AQA A-level Biology paper 1 Exam

AQA A-level Biology paper 1 Benedict's test - Answer- Which food test is heated in a water bath? Sucrose - Answer- Which disaccharide is not a reducing sugar? Test for non-reducing sugars - Answer- Add acid. Neutralise. Add Benedicts. Heat. Hydrolysis - Answer- Reaction performed by dilute HCl in the non reducing sugar test. Glucose + fructose - Answer- During the non-reducing sugar test what is sucrose hydrolysed into? Alpha - Answer- Which type of glucose makes up starch? amylose and amylopectin - Answer- Names of two types of starch Amylose - Answer- Coiled, compact form of starch. Stored easily. Amylopectin - Answer- Branched form of starch. More easily hydrolysed. surface area - Answer- Branched carbohydrates have a higher _____ for enzymes to work on. Glycogen - Answer- Carbohydrate store in animals branched - Answer- Glycogen is.... metabolic rate - Answer- Glycogen is more branched than amylopectin because animals have a higher _____________ osmotically inactive. - Answer- Starch is insoluble and therefore .... Beta - Answer- What type of glucose is cellulose made from? Alpha and beta glucose - Answer- H and OH swapped on Carbon 1. Fibrils - Answer- Cellulose forms long chains called... H bonds - Answer- Cellulose molecules are crosslinked by strength - Answer- Cross linking of cellulose molecules gives them... Triglycerides - Answer- _______ are a good source of energy because they have a high ratio of energy-storing carbon-hydrogen bonds what are the roles of lipids? - Answer- 1. source of energy 2. waterproofing 3. insulation 4. protection how does the structure of phospholipids relate to their properties? - Answer- 1. polar, therefore will position itself to form a bilayer 2. the structure allows them to form glycolipids by combining with carbohydrates within the cell-surface membrane. these are important in cell recognition. draw the structure of an amino acid - Answer- draw how a dipeptide forms - Answer- what is meant by 'primary sequence' of a protein - Answer- The unique sequence of amino acids that make up a protein or polypeptide chain what is meant by 'secondary sequence' of a protein - Answer- The way in which the primary structure of a polypeptide chain folds e.g. alpha helix or beta pleated sheets. shape is held by H bonds. what is meant by 'tertiary sequence' of a protein - Answer- This is the overall 3-D structure of the protein. The shape of the protein is held together by H bonds and ionic bonds and disulfide bridges. what is meant by 'quaternary sequence' of a protein - Answer- If a protein is made up of several polypeptide chains that are linked in various ways, the way they are arranged is called the quaternary structure. Biuret is made up of... - Answer- equal volumes and copper sulphate and sodium hydroxide what are fiberous proteins made up of? - Answer- made of long molecules arranged to form fibres (e.g. in keratin). Several helices may be wound around each other to form very strong fibres. what are globular proteins made up of? - Answer- made of chains folded into a compact structure. One of the most important classes are the enzymes. Although these folds are less regular than in a helix, they are highly specific and a particular protein will always be folded in the same way. what kind of protein is collagen? - Answer- fibrous what kind of protein is haemoglobin? - Answer- globular