Genetics HW 3
What is a nucleotide?
- A five carbon sugar - A phosphate group - One of the 5 nitrogenous bases
RNA strands differ from DNA strands in which way?
- Contains ribose instead of deoxyribose - It is usually single stranded - It contains Uracil instead of thymine
DNA polymerases in DNA replication .....
- can attach to new nucleotides only in the 5' to 3' direction of the growing strand - must begin synthesis using a primer or existing DNA strand - DNA polymerases must have a template strand to copy from
How many origins of replication does a bacterial chromosome contain?
1
About how many DNA wrap around a histone complex?
146
Which component of the eukaryotic 60S ribosomal subunit is the peptidyl transferase (i.e. acts as a ribozyme to catalyze peptide formation)?
28s rRNA
The proofreading of the DNA occurs where?
3' to 5' direction
One strand of DNA is 5'- AGGCCTTA- 3'. What is the opposite strand?
3'- TCCGGAAT-5'
The zigzag and solenoid models are associated with what level of DNA organization?
30 nm fiber
How many general transcription factors are needed for eukaryotic transcription?
5
How many types of histone proteins are there (not including variants)?
5
DNA helicase enzymes move in what direction along the DNA during replication?
5' to 3'
Define a chromosome territory?
A region in the nucleus that is occupied by a single chromosome
What form of DNA is the most common in living organisms?
B DNA
What is the purpose of phosphorylating the carboxy terminal domain (CTD) of RNA Polymerase II?
Convert from the initiation to the elongation stage of transcription
DNA methylation occurs where and results in what?
CpG islands, blocking transcription of downstream gene
Which enzyme is responsible for the majority of DNA synthesis during prokaryotic replication?
DNA polymerase III
Which enzyme synthesizes most of the lagging strand of the DNA in bacteria?
DNA polymerase III
A functional protein is made up of the information contained within what region of DNA?
Exons
TRUE or FALSE: DNA polymerase III has the ability to begin synthesis of the new daughter strands immediately following the formation of the replication fork.
FLASE
You are studying DNA replication in human cells. You discover a mutant cell line that can carry out DNA replication, but the final product contains both RNA and DNA fragments. What enzyme is likely to be missing in this cell line?
Flap endonuclease
Areas of the chromosome that are highly condensed and transcriptionally inactive are called what?
Heterochromatin
What are histone variants?
Histone proteins that have slightly different amino acid sequences and specialized functions
DNA sequences that act to block the effects of control elements of one gene on another gene are known as what?
Insulators
What site of the ribosome is primarily responsible for holding the growing polypeptide?
P
The backbone of the DNA is formed by what kind of bonds?
Phosphodiester bonds
What is not a eukaryotic regulatory unit?
Pribnow box
TRUE or FALSE: One would expect heterochromatic regions of DNA to be more compacted than euchromatic regions.
TRUE
TRUE or FALSE: Steroid hormones are an example of an effector, which regulates regulatory transcription factor activity.
TRUE
TRUE or FALSE: The ability of the DNA polymerase to remove mismatched bases is called exonuclease cleavage or proofreading.
TRUE
TRUE or FALSE: The helical shape of the DNA contains major and minor grooves, which assist in the regulating of gene expression.
TRUE
What is found at the end of a eukaryotic chromosome?
Telomeres
The majority of the nonrepetitive genes in an organism are found where?
Unique sequences
Chromatin remodeling complexes after nucleosomes, this occurs when...
complexes of ATP-dependent proteins may reposition, evict, or change nucleosome composition.
What is not part of the eukaryotic preinitiation complex?
mediator
The correct order of compaction from least compacted to most compacted would be:
naked DNA, nucleosome, 30 nm fiber, radial loop, metaphase chromosome
Regulatory transcription factors may influence gene expression in which of the following ways?
recruiting proteins to the promoter to enhace chromatin compaction
The primary structure of a protein refers to...
the linear sequence of the amino acids