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Chapter 5: DNA, Gene Expression, and Biotechnology. What is the code and how is it harnessed?. Lectures by Mark Manteuffel, St. Louis Community College; Clicker Questions by Kristen Curran, University of Wisconsin-Whitewater. Learning Objectives. Describe what DNA is and what it does.

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chapter 5 dna gene expression and biotechnology

Chapter 5: DNA, Gene Expression, and Biotechnology

What is the code and how is it harnessed?

Lectures by Mark Manteuffel, St. Louis Community College; Clicker Questions by Kristen Curran, University of Wisconsin-Whitewater

learning objectives
Learning Objectives
  • Describe what DNA is and what it does.
  • Explain the process of gene expression and the collaboration of nature and nurture.
  • Explain the causes and effects of damage to the genetic code.
  • Describe biotechnology and its implications for human health.
  • Discuss biotechnology in agriculture.
  • Discuss biotechnology today and tomorrow.
aim how is dna structured

AIM:How is DNA structured?

Do Now:

Where is DNA found and why is it important?

5 1 the dna 200

5.1 “The DNA 200”

Knowledge about DNA is increasing justice in the world.

slide8
Selfish dictators may owe their behaviour partly to their genes, according to a study that claims to have found a genetic link to ruthlessness.

–Nature, April 2008

Whether a man has one type of gene versus another could help decide whether he’s good “husband material,” a new study suggests.

–Washington Post, September 2008

take home message 5 1
Take-home message 5.1
  • DNA is a molecule that all living organisms carry in every cell in their body.
take home message 5 11
Take-home message 5.1
  • Unique in virtually every person, DNA can serve as an individual identifier, left behind us as we go about our lives.
  • This is a fact that is used increasingly to ensure greater justice in our society, such as through establishing the innocence of individuals wrongly convicted of crimes.
slide12

5.2 The DNA molecule contains instructions for the development and functioning of all living organisms.

two important features of dna
Two Important Features of DNA

(1) DNA contains the instructions on how to create a body and control its growth and development.

(2) The instructions encoded in the DNA molecule are passed down from parent to offspring. (Where have we recently seen this concept?)

dna double helix

DNA “Double Helix”

Nucleic acids and nucleotides

sugars phosphates and bases
Sugars, Phosphates, and Bases

A, T, C, and G

Base pairs

AllTeachersGoCrazy

which answer will base pair with the following sequence agttctcatgt
Which answer will base pair with the following sequence?AGTTCTCATGT

AGTTCTCATGT

ACATGAGAACT

TCAAGAGTACA

UCAAGAGUACA

how does dna replicate why is this an important process
How does DNA replicate?Why is this an important process?

DNA replication

  • DNA original strand “unzips” by breaking the hydrogen bonds between the complimentary base pairs.
  • New free floating nucleotides form new hydrogen bonds with the appropriate base pair with the help of DNA polymerase.
  • Two new identical of DNA molecules result, each with one strand of the original DNA as one side of the sugar-phospahate backbone.
take home message 5 2
Take-home message 5.2
  • DNA is a nucleic acid, a macromolecule that stores information.
  • It consists of individual units called nucleotides: a sugar, a phosphate group, and a nitrogen-containing base.
take home message 5 21
Take-home message 5.2
  • DNA’s structure resembles a twisted ladder, with the sugar and phosphate groups serving as the backbones of the molecule and base pairs serving as the rungs.
activity
ACTIVITY

Make your own DNA model.

exit slip
EXIT SLIP

Answer the AIM

How is DNA structured?

5 3 genes are sections of dna that contain instructions for making proteins

5.3 Genes are sections of DNA that contain instructions for making proteins.

Why is DNA considered the universal code for all life on earth?

the number of chromosomes varies from species to species
The number of chromosomes varies from species to species.
  • Corn has 10 unique chromosomes.
  • Fruit flies have only four.
  • Dogs and chickens have 39 different chromosomes.
  • Goldfish have 47 chromosomes.
  • Individuals in each of these species inherit one copy of each chromosome from each parent.
genes
Genes
  • A sequence of bases in a DNA molecule that carries the information necessary for producing a functional product, usually a protein molecule or RNA
slide31
Different people can have free or attached earlobes. The DNA that encodes for making free or attached earlobes is called a(n) ________, and there are two different versions of it, called __________.

allele; genes

trait; alleles

gene; trait

gene; alleles

take home message 5 3
Take-home message 5.3
  • DNA is a universal language that provides the instructions for building all the structures of all living organisms.
  • The full set of DNA an organism carries is called its genome.
take home message 5 31
Take-home message 5.3
  • In prokaryotes, the DNA occurs in circular pieces.
  • In eukaryotes, the genome is divided among smaller, linear strands of DNA called chromosomes.
take home message 5 32
Take-home message 5.3
  • A gene is a sequence of bases in a DNA molecule that carries the information necessary for producing a functional product, usually a protein molecule or RNA.
take home message 5 4
Take-home message 5.4
  • Only a small fraction of the DNA in eukaryotic species codes for genes.
  • The function of the rest is still a mystery.
slide37
Genotype
    • all of the genes contained in an organism
  • Phenotype
    • the physical manifestations of the instructions
slide39
Which molecule acts as a “middle man” between the nucleus, where transcription occurs, and the cytoplasm, where translation occurs?

