Topic 3 - Genetic Regulation

Question 1

Gene Expression

Answer 1

Gene expression is the process by which the information stored in a gene is converted into a functional product, such as a protein or RNA molecule. Gene regulation refers to the mechanisms by which the expression of a gene is controlled, and it can occur at various stages of gene expression, including transcription, splicing, translation, and post-translational modification.
- determines whether or not a gene is turned “on” or “off”
- allows cell/tissue differentiation
- regulation of genes through the development
- In bacteria, gene regulation maintains internal flexibility (turning genes on and off in response to the environment)

Question 2

Gene

Answer 2

A sequence of DNA that encodes a specific trait/product.

Question 3

Structural Genes

Answer 3

DNA sequence that encodes a protein that functions in metabolism or biosynthesis or that has a structural role in the cell.

Question 4

Regulatory Genes

Answer 4

DNA sequence that encodes a protein or RNA molecule that interacts with other DNA sequences and affects transcription or translation of those sequences.
- Regulatory genes are a type of gene that produce DNA-binding proteins called transcription factors (TFs), which control the expression of other genes. Transcription factors bind to specific DNA sequences, located near the target genes and regulate their expression by modulating the rate of transcription initiation by RNA polymerase.

Question 5

Regulatory Elements

Answer 5

DNA sequence that affects the transcription of other DNA sequences to which it is physically linked; DNA sequences that are not transcribed but play a role in regulating other nucleotide sequences.

Question 6

DNA-Binding Proteins

Answer 6

• produced by regulatory genes
• DNA binding proteins can recognize information in the major and minor grooves of DNA - recognize specific sequences and will bind at those specific sequences
• DNA binding proteins form H bonds with groups on the bases that are able to form H bonds

Question 7

Domains

Answer 7

• approx 60-90 amino acids long
• responsible for doing a specific job or forming a specific structure

Proteins are composed of one or more structural domains, each of which is responsible for performing a specific function or adopting a specific three-dimensional structure. Domains can be thought of as independent units within a protein that have their own unique properties and functions. Some domains bind specific ligands or other proteins, while others have enzymatic activity or are involved in structural stability. The specific combination and arrangement of domains within a protein determine its overall function and can be used to classify proteins into functional categories.

Question 8

Motif

Answer 8

Within the binding domain, a simple structure that provides specificity; a specific sequence of amino acids (aa) that recognizes the DNA sequence
- motifs are simple structures that can fit into a major groove of the DNA double helix
- allows for the specificity of transcription factors

Within the DNA-binding domain of a transcription factor, there are often specific short amino acid sequences, called recognition motifs, that are responsible for recognizing and binding to specific DNA sequences. The recognition motifs are typically composed of a few conserved amino acids that form a specific pattern and provide specificity to the DNA binding interaction.

Question 9

Transcription factors

Answer 9

The protein binds to DNA sequences in eukaryotic cells and affects levels of transcription.

Question 10

DNA-binding proteins can be grouped into several types on the basis of their domains, three are:

Answer 10

• helix-turn-helix
• zinc fingers
• leucine zipper

Question 11

Helix-turn-helix motif

Answer 11

Consists of two alpha helices connected by a turn and is a common bacterial regulator protein

Question 12

zinc fingers motif

Answer 12

consists of a loop of amino acids containing a zinc ion; shred by many eukaryotic regulatory proteins