© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 1 1a Draw an animal cell. Label the cell membrane, cytoplasm and nucleus. A: B1.8 Questions and answers nucleus cytoplasm cell membrane

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 2 b In which part of the cell are chromosomes found? A:Nucleus. c What are chromosomes made of? A:DNA. B1.8 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.7 Questions and answers 2a How many chromosomes in total are usually found in a human body cell? A:46. b How many pairs are there? A:23. 3

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.7 Questions and answers 3a Where are genes found? A:On chromosomes (also accept in nucleus or in DNA) b What do genes do? A:They control what the organism’s characteristics are/contain the instructions for characteristics. 4

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 5 4What are alleles? A:Different versions of the same gene. 5Where, inside a cell, did the mistake occur that caused some mouse-like animals to get long fingers? A:A gene/allele (also accept in nucleus or in DNA). B1.7 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 6 6How does the idea of alleles help us to explain why we all look different? A:We all inherit the same genes but since they come in many different versions (alleles) we all inherit different sets of alleles. B1.7 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 7 7How would you add to the book analogy above to include alleles? A:The matching sentences in a pair of books are very slightly different. B1.7 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.7 Questions and answers 8Use your knowledge of cells and genes to explain how a scientist would find out whether blood at a crime scene belongs to the victim or to a potential suspect. A: Blood contains cells that contain DNA [1] look at DNA/alleles in the blood from the crime scene [1] take sample from the victim and look at the DNA/alleles [1] compare the two samples [1] every person has a different set of alleles [1] so if the DNA does not match it must be the blood from a suspect [1] © Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 8