DNA Gene Expression and Mutations

Only a small fraction of ​ (a)   in a cell are ever expressed. Each ​cell is ​ (b)   to carry out a certain task and will only need to express ​ (c)   genes. ​ (d)   is the process by which specific genes are ​ (e)   to produce a required protein.

• genes
• specialised
• certain
• Gene expression
• activated

Tags

NGSS.HS-LS1-1

Which processes are involved in gene expression (select all that apply)

• Translation

• DNA Replication

• Transcription

• RNA Synthesis

Tags

NGSS.HS-LS1-1

Match the following

• tRNA

• Transfer RNA has a cloverleaf shape. It is made from a single strand of RNA which folds due to base pairing to form this unusual shape. It has a triplet anti-codon site and an attachment site for a specific amino acid.

• mRNA

• Ribosomal RNA and proteins form the ribosome. The ribosome is the structure where protein synthesis takes place.

• rRNA

• Messenger RNA is a linear molecule which carries a copy of the gene to be expressed from the nucleus. Every group of three bases (a 'triplet') is described as a codon because each one codes for an amino acid.

Tags

NGSS.HS-LS1-6

What are the coding regions of a gene called?

Tags

NGSS.HS-LS1-1

What are the intervening non coding regions of a gene called?

Ricin is a naturally occurring, powerful poison that affects eukaryotic organisms. Large mammals that ingest small amounts of ricin can die within three to five days. Studies have concluded that ricin stops the movement of a ribosome along a specific molecule. This specific molecule has been labelled Molecule X in the diagram.

What is the name of molecule X?

• A - rRNA

• B - tRNA

• C - mRNA

• D - pre-mRNA

Answer explanation

The image shows a ribosome move along a molecule. This must be an image of translation occurring, therefore the molecule must be mRNA.

Ricin is a naturally occurring, powerful poison that affects eukaryotic organisms. Large mammals that ingest small amounts of ricin can die within three to five days. Studies have concluded that ricin stops the movement of a ribosome along a specific molecule. This specific molecule has been labelled Molecule X in the diagram.

Eukaryotic organisms die from ricin poisoning because the ricin immediately causes

• A - nerve damage to motor neurons

• B - the process of mitosis in the cells to stop

• C - irreversible damage to DNA in the nuclei of cells

• D - the process of protein synthesis in cells to stop

Answer explanation

The image shows translation occurring. Therefore ricin affects the process of protein synthesis.

In eukaryotes, proteins that help the RNA polymerase bind to the regulatory region for transcription are called ____________.

• transcription factors
• topoisomerase
• regulatory genes
• activators

Regulatory proteins (transcription factors) may

• encourage transcription

• prevent transcription

• stop transcription once its started

• either encourage or prevent transcription

The study of the inherited changes in gene expression that occur without a change in gene sequence and influence how an organism's genes express themselves. Mechanisms are influenced by food and environment. They play an important role in the fetal basis of adult disease susceptibility.

• bionomics

• genomics

• genetics

• epigenetics