Gene Expression Unit 1 Flashcards
Describe 3 differences between DNA and RNA
- DNA is double stranded and RNA is single stranded
- Deoxyribose sugar is the nucleotide present in DNA and Ribose sugar is the nucleotide present in RNA
- The base partner for Adenine is Thymine in DNA and Uracil in RNA
Name the two stages involved in Gene Expression
Transcription and Translation
In which region of the cell does transcription take place ?
In the nucleus
Name the region on the DNA strand where transcription begins
Promoter region
Name the enzyme involved in transcription
RNA polymerase
Name the region on the DNA strand where transcription end
Terminator
What name is given to the strand formed initially after transcription ?
Primary transcript of mRNA
What process follows the formation of the primary transcript of mRNA ?
Splicing
Where does the process of splicing occur ?
In the nucleus
During splicing, what parts are cut out ?
Non coding regions called introns
During splicing, what regions are retained ?
Coding regions called exons
The same piece of DNA can be used to make several proteins due to the facts that on occasions different regions can act as introns and exons, what name is given to this ?
Alternative RNA splicing
In which part of the cell does translation occur ?
Ribosome
Where are tRNA molecules found ?
In the cytoplasm
What name is given to every 3 bases on mRNA ?
A codon
What name is given to the three bases at one end of a tRNA molecule ?
An anticodon
The anticodon acts as a codeword to attach something to the other end of the tRNA, what is it that attaches ?
An amino acid
How many different amino acids exist ?
20
A mRNA strand attaches at a ribosome binding site, where does the process of translation begin ?
Start codon
What type of bonds form between codons and anticodons as they pair up ?
Hydrogen bonds
Amino acids start to align with one another when tRNA anticodons join up with mRNA codons, what type of bond forms between adjacent amino acids ?
Mainly peptide bonds
When does the process of translation stop ?
When a stop codon is reached
What happens to the tRNA and mRNA at the end of translation ?
It detaches from the ribosome and is released back into the cytoplasm for reuse
What other type of bond can be found between a polypeptide a paper from peptide bonds ?
Hydrogen bonds
Name some functions of the proteins produced in gene expression ?
- Enzymes
- Hormones
- Antibodies
- Structural proteins
What combination of factors determine the overall phenotype of an individual ?
Genotype and environmental factors
How is a cells genotype determined ?
By the sequence of the DNA bases in its genetic code
How is a cells phenotype determined ?
By the proteins that are synthesised when the genes are exposed
Where does the information get copied and transported to ?
The ribosome
The copying and transport of the DNA code requires a second molecule of what ?
mRNA
What does the code copied from DNA have to be read by ?
A special ‘protein building’ machine called a ribosome
A ribosome is built from what ?
A second type of RNA called rRNA
The assembly of proteins requires amino acids to be called into position. This requires what ?
A third type of RNA called tRNA
What is translation ?
The assembly of proteins requiring amino acids to be called into position. This requires a third type of RNA called tRNA
What is transcription?
Transcription is the synthesis of mRNA from a section of DNA
What does mRNA do ?
It copies a section of the DNA and carries it into the cytoplasm to a ‘protein building’ called a ribosome
What does tRNA do ?
It carries the amino acids into position at the ribosome. This process is called translation
What is rRNA ?
The RNA part of a ribosome which aids protein synthesis
What is RNA Polymerase responsible for ?
This enzyme is responsible for transcription at it moves along the gene, unwinding and opening the DNA strand
What does RNA polymerase form ?
The mRNA strand by joining nucleotides together
What end can nucleotides join onto ?
The 3’ end of the mRNA strand
What is splicing ?
These are long sections of DNA that do not code for a polypeptide. These are called introns
