Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
46 Cards in this Set
- Front
- Back
|
Where are nucleic acids located in prokaryotes?
|
cytosol
|
|
|
Where are nucleic acids located in eukaryotes?
|
mainly in the nucleus, some in the mitochondria and ribosomes
|
|
|
What are 4 functions of nucleic acids?
|
1) Storage and transfer of genetic info (DNA, RNA, mRNA)
2) Regulation of protein expression (RNA siRNA) 3) Protein synthesis (tRNA, rRNA) 4) Catalytic functions (ribozymes) |
|
|
How many rings does a purine have? Pyrimidine?
|
2, 1
|
|
|
Which nitrogenous bases are purines?
|
Adenine, Guanine
|
|
|
Which bases are pyrimidines?
|
Cytosine and Thymine (or Uracil in rna)
|
|
|
Which base can methylated in DNA? RNA?
|
Cytosine, all of them
|
|
|
if Cytosine becomes methylated, it then becomes also known as
|
Thymine
|
|
|
MEMORIZE STRUCTURES OF ALL BASES
|
DO IT
|
|
|
What are some of the functions of methylated bases?
|
1) protect your DNA from bad DNA
2) error correction 3) protection from nucleases |
|
|
There is one uncommon base that is used especially in tRNA. What is it's name(s)
|
Inosine aka hypoxanthine
|
|
|
What is a nucleoside?
|
a nitrogenous based attached to a sugar
|
|
|
if adenine is attached to a sugar with an H on carbon 2, what would it be called?
|
Deoxyadenosine
|
|
|
if cystosine was attached to a sugar with an OH on carbon 2, what would it be called?
|
Cytidine
|
|
|
How do you name a nucleoside?
|
1)Identifying what element is on Carbon 2 (H is DNA, OH is RNA)
2) Add deoxy if it for DNA 3) If it is a pyrimidine, it will end with 'idine" If it is a purine, it will send with 'osine' |
|
|
What is a nucleotide?
|
A nucleoside attached to a phosphate backbone
|
|
|
an example of an important nucleotide that is involved in cellular energy would be
|
ATP (adenosine triposphate)
|
|
|
How are nucleotides bound together?
|
Phosphodiester bonds
|
|
|
DNA and RNA start at which end (5' or 3')
|
5'
|
|
|
Why is it called the 5' end?
|
The phosphate is connected to carbon 5 on the initial nucleotide
|
|
|
Why is it called the 3' end?
|
the last phosphodiester bond (hydroxyl) on the last nucleotide is connected to Carbon 3
|
|
|
1) what base pairs with A?
2) what base pairs with G? |
1) T or U (in RNA)
2) C |
|
|
What is a wobble pair?
|
When two bases bond that aren't normally paired together
|
|
|
What is the predominant conformation for DNA?
|
B-form (right-handed)
|
|
|
What is the predominant conformation for RNA?
|
A-form (left-handed)
|
|
|
Besides B form, DNA can also take on this conformation.
|
Z form (left handed)
|
|
|
B form of DNA is typical under what conditions?
|
normal physiological conditions
|
|
|
A Z-form of DNA would occur under what conditions?
|
when alternating purine and pyrimidine sequences exist.
|
|
|
What implied role does the purine-pyrimidine Z form of DNA have?
|
A possible role in gene regulation
|
|
|
Is RNA single stranded or double stranded?
|
single
|
|
|
how would a single stranded RNA create loops?
|
Some of the bases are compliments...therefore they would pair up to form a helix. When bases can't pair up, then form loops or bulges
|
|
|
What is supercoiling?
|
Further twists on the double helix
|
|
|
What enyzyme introduces negative supercoiling?
|
DNA gyrase
|
|
|
Negative supercoils go clockwise or counterclockwise?
|
counterclockwise
|
|
|
Positive supercoils to clockwise or counterclockwise?
|
clockwise
|
|
|
What role does a topoisomerase play in supercoiling?
|
To reduce supercoiling
|
|
|
What is a Class I topoisomerase?
|
it cuts the backbone of the supercoiled strand and passes and other strand through
|
|
|
What is a class II topoisomerase?
|
it cuts both backbones and passes through another part of DNA
|
|
|
how many possible start points do prokaryotic DNA have?
|
1, becuase it is circular,
|
|
|
is DNA circular?
|
no, linear
|
|
|
How is DNA packaged?
|
It is packaged by forming nucleosomes, which are 146 bases pairs of DNA wrapped about a histone protein
|
|
|
Protein/DNA material is called ____
|
chromatin
|
|
|
A single chromosome fiber is called a
|
chromatid
|
|
|
Why does DNA store genetic information and RNA does not?
|
There is spontaneous breakdown and mutations of RNA, short half life (4 years as oppose to DNA's 100000 years)
|
|
|
What are endonucleases?
|
they hydrolize (cleave) phosphodiester bonds that are in the middle of a nucleic acid
|
|
|
What are Exonucleases?
|
They cleave phosphodiester bonds from free ends of nucleic acids
|
