Final Exam Flashcards
Synonymous
Mutation that does not change the amino acid
Transition
Substitutions of a purine for a purine base
Meiosis
Creation of four daughter cells from a single parent cell
Transversion
Substitutions of a purine base for a pyrimidine base
Chromatin
DNA with a protein scaffold
Quanternary
A higher order of structure involving more than one protein
Peptide
Chemical bonds connecting amino acids
Mitosis
Formation of two cells from one cell
Tertiary
Describes the three dimensional structure of a protein
Phosphodiester
Bonds formed along the pentose sugar backbone of a polynucleotide
Nucleosome
the fundamental repeating unit of chromosome
Heterochromatin
Stains more darkly and has inactive genes
Neutral
missense mutation that changes one AA for another chemically similar AA
Euchromatin
Stains lightly and has active genes
Nucleotides (A,C,G,T,U) are classified into two categories based on their ring structure. _______ have a single ring and are “CUT” from _______ which have a double ring structure
Pyrimidine
Purine
Characteristics of a model organism
inexpensive to raise and keep
ability to adapt to a lab environment
short generation interval
lots of offspring
Eukaryotic cells have the majority of their DNA present in the nucleus but they also have organelles in the cytoplasm that contains their own DNA. We listed two fundamental differences between the DNA contained in the nucleus and the DNA contained in the mitochondria/chloroplast. What are those two characteristics of mtDNA and cpDNA
Circular
Uniparental inheritence
T/F
The nitrogenous base in nucleic acids is attached to the 1’ carbon of the pentose sugar
True
T/F
The regulatory promotor of a gene is located immediately upstream of the transcription start site which is immediately upstream of the core promotor
F
Core promotor site is immediately upstream of the TSS
T/F
Exons must be spliced out of the pre-mRNA molecule so that only the introns are left in the mature mRNA
F
Introns must be spliced out of the pre-mRNA molecule so that only the exons are left in the mature mRNA
T/F
Enhancers function to control gene expression and are typically upstream of a gene but can also be downstream from the coding region
True
T/F
Okazaki fragments are fragments of DNA that occur on the leading strand during DNA replication
False
Occur on lagging strands
T/F
Replication of DNA is initiated by RNA primers that are later removed
True
When Meselson and Stahl designed their experiments to determine how DNA replicates, they could have chosen to radiolabel any number of different elements. Why did they choose to label nitrogen?
It is an essential component of DNA
During nucleic acid polymerization, two phosphate groups are cleaved from the incoming dNTP providing the energy needed to form a bond between the previously incorporated nucleotide and the incoming nucleotide. Why is it important that this energy comes from the incoming nucleotide versus from the existing nucleotide of the growing chain?
What is the name of the modification that is added to eukaryotic pre-mRNA very shortly after transcription begins and it functions to stabilize the pre-mRNA and is necessary for initiation of translation
5’ cap
Poly A Tail
Polynucleotides (DNA/RNA) are polymers of nucleotide subunits. Similarly, all proteins are polymers composed of what subunit?
Amino acids
Crossing over (recombination) is an important source of genetic variation. which of the following is true of recombination?
A. it allows for multiple protein isoforms to e translated from one template
B. It occurs during prophase
C. it occurs during both mitosis and meiosis
D. both (a) and (b) are true
E. None of the above are true
B. it occurs during prophase
A cell in G1 stage of development contains 2 total chromosomes. How many chromosomes would be present in a cell from the same organism if it were in:
a) anaphase I of meiosis
B) Prophase of mitosis
A) 4
B) 2
There were three early theories as to the model of DNA replication. Which model ended up being proven correct
semiconservative
What are the three basic building blocks of a nucleic acid?
Pentose sugar
phosphate linker
nitrogenous base
Even before nucleic acids were identified as the genetic material, biologist recognized that, whatever the nature of the genetic material, it must possess four important characteristics, what are they?
Ability to store info
Ability to copy info
Ability to retrieve info
Ability to vary
If a double stranded DNA molecule is 15% cytosine, what are the percentages of all the other bases in the molecule
15% cytosine
15%G
35% A
35% T
When DNA replicates (is copied), at each replication fork, synthesis of the leading strand proceeds continuously and that of the lagging strand proceeds discontinuously. Discontinuous replication on the lagging stand is a result of which property of DNA?
antiparallel nucleotide strands
Which of the following phrases does not describe a function of a promotor
a) serves as a sequence to which transcription machinery binds
b) signals where transcription ends
c) determines which DNA strand is the template
d) all the above are functions of the promotor
b) signals where transcription ends
DNA and RNA have directionality (polarity) based on the 5’ and 3’ ends of which building block of the nucleic acid molecule,
pentose sugar
Proteins also have directionality based on the individual building blocks of the molecule. We describe the directionality of a protein based on the ______ and ______ ends of the molecule
amino
carboxy
The genetic code is said to be ______, i.e. more than one triplet of nucleotides can code for a single amino acid
degenerate
The process of translation to synthesize a protein stops when the ribosome encounters a stop codon. How or why do the stop codons stop translation?
There are no tRNAs for stop codons
In eukaryotic organisms, why does DNA replication start at many locations along the DNA molecules?
To speed up the process since there is alot of DNA to replicate
There were two very important processes that occur in meiosis that contribute to the creation of genetic variation. What are those two processes called
crossing over
independent assortment
The primary sequences of both DNA and RNA are capable of forming higher level secondary structures. What is the common secondary structure of DNA
Double helix