AQA A-Level Biology Paper 1| Questions With 100% Correct Answers | Verified

Describe the role of a ribosome in the production of a polypeptide. /3 - 1. 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 codon); Describe the structure of glycogen. /2 - 1. Polysaccharide of α-glucose; OR polymer of α-glucose; 2. (Joined by) glycosidic bonds OR Branched structure; NHE3 actively transports one sodium ion into the cell in exchange for one proton (hydrogen ion) out of the cell. Use your knowledge of transport across cell membranes to suggest how NHE3 does this. /3 - 1. Co-transport; 2. Uses (hydrolysis of) ATP; 3. Sodium ion and proton bind to the protein; 4. Protein changes shape (to move sodium ion and/or proton across the membrane); Explain the curves for max protease activity over time at 50C and 60C. /4 - 1. Both denatured (by high temperature); 2. Denaturation faster at 60 °C due to more (kinetic) energy; 3. Breaks hydrogen/ionic bonds (between amino acids/R groups);