Gene Expression Review

Transcription

100

This is the type of molecule that is produced when a gene is transcribed.

mRNA

200

This is the name of the enzyme that carries out most of the processes of transcription.

RNA Polymerase

300

The strand of DNA which is NOT directly used to produce the mRNA transcript is called the:

Coding strand / Sense strand / Non-template strand

400

In eukaryotes, after transcription has concluded, there are THREE additional changes to the mRNA that need to be made; this is often called mRNA processing. What are these three changes that are made to the mRNA?

Splicing, 5' cap, 3' poly-A tail

500

In the case of some genes, their mRNA transcripts will sometimes have specific exons removed along with introns, creating transcripts with different combinations of exons. What is the end result of doing this? (I.e. What kinds of things does this allow for?)

Alternative splicing ; multiple different proteins produced from the same gene

Transcriptional Regulation

100

This is the name for a region of the DNA where an enzyme will bind to initiate transcription.

Promoter

200

This is the name for a type of protein that controls the rate of transcription of other genes.

Transcription Factor

300

This is the name for sequences of DNA near (or sometimes far from) a gene that allow specific proteins to regulate that gene's expression. 

Regulatory Sequences / Enhancers & Silencers

400

Name the protein complexes that DNA winds around as chromatin, AND name the individual smaller proteins that these complexes are made of.

Nucleosomes ; Histones

500

How can environmental pollutants such as cigarette smoke alter expression of a gene WITHOUT causing mutations?

DNA methylation / epigenetic changes

Translation

100

This is the type of molecule that is produced when an mRNA transcript is translated. 

Protein / Polypeptide

200

These are the small organelles that carry out translation. 

Ribosomes

300

This is the type of molecule that ribosomes are made out of:

Ribosomal RNA (rRNA)

400

Where can free and bound ribosomes each be found in the cell?

Floating in the cytoplasm (free) and attached to the rough ER (bound)

500

What happens at the A, P, and E sites within a ribosome?

A = tRNA arrives

P = the amino acid chain is transferred onto the new tRNA, thus adding its amino acid to the chain

E = the tRNA here transfers the chain to the one in the P site and then leaves

Genetic Code

100

A unit of information in mRNA that consists of three nucleotide bases is called a:

Codon

200

A set of three nucleotide bases on a molecule of tRNA that will allow it to correctly bind to mRNA is called a:

Anticodon

300

Translate this mRNA sequence into an amino acid sequence: 

AUG GUA CAU GCG UGA

Met - Val - His - Ala (- STOP)

400

What happens when a ribosome reads a STOP codon?

Ribosome disassembles, mRNA is released, new protein is released

500

The DNA sequence TAC CAA CGC ATT in a gene becomes damaged and mutates. Two bases are changed, and the sequence now is TAC CAT CGG ATT.

What is the effect on the protein that would be produced?

No effect

Miscellaneous

100

Where does transcription take place in eukaryotes?

In the nucleus

200

A cell needs to produce a channel protein to transport ions across its cell membrane. Would this cell produce this protein at a free ribosome or a bound ribosome?

Bound ribosome

300

What is a polysome?

A "structure" that is formed when many ribosomes bind to an mRNA transcript and translate it at the same time.

400

What is the role of the enzyme aminoacyl tRNA synthetase?

"Re-charge" tRNAs by adding new amino acids, allows them to be re-used, saves energy

500

Prokaryotic organisms can transcribe AND translate a gene at the exact same time. What makes this possible / why can't eukaryotes do this?

Nucleus / Splicing