[GENETICS LEC FINALS] TO1

What was the acidic substance isolated from cell nuclei by Friedrich Miescher in 1869?

Nuclein

What did Phoebus Levene propose in his early tetranucleotide model of DNA?

Four types of nucleotides

Before 1940, which chromosome component was favored as the genetic material because of its greater complexity and diversity?

Protein

What are the four crucial characteristics required of genetic material?

Replication, storage, expression, and mutation

What process allows genetic material to make copies of itself?

Replication

What characteristic allows genetic material to preserve hereditary instructions?

Storage of genetic information

What process uses stored genetic information to produce functional products such as proteins?

Expression of genetic information

What process introduces changes in genetic information and contributes to variation?

Mutation

What central dogma describes the usual flow of genetic information in cells?

DNA-RNA-PROTEIN

What process copies genetic information from DNA into RNA?

Transcription

What process uses mRNA information to synthesize a protein?

Translation

Which type of RNA carries coding information from a gene to the ribosome?

mRNA

Which cellular structure performs translation using mRNA?

Ribosome

Which scientist discovered the phenomenon in which bacteria acquired hereditary characteristics from other bacterial material?

Frederick Griffith

Which bacterium did Griffith study in his transformation experiments?

Diplococcus pneumoniae

What characteristic made Griffith's S strain appear smooth and shiny on agar plates?

Polysaccharide capsule

Which bacterial strain had a capsule and was virulent in Griffith's experiment?

S strain

Which bacterial strain lacked a capsule and was avirulent in Griffith's experiment?

R strain

What term describes a microorganism's ability to cause disease?

Virulence

What happened when Griffith injected live S-strain bacteria into mice?

The mice died

What happened when Griffith injected live R-strain bacteria into mice?

The mice survived

What happened when Griffith injected heat-killed S-strain bacteria into mice?

The mice survived

What happened when Griffith injected a mixture of live R bacteria and heat-killed S bacteria into mice?

The mice died

What phenomenon did Griffith name after observing that live R bacteria acquired characteristics of the S strain?

Transformation

What unexpected bacterial form was recovered from mice injected with live R bacteria and heat-killed S bacteria?

Live S bacteria

What did Griffith's experiments establish without identifying the responsible molecule?

Bacterial transformation

Which three scientists investigated the chemical nature of Griffith's transforming principle in 1944?

Avery, MacLeod, and McCarty

What enzyme did Avery and colleagues use to test whether DNA was required for transformation?

DNase

What does DNase stand for, and what molecule does it degrade?

Deoxyribonuclease, dna

What happened to bacterial transformation when the DNA in the transforming material was destroyed?

Transformation stopped

What conclusion did Avery, MacLeod, and McCarty draw from their transformation experiments?

DNA is the transforming principle

Which two organisms were studied by Hershey and Chase to determine whether DNA or protein directs viral reproduction?

Escherichia coli and bacteriophage T2

What is a bacteriophage, the virus used in the Hershey–Chase experiment?

A virus that infects bacteria

Which radioactive isotope did Hershey and Chase use to label phage DNA?

32P

Which radioactive isotope did Hershey and Chase use to label phage proteins?

35S

After infection, which radioactive label entered the bacterial cells and was associated with progeny phages?

32P

What did the Hershey–Chase experiment establish about the material directing phage reproduction?

DNA

Where is most of the DNA found in a typical eukaryotic cell?

Nucleus

Which two eukaryotic organelles also contain their own DNA?

Mitochondria and chloroplasts

At approximately what ultraviolet wavelength do DNA and RNA absorb most strongly, according to the PDF?

260 nm

At approximately what ultraviolet wavelength do proteins absorb most strongly, according to the PDF?

280 nm

What indirect evidence uses the relationship between UV absorption and mutation frequency to support nucleic acids as genetic material?

Mutagenesis evidence

What technology allows researchers to combine DNA from different sources and study gene expression?

Recombinant DNA technology

Which human gene was described in the PDF as being introduced into a fertilized mouse egg to study gene expression?

Human-globin gene

What type of genetic material is found in Tobacco Mosaic Virus, according to the PDF?

RNA

What enzyme allows retroviruses to synthesize DNA using an RNA template?

Reverse transcriptase

What is the name of the process in which RNA serves as a template for DNA synthesis?

Reverse transcription

Which human immunodeficiency virus is identified in the PDF as an example of a retrovirus?

HIV

What three components make up a nucleotide?

