Question

1. which two statements are true about dna and mrna functions? a. dna is self - replicating, mrna is made from dna. b. mrna is self - replicating. c. dna produces trna directly. d. mrna and trna interact during protein synthesis. 2. a child has two extra codons compared to parents’ dna. how? a. insertion during dna replication b. insertion during meiosis c. substitution during dna replication d. substitution during meiosis 3. what rna type has an amino acid attachment site? a. mrna b. rrna c. trna d. mirna 4. before mitosis, what must dna do? a. bases pair b. bases join by dna polymerase c. dna separates into single strands d. dna acts as template before separation 5. what mutation causes early stop codon from extra nucleotide in mrna? a. replication error insertion b. crossing over error c. nondisjunction in meiosis d. translocation in transcription 6. which explains genetic code translation into amino acid sequence? a. dna triplet → mrna codon → protein amino acid b. dna triplet → rrna coding c. mrna codon → trna codon → three amino acids d. rrna codon → trna codon → two amino acids

Explanation:

1. DNA replicates itself and mRNA is transcribed from DNA. During protein synthesis, mRNA and tRNA interact. mRNA is not self - replicating and DNA does not produce tRNA directly.
2. Insertion during DNA replication can add extra codons. Insertion during meiosis is less likely to be the cause in this context compared to replication errors. Substitution does not add codons.
3. tRNA has an amino - acid attachment site for carrying amino acids to the ribosome during translation.
4. Before mitosis, DNA must act as a template for replication before separating into single strands. Bases pair during replication and are joined by DNA polymerase, but the key step before mitosis is acting as a template.
5. A replication error insertion can cause an early stop codon due to a frameshift mutation when an extra nucleotide is added to mRNA.
6. The genetic code translation involves DNA triplets being transcribed into mRNA codons which are then translated into protein amino - acid sequences.

Answer:

1. A. DNA is self - replicating, mRNA is made from DNA; D. mRNA and tRNA interact during protein synthesis
2. A. Insertion during DNA replication
3. C. tRNA
4. D. DNA acts as template before separation
5. A. Replication error insertion
6. A. DNA triplet → mRNA codon → protein amino acid