Ch.9 DNA Structure and Analysis

Four major characteristics needed for molecule to serve as genetic material

Replicate

Storage of information

Expression of information

Variation by mutation

Transcription

synthesis of RNA from information in DNA

Translation

Uses information in mRNA to synthesize proteins

Central Dogma

DNA→RNA→Protein

_ is the source of variation among organisms through the process of _.

Genetic material; mutation

_ in DNA reflected in transcription and translation affecting specific protein

Mutation

_ and _ are major candidates for genetic material

Proteins; nucleic acids

Who isolated cell nuclei in 1868?

Miescher

Miescher derived an acid substance containing DNA called

nuclein

In 1910, Levene proposed the _

Tetranucleotide hypothesis

Tetranucleotide hypothesis

DNA contains equal amounts of 4 nucleotides (later proven incorrect)

In 1944, Avery, MacLeod, and McCarty published proof that _ is the biomolecule responsible for heredity.

DNA

Griffith experimented with transforming Streptococcus pneumoniae _ strain into _ strain.

R;S

Avery, MacLeod, and McCarty demonstrated that the transforming principle was _, not _.

DNA; protein

Hershey and Chase demonstrated that DNA, not protein, is the genetic material using _ and _.

E. coli and bacteriophage T2

In transfection experiments, E.coli is treated with enzyme _, which _ outer cell wall in bacteria.

lysozyme; destroys

protoplasts

enzymatically treated cells

When protoplasts are used, the virus does not need to be intact for _ to occur.

infection

Viral _ contains all necessary information for production of mature viruses.

DNA

_ is abundant in cytoplasm; _ is not.

Protein; DNA

DNA is present in these organelles

Mitochondria and chloroplasts

_ is found everywhere in the cell

Protein

Most mutagenic wavelength is at _ nm.

260

DNA and RNA absorb UV at _ nm.

260

Protein absorbs UV at _ nm.

280

Wavelength at which no significant mutagenic effects are observed

280 nm

Molecule serving as genetic material is expected to absorb at _ wavelength

mutagenic

Recombinant DNA technology

Splicing together DNA sequences from different organisms (Ex. Human Hormone Insulin)

Genomics

Full set of DNA sequences in an organism

Can compare genomes of individuals to analyze heritable disorders

RNA replicase

enzyme needed for replication

Retroviruses

RNA-containing viruses

RNA serves as template in _ process using enzyme _.

reverse transcription; reverse transcriptase

RNA transcriptase

RNA-dependent DNA polymerase enzyme

DNA can be incorporated into the host cell's genome

When transcribed, copies of the original retroviral RNA chromosomes are produced

Ex. HIV

DNA is a

nucleic acid

Nucleotides

building blocks of nucleic acid

Nitrogenous bases

purines and pyrimidines

Nucleotides consist of a

Nitrogenous base, pentose sugar, and phosphate group

Purines (9 member double ring)

Adenine and Guanine

Pyrimidines (6 member single ring)

Cytosine, Thymine, and Uracil

The bases in DNA are

A, C, T, G

The bases in RNA are

A, C, U, G

RNA contains _ sugar

ribose

RNA has a _ group at C-2’.

hydroxyl

DNA contains _ sugar.

deoxyribose

DNA has a _ atom at C-2’.

hydrogen

Nucleoside

contains a nitrogenous base and pentose sugar

Nucleotide

Nucleoside with phosphate froup added

Nucleoside monophosphates (NMP)

a nucleotide

Nucleoside diphosphates (NDP)

Nucleotide with addition of two phosphate groups

Nucleoside triphosphates (NTP)

Nucleotide with addition of three phosphate groups (ATP and GTP)

Triphosphates serve as _ during nucleic acid synthesis

precursor molecules

Phosphodiester bonds

Linkage between 2 mononucleotides

Involves a phosphate group linked to 2 sugars

Oligonucleotides

short chains consisting of around 20 nucleotides

store genetic information

Chargaff

chromatographic methods used to separate the 4 DNA bases

The amount of adenine is equal to the amount of _

thymine

The amount of guanine is equal to the amount of _.

cytosine

The sum of purines (A+G) is equal to the sum of

pyrimidines (C+T)

The Watson and Crick model proposed DNA as

Double helix

Two antiparallel chains with orientations running in opposite directions

Paired nitrogenous bases

Major and minor grooves

A-DNA

more compact than B-DNA

Prevalent under high-salt or dehydration conditions

Z-DNA

Left-handed double helix

Has zig-zag conformation

_ can be single our double stranded

RNAs

Animal _ have double stranded helices

viruses

Ribosomal RNAs (rRNAs) have components of ribosomes for _ during translation

protein synthesis

Messenger RNAs (mRNAs) carry _ from gene to ribosome

genetic information

Transfer RNAs (tRNAs) carry _ to ribosome for protein synthesis

amino acids

Telomerase RNA and RNA primers are involved in _ at chromosome ends (telomeres)

DNA replication

Small nuclear RNA (snRNA) process _

mRNAs

Hyperchromic shift

Heat is added to DNA, causing the double helix to unwind, decreasing the viscosity of nucleic acids and increasing the absorption of UV light

Hyperchromic shift during DNA denaturation used to determine _

melting temperature

Melting temperature method in hyperchromic shift is used for estimating _

base composition of DNA

Molecular hybridization

denaturation/renaturation of nucleic acids

Fluorescent in situ hybridization (FISH)

uses fluorescent probes to monitor hybridization

Probes

nucleic acids that will hybridize only with specific chromosomal areas

Probes added in FISH

ssDNA or RNA

Nucleic acid electrophoresis

separated DNA and RNA fragments by size