AQA A-Level Biology. 3.2 - Cells.| Questions With 100% Correct Answers | Verified

Structure of Nucleus. - 1. Nuclear envelope: double membrane surrounding nucleus, outer membrane continuous with the (R)ER of the cell. 2. Nuclear pores: allow the passage of larger molecules, such as mRNA, out of the nucleus. 3. Nucleoplasm: granular, jelly-like material making up the bulk of the nucleus. 4. Chromosomes: protein-bound, linear DNA. 5. Nucleolus: small spherical region(s) in nucleoplasm. Manufactures ribosomal RNA and assembles ribosomes. Function of Nucleus. - 1. Controls cell's activities - produces mRNA and tRNA - protein synthesis. Controls entry and exit of materials, and contains nuclear reactions. 2. Retains genetic material in the form of DNA and chromosomes. 3. Manufactures ribosomal RNA and ribosomes. Structure of Mitochondria. - 1. Double membrane surrounding organelle - controls entry and exit of material. 2. Cristae - extensions of the inner membrane, providing a large surface area for the attachment of enzymes and other proteins during respiration. 3. Matrix - makes up the remainder - contains proteins, lipids, ribosomes and DNA