Ch. 3.5 Nucleic Acids

What are the two types of nucleic acids?

DNA (deoxyribonucleic acid) and RNA (ribonucleic acid)

What is the function of DNA in living organisms?

DNA carries the cell’s genetic blueprint and instructions for its functioning.

What are genes?

Discrete units of inheritance made of DNA.

How does RNA function in the cell?

RNA acts as an intermediary that delivers DNA’s instructions to other parts of the cell.

Where is DNA located in eukaryotic cells?

In the nucleus.

Where is DNA located in prokaryotic cells?

In the cytoplasm.

Do prokaryotic cells have membrane-enclosed organelles?

No

Which organelles in eukaryotic cells have their own DNA?

Mitochondria and chloroplasts.

In what form does eukaryotic DNA exist?

As multiple linear chromosomes made of chromatin.

What are the functions of DNA?

Provides instructions for protein synthesis and its own replication.

What is unique about DNA compared to other molecules?

It includes instructions for its own replication.

What are DNA and RNA made of?

Nucleotides.

What are the three components of a nucleotide?

A five-carbon sugar (pentose), a negatively charged phosphate group, and a nitrogenous base.

What are the nitrogenous bases in DNA?

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

What are the nitrogenous bases in RNA?

Adenine (A), Uracil (U), Guanine (G), and Cytosine (C).

How are nucleotides linked together?

By phosphodiester bonds.

What is involved in the formation of a phosphodiester bond?

The removal of one molecule of water and two phosphate groups.

What structure does DNA form?

A double helix.

How is the DNA double helix held together?

By hydrogen bonds.

What allows DNA to make copies of itself during cell division?

Complementary base pairing.

What is the role of complementary base pairing in transcription?

It allows transcription of DNA’s genetic information to messenger RNA (mRNA).

What is mRNA?

Messenger RNA acts as an intermediary between DNA in the nucleus and protein synthesis in the cytoplasm.

Why does mRNA exist?

So DNA can stay in the nucleus while its transcribed copy (mRNA) is used in protein synthesis.

What are the two main processes involving RNA in protein synthesis?

Transcription and translation.

What are the key differences between DNA and RNA?

DNA:

• Usually double-stranded

• Remains in the nucleus

• Carries genetic information

• Sugar is deoxyribose

• Nitrogenous bases: A, T, G, C

RNA:

• Usually single-stranded

• Leaves the nucleus

• Involved in protein synthesis

• Sugar is ribose

• Nitrogenous bases: A, U, G, C