Module 9: DNA, RNA, and Protein Synthesis

Flashcards covering DNA structure, replication, transcription, translation, and types of mutations.

What is the basic structure of a DNA strand?

A chain of nucleotide subunits with a sugar-phosphate backbone and nitrogen-containing bases

Which sugar is found in DNA?

Deoxyribose

What is the overall shape of a DNA molecule?

A double helix composed of two complementary strands

What type of bonds hold the nitrogen bases of DNA together?

Hydrogen bonds

State the base-pairing rules in DNA.

Adenine pairs with thymine (A=T) and cytosine pairs with guanine (C≡G)

How does DNA replication occur?

The two parental strands separate and each serves as a template for synthesis of a new complementary strand

What is the result of DNA replication?

Two identical DNA molecules, each containing one old strand and one new strand (semi-conservative replication)

What happens at the origin of replication?

The DNA strands separate, forming replication bubbles where new strand synthesis begins

How does DNA direct traits in an organism?

By coding for proteins through the processes of transcription and translation

List three key differences between RNA and DNA.

RNA is single-stranded, contains the sugar ribose, and uses uracil instead of thymine

Name the three types of RNA and give their primary functions.

mRNA carries the genetic code, tRNA brings amino acids to the ribosome, and rRNA forms part of the ribosome’s structure

What is transcription?

The synthesis of mRNA from a DNA template in the nucleus

What is translation?

The assembly of a protein at a ribosome using the sequence encoded in mRNA

Describe the typical flow of genetic information in a cell.

DNA → RNA → Protein

Define a mutation.

Any change in the genetic material of a cell

What is a point mutation?

A change in a single base pair within a gene

How can a point mutation affect a protein?

It may alter the amino-acid sequence, potentially changing the protein’s function

What is a frameshift mutation and why is it often severe?

An insertion or deletion that shifts the reading frame of the genetic code, usually disrupting the entire downstream amino-acid sequence