Exam 2 Flashcards
Purine
Double ringed nucleotide
Start codon
indicates where to initiate translation
TRANS-ACTING ELEMENTS
protein that binds to cis-acting to control gene expression
pyrimidine
single ringed nucleotide
stop codon
indicates where to end translation
cis-acting element
sequence of DNA that may enhance or silence DNA when acted upon
Promoter
indicates where to initiate transcription
sense codon
3 mRNA bases that code for an amino acid
Protein-coding gene
encodes a polypeptide
terminator
indicates where to end transcription
DNA and RNA are _______
nucleic acids
Ribosomes can be found in DNA
What would the complementary strand to the following DNA strand?
5’ GCATAGGCC 3’
3’ CGTATCCGG 5’
Eukaryotic organisms have circular DNA.
fasle
Chromatin is made of
DNA and proteins (histones)
What is the repeating structural unit in chromatin called?
nucleosome
Heterochromatin is highly compact and transcriptionally inactive.
True
What is the term for a segment of nucleotides in between the sections that actually code for something?
Introns
Genome size does not equate to species complexity
true
moderately and highly repetitive sections of DNA typically code for what?
Transposons
DNA replication results in ________
Two daughter molecules identical to the parent molecule
What enzyme bids Okazaki fragments
DNA ligase
What enzyme prevents the parent strand from rebounding while the daughter strands are built?
Single-strand binding proteins
What enzyme lays RNA primers before the addition of new nucleotides to daughter strands?
Primase
What enzyme breaks hydrogen bonds between DNA strands in DNA replication
DNA helicase
what is a major difference between the Holiday and Double-strand break model?
*The amount/ types of enzymes involved
*The amount of strands initially broken to begin the process
what protein complex is responsible for aiding in double-strand break model strand invasion?
RecA
RNA polymerase II transcribes what?
mRNA
Which enzyme plays a role in RNA modification?
Spliceosome
Why are polyA tails important
*protects mRNA from shortening
*helps mRNA exit the nucleus
*regulates gene expression
a protein can be made of one or many polypeptides
true
amino acids are bound by what
peptide bonds
What is the term for the characteristic of the genetic code having more than one codon specifying the same amino acid?
degeneracy
If two codons code for the same amino acid, what are they?
synonymous codons
Since there are 20 types of amino acids, how many types of aminoacyl-tRNA synthetase are there?
20
all proteins will have a quaternary structure
false
3 things a nucleotide is composed of
- at least one phosphate group
- a pentose sugar
- a nitrogenous base
what are the two suggestions for why transposition occurs
1) The selfish DNA hypothesis states that transposons proliferate without causing harm, so there is no reason for it to not happen.
2) The Exon shuffling hypothesis, which says this occurs because it offer some sort of advantage and broadens the gene pool.
What concept/process do the Holliday model and double-strand break model attempt to explain?
The Holliday model and the double-strand break model attempt to explain Homologus recombination.
What is the central dogma of genetics? Utilize the terms “collinearity” and “gene expression.”
The central dogma of genetics is DNA to RNA to Proteins. During Collinearity the sequences in our genes dictates the amino acid sequences our bodies make. Gene expression takes the information from the amino acids and gives it a specific funtion.
Describe what happens during each stage of Transcription:
Initiation:
Elongation:
Termination:
Initiation: the intitial binding of RNA polymerase to the promoter in order to begin RNA synthesis.
Elongation: the synthesis of RNA using DNA as a template
Termination: release of the newly made RNA transcript and RNA polymearase from the DNA
A. What role do ribosomes play in protein synthesis?
B. What happens at the A, E, and P sites?
A. Ribosomes conatin discrete sites where tRNA binds and the poplypeptide is synthesized.
B. Aminocyl (A site) - where a charged tRNA initially binds
Peptidyl (P site) - carries a tRNA along with a polypeptide
Exit (E site) - where an uncharged tRNA exits
