Microbio Chapter 1

Notes on First slide lecture

Molecular Biology

Study of the molecular basis of biological activity

what are nucleic acids made of?

DNA, RNA

Nucleic Acids

Life’s instructions

What are proteins made of?

Amino Acids

Proteins

Life’s workhorse

What is the product of genes (DNA)

RNA and proteins

Chromosome

discrete unit of the genome (each chromosome carries many genes)

Gene

Carries information to produce proteins

Locus

position on a chromosome at which the gene for a particular trait resides; it may be occupied by any one of the alleles for the gene

Allele

One of the several alternative forms of a gene occupying a given locus on a chromosome

What was the discovery of Griffiths experiment?

provided the first support that genetic material can be transferred between bacterial cells “transforming principle”

what was the discovery of Hershey-Chases experiment?

DNA is the genetic material of viruses

Transgenesis

DNA can be used to introduce new genetic traits into organisms (permanent change)

Transfection

acquisition of new genetic markers by incorporation of naked DNA in eukaryotic (usually animal) cells

Nucleotide

a nucleoside linked to to a phosphate group on one carbon of the deoxyribose

What four bases does DNA contain?

Adenine (A), Guanine (G), Cytosine (C), and Thymine (T)

What four bases does RNA contain?

Adenine (A), Guanine (G), Cytosine (C), and Uracil (U)

Which bases are purines?

Adenine (A), and Guanine (G)

Which bases are pyrimidines?

Thymine (T), Cytosine (C), and Uracil (U)

Nucleoside

Consist of a ribose sugar attached to a nitrogenous base and a phosphate

What makes DNA unique to RNA?

deoxyribose sugar (2’-H)

What makes RNA unique to DNA?

Ribose sugar (2’-OH)

Is DNA or RNA more susceptible to hydrolysis?

RNA because it is less stable in the cell

What is the backbone of DNA and RNA?

Sugar-Phosphate chain with nitrogenous bases linked

What does the 5’ end of DNA/RNA represent?

phosphate group

What does the free 3’ end of DNA/RNA represent?

-OH (except in a circular DNA molecule e.g. plasmid)

Phosphodiester bond

strong covalent bond between the 3’ carbon of one sugar and the 5’ carbon of the next sugar

what shape is DNA?

Double helix

B-Form of DNA

double helix consisting of two polynucleotide chains that run antiparallel

which nitrogenous base pairs with Adenine in DNA?

Thymine

Which nitrogenous base pairs with Adenine in RNA?

Uracil

what nitrogenous base pairs with Cystine in DNA?

Guanine

How do the complemetary bases connect?

Hydrogen bonds

Pyridine

Single ring structure

Purine

Double ring structure

what structure pairs with pyridine?

purine

How would you write a single stand of DNA?

5’ to 3’

What is the anti parallel strand of 5’-AGTCGGT-3’?

5’-ACCGACT-3’

What is the diameter of the double helix?

~ 20 Angstrom

How many angstrom is a complete turn?

34 Angstrom

how many base pairs are there per turn?

~10 base pairs

Major groove

Wide groove of the double helix

Minor groove

narrow groove of the double helix

What differentiates the major and minor grooves of the double helix?

nucleotide accessibility

What is this secondary structure?

Beta Sheet

What is this secondary structure?

Alpha helix

What is this secondary motif?

TIM Barrel (alpha/ beta barrel)

What is this secondary motif?

Helix-loop-helix

what is this secondary motif?

Zinc Finger

What is the primary structure of a protein?

Amino acid sequence

What is the secondary structure of a protein?

local spatial conformation of the polypeptide backbone

What does heating do to DNA?

causes the two strands of a DNA duplex to separate (Denature)

Melting point (Tm)

midpoint of the temperature range for denaturation

What does cooling do to DNA?

complementary single strands anneal (Renaturation)

What does denaturation do to phosphodiester bonds?

They will not break

semiconservative replication

one parent strand is used as a template for a daughter strand

DNA polymerases

enzyme that forms new DNA strand by matching nucleotides to the parent strand

where does DNA polymerases act?

separated DNA strands at the replication fork

nucleases

enzymes that degrade nucleic acids by breaking phosphate bonds between nucleotides

endonucleases

starts pairing nucleotides within the nucleic acid sequence

Exonuclease

starts pairing nucleotides at the end of the nucleic acid sequence

What is DNA converted into via transcription?

RNA

What is RNA converted into via translation?

polypeptide

what is RNA turned into via reverse transcription?

DNA