SS Biology Week 3 Summative Review

What is the base pairing rule for DNA?

• A-U, C-G

• A-T, C-G

• A-C, T-G

• A-G, T-C

Answer explanation

The base pairing rule for DNA states that adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). Therefore, the correct answer is A-T, C-G.

Which of the following best describes the function of mRNA?

• Transports amino acids

• Stores genetic material

• Carries DNA’s message to the ribosome

• Replicates DNA

Answer explanation

mRNA, or messenger RNA, carries the genetic information from DNA to the ribosome, where proteins are synthesized. This function is crucial for translating the genetic code into functional proteins.

What is the product of transcription?

• DNA

• RNA

• Protein

• Amino acid

Answer explanation

The product of transcription is RNA, which is synthesized from a DNA template. This process involves copying the genetic information from DNA into RNA, which then plays a crucial role in protein synthesis.

Where in the cell does transcription occur?

• Cytoplasm

• Ribosome

• Mitochondria

• Nucleus

Answer explanation

Transcription occurs in the nucleus, where DNA is transcribed into mRNA. The cytoplasm is where translation occurs, while ribosomes are the sites of protein synthesis, and mitochondria are involved in energy production.

A codon is made of:

• One base

• Two amino acids

• Three nucleotides

• Four sugars

Answer explanation

A codon consists of three nucleotides, which are sequences of DNA or RNA that correspond to specific amino acids. Therefore, the correct answer is 'Three nucleotides'.

What molecule is made during translation?

• DNA

• mRNA

• Protein

• tRNA

Answer explanation

During translation, the ribosome synthesizes proteins by linking amino acids together based on the sequence of mRNA. Therefore, the correct answer is protein, as it is the molecule produced in this process.

DNA replication results in:

• Two identical DNA molecules

• One half of the original strand

• One RNA and one DNA strand

• Two different protein molecules

Answer explanation

DNA replication produces two identical DNA molecules, each consisting of one original strand and one newly synthesized strand, ensuring genetic continuity.

Tags

NGSS.HS-LS3-2

What kind of mutation changes only one base but does not affect the amino acid?

• Missense

• Nonsense

• Silent

• Frameshift

Answer explanation

A silent mutation changes one base in the DNA sequence but does not alter the amino acid produced. This occurs due to the redundancy in the genetic code, where multiple codons can code for the same amino acid.

A deletion mutation would most likely result in:

• A longer protein

• No change

• A frameshift

• An extra chromosome

Answer explanation

A deletion mutation removes nucleotides, which can shift the reading frame of the genetic code. This frameshift alters the entire downstream amino acid sequence, likely resulting in a nonfunctional protein.

Tags

NGSS.HS-LS3-2

Which type of mutation would likely have the biggest effect?

• Silent

• Missense

• Frameshift

• Point mutation

Answer explanation

A frameshift mutation alters the reading frame of the genetic code, potentially changing every amino acid downstream. This can lead to significant functional changes in the resulting protein, making it the most impactful type of mutation.

Tags

NGSS.HS-LS3-2