Chapter 14 - RNA Flashcards
Differences between DNA and RNA (3)
- DNA uses Thymine (T) and RNA uses Uracil (U)
- DNA uses deoxyribose and RNA uses ribose
- DNA is double-stranded and RNA is single-stranded
mRNA
Messenger RNA and is the complimentary RNA strand to a gene on the DNA
rRNA
Combines with proteins to make up the ribosome
tRNA
Brings the correct amino acid to the ribosome and matches the mRNA sequence
Transcription
- The process by which a mRNA complimentary strand is made for a gene
- DNA is used as a template to create the RNA
What enzyme creates the complimentary mRNA strand?
RNA polymerase
Promoter
A portion of DNA that RNA polymerase binds during the process of transcription
How is mRNA processed in eukaryotic cells?
By removing the intron
What is spliced back together on the mRNA?
Exons
What is added to the mRNA to create a mature manuscript?
A cap and tail
From the nucleus, where does the mRNA travel to?
The cytoplasm
Translation
The process by which the mRNA is used to create a protein
How many bases make up a codon?
3
AUG
- The start codon
- Codes for Methionine
How many stop codons are there?
3
Anticodon
On the tRNA strand and is complementary to the codon on the mRNA
What does the tRNA bring to the ribosome where it is transferred to the growing polypeptide chain?
The correct amino acid
Where does translation occur in eukaryotes and prokaryotes?
- Eukaryotes: Nucleus
- Prokaryotes: Cytoplasm
The central dogma of molecular biology
DNA -> RNA -> Proteins
Where are genes that operate together located in prokaryotes?
The operon
The lac operon encodes proteins needed to transport the disaccharide ____.
Lactose
The operator region
The region of DNA where the lac repressor binds
What does the lac repressor prevent RNA polymerase from binding, therefore preventing transcription?
The promoter region
If lactose is present, what does the lac repressor change?
Shape
Transcription factors
Proteins in eukaryotes that bind DNA sequences and control gene expression
What do transcription factors bind?
The enhancer region of DNA and the TATA box
Homeotic genes
Master control genes for development
Homeobox genes
A portion of about 180-bases that are very similar between species
Hox genes
The collection of homeobox genes in fruit flies
Epigenetics
Control gene expression by wrapping the DNA tightly around the nucleosome
What can also be an influence on gene expression?
The environment
Mutation
A change that is made in the DNA when replicating
What two things can mutations affect?
Gene sequences and chromosomes
Point mutations
Involve one nucleotide changing within a gene
Substitution
One nucleotide is replaced by another
Insertion
One nucleotide is added to a gene
Deletion (gene sequence)
One nucleotide is removed from a gene
Deletion (chromosome)
One portion of the chromosome is removed
Duplication
One portion of the chromosome is duplicated
Inversion
- The order of a part of a chromosome is switched
- Can occur during crossing over in meiosis
Translocation
A portion of one chromosome attaches to another chromosome
Mutagen
A chemical or physical agent in the environment that causes a mutation
