Molecular biology simplified

What is the monomer of DNA and RNA?

Nucleotides.

What are the three components of a nucleotide?

A phosphate group, a pentose sugar, and a nitrogenous base.

What is the difference between DNA and RNA?

DNA has deoxyribose; RNA has ribose.

DNA is double stranded; RNA is single stranded

DNA has no oxygen; RNA has an oxygen

Which nitrogenous bases pair together in DNA?

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

Which nitrogenous bases pair in RNA?

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

What type of bond is between complementary bases together in DNA?

Hydrogen bonds.

What type of bond connects nucleotides in a single strand of DNA?

Covalent bonds (Phosphodiester bonds)

What is the role of helicase in DNA replication?

To unwind and separate the two strands of DNA.

What is the role of DNA polymerase?

To add complementary nucleotides to the new DNA strand during replication.

Transcription?

The process by which DNA is copied into a complimentary mRNA

Where does transcription occur?

In the nucleus.

Translation?

The mRNA sequence is decoded by ribosomes to assemble a polypeptide chain.

Where does translation occur?

Ribosome.

What is the function of tRNA?

To bring amino acids to the ribosome during translation.

What is a codon?

A sequence of three nucleotides on mRNA that codes for one amino acid.

What is an anticodon?

A sequence of three nucleotides on tRNA complementary to an mRNA codon.

What is ATP and its role in cells?

Adenosine triphosphate; the primary energy carrier in cells.

What is a condensation reaction?

A reaction where two molecules are joined by removing a water molecule.

What is a hydrolysis reaction?

A reaction where a molecule is split into two by adding water.

What is the function of enzymes in metabolism?

To speed up chemical reactions by lowering activation energy.

What is meant by the term 'metabolism'?

All chemical reactions occurring in an organism.

Outline the process of dna replication

• Helicase breaks hydrogen bonds, unwinding the double helix.

• The two new strands act as a template

• Free nucleotides are placed with exposed pairs

• DNA polymerase joins strands together forming two identical dna molecules

Outline transcription?

• RNA polymerase unwinds the double helix

• Polymerase positions RNA nucleotides for complimentary base pairing forming an mRNA strand

• mRNA leaves and DNA rewinds

Outline translation?

• mRNA binds to a ribosome

• tRNA brings amino acid with complimentary base codon

• Anticodons form complementary base pairs with codons

• Ribosomes join amino acids with peptide bonds and the process repeates itself until a stop codon

Subsitution?

One base replaced

Deletion?

One or more bases removed causing a frame shift mutation

Insertion?

One or more base codons added causing a frameshift mutation

Silent mutation?

No change in amino acid

Missense mutation?

One amino acid changedN

Nonsense mutation?

Premature stop codon

Frameshift mutation?

Instertion or deletion of bases not in multiples of 3 changing all codons after