AS Level Biology May June 2025 P11 | Part 2 | Solved Past Paper | MCQ Answers | Biology 9700

In this video i am solving MAY JUNE 2025 PAPER 11 of AS LEVEL BIOLOGY 9700 PART 1    • AS LEVEL BIOLOGY | May June 2025 P11 | par...   0:00 - INTRO 0:25 - Q21 Which processes are used by stem cells during tissue repair? 1 cytokinesis 2 DNA replication 3 transcription 3:33 - Q22 The enzyme telomerase prevents loss of telomeres after many mitotic cell cycles. Which cells transcribe a high concentration of telomerase? 7:23 - Q23 Which statements are correct? 1 All polypeptides are coded for by genes. 2 All genes are made up of a sequence of nucleotides. 10:02 - Q24A double-stranded DNA molecule was analysed and 29% of its nucleotide bases were found to be adenine. Which percentage of its nucleotide bases will be cytosine? 12:07 - Q25 In some cells, non-coding sequences of RNA are removed after transcription. Which row correctly states the name of these non-coding sequences of RNA and the type of cell in which the non-coding sequences are removed? 13:31 - Q26 Water potentials were measured inside a leaf cell, in the air spaces of the leaf and in the atmosphere. Which values of water potential () would allow water to move from the leaf to the atmosphere? 15:53 - Q27 Three samples of liquid were taken from different locations in a plant and tested to measure the concentration of four solutes. The results are shown 17:11 - Q28 A heated band was wrapped around the stem of a plant at a height of 1m above the ground and left for 10 minutes. How will heating a small section of the stem to 60 °C affect the transport of phloem sap and xylem sap between the roots and leaves? 18:46 - Q29 The diagram shows the structure of an amphibian heart and the movement of blood through it. Which statements about differences between the amphibian heart and a human heart are correct? 20:28 - Q30 A mutation in one of the genes that codes for haemoglobin changes the affinity of haemoglobin for oxygen. This mutation lowers the partial pressure of oxygen at which haemoglobin is 50% saturated with oxygen. 23:15 - Q31 Which processes are responsible for the Bohr shift? Carbon dioxide reacts with haemoglobin to form carbaminohaemoglobin. 26:12 - Q32 A student viewed a drop of human blood with a microscope and described a cell as having a very large diameter and a U-shaped nucleus that occupies half the volume of the cell. Which type of cell was the student viewing? 28:12 - Q33 How many times must an oxygen molecule pass through a cell surface membrane to get from the air in the alveolus to the haemoglobin in a red blood cell 30:37 - Q34Asthma can affect children and adults. The air passages become narrower, severely restricting the flow of air into the lungs. Salbutamol is a drug that widens the air passages to relieve the symptoms of asthma. How does salbutamol relieve the symptoms of asthma? 33:28 - Q35 The photomicrograph shows the transverse section of part of the trachea. Which letter represents a tissue that can contract and relax to adjust the diameter of the airways? 35:42 - Q36 Which statements about an infectious disease may be correct? It can be caused by a protoctist.It can be transmitted by an insect vector 38:09 - Q37 Which statements explain why cholera has not been eradicated by vaccination? There is limited availability of an affordable vaccine. Protection takes several weeks to develop after vaccination. 43:18 - Q38 Antibiotic resistance is a serious threat to global health. Which statement describes a step that can be taken to reduce the impact of antibiotic resistance? 45:08 - Q39 Tetanus is an infectious disease caused by a type of bacterium. This bacterium produces a protein that is a toxin which causes illness. Scientists have produced a vaccine for tetanus which contains a harmless form of the toxin called a toxoid. The toxoid is produced by mixing the toxin with the chemical formaldehyde. This chemical binds to the toxin making it harmless. Which statement about the tetanus vaccine is correct? 47:37 - Q40 What is an effect on the immune system of a reduced number of T-helper cells?