OCR 2023 Biology AH420/02: Biological diversity A Level Question Paper & Mark Scheme (Merged)

2 OCR 2023 Section A You should spend a maximum of 20 minutes on this section. Write your answer to each question in the box provided. 1 Which option correctly describes a tissue? A A group of cells performing similar functions B A group of organs performing a specific function C A group of similar cells performing a specific function D A group of similar cells performing a variety of functions Your answer [1] 2 Bone marrow stem cells are a source of erythrocytes. Which statement about bone marrow stem cells and their role in the production of erythrocytes is correct? A Bone marrow stem cells are totipotent and can therefore differentiate into any type of cell. B Erythrocytes are the only blood cell produced from bone marrow stem cells. C Erythrocytes need to be replaced from bone marrow stem cells because erythrocytes are unable to undergo mitosis. D In humans, differentiation of bone marrow stem cells into erythrocytes involves the synthesis of a haploid nucleus. Your answer [1] 3 OCR 2023 Turn over 3 Which option correctly describes the sequence of events during the cell cycle? A Cytokinesis interphase G1 G2 S mitosis B Cytokinesis mitosis interphase C G2 mitosis cytokinesis G1 S D Mitosis interphase cytokinesis Your answer [1] 4 Scientists crossed two plants that were heterozygous for two different genes. Both plants had the same genotype, AaBb. The genotypes and ratios of the offspring resulting from this cross wer