Genetic Engineering Exam One

University of Arkansas w/ Adam Pare (spring 26')

What is the process by which genetic information is copied from DNA into a functional RNA or protein?

Gene expression.

A gene is a sequence of DNA nucleotides that _ a protein or a functional RNA.

encodes

In the context of genetics, what does the term 'encodes' mean?

It means 'contains the information for'.

What molecule serves as the template during transcription?

DNA.

What is the primary product of transcription?

Messenger RNA (mRNA).

The process of synthesizing a protein from an mRNA template is called _.

translation

What cellular machinery is responsible for translation?

The ribosome.

What is the final product of the translation of mRNA?

A protein.

Why is it generally impractical to modify proteins directly in a cell?

Because there are thousands of copies of each protein, making it too much work to modify every one.

What is the most effective way for a scientist to alter the amino-acid sequence of a protein?

To alter the gene (DNA) that encodes that protein.

The two DNA strands are held together by what type of bond between complementary bases?

Hydrogen bonds.

In DNA base pairing, Adenine (A) always binds with which nucleotide?

Thymine (T).

In DNA base pairing, Cytosine (C) always binds with which nucleotide?

Guanine (G).

How many hydrogen bonds form between Guanine (G) and Cytosine (C)?

Three.

How many hydrogen bonds form between Adenine (A) and Thymine (T)?

Two.

The alternating sugar and phosphate groups form the _ of a DNA strand.

sugar-phosphate backbone

The two polynucleotide chains of a DNA double helix run in opposite directions, a property known as being _.

antiparallel

What chemical group is found at the 5' end of a DNA strand?

A phosphate group.

What chemical group is found at the 3' end of a DNA strand?

A hydroxyl (-OH) group.

The 5' and 3' designations of a DNA strand establish its _, which is crucial for how it is read during replication and transcription.

polarity (or directionality)

Due to complementary base pairing, the two DNA strands are considered _, meaning the sequence of one strand determines the sequence of the other.

redundant

What is the main function of DNA in a cell?

To act as an information storage system.

What part of a gene serves as the binding site for RNA polymerase and indicates where transcription should begin?

The promoter.

The orientation of a gene's _ determines the direction of transcription.

promoter

What is the term for the DNA sequence that is copied into mRNA when a gene is expressed?

The transcribed region.

What DNA sequence signals the end of transcription?

The terminator.

Transcription always starts at the _, proceeds through the transcribed region, and ends at the terminator.

promoter

What is a 'consensus sequence' in genetics?

An idealized sequence derived by comparing many different actual sequences, representing a common pattern.

How have scientists determined the consensus sequences for promoters and other gene parts?

By identifying and comparing the sequences of many different genes.

What general term describes DNA sequences like enhancers and silencers that control the rate, timing, and location of gene expression?

Regulatory elements.

Proteins that bind to specific DNA sequences to control the rate of transcription are known as _.

Transcription Factors (TFs)

What is the function of an activator transcription factor?

It binds to a regulatory element and causes gene expression to increase.

What is the function of a repressor transcription factor?

It binds to a regulatory element and inhibits or silences gene expression.

Regulatory elements that bind activators to increase gene expression are often called _.

enhancers

Regulatory elements that bind repressors to decrease or stop gene expression are often called _.

silencers

Where can regulatory elements be located relative to the gene they control?

They can be located near, far, upstream, downstream, or even within introns of the gene.

What are the two active sites typically found on repressor proteins?

A DNA-binding domain and an allosteric domain.

What is the function of the DNA-binding domain of a repressor protein?

It binds to specific DNA sequences, such as operators.

What is the function of the allosteric domain of a repressor protein?

It binds to another molecule (an inducer), which causes a change in the shape of the DNA-binding domain.

What is a 'functional RNA'?

An RNA molecule that directly performs a biochemical function rather than just serving as a messenger.

What is the role of Transfer RNAs (tRNAs)?

They bind to specific amino acids and transfer them to the ribosome during translation.

What is the role of Ribosomal RNAs (rRNAs)?

They combine with proteins to form the structure of ribosomes.

What is the role of Small Nuclear RNAs (snRNAs)?

They play a role in mRNA processing, such as splicing.

What is the role of MicroRNAs (miRNAs)?

They are involved in the post-transcriptional regulation of mRNA.

Term: Alleles

Different variants of a specific gene that arise via mutation.

What are chromosomes composed of?

Long molecules of double-stranded DNA.

The study of how genetic information is encoded, replicated, and expressed is known as _ genetics.

molecular

The study of the principles of heredity and how traits are passed between generations is known as _ genetics.

transmission

Negative control of transcription involves a _ that inhibits the process.

repressor

Positive control of transcription involves an _ that binds to a sequence to regulate transcription.

activator

In the analogy of biological engineering, cellular machinery like ribosomes and enzymes are considered the 'universal _'.

hardware

In the analogy of biological engineering, a new DNA template provided to a cell is considered the 'genetic _'.

software

A _ is a powerful tool in molecular biology used to identify regulatory elements by linking a test DNA sequence to a gene that produces an easily detectable molecule.

reporter gene

_ molecules are formed in a lab by bringing together genetic material from multiple sources to create sequences not found in nature.

Recombinant DNA

The _ of a DNA double helix is essential for forming stable hydrogen bonds between complementary bases.

antiparallel orientation

The chemical bonds that link adjacent nucleotides together in a single DNA strand, forming the backbone, are called _ bonds.

phosphodiester

A phosphodiester bond forms between the 3' group of one nucleotide and the 5' group of the next.

hydroxyl; phosphate