DNA and RNA

The two main types of mutations are gene mutations and chromosomal mutations. Gene mutations that involve changes in one or a few nucleotides are known as point mutations because they occur at a single point in the DNA sequence. They generally occur during replication. The three types of point mutation are substitutions, insertions, and deletions. Chromosomal mutations involve changes in the number or structure of chromosomes. These mutations can change the location of genes on chromosomes and can even change the number of copies of some genes. The four types are deletion, duplication, inversion, and translocation.

Describe the two main types of mutations.

The three main differences between RNA and DNA are: The sugar in RNA is ribose instead of deoxyribose. RNA is generally single-stranded and not double-stranded. RNA contains uracil instead of thymine.

Describe three main differences between RNA and DNA.

During transcription, segments of DNA serve as templates to produce complementary RNA molecules. RNA polymerase is required to bind to DNA strands and separate them.

Describe what happens during transcription.

ribosome

During translation, mRNA attaches itself to this organelle.

codon; amino acid

Every three bases of an mRNA makes up a ________________ and codes for an ___________________.

They both include a sugar. They both consist of long chains of nucleotides. They both contain adenine, cytosine, and guanine. DNA has deoxyribose, but RNA has ribose. DNA is double stranded, but RNA is single stranded. DNA has thymine, but RNA has uracil.

How are DNA and RNA similar, and how are they different?

The effects of mutations on genes vary widely. Some have little or no effect; and some produce beneficial variations. Some negatively disrupt gene function. Mutations often produce proteins with new or altered functions that can be useful to organisms in different or changing environments.

How do mutations affect genes?

Replication in most prokaryotic cells starts from a single point and proceeds in two directions until the entire chromosome is copied. In eukaryotic cells, replication may begin at dozens or even hundreds of places on the DNA molecule, proceeding in both directions until each chromosome is completely copied.

How does DNA replication differ in prokaryotic cells and eukaryotic cells?

There are three important differences between RNA and DNA: 1. the sugar in RNA is ribose instead of deoxyribose, 2. RNA is generally single-stranded and not double-stranded, and 3. RNA contains uracil in place of thymine.

How does RNA differ from DNA?

A cell interprets the genetic code by reading codons (three nitrogenous bases that correspond to one amino acid.

How does a cell interpret the genetic code?

In transcription, segments of DNA serve as templates to produce complementary RNA molecules.

How does the cell make RNA?

DNA is replicated during the S phase of Interphase. The DNA molecule separates into two strands and then produces two new complementary strands following the rules of base pairing. Each strand of the double helix of DNA serves as a template, or model, for the new strand. The two strands of the double helix "unzip" and allow the two replication forks to form. As each new strand forms, new bases are added following the rules of base pairing. Each DNA molecule resulting from replication has one original strand and one new strand.

How is DNA replicated?

nucleus.

In eukaryotes, nearly all the DNA is found in the

amino acid.

In messenger RNA, each codon specifies a particular

cytoplasm.

In prokaryotes, DNA molecules are located in the

DNA is a nucleic acid made up of nucleotides joined into long strands or chains by covalent bonds.

List the chemical components of DNA.

In Griffith's experiment, he concluded that when the dead (hazardous) bacteria and the harmless bacteria were combined, "a chemical factor transferred from the heat-killed cells" into the harmless bacteria. Griffith next named this process "transformation" because the chemical factor changed the harmless bacteria so that it was harmful. The disease could be caused by the offspring of the transformed cell, so the transforming factor was a gene. Avery's experiment concluded that DNA was the transforming factor in transformation. "The nucleic acid DNA stores and transmits genetic information from one generation of bacteria to the next."

List the conclusions that Griffith and Avery drew from their experiments.

The three main types of RNA are messenger RNA- carry instructions for amino acid assembly to other parts of the cell ribosomal RNA- combine with proteins to form ribosomes transfer RNA- carry amino acids to ribosomes during protein synthesis

List the three main types of RNA, and explain what they do.

weak hydrogen bonds between nitrogenous bases.

The bonds that hold the two strands of DNA together come from

lysine

The codon AAG codes for what amino acid?

what amino acid the tRNA brings over

The codon of the mRNA determines what?

DNA polymerase.

The main enzyme involved in linking individual nucleotides into DNA molecules is

20.

The number of codons in the genetic code is

transformation.

The process by which one strain of bacterium is apparently changed into another strain is called

transcription.

