Non-nuclear inheritance Flashcards
Where is most DNA and genes in a cell located?
The nucleus
Other than the nucleus, where can DNA be found?
The mitochondria and chloroplasts
What are non-nuclear genes?
Genes which are present as small circles of DNA in mitochondria and chloroplast
What is another name for non-nuclear genes?
Extra-nuclear
How are non-nuclear genes passed on to offspring?
They reproduce by themselves and pass on their genes to the resulting organelles
Give an example non-nuclear inheritance in plants?
In plants, mitochondria and chloroplasts are normally passed on to the next generation in the cytoplasm of the egg. Pollen does not contain these organelles
Describe non-nuclear inheritance in animals
Mitochondria are in the tail of the sperm but only the head joins with the egg during fertilisation which mean mitochondria from the sperm (father) are not passed on to the zygote.
Why are mitochondria and chloroplasts said to follow a maternal line of inheritance?
In humans, mitochondrial DNA is inherited only from the mother and in plants mitochondrial and chloroplasts are passed on in the cytoplasm of the egg therefore the male/fathers have no part in the transfer of mom-nuclear genes
How are some rare disorders inherited from mothers?
As they are controlled by non-nuclear genes located on mDNA
What is mDNA?
Mitochondrial DNA
What systems are usually affected by non-nuclear gene disorders?
They usually involve a lack of energy (ATP) and affect systems with high energy demands such as the muscular and nervous system
How does the father of a human child not pass on their non-nuclear genes in the mitochondria of their sperm?
As the mitochondria from the father is located in the tail of the sperm which stays outside the egg during fertilisation, therefore the non-nuclear genes are not transferred on to the zygote
