2.3 Nucleotides + Nucleic acids Flashcards
Components of DNA nucleotide?
Deoxyribose (polymer of nucleotide, phosphate group, and one organic base (adenine, cytosine, guanine or thymine)
Components of RNA nucleotide?
Ribose (polymer of nucleotide) , a phosphate group, and one organic base (adenine, cytosine, guanine or uracil)
Nucleotides join together by?
Phosphodiester bonds
- Condensation
DNA and RNA both…?
Carry information
What does RNA do?
RNA transfers genetic info from DNA to ribosomes
What does DNA do?
DNA holds genetic information
Nucleotides consists of..?
Pentose (5 carbon sugar), organic base and phosphate group
DNA molecules are…
Double helix, composed of 2 polynucleotides joined together by hydrogen bonds.
RNA molecules are…
Short and single polynucleotide chains
What is ATP?
Adenosine Trisphosphate = contains base adenine, sugar ribose and 3 phosphate group
What does ATP and ADP do?
Store and transports energy in cells
Adenine and Guanine bases are called?
Purine
Cytosine and Thymine bases are called?
Pyrimidine
What are purines?
Two C nitrogen rings joined together
What are pyrimidine?
One C nitrogen rings
(smaller)
What is ADP?
Adenosine Triphosphate = contains base adenine, sugar ribose and 2 phosphate groups
When energy is used ADP + P turns into..
ATP
When energy is released ATP turns into…
ADP
Nucleotides join together to form?
Polynucleotides
Two polynucleotides strands join together to form?
Double helix - 2 DNA strands join by H bonding between bases
Complementary pairing?
A - T
G - C
Self replication of DNA?
(SEMI CONSERVATIVE = ONE NEW STRAND, ONE ORIGINAL)
- Double helix unwinds, H bonds between complementary bases break using DNA helicase (enzyme), this separates two strands of DNA
- Both strands are used as templates, complementary base pairing occurs between the template + free nucleotides
- Adjacent nucleotides are joined by phosphodiester bonds (condensation) using DNA polymerase (enzyme)
What is a gene?
Sequence of DNA nucleotides that codes for a protein
Each amino acid is coded by a sequence of…
Three bases (triplet)
what is a triplet code?
Read in groups of 3 bases
Three bases are?
A codon
What is a codon?
Represents one amino acid
What is mRNA?
Messenger RNA (complementary to DNA)
- made in nucleus
- carries genetic code to cytoplasm, used to make a protein in translation
What is tRNA?
Transfer RNA (found in cytoplasm carries amino acids to ribosomes)
- found in cytoplasm
has amino acid binding site
carries amino acids to ribosomes during translation
What is rRNA?
Ribosomal RNA (found in ribosomes)
- forms two subunits in a ribosome
moves along mRNA strand in synthesis, helps catalyse formation of peptide bonds
Genetic code is non overlapping and this means?
Base triplets don’t share bases.
Genetic code is degenerate and this means?
Amino acids can be coded for by more than one codon
64 combinations -> 20 amino acids
Genetic code is universal and this means?
All organisms use the same base code (ATGCU)
What is transcription?
First stage of protein synthesis.
During this a copy of mRNA copy of a gene (section of DNA) is made in the nucleus
Transcription steps?
DNA unwinds, unzips
mRNA strand built
free RNA nucleotides pair up (complementary)
sugar phosphate backbone bonded by RNA polymerase
hydrogen bonds break (mRNA + DNA)
mRNA leaves nucleus
What is translation?
Occurs at the ribosomes in the cytoplasm.
During this, amino acids are joined together to make a polypeptide chain (protein) following the sequence of codons carried by the mRNA
Translation steps?
mRNA moves to ribosomes, binds to subunit of ribosome
tRNA (with complementary anticodons) binds to mRNA start codon
specific amino acids attached to tRNA, start codon codes for methionine (AUG)
peptide bonds formed between amino acids (condensation reactions)
catalysed by peptidyl transferase
stop codon - end of polypeptide chain