The process by which the genetic code of DNA is copied into a strand of RNA is called

translation.

The process of making proteins on the ribosome based on instructions from messenger RNA is called

[A]=[T], [G]=[C]

These are the correct base pairing rules of DNA.

DNA- adenine, thymine, cytosine, guanine; RNA- adenine, uracil, cytosine, guanine

These are the nitrogen bases found in DNA and RNA.

DNA-deoxyribose, RNA-ribose

These are the sugars found in DNA and RNA.

messenger RNA, ribosomal RNA, transfer RNA

These are the three types of RNA.

substitution/point mutation/gene mutation

This is a mutation in which one nucleotide is changed.

translocation

This is a mutation when a part of a chromosome breaks off and attaches to another chromosome.

a gene

This is a piece of DNA that is transcribed and then translated into a protein.

DNA is a double helix, while RNA is single-stranded.

This is the difference between the shape of DNA and RNA molecules.

DNA polymerase

This is the enzyme that brings in new nucleotides during DNA replication.

The DNA unzips at the replication fork.

This is the first step in DNA replication. What do we call this part where replication starts?

messenger RNA

This is transcribed during transcription.

the X-ray diffraction picture of DNA

This was Rosalind Franklin's contribution to the discovery of DNA structure.

the nucleus

Transcription occurs here.

methionine, glycine, serine, STOP

What amino acid sequence would be translated from the mRNA strand: AUGGGAUCAUGA?

Mutations are heritable changes in genetic information.

What are mutations?

deletion, duplication, inversion, translocation

What are some types of chromosomal mutations?

adenine, thymine, cytosine, guanine

What are the 4 bases in DNA?

adenine, uracil, cytosine, guanine

What are the 4 bases in RNA?

DNA is a nucleic acid made up of nucleotides joined into long strands or chains by covalent bonds.

What are the chemical components of DNA?

anticodon; complimentary to the codon to allow that amino acid to be removed

What are the three bases of a tRNA called and why are they needed?

The three key roles of DNA are storing, copying, and transmitting the genetic information in a cell.

What are the three key roles of DNA?

a 5-carbon sugar, a phosphate group, and a nitrogenous base

What are the three parts of a nucleotide?

peptide bond

What bond holds the amino acids in a polypeptide chain together?

By observing bacterial transformation, Avery and other scientists discovered that the nucleic acid DNA stores and transmits genetic information from one generation of bacteria to the next.

What clues did bacterial transformation yield about the gene?

The clues in Franklin's X-ray pattern enabled Watson and Crick to build a model that explained the specific structure and properties of DNA.

What clues helped scientists solve the structure of DNA?

Hershey and Chase concluded that the genetic material of the bacteriophage was DNA, not protein... DNA was the genetic material found in genes—not just in viruses and bacteria, nut in all living cells.

What conclusion did Hershey and Chase draw from their experiments?

RNA is usually single-stranded and contains the base uracil.

What describes RNA?

bacteria

What do bacteriophages infect?

their genetic information

What do bacteriophages inject into their host?

amino acids

What do codons code for?

polypeptide chain

What do we call a chain of amino acids?

a codon

What do we call a group of 3 nucleotides on a strand of mRNA?

transcription

What do we call the process of making RNA from DNA?

The double-helix model explains Chargaff's rule of base pairing and how the two strands of DNA are held together.

What does the double-helix model tell us about DNA?

mRNA leaves the nucleus to find a ribosome.

What happens at the end of transcription?

During translation, ribosomes attach to mRNA molecules, and tRNA molecules bring the proper amino acids into the ribosomes. Next, the ribosome attaches the amino acids to the polypeptide chain. The ribosome then forms peptide bonds between amino acids. The polypeptide chain continues growing until the ribosome reaches a stop codon.

What happens during translation?

the "reading frame" of the genetic frame is shifted by inserting or deleting a nucleotide. By shifting the reading frame, frameshift mutations can change every amino acid that follows the point of the mutation. They can alter a protein so much that it is unable to perform its normal functions.

What happens in a frameshift mutation?

[A] = [T] and [G] = [C]

What is Chargaff's rule?

polypeptide chain

What is a chain of amino acids called?

a change in the genetic material of a cell

What is a mutation?

a gene mutation in which a single base pair in DNA has been changed

What is a point mutation?

three codons that signal the end of protein synthesis

What is a stop codon?

Some codons specify the same amino acid.

