Lecture 6 Flashcards
Functions of nucleic acids
-store/transmit generic info
-enzyme
-translates genetic code
(-monomer of one nucleic acid can act as an E source)
Two types of nucleic acids
- DNA
- RNA
Monomers of nucleic acids
Nucleotides
Nucleotide structure
Nitrogenous base, pentose sugar, phosphate group
What is the most important monomer
ATP
Bases of DNA
Adenine, guanine, cytosine, thymine
Bases of RNA
Adenine, guanine, cytosine, uracil
DNA and RNA strands
D : double stranded
R : Single stranded
Red ribbon in dna is
Sugar-phosphate backbone, protects the bases
Bases in dna are (function)
Structures that code for molecular info
Which base bonds with which
(Complementary base pairing)
A and T
C and G
RNA shape
Can fold on itself to form 3D molecules
RNA functions
Transmit molecular info (mRNA)
Enzyme (ribosome)
Translation of genetic code (tRNA)
What does dna carry
Genes
Genes carry info that allows cells to
Control placement of am ac
Sequence of nucleotides =
Different proteins
For dna info to get converted into protein it goes through
Protein synthesis
2 steps of protein synthesis
Transcription
Translation
What does dna do during transcription
Double strands seperate temporarily
Role of mRNA in transcription
Nucleotides bond to complementary dna nucleotides on one strand
Transcription is
Transfer of dna info to mRNA
Translation is
Assembly of prot structure according to instructions (codon sequence) on mRNA
What is a codon
Group of 3 nucleotides on mRNAs (ex AUG GGA UUU …)
What is a transfer RNA (tRNA)
Other RNA that has anticodons complementary to codons on mRNA at one end and am ac on other end
Each tRNA is unique bc
Has unique anticodon, can only attach to one kind of am ac
Role of tRNA
Position each am ac in order from sequence of codons on mRNA
Stop codons :
UAA UAG UGA
Job of ribosomes
Properly link am ac together
How do ribosomes work
Attach to start of mRNA, moves along mRNA when tRNA attaches, aligns first am acs and helps form cov bonds between them
Ribosomes act as enzymes by
Accelerating peptide bond formation between am acs through dehydration synthesis
When ribosome reaches stop codon :
Release protein comes in, polypeptide chain free (released into cytoplasm), folds into specific shape and becomes functioning protein
What determines prot shape
- Dna sequence determines am ac sequence, which determines prot shape
Mutation (genetic code change) affects a cell bc
Am ac sequence change -> prot shape change -> disrupts its normal activity
