Nucleic Acids and Protein Synthesis

This set of flashcards is designed to help students review key concepts related to nucleic acids and protein synthesis in preparation for exams.

What are the three components of a nucleotide?

A nitrogen-containing base, a sugar, and a phosphate group.

Which four bases are found in DNA?

Adenine (A), Guanine (G), Cytosine (C), and Thymine (T).

In RNA, which base replaces thymine?

Uracil (U) replaces thymine.

What is the sugar component of RNA?

Ribose.

What is the sugar component of DNA?

Deoxyribose.

How are nucleosides formed?

By combining a sugar and a nitrogenous base.

What distinguishes a nucleotide from a nucleoside?

A nucleotide has a phosphate group bonded to the sugar.

Which bases are classified as purines?

Adenine and Guanine.

Which bases are classified as pyrimidines?

Cytosine, Uracil, and Thymine.

What type of bond is formed between the sugar and phosphate in nucleotides?

Phosphodiester bond.

What is the primary structure of nucleic acids?

The unique sequence of bases.

What is DNA replication?

The process of copying the DNA to transfer genetic information to new cells.

What enzyme catalyzes the unwinding of DNA during replication?

Helicase.

What is produced at the end of DNA replication?

Two identical daughter DNA strands.

How do complementary bases pair in DNA?

Adenine pairs with Thymine, and Guanine pairs with Cytosine.

What does semi-conservative replication mean?

Each daughter DNA molecule contains one original strand and one new strand.

What is mRNA?

Messenger RNA that carries genetic information from DNA.

What is the function of tRNA?

Transfer RNA that brings specific amino acids to the ribosome for protein synthesis.

What is rRNA?

Ribosomal RNA that combines with proteins to form ribosomes.

What are codons?

Three-nucleotide sequences in mRNA that specify amino acids.

What initiates protein synthesis?

The start codon AUG in mRNA.

What is a mutation?

A change in the nucleotide sequence of DNA.

What is a point mutation?

The replacement of one base in the DNA sequence with another.

What is a deletion mutation?

A base is removed from the DNA sequence.

What is an insertion mutation?

A base is added to the DNA sequence.

What is the role of DNA polymerase during replication?

It catalyzes the formation of phosphodiester bonds between nucleotides.

What are the main differences between DNA and RNA?

DNA is double-stranded with deoxyribose, whereas RNA is single-stranded with ribose.

How many hydrogen bonds link adenine and thymine?

Two hydrogen bonds.

How many hydrogen bonds link guanine and cytosine?

Three hydrogen bonds.

What is the significance of the 5' and 3' ends in nucleic acids?

They indicate the direction of the nucleic acid strand.

What happens during transcription?

A section of DNA is copied into mRNA.

How does reverse transcription occur?

Viral RNA is converted back into DNA via reverse transcriptase.

What is recombinant DNA?

DNA formed by combining DNA from two different organisms.

What do restriction enzymes do?

They cut DNA at specific sequences.

What are therapeutic products of recombinant DNA technology?

Examples include human insulin, erythropoietin, and growth hormones.

What is the purpose of polymerase chain reaction (PCR)?

To amplify small segments of DNA.

What types of genes are screened using PCR?

Genes associated with conditions like breast cancer.

What does a stop codon signal?

The termination of protein synthesis.

What are the three stop codons?

UGA, UAA, and UAG.

Define a germ cell mutation.

A mutation occurring in sperm or egg cells affecting offspring.

What does a silent mutation imply?

A change that does not alter the amino acid sequence.

What is a common consequence of mutations?

Altered protein function and potential genetic diseases.

What is translocation during protein synthesis?

The movement of a ribosome along mRNA as new tRNAs bring amino acids.

What happens to the polypeptide during chain termination?

It is released from the ribosome.

What is the role of a protease in viral replication?

It processes viral proteins needed for new virus particles.

What is the double-helix structure of DNA?

Two polynucleotide strands twisted around each other.

What defines the genetic code?

The specific sequence of codons that dictate the amino acid sequence in proteins.

What do mutations and their impacts lead to in populations?

Genetic diversity and evolution.

How does a retrovirus reproduce its genetic material?

By reverse transcription to make DNA from RNA.

What is the purpose of anti-viral drugs in relation to proteases?

To inhibit the synthesis of viral proteins.