biology copyright pearson prentice hall. 12–1 dna copyright pearson prentice hall

Biology

Copyright Pearson Prentice Hall

12–1 DNA


Bell Work 4-20-20151. What is the control center of a cell?

2. What are the 3 critical things genes were known to do by the early scientist? (p. 291)

Learning Target

I can explain how scientist discovered the relationship between genes and DNA.

Learning Target

I can explain how scientist discovered the relationship between genes and DNA.

Agenda:

1.Bell Work / LT

2.Biologist Timeline

??????What was Fredrick Griffith trying to learn?

Why was he trying to learn how bacteria made people sick?

Why is it important to learn how bacteria causes diseases?

Griffith and Transformation


In 1928, British scientist Fredrick Griffith was trying to learn how certain types of bacteria caused pneumonia.

He isolated two different strains of pneumonia bacteria from mice and grew them in his lab.


Griffith made two observations:

(1) The disease-causing strain of bacteria grew into smooth colonies on culture plates.

(2) The harmless strain grew into colonies with rough edges.

Who can describe Griffiths first experiment?


Griffith's Experiments

Griffith set up four individual experiments.

Experiment 1: Mice were injected with the disease-causing strain of bacteria. The mice developed pneumonia and died.

Second experiment?


Experiment 2: Mice were injected with the harmless strain of bacteria. These mice didn’t get sick.

Harmless bacteria (rough colonies)

Lives

Third experiment?



Experiment 3: Griffith heated the disease-causing bacteria. He then injected the heat-killed bacteria into the mice. The mice survived.

Heat-killed disease-causing bacteria (smooth colonies)

Lives

Fourth experiment?



Experiment 4: Griffith mixed his heat-killed, disease-causing bacteria with live, harmless bacteria and injected the mixture into the mice. The mice developed pneumonia and died.

What did Griffith conclude?


Griffith concluded that the heat-killed bacteria passed their disease-causing ability to the harmless strain.


What did Griffith call this process of changing one molecule into another?



Transformation

Griffith called this process transformation because one strain of bacteria (the harmless strain) had changed permanently into another (the disease-causing strain).

Griffith hypothesized that a factor must contain information that could change harmless bacteria into disease-causing ones.


What did Avery want to determine?


Avery and DNA

Avery and DNA

Oswald Avery repeated Griffith’s work to determine which molecule was most important for transformation.

Avery and his colleagues made an extract from the heat-killed bacteria that they treated with enzymes.


How did Avery go about this testing?

Avery and DNA

The enzymes destroyed proteins, lipids, carbohydrates, and other molecules, including the nucleic acid RNA.

Transformation still occurred.

What is the next step Avery took?

Avery and DNA

Avery and other scientists repeated the experiment using enzymes that would break down DNA.

When DNA was destroyed, transformation did not occur. Therefore, they concluded that DNA was the transforming factor.

What was Avery's conclusion?


Avery and DNA

Avery and other scientists discovered that the nucleic acid DNA stores and transmits the genetic information from one generation of an organism to the next.

What question did Hershey and Chase want answers to?

The Hershey-Chase ExperimentThe Hershey-Chase Experiment

Alfred Hershey and Martha Chase studied viruses—nonliving particles smaller than a cell that can infect living organisms.


The Hershey-Chase Experiment

Wanted to know if genes were made of protein or DNA.

Bacteriophages

A virus that infects bacteria is known as a bacteriophage.

Bacteriophages are composed of a DNA or RNA core and a protein coat.


How did they go about their experiment?


They grew viruses in cultures containing radioactive isotopes of phosphorus-32 (32P) and sulfur-35 (35S).


If 35S was found in the bacteria, it would mean that the viruses’ protein had been injected into the bacteria.

Bacteriophage withsuffur-35 in protein coat

Phage infects bacterium

No radioactivity inside bacterium


If 32P was found in the bacteria, then it was the DNA that had been injected.

Bacteriophage withphosphorus-32 in DNA

Phage infects bacterium

Radioactivity inside bacterium

What did they find in the bacteria?



Nearly all the radioactivity in the bacteria was from phosphorus (32P).

Hershey and Chase concluded that the genetic material of the bacteriophage was DNA, not protein.

The Components and Structure of DNA


DNA is made up of nucleotides.

A nucleotide is a monomer of nucleic acids made up of:

Deoxyribose – 5-carbon Sugar

Phosphate Group

Nitrogenous Base


There are four kinds of bases in in DNA:

adenineguanine cytosinethymine



Chargaff's Rules

Erwin Chargaff discovered that:The percentages of guanine [G] and

cytosine [C] bases are almost equal in any sample of DNA.

