DNA use in cell
What are the differences between DNA and RNA
i. RNA is single-stranded
ii. RNA has the sugar ribose instead of deoxyribose
iii. RNA has the base uracil (U) instead of thymine (T)
What are introns and exons
The coding segments of DNA are called exons, and the noncoding segments are called introns
The coding segments are called exons, and the noncoding segments are called introns
What happens during initiation of transcription
tRNA and mRNA bind to a ribosome
a. The preinitiation complex scans the mRNA for an initiation codon, AUG, which codes for methionine
b. The initiation complex forms
c. The large ribosomal subunit joins the complex
substituations, deletions, and insertions
This term refers to DNA that has been altered to contain genes or gene segments from different organisms, creating transgenic organisms.
recombinant DNA
a. mRNA
b. rRNA
c. tRNA
What are the three steps of transcription
Initiation, Elongation, and Termination
What happens during elongation of translation
amino acids are added one at a time to the growing protein chain
a. The ribosome holds two mRNA codons in both binding sites
b. The complex moves one codon along mRNA
What four different effects can substitutions cause
i. The amino acid sequence of a protein may be unchanged
ii. The amino acid sequence may be altered, but protein function may be unchanged
iii. Protein function may be changed by an altered amino acid sequence
iv. Protein function may be destroyed by a premature stop codon
This technique is used to amplify tiny amounts of DNA into virtually unlimited quantities through temperature cycling.
PCR
What is the function of each kind of RNA (Mrna, Trna, Rrna)
Messenger RNA carries the code for protein synthesis from DNA to ribosomes; Transfer RNA carries amino acids to the ribosomes; Ribosomal RNA and proteins form ribosomes
How does transcription begin
Begins When RNA Polymerase Binds to the Promoter of a Gene
1. RNA polymerase binds at the promoter region (TATAAA sequence)
2. The DNA begins to unwind
What kind of bond forms between two amino acids
peptide bond
This type of RNA can bind to mRNA to interfere with translation, regulating how much protein is produced from a gene.
microRNA
This molecular tool uses the enzyme Cas9 and RNA to make precise changes to a cell’s DNA, making genome editing much simpler.
CRISPR
Explain transcription and translation (including locations)
In transcription, the information contained in the DNA of a specific gene is copied into RNA ;This process occurs in the nucleus
During protein synthesis, or translation, the mRNA base sequence is decoded into an amino acid sequence (occurs in cytoplasm)
What happens in elongation
Elongation Generates a Growing Strand of RNA
1. RNA polymerase synthesizes RNA that is complementary to template strand of DNA
What happens during termination of translation
a. Translation stops when the stop codon is reached
b. Ribosome releases the complete protein
c. Ribosome and mRNA dissociate
Eukaryotic gene expression can be regulated at multiple steps — including transcription frequency, mRNA stability, and this post-translational process that can control protein activity.
protein modification (or protein degradation)
In forensic science, this type of DNA sequence—2 to 5 nucleotides long and repeated many times—is used to identify individuals.
short tandem repeats
What are features of the genetic code
1. Uses Three Nucleotides to Specify an Amino Acid
2. start and stop codons
3. redundant (more than one codon for many amino acids)
4. Anticodons in the tRNA are complementary to the codons in mRNA
1. RNA polymerase continues down the template strand of DNA until it reaches a sequence of bases called the termination signal
a. RNA polymerase then releases the completed RNA and detaches from the DNA
Summarize transcription
Transcription of a protein-coding gene produces an mRNA that is complementary to DNA,
and starting with AUG, each codon in mRNA is a sequence of three bases that specifies
an amino acid or a “stop”
Enzymes in the cytoplasm attach the appropriate amino acid to tRNA
During translation, tRNAs carry their attached amino acid to the ribosome based on the tRNA anticodon
The amino acids are linked together to form a protein
These epigenetic modifications can either suppress or enhance transcription by altering DNA or histones, and can even inactivate an X chromosome by forming a Barr body
epigenetic controls (such as DNA methylation and histone modification)
What are the three major differences between traditional agriculture and modern genetic engineering
a. Genetic engineering can produce massive changes in a single generation
b. Genetic engineering can combine genetic material from very different species
c. Genetic engineering can create genes that never existed before