Micro Chapter 8 Flashcards
What is a polynucleotide?
multiple nucleotides twisted together
How many hydrogen bonds are there between A and T?
two
How many hydrogen bonds are there between G and C?
three
What is the purpose of hydrogen bonds?
provide stable
structure
What is a gene?
- segment of DNA
- functional product
What is the purpose of the Antiparallel nature of DNA?
- allows bases to be close to each other
What does DNA Helicase do?
- enzyme
- “unzips” DNA for replication
What is DNA Gyrase?
- stabilizes the helix
Describe replication of the leading strand
- uses DNA polymerase
- results in 5’–>3’ old strand and 3’–>5’ new strand
Describe replication of the lagging strand
- RNA polymerase acts as primer
- DNA polymerase adds new nucleotides in short fragments (Okazaki segments)
- DNA ligase seals the gap
Describe how replication is different in bacteria cells
- only one strand of DNA
- DNA is circular
- has origin of replication and replication termination point
What is the difference between transcription and replication?
- Transcription is the replication of DNA that results in RNA
- only results in one strand because RNA is single stranded
Describe Eukaryote RNA splicing
- removal of introns and joining of exons in eukaryotic mRNA, tRNA or rRNA
- accomplished with the help of spliceosomes, which remove introns from the genes in RNA
What is a splicosome composed of?
-a mixture of protein and small RNA molecules.
How does Leukemia effect transcription?
- causes short interfering RNA to combine with mRNA and a polymer which causes cell death
- cell too mutated with these genes
Describe Translation
- tRNA’s anticodon matches with mRNA’s start codon
- more tRNA come and bond to the following chain in the sequence and as they do so their matching amino acids join to the previous amino acid (MET) forming a polypeptide chain
Describe the structure of tRNA
- one end has an amino acid (usually MET) and the other has an anticodon (usually UAC)
- the ends always “match” each other ie. each amino acid always has the same anticodon matched to it
What is the difference between a prokaryotic genome and a eukaryotic genome?
-prokaryotic- genetic material floats free in cell, mostly coding DNA, double stranded circular DNA called plasmids
