UNIT 6: Gene Expression and Regulation Flashcards
What macromolecule makes up DNA?
Nucleic Acid
What is the monomer of nucleic acid?
Nucleotides
What elements make up DNA?
C - Carbon
H - Hydrogen
O - Oxygen
N - Nitrogen
P - Phosphorus
What makes up the structure of a nucleotide?
1) phosphate
2) 5-carbon sugar
3) Nitrogenous base
What bond holds 2 nitrogenous bases together?
weak hydrogen bonds
What bond attaches the phosphate to the 5-carbon sugar to form the backbone of DNA?
Phosphodiester bonds
What is the name of the strand that runs from 3’ to 5’?
leading strand
what is the name of the strand that runs from 5’ to 3’?
lagging strand
What nitrogenous bases are purines?
Adenine
Guanine
What is a purine?
Double ring structure
What is a pyimidine?
Single ring structure
What nitrogenous bases are pyrimidines?
Thymine
Cytosine
(Uracil - RNA)
Where does DNA replication occur?
(eukaryotes)
Nucleus
When does DNA replication occur?
S-phase of interphase
(cell cycle and meiosis)
What enzymes are involved in DNA replication?
1) Helicase
2) Topoismomerase
3) DNA Polymerase
4) Ligase
What does the Helicase do in DNA replication?
unzips/unwinds the double strands of DNA by BREAKING hydrogen bonds
What does the topoismomerase do in DNA replication?
relaxes strands and prevents super-coiling
What does DNA polymerase do in DNA replication?
joins free-floating nucleotides together to make the new complimentary strand using the original strand as a template
In what direction does DNA polymerase build during DNA replication?
5’ to 3’
What does Ligase do during DNA replication
joins together Okazaki fragments on the lagging strand
What is the structure of chromosomes in prokaryotes?
Circular chromosomesW
What is the structure of chromosomes in eukaryotes?
multiple linear chromosomes
What are plasmids?
small extra-chromosomal double-stranded DNA
Do both eukaryotes and prokaryotes contain plasmids?
Yes
What is the 5’ end of DNA referred to as?
Phosphate terminus
What is the 3’ end of DNA referred to as?
Hydroxyl terminus (OH)
What is the replication fork in DNA?
the location where the 2 DNA strands are seperated
What is horizontal acquisition?
exchange of genetic information between different genomes or between unrelated organisms
In what organism does horizontal acquisition occur in?
prokaryotes
What types of horizontal acqusitions are there?
1) Transformation
2) Transduction
3) Conjugation
4) Transposition
What is a transformation in horizontal acquisition?
the uptake of naked DNA from an external source
What is transduction in horizontal acquisition?
the transmission of foreign DNA into a cell when a viral genome integrates with the host genome
What is conjugation in horizontal acquisition?
the transfer of DNA between cells through an external cell extension
What is transposition in horizontal acquisition?
the movement of DNA segments between DNA molecules
What is the process that uses DNA to make RNA
Transcription
What is the process that uses RNA to make a protein?
Translation
What 3 types of RNA molecules are involved in DNA transcription and RNA processing?
1) Messenger RNA (mRNA)
2) Transfer RNA (tRNA)
3) Ribosomal RNA (rRNA)
What does mRNA do in DNA transcription and RNA processing?
it carries genetic information from DNA to the ribosomes
What does tRNA do in DNA transcription and RNA processing?
its recruited to the ribosomes to help create a specific polypeptide sequence
What does rRNA do in DNA transcription and RNA processing?
functional units of ribosomes responsible for protein assembly
What are introns?
(think intruders)
sequences of the mRNA transcript that DO NOT CODE for amino acids
What are exons?
(Think expressed)
sequences of an mRNA transcript that DO CODE for amino acids
Where does translation occur?
RibosomesH
How do retroviruses introduce viral RNA (not DNA) into host cells?
through reverse transcriptase
What is reverse transcriptase?
an enzyme that copies the viral DNA into viral RNA
