Chapter 17: Gene Expression Flashcards
This deck is designed to aid you in understanding the processes that occur in gene expression/protein synthesis.
What is gene expression/protein synthesis?
Is the process by which DNA directs the synthesis of proteins, hence why it can also be called protein synthesis
What is a protein?
Is a naturally occurring, complex substance that consists of amino acid molecules joined by special connections called peptide bonds/amide bonds
Where can proteins be found? Name some types.
Proteins are present in all living organisms and include many essential biological compounds, such as enzymes, hormones, and antibodies
What are the two parts of gene expression in order?
Transcription
Translation
Explain the central dogma of (molecular) biology.
DNA will be used to create RNA via transcription. RNA will be used to create proteins via translation.
What is transcription?
Is the process of making an mRNA (messenger Ribonucleic Acid) copy from a DNA gene sequence; occurs inside the nucleus
What are the three types of RNA?
Pre-mRNA
mRNA
tRNA
What is the first step of transcription?
In the nucleus, a segment of DNA that codes for a specific gene is unwound
What is the second step of transcription?
One of the two strands of DNA will be the template strand
What is the template strand?
Refers to the specific strand of DNA that will be replicated [transcribed] into RNA
What is the third step of transcription?
RNA Polymerase travels along the template strand and creates the pre-mRNA
What is RNA Polymerase?
An enzyme
What is the fourth step of transcription?
Pre-mRNA is then modified, still in the nucleus, and converted to mRNA
Is it true that a strand is classified as mRNA only once it has been modified and is ready to leave the nucleus?
Yes
What does thymine change into during the process of transcription?
Urasil (U)
What is the nontemplate strand also called?
Coding strand
How can you tell the difference between DNA and RNA?
DNA: -generally double-stranded -has thymine instead of uracil RNA: -generally single-stranded -has uracil instead of thymine
What are the few exceptions to the general structure of DNA and RNA in organisms?
Viruses
What is a translation?
Is the process by which a cell makes proteins using the genetic information carried in messenger RNA (mRNA)
What is the first step of translation?
Once the mRNA strand has left the nucleus, it enters the cytoplasm and will eventually connect to a ribosome
What is the second step of translation?
Once the mRNA strand attaches to the ribosome, the ribosome “reads” the nucleotide sequence three (3) nucleotides at a time; each three nucleotide sequence is called a codon and the first codon is the start codon
What is the third step of translation?
The mRNA will continue to be read by the ribosome until a stop codon is reached
What is the fourth step of translation?
As the ribosome moves along the mRNA strand, tRNA molecules bind to the ribosome as well; each tRNA molecule comes with a specific amino acid that pairs with a specific codon from the amino acid
What is the fifth step of translation?
The amino acid chain (also called a polypeptide chain) folds itself into different shapes, resulting in a protein