The percentages of adenine [A] and thymine [T] bases are almost equal in any sample of DNA.



X-Ray Evidence

Rosalind Franklin used X-ray diffraction to get information about the structure of DNA.

She aimed an X-ray beam at concentrated DNA samples and recorded the scattering pattern of the X-rays on film.


The Double Helix Using clues from Franklin’s pattern, James Watson and Francis Crick built a model that explained how DNA carried information and could be copied.

Watson and Crick's model of DNA was a double helix, in which two strands were wound around each other.

The Components and Structure of DNADNA Double Helix


Watson and Crick discovered that hydrogen bonds can form only between certain base pairs—adenine and thymine, and guanine and cytosine.

This principle is called base pairing.

Bell Work 4-21-20151. What does a double helix look like?

2. Use the scissors on your desk to cut out the pieces for a double helix.

Learning Target.

I can explain a double helix.

Learning Target.

I can explain a double helix.

Agenda

1.Bell Work / LT

2.Plickers

3.Activity

4.Discussion

Bell Work 4-22-2015

1. What does a double helix look like?

2. What is the pattern for base pairing?

3. Name the molecules that make up the sides of the DNA Ladder.

Learning Target

I can explain the structure of a double helix.

Learning Target

I can explain the structure of a double helix.

Agenda

1.Bell Work / LT

2.Review Assignment

3.Activity

4.Plickers


12–1

Avery and other scientists discovered that

DNA is found in a protein coat.

DNA stores and transmits genetic information from one generation to the next.

transformation does not affect bacteria.

proteins transmit genetic information from one generation to the next.


12–1

The Hershey-Chase experiment was based on the fact that

DNA has both sulfur and phosphorus in its structure.

protein has both sulfur and phosphorus in its structure.

both DNA and protein have no phosphorus or sulfur in their structure.

DNA has only phosphorus, while protein has only sulfur in its structure.


12–1

DNA is a long molecule made of monomers called

nucleotides.

purines.

pyrimidines.

sugars.


12–1

Chargaff's rules state that the number of guanine nucleotides must equal the number of

cytosine nucleotides.

adenine nucleotides.

thymine nucleotides.

thymine plus adenine nucleotides.


12–1

In DNA, the following base pairs occur:

A with C, and G with T.

A with T, and C with G.

A with G, and C with T.

A with T, and C with T.



12-2 Chromosomes and DNA Replication

Bell Work 4-21-2015

1. Considering your knowledge of DNA, what might happen if bases paired incorrectly?

2. What is the pattern for base pairing?

3. Name the molecules that make up the sides of the DNA Ladder.

Learning Target

I can explain DNA replication.

Learning Target

I can explain DNA replication.

Agenda

1.Bell Work / LT

2.Discussion of RNA

3.Assignment

4.Quizlet

Research

Where is DNA found in both prokaryotic and eukaryotic cells?


DNA and Chromosomes

DNA and Chromosomes

In prokaryotic cells, DNA is located in the cytoplasm.

Most prokaryotes have a single DNA molecule containing nearly all of the cell’s genetic information.


DNA and Chromosomes

Chromosome

E. Coli Bacterium

Bases on the Chromosomes


DNA and Chromosomes

Many eukaryotes have 1000 times the amount of DNA as prokaryotes.

Eukaryotic DNA is located in the cell nucleus inside chromosomes.number of chromosomes varies widely from one species to the next.


DNA and Chromosomes

Chromosome StructureEukaryotic chromosomes contain DNA and

protein, tightly packed together to form chromatin.

Chromatin consists of DNA tightly coiled around proteins called histones.

DNA and histone molecules form nucleosomes.

Nucleosomes pack together, forming a thick fiber.


DNA and Chromosomes

Eukaryotic Chromosome Structure

Chromosome

Supercoils

Nucleosome

DNA double helix

Histones

Coils

Research

What is DNA Replication?

https://www.youtube.com/watch?v=27TxKoFU2Nw


DNA Replication

DNA Replication

Each strand of the DNA double helix has all the information needed to reconstruct the other half by the mechanism of base pairing.

In most prokaryotes, DNA replication begins at a single point and continues in two directions.


DNA Replication

In eukaryotic chromosomes, DNA replication occurs at hundreds of places. Replication proceeds in both directions until each chromosome is completely copied.

The sites where separation and replication occur are called replication forks.


DNA Replication

Duplicating DNA

Before a cell divides, it duplicates its DNA in a process called replication.

Replication ensures that each resulting cell will have a complete set of DNA.


