Term 3 Week 8 Unit 6 Test Review

Front

What is the composition of a double-stranded DNA nucleic acid in terms of nitrogenous bases?

Back

In double-stranded DNA, adenine pairs with thymine, and guanine pairs with cytosine. The composition must follow Chargaff's rules, where the percentage of adenine equals thymine, and the percentage of guanine equals cytosine.

Front

How many nucleotides are needed to code for a polypeptide chain of 100 amino acids?

Back

A polypeptide chain of 100 amino acids requires 303 nucleotides in mRNA because each amino acid is coded by a triplet of nucleotides (codon), plus 3 additional nucleotides for the start and stop codons.

Front

What is an insertion mutation?

Back

An insertion mutation occurs when one or more nucleotide pairs are added into a DNA sequence, which can lead to a shift in the reading frame during translation.

Front

What is the difference between leading and lagging strand synthesis during DNA replication?

Back

The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is synthesized discontinuously in short segments called Okazaki fragments.

Front

Which sugar is found in DNA nucleotides?

Back

Deoxyribose sugar is found in DNA nucleotides, while ribose sugar is found in RNA nucleotides.

Front

What is the role of phosphate in DNA nucleotides?

Back

Phosphate groups link the sugar molecules of adjacent nucleotides, forming the backbone of the DNA strand.

Front

What is a substitution mutation?

Back

A substitution mutation occurs when one nucleotide in the DNA sequence is replaced by another, potentially altering the amino acid sequence of the resulting protein.

Front

What is the significance of the 5' and 3' ends of a DNA strand?

Back

The 5' end has a phosphate group, while the 3' end has a hydroxyl group. This directionality is crucial for DNA replication and transcription.

Front

What is the function of mRNA in protein synthesis?

Back

mRNA (messenger RNA) carries the genetic information from DNA to the ribosome, where it serves as a template for protein synthesis.

Front

What are Okazaki fragments?

Back

Okazaki fragments are short sequences of DNA nucleotides synthesized on the lagging strand during DNA replication.