What is a true statement about the genetic code?

a polypeptide chain

What is made during translation?

The central dogma of molecular biology is that information is transferred from DNA to RNA to protein.

What is the "central dogma" of molecular biology?

ATGGTCT

What is the complementary strand to TACCAGA?

ATGGCTA

What is the complimentary strand to the DNA strand: TACCGAT?

The genetic code is read three "letters" at a time, so that each "word" is three bases long and corresponds to a single amino acid.

What is the genetic code, and how is it read?

DNA polymerase

What is the main enzyme that is involved in DNA replication?

replication

What is the name of the process in which DNA copies itself?

The DNA that makes up genes must be capable of storing, copying, and transmitting the genetic information in a cell.

What is the role of DNA in heredity?

DNA polymerase is an enzyme that joins individual nucleotides to produce a new strand of DNA. It also "proofreads" each new DNA strand, so that each molecule is a near-perfect copy of the original.

What is the role of DNA polymerase in DNA replication?

It signals the end of the polypeptide chain and the chain is released.

What is the significance of a stop codon?

sugar and phosphates

What makes up the backbone of DNA?

nitrogenous bases

What makes up the steps of DNA?

Hershey and Chase's experiment with bacteriophages confirmed Avery's results, convincing many scientists that DNA was the genetic material found in genes—not just in viruses and bacteria, but in all living cells.

What role did bacterial viruses play in identifying genetic material?

DNA polymerase is a enzyme that joins individual nucleotides to produce a new strand of DNA.

What role does DNA polymerase play in copying DNA?

Ribosomes use the sequence of codons in mRNA to assemble amino acids into polypeptide chains.

What role does the ribosome play in assembling proteins?

ribose

What sugar is present in RNA?

It joins individual nucleotides to produce a new strand of DNA. It "proofreads" each new DNA strand, so that each molecule is a near-perfect copy of the original.

What two things does DNA polymerase do?

ribosomal RNA

What type of RNA carries the amino acid to the ribosome?

messenger RNA

What type of RNA is made during transcription?

hydrogen bonds

What type of bond holds DNA's nitrogen bases together?

She used X-ray diffraction to get information about the structure of the DNA molecule. Her X-ray showed that two strands in DNA are twisted into a helix and that the nitrogenous bases are near the center of the DNA molecule.

What was Rosalind Franklin's contribution to the discovery of DNA's structure?

When Avery repeated Griffith's experiment, the experimental variable was the enzymes that were used.

What was the experimental variable that Avery used when he repeated Griffith's work?

Griffith discovered transformation and Avery discovered that DNA was responsible for transformation.

What were Griffith and Avery's contributions to our understanding of DNA?

UCCAUGAUC

What would be the mRNA transcribed from the gene: AGGTACTAG?

Chargaff's rule states that [A]=[T] and [G]=[C]. Rosalind Franklin used X-ray diffraction to photograph the DNA, which had a helix-shaped formation. Watson and Crick modeled the DNA and explained its structure and function.

Describe the discoveries that led to the modeling of DNA.

mutation

change in the genetic material of a cell

mutagen

chemical or physical agents in the environment that interact with DNA and may cause a mutation

genetic code

collection of codons of mRNA, each of which directs the incorporation of a particular amino acid into a protein during protein synthesis

polyploidy

condition in which an organism has extra sets of chromosomes

RNA polymerase

enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template

exon

expressed sequence of DNA; codes for a protein

point mutation

gene mutation in which a single base pair in DNA has been changed

anticodon

group of three bases on a tRNA molecule that are complementary to the three bases of a codon of mRNA

codon

group of three nucleotide bases in mRNA that specify a particular amino acid to be incorporated onto a protein

bacteriophage

kind of virus that infects bacteria

polypeptide

long chain of amino acids that makes proteins

frameshift mutation

mutation that shifts the "reading frame" of the genetic message by inserting or deleting a nucleotide

DNA polymerase

principle enzyme involved in DNA replication

base pairing

principle that bonds in DNA can form only between adenine and thymine and between guanine and cytosine

gene expression

process by which a gene produces its product and the product carries out its function

translation

process by which the sequence of bases of an mRNA is converted into the sequence of amino acids of a protein

transformation

process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria

replication

process of copying DNA prior to cell division

telomere

repetitive DNA at the end of a eukaryotic chromosome

intron

sequence of DNA that is not involved in coding for a protein

ribonucleic acid (RNA)

single-stranded nucleic acid that contains the sugar ribose

promoter

specific region of a gene where RNA polymerase can bind and begin transcription

transcription

synthesis of an RNA molecule from a DNA template

frameshift mutation

the mutation that changes the reading frame like in THE FAT CAT ATE THE RAT THE ATC ATA TET HER AT

messenger RNA

type of RNA that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell

transfer RNA

type of RNA that carries each amino acid to a ribosome during protein synthesis

ribosomal RNA

type of RNA that combines with proteins to form ribosomes

an amino acid.

