جین کا اظہار اور تغیر

Written by Dr. Hira Salman (Biology)

ایم ڈی کیٹ · حیاتیات · 8 سوالات

نام: ____________________ تاریخ: ____________

Transcription is the process by which:
- A Protein is made from mRNA
- B tRNA is destroyed
- C DNA is copied
- D mRNA is made from a DNA template
A codon is a sequence of how many nucleotides on mRNA?
- A Two
- B Six
- C Three
- D Four
Which codon is the usual start codon, and which amino acid does it code for?
- A UGA, tryptophan
- B AUG, methionine
- C UAA, stop
- D GGG, glycine
How many different codons are possible?
- A 20
- B 61
- C 4
- D 64
Translation takes place at the:
- A Golgi apparatus
- B Nucleolus
- C Lysosome
- D Ribosome
A point mutation that changes a codon but not the amino acid it codes for is called:
- A Silent
- B Nonsense
- C Frameshift
- D Missense
Sickle cell anaemia is caused by a change in beta globin in which glutamic acid is replaced by:
- A Lysine
- B Valine
- C Alanine
- D Glycine
Transfer RNA (tRNA) carries:
- A A start codon only
- B An amino acid and has an anticodon
- C DNA to the ribosome
- D Ribosomes to the nucleus

جوابی کلید

1. D, 2. C, 3. B, 4. D, 5. D, 6. A, 7. B, 8. B

During transcription, RNA polymerase builds an mRNA copy of a gene.
Each codon has three nucleotides and codes for one amino acid or a stop signal.
Translation normally begins at AUG, which codes for methionine.
Four bases in groups of three give 4 x 4 x 4 = 64 codons.
Ribosomes read the mRNA and join amino acids in the order it specifies.
The genetic code is redundant, so some changes do not alter the protein. These are silent mutations.
A single base change causes glutamic acid to be replaced by valine in haemoglobin, which makes the red cells sickle-shaped.
Each tRNA carries one amino acid and has an anticodon that pairs with a codon on mRNA.