18-Nucleic acid 2 Flashcards
- are polymer of nucleotides linked together via a phosphodiester linkage
- 2 types are DNA and RNA
Nucleic acids
- long macromolecule made up of dNMPs joined together by phosphodiester bond (3’–5’)
- in eukaryotic cells: located in nucleus / in the mitochondria (shape is linear supercoiled)
- in prokaryotic cells: located in nucleoid (shape is closed circular)
DNA
properties of a double helix (duplex):
1- read from ………. end
2-G—_ and A—_
3- are antiparallel where one strand is …… and the opposite is …… connected with Hbonding
1-5’–3’
2- G–C and A–T
3- 5’ to 3’ , 3’ to 5’
DNA structure:
1- the deoxyribose and phosphate form the …..
2- the nitrogenous bases within the nucleotides form the …….. and located inside the duplex
3-the helix is ……… from outside due to the presence of negatively charged phosphate groups
1- backbone
2-H-bonding
3-Hydrophilic
site of enzymatic recognition and regulation
Major groove
1-the two strands are ……. to each other by H bonds
2-between A and T there are … hydrogen bonds
3-between C and G there are … hydrogen bonds
1-complementary
2- two
3- three
the base pairing (A with T, G with C) is called …………
-states the number of purines = number of pyrimidines
Chargaff’s rule
DNA (in eukaryote) is wrapped around a core of proteins called …….
-contributes to the compact structure of chromosomal DNA
Histones
functions of ……. :
1-storage and transfer
2-protein synthesis
DNA
a DNA is divided up into functional units called …….
- provide instructions for a protein
Genes
the process in which the genetic information flows from DNA to RNA to make a functional protein
central dogma
1-…….: the DNA sequence of a gene is copied to make an mRNA molecule
2-……: mRNA sequence is decoded to specify the amino acid sequence of a protein
1- Transcription
2- Translation
How does DNA preserve info in genes?
3 nucleotide makes one code
one code makes one amino acid
DNA replication begins when the enzyme …….. unwinds the double helix of the DNA by breaking the hydrogen bonds
Helicase
………. are short sequences of nucleotides that signal DNA polymerase enzyme to begin the synthesis of the new daughter complementary strand
Primers
the enzyme …………. catalyzes the formation of phosphodiester bonds between free complimentary nucleotides
DNA polymerase
1- DNA polymerase can synthesize DNA only in the …….. direction
2- the ……… strand is synthesized continuously (3’ to 5’)
3- ……… strand synthesized discontinuously forming ………….(5’ to 3’)
1- 5’ to 3’
2- leading
3- lagging, Okazaki fragments
a protein called ………. connects the fragments by catalyzing the formation of phosphodiester bonds
DNA ligase
a principle in which the nitrogenous bases of the DNA molecules bond with one another
Base pairing
- polymer of nucleotides attached covalently via a phosphodiester linkage
- usually single-stranded
- vary in size (smaller than DNA)
- contains Ribose sugar and contains Uracil
- no specific structure (coils on itself)
- it has the 3’ end and 5’ end
- present in viruses, bacteria, animals
RNA
present in the nucleus and transfer to the ribosome
-resulted from the transcription of a copy of one strand of DNA
-carries genetic information that encodes for proteins (template)
in eukaryotes, it has a cap in the 5’ end and a poly (A) tail in the 3’ end.
mRNA
small ssRNA (single strand) that possesses the shape of clover leave located in cytoplasm or mitochondria
- it pairs up with mRNA
- it carries amino acids to the ribosome for protein synthesis
- amino acids are attached to the 3’ end
tRNA
RNA of the ribosome
- it is a nucleoprotein responsible for protein biosynthesis
- main function is not fully understood
rRNA
What’s identical to both RNA and DNA?
the sugar to phosphate linkages