Nitrogenous base, pentose sugar, and phosphate group

What are the four nitrogenous bases found in DNA?

Adenine, thymine, guanine, and cytosine

Which nitrogenous bases have double-ring structures?

Purines

Which two nitrogenous bases are classified as purines?

Adenine and guanine

Which nitrogenous bases have single-ring structures?

Pyrimidines

Which three nitrogenous bases are classified as pyrimidines across DNA and RNA?

Cytosine, thymine, and uracil

Which pentose sugar is present in DNA?

Deoxyribose

Which pentose sugar is present in RNA?

Ribose

What structural difference distinguishes deoxyribose from ribose at the 2′ carbon?

H

What molecule consists of a nitrogenous base attached to a pentose sugar without a phosphate group?

Nucleoside

What molecule consists of a nitrogenous base, a pentose sugar, and at least one phosphate group?

Nucleotide

At which carbon of the pentose sugar does the nitrogenous base attach?

c1

Which atom of a purine base forms the sugar linkage in a nucleoside?

N-9

Which atom of a pyrimidine base forms the sugar linkage in a nucleoside?

N-1

What type of bond connects the nitrogenous base to the sugar in a nucleoside?

B-N-glycosidic bond

What are nucleoside diphosphates abbreviated as?

NDPs

What are nucleoside triphosphates abbreviated as?

NTPs

Which four deoxyribonucleoside triphosphates are used as DNA synthesis precursors?

dATP, dTTP, dGTP, and dCTP

What is the name of the bond that connects adjacent nucleotides in a polynucleotide chain?

Phosphodiester bond

What type of nucleic acid chain consists of a short sequence of approximately 30 or fewer nucleotides, as described in the PDF?

Oligonucleotide

What term describes a longer chain of linked nucleotides?

Polynucleotide

Which two ends define the directionality of a DNA strand?

5′ end and 3′ end

What does the term antiparallel mean when describing the two strands of DNA?

opposite directions

Which scientist's base-composition studies established the relationships between DNA bases known as Chargaff's rules?

Erwin Chargaff

According to the PDF, must the percentage of G + C equal the percentage of A + T in every organism?

No

Which scientist's X-ray diffraction work provided important evidence for the helical structure of DNA?

Rosalind Franklin

What technique uses the scattering of X-rays to reveal information about a molecule's structure?

X-ray diffraction

What is the name commonly associated with Rosalind Franklin's famous X-ray diffraction image of DNA?

Photo 51

Which two scientists proposed the double-helical model of DNA in 1953?

James Watson and Francis Crick

What is the overall shape of the DNA molecule described by the Watson–Crick model?

Right-handed double helix

Where are the nitrogenous bases located in the DNA double helix?

Inside the helix

Which structural components form the outer sides of the DNA double helix?

Sugar-phosphate backbones

Which nitrogenous base pairs with adenine in DNA?

Thymine

Which nitrogenous base pairs with guanine in DNA?

Cytosine

How many hydrogen bonds form between adenine and thymine in standard DNA base pairing?

Two

How many hydrogen bonds form between guanine and cytosine in standard DNA base pairing?

Three

What term describes the specific pairing of A with T and G with C?

Complementarity

Why do standard DNA base pairs consist of one purine and one pyrimidine?

consistent helix diameter

What is the approximate distance between adjacent base pairs in the Watson–Crick model?

0.34 nm

What is the approximate length of one complete turn of the DNA double helix?

3.4 nm

Approximately how many base pairs occur in one complete turn of the DNA helix in the PDF's model?

10 base pairs

What is the approximate diameter of the DNA double helix in the Watson–Crick model?

2.0 nm

What are the wider and narrower grooves running along the DNA double helix called?

Major groove and minor groove

Which replication model produces daughter DNA molecules containing one parental strand and one newly synthesized strand?

Semiconservative replication

Which proposed replication model preserves the original double helix intact while producing an entirely new double helix?

Conservative replication

Which proposed replication model produces DNA strands containing interspersed old and new segments?

Dispersive replication

Which experimental technique uses radioactive labels to identify their locations in cells or chromosomes?

Autoradiography

Which radioactive nucleotide was used in the PDF's discussion of semiconservative replication in Vicia faba root tips?

3H-THYMIDINE

What is the specific DNA region where replication begins called?

Origin of replication

What is the unwound region of DNA where synthesis occurs called?

Replication fork

What is the stretch of DNA replicated from one origin during a single initiation event called?

Replicon

What is the name of the replication origin in Escherichia coli described in the PDF?

oriC