A nucleotide does not contain

GUAAUA

A single-base mutation in a messenger RNA molecule could transcribe the DNA sequence CAGTAT into

mutagen.

A substance that can cause a change in the DNA code of an organism is called a

A=T and C=G

According to Chargaff's rule of base pairing, what is true about DNA?

viruses.

Bacteriophages are

carry and make copies of information.

Before DNA could definitively be shown to be the genetic material in cells, scientists had to show that it could

mutations.

Changes in DNA sequences that affect genetic information are known as

Insertions and deletions are point mutations in which one base is inserted or removed from the DNA sequence. In a substitution, one base is changed to a different base.

Compare and contrast a deletion, an insertion, and a substitution mutation.

A DNA nucleotide is made up of deoxyribose, a phosphate, and a nitrogen base (ATCG). An RNA nucleotide is made up of ribose, a phosphate, and a nitrogen base (AUCG).

Compare and contrast the nucleotide of DNA to a nucleotide of RNA.

transfer RNA

On what type of RNA are anticodons located?

It occurs during interphase in the nucleus. It is important so that genetic information is not lost during cell division.

When does DNA replication occur, where does it occur, and why is it important?

The cells of most prokaryotes have a singular, circular DNA molecule in the cytoplasm, containing nearly all the cell's genetic information. Eukaryotic cells can have up to 1000 times more DNA. Nearly all of the DNA of eukaryotic cells is found in the nucleus, packaged into chromosomes. Eukaryotic chromosomes consist of DNA, tightly packed together with proteins to form a substance called chromatin. Together, the DNA and his tone molecules form beadlike structures called nucleosides.

Where and in what form is prokaryotic DNA found? Where is eukaryotic DNA found?

nucleus

Where does transcription occur?

in the cytoplasm on the ribosome

Where does translation occur?

Alfred Hershey and Martha Chase

Which of the following researchers used radioactive markers in experiments to show that DNA was the genetic material in cells?

Frederick Griffith

Who discovered transformation?

Hershey and Chase

Who discovered what bacteriophages infect and what they inject?

Oswald Avery

Who repeated Griffith's experiment and determined DNA was responsible for transformation?

Watson and Crick

Who was awarded the Nobel Prize for discovery of the 3D structure of the double helix?

Hydrogen bonds are essential to DNA's structure because the bonds join the nitrogenous bases together.

Why are hydrogen bonds so essential to the structure of DNA?

They grew viruses in cultures that constrained both radioactive phosphorus (for proteins) and radioactive sulfur (for DNA) because in testing they needed to see if the DNA or the proteins caused the infection. If they had only used one, they would not have been able to discover if it was the DNA or the proteins because there could have been traces of the substances in the cells prior to injection.

Why did Hershey and Chase grow viruses in cultures that contained both radioactive phosphorus and radioactive sulfur? What might have happened if they had used only one radioactive substance?

It is important for a single gene to be able to produce many of the same RNA molecules because they might be needed if one is unable to function or if one strand is needed in many places.

Why is it important for a single gene to be able to produce hundreds or thousands of the same RNA molecules?

This arrangement enables the nitrogenous bases on both strands to come into contact at the center of the molecule. It also allows each strand of the double helix to carry a sequence of nucleotides, arranged almost like letter in a four-letter alphabet.

Why is it significant that the two strands of DNA are antiparallel?

The genetic code is considered universal because although some organisms show slight variations in the amino acids assigned to particular codons, the code is always read three bases at a time and in the same direction. Despite their enormous diversity in form and function, living organisms display remarkable unity at life's most basic level, the molecular biology of the gene.

Why is the genetic code considered universal?

The storage of genetic information explains why chromosomes are separated carefully in mitosis because each sister chromatid must get an equal amount of DNA so that it has all the required information to function.

Why would the storage of genetic information in genes help explain why chromosomes are separated so carefully during mitosis?