DNA HELIX AND YOU Flashcards
What is nucleic acids? Give 2 examples.
- Nucleic acids are composed of nucleotides.
- Nucleotides are composed of sugar, phosphate and nitrogenous base which are uracil, thymine, cytosine, adenine and guanine.
- It carries and stores the hereditary informations.
- Examples of nucleic acid are DNA and RNA.
- DNA: Stores genetic information that is used in development and functioning of all organisms.
- RNA: translating the genetic information from DNA to protein.
What is the basic structure of nucleotides?
Nucleotides = phosphate + sugar + nitrogenous base
What is the basic structure of nucleoside?
Nucleoside: sugar + nitrogenous base
What is the examples of purine?
Adenine and guanine
What is the examples of pyrimidines?
Cytosine, uracil and thymine
Sugar and nitrogenous base is connected by …
N- glycosidic bond
List 3 functions of nucleotides and give examples for each function. (5)
- Nucleotides is a building block for nucleic acid such as RNA and DNA.
- Nucleotides is a high energy source such as ATP and GTP.
- Nucleotides is a methyl donor such as S- adenosyl methionine (SAM).
What is the difference between DNA and RNA?
DNA
- Feature: Double helical structure.
- Sugar used: Deoxyribose
- Function: Store genetic information for development and functioning of all organisms
- Base pairs: AT-CG
- Base used: Thymine
- Origin/ synthesis: self- replicating
RNA
- Feature: Single stranded structure.
- Sugar used: ribose
- Function: Translate the genetic information from the DNA by transferring the amino acids to ribosomes to convert to protein
- Base pairs: AU-CG
- Base used: Uracil
- Origin/ synthesis: Synthesised from DNA`
TRUE OR FALSE
A. The nitrogenous base for DNA are adenine, guanine, cytosine and uracil.
B. The amount of adenine is equal to tyrosine.
C. DNA sequence is read from 5’ to 3’ end
D. RNA have double helix structure.
E. RNA is to translate the genetic information from the DNA to protein.
A. The nitrogenous base for DNA are adenine, guanine, cytosine and uracil. (FALSE: Uracil is for RNA. Tyrosine is for DNA)
B. The amount of adenine is equal to tyrosine (TRUE).
C. DNA sequence is read from 5’ to 3’ end (TRUE)
D. RNA have double helix structure. (FALSE: RNA has single stranded while DNA double stranded)
E. RNA is to translate the genetic information from the DNA to protein. (TRUE)
Briefly explain the primary structure of DNA
- Primary structure of DNA is a linear sequence of nucleotides that are linked together by a phosphodiester bond.
- Its sequence is determined during DNA replication and a slight change in primary structure can affect a protein’s conformation and ability to function.
Briefly explain the secondary structure of DNA
- The secondary structure of DNA is a double helix structure where the 2 strands are held together by the hydrogen bond.
- Between G-C, there are 3 hydrogen bonds.
- While A-T, there are 2 hydrogen bonds.
Briefly explain the tertiary structure of DNA
- The tertiary structure of DNA is the supercoiling.
- Supercoiling refers to the further coiling and twisting of the DNA helix
- Further twisting are going to make the DNA more compact
Briefly describe the quaternary structure of DNA
- The quaternary structure of DNA is referring to the higher- level of organisation of nucleic acid.
- It interact between seperate nucleic acid or other molecules.
- As for example, chromatin which leads to its interaction with the histone protein.
Double helix consist of:
- 2 sugar phosphate backbones
- nitrogenous bases towards the interior of the molecules
- bases form hydrogen bonds with complementary bases on the opposite sugar- phosphate backbone
DNA sequence are bound through the ___.
phosphodiester bonds
DNA sequence always written from ___.
5’ end to 3’ end
State the function of DNA.
- Storage of genetic information
- Self duplication and inheritance
- code for protein: information is encoded in the order of the nitrogenous bases
State the types of DNA.
- Nuclear DNA
- Mitochondrial DNA
- Viral DNA
State the characteristics of nuclear DNA.
Nuclear DNA:
1. Can be found in the nucleus
2. Double hexlic
3. Responsible for majority of cellular f(x).
4. Packaged into chromosomes and passed from parents to off springs
State the characteristics of mitochondria DNA.
Mitochondria DNA:
- Double stranded and circular
- Each mitochondria consist of 2 to 10 mtDNA copies.
- The genome codes for 13 protein subunits of the electron transport chain, a large and small rRNAs and 22 tRNAs.
- mtDNA is maternally inherited
- very susceptible to reactive oxygen species but has a high repair capabilities.
State the characteristics of viral DNA.
Viral DNA:
- either DNA or RNA as the nucleic acid
- most viruses have RNA.
- plant viruses tend to have ssRNA and bacteriophages tend to have dsDNA.
- shape of DNA can be:
1. circular such as herpes virus
2. linear such as parvovirus
State the types of RNA.
- mRNA
- tRNA
- rRNA
- snRNA
- miRNA
DNA is denatured by:
increasing the temperature
decreasing the salt conc
adding alkaline sol.
