M5: Polypeptide synthesis

Question 1

what are polypeptides?

Answer 1

chains of amino acids linked by peptide bonds. these join to form proteins

Question 2

what is gene concept?

Answer 2

genes in cells contian all information for synthesis and functioning of cellular components

Question 3

gene expression?

Answer 3

only some genes are expressed or switched on in each cell, eg skin cells switch on genes for melanin

Question 4

what are the 3 process of gene expression?

Answer 4

• transcription (nucleus)
• RNA processing (nucleus)
• translation (cytoplasm)

Question 5

what are exons?

Answer 5

regions of a gene that are expressed

Question 6

what are introns?

Answer 6

non coding regions that are spliced out of mRNA during processing

Question 7

What is polypeptide synthesis?

Answer 7

When DNA is too large to leave the nucleus, cells make a particular group of proteins and mRNA carries a copy of the relevant DNA to ribosomes

Question 8

What is pre-mrna?

Answer 8

When mRNA is transcribed from DNA

Question 9

What are the two types of codons?

Answer 9

• start codon: indicates where translation should begin
• stop codon: signals where to halt protein synthesis, eg, UAA, UAG

Question 10

Function and importance of polypeptide synthesis?

Answer 10

each gene is a section of DNA containing a specific sequence of bases encoding an inheritable trait which determines particular characteristics