6. Primary structure of nucleic acids.

What is the primary structure of nucleic acids?

The sequence of nucleotides (nucleoside monophosphates) that make up DNA and RNA.

What are the building blocks of nucleic acids?

Nucleotides, which consist of a 5-carbon sugar, a nitrogenous base (purine or pyrimidine), and a phosphate group.

What are the purines and pyrimidines in nucleic acids?

Purines: Adenine (A) and Guanine (G). Pyrimidines: Thymine (T) and Cytosine (C) in DNA, Uracil (U) in RNA.

What is the structure of DNA?

A double helix where the sugar-phosphate backbone forms the structure, and nitrogen bases pair through hydrogen bonds.

What are the base pairings in DNA?

Adenine (A) pairs with Thymine (T) via 2 hydrogen bonds, and Cytosine (C) pairs with Guanine (G) via 3 hydrogen bonds.

What does "anti-parallel" mean in the context of DNA?

The two strands of DNA run in opposite directions: one from 5' to 3' and the other from 3' to 5'.

What are the types of RNA?

1. mRNA (Messenger RNA) 2. tRNA (Transfer RNA) 3. rRNA (Ribosomal RNA) 4. snRNA (Small nuclear RNA).

What is the function of mRNA?

It encodes the amino acid sequence of a polypeptide and transports this code to the ribosome for protein synthesis.

What is the function of tRNA?

It brings amino acids to ribosomes during translation, according to the mRNA code.

What is the function of rRNA?

It makes up the ribosome along with ribosomal proteins, facilitating protein synthesis.

What is the function of snRNA?

It forms complexes with proteins to help with RNA processing in eukaryotes.

What are nucleosomes?

The smallest structural unit of chromatin, consisting of DNA coiled around a core of eight histone proteins.

Why are histones important in DNA structure?

They help compress DNA into chromosomes by allowing DNA to coil around them, forming nucleosomes.

What is the role of nonhistone proteins in chromatin?

They provide structural and regulatory roles, forming the scaffold structure of DNA after histones are removed.

What happens during DNA denaturation?

Heating DNA above 90°C causes it to separate into single strands by breaking hydrogen bonds between complementary base pairs.

What is the hyperchromic effect?

An increase in UV light absorbance when DNA is denatured, indicating the separation of its strands.

What happens during DNA renaturation?

When cooled, the DNA strands recombine into a double helix through hydrogen bond formation between complementary base pairs.

What is the hyperchromic effect in renaturation?

A decrease in UV absorbance when complementary strands come together during renaturation.

What is a ribozyme?

A ribonucleic acid (RNA) molecule that catalyzes chemical reactions, like joining amino acids during protein synthesis.

Where are ribozymes found?

In the large subunit of the ribosome, where they play a role in protein synthesis and other vital reactions.

What is the function of microRNAs?

They regulate gene expression post-transcription by binding to the 3'-UTR of target mRNAs, suppressing protein synthesis.

How do microRNAs regulate gene expression?

They destabilize the mRNA and silence translation by binding to complementary sequences in the mRNA.

What is RNA splicing?

The process in which exons are joined together in pre-mRNA through two transesterification reactions, removing introns.