1) DNA Intro.
mRNA
Messenger RNA conveys genetic info from DNA to the protein
miRNA
Micro RNA -Small dsRNA, very short, binds to mRNA; regulates stability of mRNA and gene expression -miRNA tags mRNA for breakdown and allows regulation for protein synthesis
Where is extrachromosomal DNA in eukaryotic cells found?
Mitochondria and chloroplasts Function: encoding genes
tRNA
Transfer RNA transports AA'S to the active site of the ribosome (translation- AA's used for protein synthesis)
How can DNA strands be separated?
breaking of hydrogen bonds through denaturation process using heat or chemicals
In which forms does cellular DNA exist?
cellular DNA exists in the form of chromosomes or extrachromosomal DNA
Examples of phenotypical traits of microorganisms (bacteria)
flagellum, slime layer, capsule, antibiotic resistance, virulence factor
What are the pairs that nucleotides form?
form base pairs (A-T; C-G) in strict fashion inside the helix held together by hydrogen bonds
What is phenotype?
genes expressed at a given time (observable characteristics)
What holds together DNA strands?
hydrogen bonds
What are the functions of major and minor grooves?
locations of protein binding
Eukaryotic chromosome*
more than one chromosome linear bound to histones
When is denaturation necessary for DNA performing its function?
necessary for reading the sequence of nitrogenous bases in the DNA molecule
What does a nucleotide consist of?
nucleoside and phosphate group
Which two components of a nucleotide comprise the backbone? How are they oriented?
phosphate and sugar phosphate residue links 5' and 3' carbons of adjacent sugar molecules
What is a hairpin loop?
protein-binding site; can form intramolecular base pairs creating a hairpin loop structure; held together by H+ bonds; can be denatured
Difference between deoxyribo- and ribonucleotides?
ribonucleotides have an extra OH group making the RNA (has oxygen) less stable than DNA (no oxygen)
Size range of genomes for major groups of organisms
smallest->largest viruses<single cell eukaryotic microbes<multicellular eukaryotes
Which nucleotides are Purines?
Adenine Guanine
What are the 2 structural types of nucleotides?
Pyrimidines & Purines
What are the structural differences b/t RNA and DNA molecules?
RNA contains uracil instead of thymine (A-U pairs instead of A-T pairs) RNA is single stranded
How is DNA organized structurally?
Antiparallel double helix
Which nucleotide pair is stronger?
G-C pair is stronger b/c held together by 3 hydrogen bonds instead of 2 (A-T)
What is the Chagraff Rule?
# of G-C pairs and A-T pairs will always be the same in a double stranded DNA molecule
Which nucleotides are Pyrimidines?
Cytosine Thymine (Uracil in RNA)
What does DNA consist of?
DNA consists of nucleotides
Bacterial chromosome*
1 chromosome circular (no loose ends) bound to histone-like proteins
What does a nucleoside consist of?
A pyrimidine or purine nitrogenous base & deoxyribose sugar
How is directionality of DNA molecule important for its function?
Allows the enzyme to read Allows cells to position DNA in a certain direction Allows recording of genetic info
What does DNA stand for? What is its function?
Deoxyribonucleic Acid; contains genetic info.
Where is extrachromosomal DNA in prokaryotic cells found?
Plasmids Function: plasmids not essential for cell survival; may carry beneficial genes such as antibiotic resistance or virulence factors
rRNA
Ribosomal RNA structural/functional elements of ribosomes catalyst for protein synthesis