6.3 Distinction between genes, alleles and a genome Flashcards
What is a nucleotide?
A sub-unit of DNA consisting of a phosphate group, nitrogenous base and a sugar
What are genes?
Sequences of bases located on chromosomes that code for specific proteins
What do proteins control?
Particular characteristic or traits of the organism
What is a genome?
The complete set of genetic instructions and the sum total of an organism’s DNA
How much DNA is in a gene?
Average gene = around 3000 base pairs
What is an allele?
The different forms of genes
What is a genotype?
Both the double set of genetic instructions present in a diploid organism and the genetic make-up of an organism at on eparticular gene locus
What’s the difference between gene and allele?
Genes control a general function while alleles produc especific expressions of that function
Example: Gene-flower colour, allele-purple and white
What is a zygote?
When two gametes fuse to form a zygote during fertilisation
How many chromosomes are in a human?
46 chromosomes, 23 pairs
What is genomics?
The study of the entire genetic make-up or genome of a species
What is diploid(2n)?
Having 2 copies of each specidic chromosome in each set
What is haploid(n)?
Having one copy of each specific chromosome in each set
Why does variation exist?
They exist due to individuals possessing different genes and alleles.
How many genes are in the human genome?
Around 20,000-25,000 genes
