AQA A LEVEL BIOLOGY EXAM BUNDLE|QUESTIONS WITH CORRECT SOLUTIONS!!

what are chromosones made of? - ANSWERdna molecules where are chromosones located? - ANSWERthe nucleus of a cell how are the chromosones normally found in a body cell? - ANSWERchromosones normally come in pairs what is the cell cycle? - ANSWERthe series of stages by which cells divide wh...

Describe the relationship between the size of an organism and its SA:V ratio - ANSWERSmaller organisms have high SA:V ratios Larger organisms have low SA:V ratios What adaptations do some organisms have for exchange (in terms of SA:V ratio)? - ANSWERThe flattened shape so that no cell is ever fa...

Why is transpiration passive and translocation active? - ANSWERThe energy for transpiration is supplied by the Sun. The energy for translocation is supplied by vascular tissue which carries out active transport, requiring ATP. What are the main features of the xylem in which water is transported?...

What kind of receptors are changes in blood pH and pressure detected by? - ANSWERchemoreceptors and pressure receptors in the aorta or carotid artery Two types of photoreceptors in the eye? - ANSWERrods and cones What colour do rods detect and why? - ANSWERBlack and white ONLY - because they ...

1. Why do we use beetroot cells to measure the effect of different variables on membrane permeability? 2. If a lot of pigment leaks out, what does this tell us about the membrane permeability? 3. If only a little amount of pigment leaks out, what does this tell us about membrane permeability?...

What is the premise behind the experiment? - ANSWER- Cell surface membranes made of phospholipid bilayer > selectively permeable. This can be changed by variables like temp and solvent conc. - As temp increases, enzymes like transport proteins lining the membrane may denature, allowing the red ...

Describe the role of a ribosome in the production of a polypeptide. /3 - ANSWER1. mRNA binds to ribosome; 2. Idea of TWO codons/binding sites; 3. tRNA with ANTICODONS binds; 4. (Catalyses) formation of PEPTIDE bond between AMINO ACIDS (held by tRNA molecules); 5. Moves along (mRNA to the next c...

large molecules often contain carbon. why? - ANSWERthey can readily form bonds with other carbon atoms. this forms a 'backbone'. other atoms can then attach. describe benedicts test for reducing sugars - ANSWERadd equal volumes of the sugar sample and benedicts reagent. heat the mixture in a w...

Benedict's test - ANSWERWhich food test is heated in a water bath? Sucrose - ANSWERWhich disaccharide is not a reducing sugar? Test for non-reducing sugars - ANSWERAdd acid. Neutralise. Add Benedicts. Heat. Hydrolysis - ANSWERReaction performed by dilute HCl in the non reducing sugar test....

________________________________________ Explain why plasma membranes are said to have a fluid mosaic structure. - ANSWER1. Fluid because the phospholipids are constantly moving. 2. Mosaic because the proteins are scattered throughout the membrane-like tiles in a mosaic. What effect does cholest...

Describe how oxygen in the air reaches capillaries surrounding alveoli in lungs - ANSWERTrachea and bronchi and bronchioles; Down pressure gradient; Down diffusion gradient; Across alveolar epithelium; Across capillary endothelium/epithelium; Difference between species richness and index of d...

Describe how you would use a biochemical test to show that a solution contained a non-reducing sugar, such as sucrose. [3] - ANSWER,first reducing sugars test; boil with dilute HCl acid then Neutralise with NaHCǑ, add benedict and heat to 95 degrees C brick red ppt forms if reducing sugar is presen...

Describe how a non-competitive inhibitor can reduce the rate of an enzyme controlled reaction - ANSWERBinds away from active site Changes shape of active site So no longer complementary so less substrate can bind How to identify a competitive inhibitor - ANSWERWith the inhibitor, it increases ...

DNA Replication - ANSWERDNA helicase breaks hydrogen bonds. Each strand acts as a template. Free nucleotides attach. Complementary base pairing occurs- AT and CG. DNA polymerase joins nucleotides. Hydrogen bonds reform. Semi-conservative replication- new DNA molecule contains one old and one new str...