Key Definitions Flashcards
All 10 cards in this deck
What is a chromosome?
A long, coiled molecule of DNA found in the nucleus, carrying many genes.
What is an allele?
A different version of the same gene.
e.g. the flower colour gene has a purple allele and a white allele.What is a dominant allele?
An allele that is expressed in the phenotype even when only one copy is present.
What does homozygous mean?
Having two identical alleles of a gene.
e.g. orWhat is a genotype?
The alleles an organism has for a characteristic.
e.g.What is a gamete?
A sex cell (sperm or egg) that carries one allele of each gene.
What is a recessive allele?
An allele that is only expressed in the phenotype when two copies are present.
What does heterozygous mean?
Having two different alleles of a gene.
e.g.What is a phenotype?
The observable (physical) characteristics of an organism.
e.g. the colour of a carrotWhat is a zygote?
The single cell formed when two gametes fuse at fertilisation.