Translation and Polypeptide Synthesis Concepts

The video tutorial introduces a genetics problem involving a gene with 141 codons. It explains the structure of mRNA, the role of codons, and the translation process that forms polypeptides. The tutorial discusses codon variability, including start and stop codons, and provides a solution to the problem by calculating the number of nucleotides and amino acids. It concludes with advice on handling stop codons in gene sequences.

How many nucleotides are present in a gene with 141 codons?

• 423 nucleotides

• 564 nucleotides

• 282 nucleotides

• 141 nucleotides

What is a key structural difference between messenger RNA and DNA?

• DNA contains uracil instead of thymine

• DNA is single-stranded, RNA is double-stranded

• RNA contains uracil instead of thymine

• RNA is double-stranded, DNA is single-stranded

What is the role of the ribosome in the translation process?

• To degrade mRNA

• To replicate DNA

• To synthesize RNA

• To attach to mRNA and synthesize polypeptides

Which codon is known as the start codon?

• UAA

• UGA

• AUG

• UAG

What is the first amino acid in a polypeptide chain?

• Glycine

• Leucine

• Valine

• Methionine

What is the significance of the N-terminus and C-terminus in a polypeptide chain?

• They are the start and end of the ribosome

• They are the start and end of the mRNA

• They are the start and end of the DNA

• They are the start and end of the polypeptide chain

How many codons specify a stop in translation?

• Three

• Two

• Four

• One

What is the relationship between codons and amino acids?

• Multiple codons can specify the same amino acid

• Codons do not relate to amino acids

• Each codon specifies multiple amino acids

• Each amino acid is specified by one codon

What is the total number of amino acids expected in a polypeptide encoded by a gene with 141 codons?

• 142 amino acids

• 141 amino acids

• 143 amino acids

• 140 amino acids

What should you do if unsure about including a stop codon in a gene sequence during an exam?

• Guess based on context

• Include it by default

• Exclude it by default

• Ask the professor for clarification