DNA & RNA Flashcards
What is the building block of DNA?
The nucleotide
Purines have a double ring structure
What are the 2 purines and 2 pyrimadines in DNA?
Pyrimadines have a single ring in their structure
Purines: Adenine & Guanine
Pyrimadines: Thymine & Cytosine
Adenine only pairs with Thymine whilst Guanine goes with Cytosine
Which of these properties are common to both DNA and RNA?
I. Contains a ribose sugar
II. Are comprised of many repeating nucleotides
III. Contains nitrogenous bases of AGCT
IV. Contains a phosphate group
V. Contains a deoxyribose sugar
A) I, II, III & V
B) I, II & IV
C) II & IV
D) I, III & IV
E) III & IV
C) II & IV
RNA has a ribose sugar whilst DNA has deoxyribose sugar
There is no Thymine in RNA, Uracil takes its place.
What bond holds complimentary base pairs together in DNA?
a) Phosphodiester bonds
b) Hydrogen bonds
c) Ionic bonds
d) Van der Waals forces
e) Induced Dipole interactions
b) Hydrogen bonds
3 H-bonds are formed between Cytosine and Guanine whilst 2 H-bonds are formed between Adenine and Thymine
What bond is formed between the phosphate group and previous ribose sugar in DNA?
a) Hydrogen bonds
b) Ionic bonds
c) Phosphodiester bonds
d) Van der Waals forces
e) Induced Dipole interactions
c) Phosphodiester bonds
How may you tell the difference between Adenine and Guanine?
In Guanine there is a carbonyl group (C=O) on C6 and in adenine there is an amine group on C6.
You could also come up with other differences that aren’t listed here
There are 3 types of RNA: mRNA tRNA & rRNA
What is the function of mRNA?
mRNA copies the gene for only one protein and transports it to the ribosome for that protein to be made
What is the function of tRNA?
tRNA transports amino acids to the ribosome to build the correct polypeptide strand by matching its anticodons with the corresponding codons of mRNA.
Which of these statements are not true about RNA?
I) Pentose sugar is deoxyribose
II) Single polynucleotide strand but may have a single or double helix
III) Manufactured in the ribosome and found throughout the cell
IV) Only 2 basic forms of mRNA & tRNA
V) Amount varies from cell to cell depending on the metabolic activity of the cell
VI) Temporary
(You can choose more than one option)
I, III & IV
RNA is made in the nucleus, has a ribose sugar and also exists as rRNA
Which of these statements about DNA are true?
I) Always has a double helix
II) Organic bases are Adenine, Thymine, Guanine & Cytosine
III) ratio of adenine to thymine & cytosine to guanine varies depending on the cell metabolic activity
IV) Found in the nucleus, mitochondria and ribosome
V) The amount is constant for all cells (excluding gametes and spores)
VI) Is chemically stable and permanent
I, II, V, VI
The ratio of A:T and C:G is always the same in DNA
DNA is also found in chloroplasts but not in the ribosome. Proteins are made in the ribosome and RNA is used to carry out the instructions there.
Where are activated nucleotides (deoxynucleoside triphosphate) made?
For DNA synthesis to occur, free nucleotides must be made
In the cytoplasm
During DNA replication:
Which enzyme is repsonsible for breaking the Hydrogen bonds between complimentary base pairs in DNA?
Helicase
Topoisomerase helps unwind the DNA at the replication forks
The following questions refers to DNA replication
What bond is formed between the phosphate group of the free nucleotide and Carbon 3 of the deoxyribose sugar of the existing strand?
Phosphodiester bond
The following questions refers to DNA replication
Exposed strands act as a template for complimentary nucleotides to be added. What enzyme is responsible for catalyzing the formation of a phosphodiester bond between the PO4 group of the free nucleotide and the deoxyribose sugar?
DNA polymeraze
DNA polymerase is very specific and only works in a 5’ -> 3’ direction
This question refers to DNA replication
Which enzyme joins segments together in the lagging strand?
Ligase
