Genes Flashcards
What are non-coding regions in DNA?
Protein binding sequences
Structural sequences
Repeat sequences
Unknown function “junk DNA”
Is the entire genome important in the functioning of a organism?
Possibly but at current understanding, DNA contain non-coding strands and coding strands. Non-coding strands have been taught to have no function but recent research suggest othewise
What are coding regions of DNA?
Contains genes which code for specific proteins
What do the protein-binding sequences in non-coding regions do?
These sequences allow for the binding of specific proteins
What do the structural sequences in non-coding regions do?
These sequences help to give the chromosome its shape. These include coding for centromeres and telomeres.
What are centromeres and what do they contain?
Centromeres (where chromosomes arm join) no specific sequence, but it is repetitive.
What are telomeres and what do they contain?
Telomeres (the ends/tips of chromosomes) which consists of TTAGGG repeat sequences
What is the importance of repeat sequences in non-coding region?
Repeat sequences are not only important for centromeres, telomeres and protein binding; they also serve as genetic markers when examining chromosomes and gene order (i.e. microsatellites)
What are di-nucleotide repeats?
Two nucleotides that continue to repeat
Ex. TATATATATA
What are tri-nucleotide repeats?
Three nucleotides which are repeated.
Ex. TACTACTACTACTAC
What do the protein- coding sequences in the coding region do?
These sequences are called genes and they code for specific proteins.
What are genes?
Inherited instruction carried on a chromosome; specific segment of DNA carrying an instruction to code for a specific protein
Does one gene code for one protein?
No
Does one gene code for different proteins?
Yes, but not always
What are introns?
Parts of the coding region of a gene that are transcribed but not translated
What are exons?
Part of the coding region of a gene that is both transcribed and translated
What do spliceosomes do?
Introns are spliced out by a complex of enzymes known as spliceosomes leaving only the sequence that will be expressed as protein (the exons)
What is the molecule called when the DNA still have spliceosomes attached to it?
pre-mRNA
What is called after the spliceosomes have removed the introns?
mRNA
How does one gene make different proteins?
EACH DIFFERENT mRNA IS TRANSLATED INTO A DIFFERENT PROTEIN this is called alternate splicing
