerol, and 2 fatty acids |
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What happens to triglycerides in water |
They form droplets. This is due to their tails being hydrophobic, so they repel against the water and face inwards |
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Why do phospholipids form bilayers |
They have hyrophilic heads, which face outwards, and hydrophilic heads, which face inwards |
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Describe the test for lipids |
1. Place a sample in a dry, grease proof test tube, add 2ml of ethanol and shake it, so the mixture dissolves. 2. Add water to the solution. 3. Any lipid should show up as a milky emulsion. 4. The more concentrated the colour, the more lipid there is. |
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What are proteins made up from |
Chains of amino Acids |
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Monomer of protein |
amino acid |
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Dipeptide |
2 amino acids joined together |
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polypeptide |
more than 2 amino acids joined together |
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protein |
made up from 1+ polypeptide chains |
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What is the general structure of an amino acid |
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How are polypeptides formed? |
Condensation reactions linking multiple amino acids together. Peptide bonds are formed between the amino acids |
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What is a primary structure |
Sequences of amino acids in a polypeptide chain |
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What is a secondary structure |
Hydrogen bonding causing polypeptide chain to coil into an Alpha helix, or fold into a Beta sheet |
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What is a tertiary structure |
An increase in coiling/folding due to more types of bonds; hydrogen, ionic and di-sulphide bridges |
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What is a quaternary structure |
Multiple polypeptide chains held together by bonds |
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What is the test for proteins |
1. Add a few drops of sodium hydroxide solution to the sample in a test tube, to make it alkaline. 2. Add some Copper (II) Sulphate solution. 3. Observe the colour change. Purple=Protein Blue=No Protein |
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What is an enzyme |
A biological catalyst which speeds up a reaction, without being used up. |
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How do enzymes speed up reactions |
Reduce the activation energy, so reactions happen more frequently |
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What is the lock and key model |
The enzyme's active site must be an exact match to the substrate |
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What is the induced fit model |
The enzyme's active site doesn't have to be an exact match, if a substrate with a similar active site attaches to it, it moulds around it, like a hand in a glove |
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What makes enzyme's active sites specific |
Their tertiary structure as they're proteins |
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What is a nucleotide |
A phosphate group, attached to a pentose sugar, which is attached to a base |
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What are DNA and RNA made from |
They're polymers of nucleotides, so theyre made up from nucleotides |
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What is the sugar in DNA called |
Deoxy-ribose |
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Which bases match with what in DNA |
Guanine-Cytosine and Adenine-Thymine |
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What sugars are found in RNA |
Ribose |
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Which bases match with what in RNA |
Guanine-Cytosine Adenine-Uracile |
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How do nucleotides join to form polynucleotides |
Condensation reactions between the phosphate of one nucleotide, and the sugar of another nucleotide. They're held together by a phospho-diester bond. The chain of sugars and phosphates is called the called sugar phosphate backbone |
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How many polynucleotide chains are found in DNA |
2, each base can only join with one other, specific base (complementary base pairing). |
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How many polynucleotide chains are found in RNA |
1 |
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How many hydrogen bonds are found between Adenine and Thyamine |
2 |
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How many hydrogen bonds are found between Guanine and Cytosine |
3 |
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Describe the structure of DNA |
2 anti parallel polynucleotide strands, twist to form a DNA double-helix. |
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Describe how 2 polynucleotide strands are joined together to make a double helix |
Hydrogen bonding between the bases, which are complementary paired (GC,AT). The strands are anti-parallel, and twist to form a helix. |
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Describe the process of semi-conservative replication |
1. DNA helicase breaks the hydrogen bonding between the two polynucleotide strands, unwinding them into 2 single strands. 2. Each single strand acts like a template. 3. Complementary base pairing causes free floating nucleotides to attach to their complementary exposed base. 4. Condensation reactions, catalysed by DNA polymerase, reform the hydrogen bonding, rejoining the nucleotide strands together. 5. Each new molecule of DNA contains 1 original DNA, and 1 new DNA strand. |
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Why does DNA polymerase move in opposite directions across the strands |
The active site of DNA polymerase is only complementary to 3'. Because the strands are anti parallel the 3' sides are on opposite ends. |
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What enzyme is involved in the formation of ATP from ADP and an inorganic phosphate ion |
ATP Synthase |
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What enzyme is involved in the breaking down of ATP into ADP |
ATP Hydrolysis |
