Molecular Genetics and Genetic Engineering

Practice questions covering DNA structure, protein synthesis, and the process and ethics of genetic engineering based on lecture notes.

What is the primary function of Deoxyribonucleic acid (DNA)?

DNA is a molecule that carries genetic information and is important for cell division and cell differentiation.

Where is DNA located in an animal cell?

DNA is located in the nucleus.

What is a gene?

A gene is a segment of DNA that codes for one polypeptide.

What are the three components of a DNA nucleotide?

A deoxyribose (sugar) molecule, a phosphate group ($PO_4$), and a nitrogenous base.

Which nitrogenous bases pair together in DNA?

Adenine (A) pairs with Thymine (T), and Guanine (G) pairs with Cytosine (C) through complementary base pairing.

What types of bonds are found in the DNA structure?

Strong covalent bonds form the sugar-phosphate backbone, while weak hydrogen bonds hold the two polynucleotide strands together between complementary bases.

How do DNA molecules form chromosomes?

A DNA molecule coils around proteins to form chromatin threads, which then condense to form a chromosome during cell division.

How is the information in DNA used to make proteins according to the central dogma?

Information in DNA is copied onto mRNA during transcription in the nucleus, and then the mRNA information is used to synthesize proteins during translation in the cytoplasm.

What are the characteristics of the genetic code?

It is a 3-base code for 1 amino acid, non-overlapping, and universal.

What replaces Thymine (T) in mRNA?

Uracil (U).

What is genetic engineering?

Genetic engineering involves the transfer of genes from one organism into the genetic material of another organism which does not have the desired gene(s).

What is a transgenic organism?

An organism which acquires a foreign gene.

What is a vector in genetic engineering?

A DNA molecule, virus, or bacterium (such as a plasmid) used to transfer a gene-of-interest into another organism.

What is a plasmid?

A circular, double-stranded DNA molecule separate from the chromosomal DNA that is capable of replicating independently.

Why are bacteria used as vectors in genetic engineering?

They have a short generation time, plasmids are easily reproduced and passed around, and they allow for the feasibility of mass culture.

What is the function of a restriction enzyme?

It recognizes and cuts DNA at a specific restriction site, often leaving 'sticky ends' (single-stranded sequences of DNA bases).

What is the role of DNA ligase in creating recombinant plasmids?

DNA ligase seals the foreign DNA fragment to the cut plasmid through the formation of covalent bonds.

How is a recombinant plasmid inserted into a bacterium?

By applying temporary heat or an electric shock to open pores in the bacterial cell surface membrane, allowing the plasmid to enter.

What are the advantages of producing human insulin via genetic engineering?

It does not induce allergic responses, is cheaper and easier to produce in large quantities, has less risk of pathogen contamination, and avoids the ethical concerns of using animal-derived insulin.

How does genetic engineering differ from selective breeding regarding species relation?

Selective breeding requires organisms to be closely related or of the same species, while genetic engineering allows genes to be inserted into non-related or different species.