IGCSE Coordinated Science: Chromosomes and Genes

IGCSE Coordinated Science: Chromosomes and Genes

Define inheritance:

Genetic information that is passed down from one generation to another.
Define the terms:

Chromosome: A thread of DNA, made up of a string of genes.
Gene: 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: Any of two or more alternative forms of a gene.
Define the terms:

Haploid nucleus: 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: A nucleus containing two sets of chromosomes (e.g., in body cells). A normal body cell, which has two sets of chromosomes, has a diploid nucleus.
Describe the inheritance of sex in humans (XX and XY chromosomes):

Males have XY chromosomes and females have XX."