DNA Replication

During DNA replication, the DNA molecule separates into two strands, then produces two new complementary strands following the rules of base pairing. Each strand of the double helix of DNA serves as a template for the new strand.


DNA Replication

Nitrogen Bases

Replication Fork

DNA Polymerase

Replication Fork

Original strandNew Strand

Growth

Growth

Research

How does replication occur?



How Replication Occurs

DNA replication is carried out by enzymes that “unzip” a molecule of DNA.

Hydrogen bonds between base pairs are broken and the two strands of DNA unwind.


DNA Replication

The principal enzyme involved in DNA replication is…. DNA polymerase joins individual nucleotides to produce a DNA molecule and then “proofreads” each new DNA strand.


12–2

In prokaryotic cells, DNA is found in the

cytoplasm.

nucleus.

ribosome.

cell membrane.


12–2

The first step in DNA replication is

producing two new strands.

separating the strands.

producing DNA polymerase.

correctly pairing bases.


12–2

A DNA molecule separates, and the sequence GCGAATTCG occurs in one strand. What is the base sequence on the other strand?

GCGAATTCG

CGCTTAAGC

TATCCGGAT

GATGGCCAG


12–2

In addition to carrying out the replication of DNA, the enzyme DNA polymerase also functions to

unzip the DNA molecule.

regulate the time copying occurs in the cell cycle.

“proofread” the new copies to minimize the number of mistakes.

wrap the new strands onto histone proteins.


12–2

The structure that may play a role in regulating how genes are “read” to make a protein is the

coil.

histone.

nucleosome.

chromatin.


12-3 RNA and Protein Synthesis12–3 RNA and Protein Synthesis

Bell Work 4-21-2015

1. What might you compare the looks of a supercoiled nucleosome to that you are familiar?

2. What is chromatin?

3. What is the job of a nucleosome?

Learning Target

I can explain the how RNA differs from DNA.

Learning Target

I can explain the how RNA differs from DNA.

Agenda

1.Bell Work / LT

2.Discussion of RNA

3.Activity / Assignment

4.Plickers

5.Quizlet

Research

How does a gene Work?



12–3 RNA and Protein Synthesis

How does a gene Work?

1. Genes are coded DNA instructions that control the production of proteins.

2. Genetic messages can be decoded by copying part of the nucleotide sequence from DNA into RNA.

3. RNA contains coded information for making proteins.

Research

What is the structure of RNA compare to DNA?



The Structure of RNA

The Structure of RNA

There are three main differences between RNA and DNA:

The sugar in RNA is ribose instead of deoxyribose.

RNA is generally single-stranded.RNA contains uracil in place of thymine.

Research

What are the 3 types of RNA?



Types of RNA

Types of RNA

There are three main types of RNA:messenger RNAribosomal RNAtransfer RNA


Types of RNA

Messenger RNA (mRNA) carries copies of instructions for

assembling amino acids into proteins.

***Serve as “messengers” from DNA to the rest of the cell


Types of RNA

Ribosomes are made up of proteins and ribosomal RNA (rRNA).


Types of RNA

During protein construction, transfer RNA (tRNA) transfers each amino acid to the ribosome.

Research

Describe Transcription.



TranscriptionDNA is copied in the form of a

complementary sequence called RNA

Requires RNA polymerase to bind to DNA and separate the DNA strands as a template to assemble the nucleotides into another DNA strand

This first process is called transcription.

The process begins at a section of DNA called a promoter, which has specific base sequence that signal where to start

Protein Synthesis

DNADNAmoleculemolecule

DNA strandDNA strand(template)(template)

33

TRANSCRIPTIONTRANSCRIPTION

CodonCodon

mRNAmRNA

TRANSLATIONTRANSLATION

ProteinProtein

Amino acidAmino acid

3355

55


Transcription

RNA

RNA polymerase

DNA

Research

What are the functions of introns and exons?



RNA Editing

RNA Editing

Some DNA within a gene is not needed to produce or code for a protein. These areas are called introns.

The DNA sequences

that code for proteins

are called exons.


RNA Editing

The introns are cut out of RNA molecules…scientist have no idea why…

The exons are the spliced together to form mRNA.

Exon IntronDNA

Pre-mRNA

mRNA

Cap Tail

Bell Work 4-22-2015

1. Compare the DNA code to something you need a code to in your daily life.

2. What are the 3 types of RNA?

3. Explain transcription.

Learning Target

I can explain the genetic code.

Learning Target

I can explain the genetic code.

Agenda

1.Bell Work / LT

2.Plickers

3.Discussion

4.Activity

Research

What is the genetic code?


