University:
University of Cambridge
Course:
0620 IGCSE | Chemistry
Academic year:

2023
Views:

28

Pages:

1
Author:

JackA1

IGCSE Coordinated Science: Chromosomes and Genes Chromosomes and Genes 1. Define inheritance Genetic information that is passed down from one generation to another. 2. Define the terms: • Chromosome as a thread of DNA, made up of a string of genes, • Gene as a length of DNA that is the unit of heredity and codes for a specific protein. A gene may be copied and passed on to the next generation • Allele as any of two or more alternative forms of a gene. 3. Define the terms: • Haploid nucleus as a nucleus containing a single set of unpaired chromosomes (e.g. sperm and egg), So a sex cell ,which has half the number of chromosomes, has a haploid nucleus • Diploid nucleus as a nucleus containing two sets of chromosomes (e.g. in body cells). A normal body cell, which has two set of chromosomesm has a diploid nucleus 4. Describe the inheritance of sex in humans (XX and XY chromosomes). Males have XY chromosomes and females have XX.