Genes Flashcards
What is a gene?
A set of instructions & a carrier of information.
Every individual human has?
A genotype and a phenotype.
What is a genotype?
A genetic constitution; what our genes will dictate in us.
What is a phenotype?
What we become when our genes interact, both with one another and with our environment & experiences.
What does a gene consist of?
A long strand of DNA.
What is a chromosome?
A double chain of DNA.
One of the functions of DNA is to?
Control gene activity.
Genes contain bases called?
guanine (G)
cytosine (C)
adenine (A)
thymine (T)
What contains the instructions for what the gene will produce?
The coding sequence.
Coding sequence?
3-letter combinations of G, C, A and T.
The coding sequence is copied, to?
Produce an RNA molecule.
What does RNA do?
It organises the synthesis of proteins that act according to the genetic instructions.
What is tRNA?
Transfer RNA.
What does tRNA do?
It transports amino acids to the ribosomes of the cell.
What is mRNA?
Messenger RNA.
What does mRNA do?
It acts as a model to form proteins.
What do the proteins (formed according to the mRNA) do?
They dictate how the organism develops.
What is a genome?
All the genes in a cell.
What does the genetic message contain?
Millions of combinations of base pairs in DNA, carried on chromosomes.
How many pairs of chromosomes do humans have in each cell?
23
What does it mean if genes are physically linked?
If one gene is inherited then the other gene that is physically linked to it is also inherited.
What are dominant genes?
Genes that always lead to certain characteristics.
What are recessive genes?
Genes that need more than one copy to produce a characteristic.
What would happen if a recessive gene is present on only one pair of chromosomes?
The characteristic won’t appear in that organism.
Characteristics can be?
Aspects of appearance, personality or behaviour.
Do genes control all human characteristics?
No; the environment also has a part to play.