The Genetic Code

The Genetic Code

The genetic code is the “language” of mRNA instructions.

The code is written using four “letters” (the bases: A, U, C, and G).

Research

What is a codon?


The Genetic Code

A codon consists of three consecutive nucleotides on mRNA that specify a particular amino acid.


The Genetic Code

There are 64 possible base codons…

Research

What is translation and where does it take place?

Nucleus

mRNACopyright Pearson Prentice Hall

TranslationTranslation

Translation is the decoding of an mRNA message into a polypeptide chain (protein).

Translation takes place on ribosomes.

During translation, the cell uses information from messenger RNA to produce proteins and tell what order they should be listed in on the polypeptide.


Translation

LysinetRNAPhenylalanine

Methionine

Ribosome

mRNAStart codon

The ribosome binds new tRNA molecules and amino acids as it moves along the mRNA.


Translation

Protein Synthesis

tRNA

Ribosome

mRNA

Lysine

Translation direction


Translation

The process continues until the ribosome reaches a stop codon.

Polypeptide

Ribosome

tRNA

mRNA


Genes and Proteins

DNA

mRNA

Protein

CodonCodon Codon

Codon Codon Codon

mRNA

Alanine Arginine Leucine

Amino acids within a polypeptide

Single strand of DNA

Bell Work 4-23-20151. Are enzymes tossed away or reused?

2. Log onto Quizlet and Study for Friday’s Vocabulary Formative.

Learning Target

I can explain DNA structure and Replication.

Learning Target

I can explain DNA structure and Replication.

Agenda

1.Bell Work / LT

2.Quizlet

3.Activity

4.Plickers

Bell Work 4-24-20151. Log onto Quizlet and study for Formative.

Learning Target

I can earn a “3” on the review formative.

Agenda

1. Bell Work / LT

2. Formative

3. Activity

DNA Replication Enzyme Wrap Up

Bell Work 4-27-20151. Study for Formative.

Learning Target

I can earn a “3” on the Formative because I studied.

Agenda

1. Bell Work / LT

2. Formative

3. Research

Research1. What are mutations?

2. Define: gene mutations, chromosomal mutations, polyploidy

3. Find and define the 2 Types of gene mutations.

4. Find examples of deletions, substitutions, translocations, insertions, inversions

5. How are genes regulated?

6. What are lac and hox genes?

7. How are lac genes turned off and on?

8. Define operon, operator, and differentiation.

9. How are eukaryotic genes regulated?


12–3

The role of a master plan in a building is similar to the role of which molecule?

messenger RNA

DNA

transfer RNA

ribosomal RNA


12–3

A base that is present in RNA but NOT in DNA is

thymine.

uracil.

cytosine.

adenine.


12–3

The nucleic acid responsible for bringing individual amino acids to the ribosome is

transfer RNA.

DNA.

messenger RNA.

ribosomal RNA.


12–3

A region of a DNA molecule that indicates to an enzyme where to bind to make RNA is the

intron.

exon.

promoter.

codon.

A codon typically carries sufficient information to specify a(an)

single base pair in RNA.

single amino acid.

entire protein.

single base pair in DNA.


12–3


12–4 Mutations

Bell work 4-28-2015

1. How can you study for the EOC?

Refer to the EOC Cheat Sheet for #1-2:

2. Which of the following chemical formulas represent an organic molecule?

A. H2O B. AgNO3 C. C12H22O11

3. Which of the following solutions has the greatest concentration of hydroxide ions?

A. Urine (pH 6) B. Rainwater (pH 5.5) C. Gastric juice (pH 2.0)

4. What is translation and where does it take place?

5. What is transcription and where does it take place?

Learning Target

I can explain genetic mutations and how genes regulate themselves.

Learning Target

I can explain genetic mutations and how genes regulate themselves.

Agenda

1.Bell Work

2.Discussion

3.Activity

Research

What are mutations?


12-4 Mutations

Mutations are changes in the genetic material.


Kinds of Mutations

Kinds of Mutations

Gene mutations - Mutations that produce changes in a single gene

Chromosomal mutations - Mutations that produce changes in whole chromosomes


Kinds of Mutations

Gene Mutations

- involve a change in one or a few nucleotides

- known as point mutations - they occur at a single point in

the DNA sequence.

Point mutations include substitutions, insertions, and deletions.


Kinds of Mutations

Substitutions

-usually affect no more than a single amino acid

-a base is changed


Kinds of Mutations

Frameshift mutations

- The effects of insertions or deletions are more dramatic.

- addition or deletion of a nucleotide causes a shift in the grouping of codons.


Kinds of Mutations

In an insertion, an extra base is inserted into a base sequence.


Kinds of Mutations

In a deletion, the loss of a single base is deleted and the reading frame is shifted.


Kinds of Mutations

Chromosomal Mutations

- involve changes in the number or structure of chromosomes.

- include deletions, duplications, inversions, and translocations.


Kinds of Mutations

Deletions involve the loss of all or part of a chromosome.


Kinds of Mutations

Duplications produce extra copies of parts of a chromosome.


Kinds of Mutations

Inversions reverse the direction of parts of chromosomes.


Kinds of Mutations

Translocations occurs when part of one chromosome breaks off and attaches to another.


Significance of Mutations

Significance of Mutations

Many mutations have little or no effect on gene expression.

Some mutations are the cause of genetic disorders.

Polyploidy is the condition in which an organism has extra sets of chromosomes.


12–4

A mutation in which all or part of a chromosome is lost is called a(an)

duplication.

deletion.

inversion.

point mutation.


12–4

A mutation that affects every amino acid following an insertion or deletion is called a(an)

frameshift mutation.

point mutation.

chromosomal mutation.

inversion.


12–4

A mutation in which a segment of a chromosome is repeated is called a(an)

deletion.

inversion.

duplication.

point mutation.


12–4

The type of point mutation that usually affects only a single amino acid is called

a deletion.

a frameshift mutation.

an insertion.

a substitution.


12–4

When two different chromosomes exchange some of their material, the mutation is called a(an)

inversion.

deletion.

substitution.

translocation.

12-5 Gene Regulation

Gene Regulation: An Example


E. coli provides an example of how gene expression can be regulated.

An operon is a group of genes that operate together.

In E. coli, these genes must be turned on so the bacterium can use lactose as food.

they are called the lac operon.


How are lac genes turned off and on?


lac genes are turned off by repressors turned on by the presence of lactose.

Gene Regulation: An Example On one side of the operon's three genes are two

regulatory regions. In the promoter (P) region, RNA polymerase

binds and then begins transcription.


The other region is the operator (O).



When the lac repressor binds to the O region, transcription is not possible.


Gene Regulation: An Example When lactose is added, sugar binds to the repressor proteins.


Gene Regulation: An Example The repressor protein changes shape and falls off the operator and

transcription is made possible.


Many genes are regulated by repressor proteins.

Some genes use proteins that speed transcription.

Sometimes regulation occurs at the level of protein synthesis.

Eukaryotic Gene Regulation

How are most eukaryotic genes controlled?



Operons are generally not found in eukaryotes.

Most eukaryotic genes are controlled individually and have regulatory sequences that are much more complex than those of the lac operon.


Many eukaryotic genes have a sequence called the TATA box.

Direction of transcription


The TATA box seems to help position RNA polymerase.



Eukaryotic promoters are usually found just before the TATA box, and consist of short DNA sequences.



Genes are regulated in a variety of ways by enhancer sequences.

Many proteins can bind to different enhancer sequences.

Some DNA-binding proteins enhance transcription by:

opening up tightly packed chromatin helping to attract RNA polymerase blocking access to genes.

Development and Differentiation

Development and DifferentiationAs cells grow and divide, they

undergo differentiation, meaning they become specialized in structure and function.

Hox genes control the differentiation of cells and tissues in the embryo.


Careful control of expression in hox genes is essential for normal development.

All hox genes are descended from the genes of common ancestors.



Hox Genes

Fruit fly chromosome

Fruit fly embryo

Adult fruit fly

Mouse chromosomes

Mouse embryo

Adult mouse


12–5

Which sequence shows the typical organization of a single gene site on a DNA strand?

start codon, regulatory site, promoter, stop codon

regulatory site, promoter, start codon, stop codon

start codon, promoter, regulatory site, stop codon

promoter, regulatory site, start codon, stop codon


12–5

A group of genes that operates together is a(an)

promoter.

operon.

operator.

intron.


12–5

Repressors function to

turn genes off.

produce lactose.

turn genes on.

slow cell division.


12–5

Which of the following is unique to the regulation of eukaryotic genes?

promoter sequences

TATA box

different start codons

regulatory proteins


12–5

Organs and tissues that develop in various parts of embryos are controlled by

regulation sites.

RNA polymerase.

hox genes.

DNA polymerase.

biology copyright pearson prentice hall. 12–1 dna copyright pearson prentice hall

Documents

diseasecausing bacteria

harmless strain of bacteria

transformation experiment

biologist timeline slide

process transformation

certain types of bacteria

bacteria smooth colonies

mice didnt