DNA

mRNA

Protein

Choices 1 and 3 are correct.

take home message 5 5
Take-home message 5.5
  • The genes in strands of DNA are a storehouse of information, an instruction book.
take home message 5 51
Take-home message 5.5

The process by which this information is used to build an organism occurs in two main steps:

  • transcription, in which a copy of the a gene’s base sequence is made, and
  • translation, in which that copy is used to direct the production of a protein.
classroom catalyst

Classroom Catalyst

Transcription Activity

slide46
Which answer shows the correct orientation of the mRNA sequence (Phosphate (5’)  Oxygen (3’)) given the DNA sequence below?5’-TCATCTATCT-3’

5’-UCAUCUAUCU-3’

5’-AGUAGAUAGA-3’

5’-AGAUAGAUGA-3’

5’-AGATAGATGA-3’

take home message 5 6
Take-home message 5.6
  • Transcription is the first step in the two-step process by which DNA directs the synthesis of proteins.
  • In transcription, a single copy of one specific gene within the DNA is made, in the form of a molecule of mRNA, which moves where it can be translated into a protein.
aim how are protein synthesized

AIM:How are protein synthesized?

Do Now:

What determines the function of an enzyme?

several ingredients must be present in the cytoplasm for translation to occur
Several ingredients must be present in the cytoplasm for translation to occur.
  • Free amino acids
  • Ribosomal units
  • Transfer RNA
classroom catalyst1

Classroom Catalyst

Translation Activity

translate the following mrna 5 cgagcaugggcuuuagg
Translate the following mRNA:5’-CGAGCAUGGGCUUUAGG...

MET-GLY-PHE-ARG…

ARG-ALA-TRP-ALA-LEU…

GLY-PHE-ARG-VAL-ARG…

ARG-PHE-GLY-MET-SER…

take home message 5 7
Take-home message 5.7
  • Translation is the second step in the two-step process by which DNA directs the synthesis of proteins.
  • In translation, the information from a gene that has been carried by the nucleotide sequence of an mRNA is read, and ingredients present in the cell’s cytoplasm are used to produce a protein.
5 8 causes and effects of mutation
5.8 Causes and effects of mutation
  • Alteration of the sequence of bases in DNA
    • can lead to changes in the structure and function of the proteins produced
    • can have a range of effects
breast cancer in humans
Breast Cancer in Humans
  • Two human genes, called BRCA1 and BRCA2
  • More than 200 different changes in the DNA sequences of these genes have been detected,
  • each of which results in an increased risk of developing breast cancer.
mutations
Mutations
  • Bad reputation
  • Tend to be disruptive
  • Very, very rare
which answer shows the mrna transcribed from the dna sequence below 5 tta tcc ttt act cat 3
Which answer shows the mRNA transcribed from the DNA sequence below?5’-TTA TCC TTT ACT CAT-3’

5’-AUG AGU AAA GGA UAA-3’

5’-AAU-AGG-AAA-UGA-GUA-3’

5’- TTA-TCC-TTT-ACT-CAT-3’

5’-UUA-AGG-AAA-TGA-GUA-3’

slide64
Which of the following changes (base substitutions and insertions are underlined and in bold) would have the most severe effect on the protein made from the mRNA in the last question?5’-AUG AGU AAA GGA UAA-3’

AUG-AGU-AAG-GGA-UAA

AUG-AGU-AAA-GGA-UAG

AUG-GUA-AAG-GAU-AA

AUG-AGU-AAA-GGA-GUA-A

take home message 5 8
Take-home message 5.8
  • Mutations are alterations in a single base or changes in large segments of DNA that include several genes.
  • They are rare and when they occur in a gene usually disrupt normal physiological functioning.
  • They play an important role in evolution.
from mutation to illness in just four steps
From mutation to illness in just four steps:

(1) A mutated gene codes for a non-functioning protein, usually an enzyme.

(2) The non-functioning enzyme can’t catalyze the reaction as it normally would, bringing it to a halt.

from mutation to illness in just four steps1
From mutation to illness in just four steps:

(3) The molecule with which the enzyme would have reacted accumulates, like a blocked assembly line.

(4) The accumulating chemical causes sickness and/or death.

why can one change in a nucleotide sequence of a gene cause a nonfunctional protein to be produced
Why can one change in a nucleotide sequence of a gene cause a nonfunctional protein to be produced?

The change can cause a stop codon to occur early in translation and the full length protein is not translated.

A substitution can result in one incorrect amino acid being present in the protein which can affect the shape of the protein and therefore its function.

An insertion or deletion can occur early in the gene and result in an incorrect translation of the protein.

All of the above.

take home message 5 9
Take-home message 5.9
  • Most genetic diseases result from individual mutations that cause a gene to produce a non-functioning enzyme, which in turn blocks the functioning of a metabolic pathway.
genetic engineering
Genetic Engineering

5.10 What is biotechnology?

  • Adding, deleting, or transplanting genes from one organism to another, to alter the organisms in useful ways
biotech advances in human health fall into three categories
Biotech advances in human health fall into three categories:

(1) producing medicines to treat diseases

(2) curing diseases

(3) preventing diseases from occurring in the first place.

slide81
If you were trying to identify the gene for insulin, which particular step of the procedure outlined below would you use?

Cut human DNA into small pieces with a restriction enzyme.

Amplify the DNA pieces with PCR.

Insert the gene into a plasmid and insert into bacteria.

Probe a gene library.

take home message 5 10
Take-home message 5.10
  • Biotechnology is the use of technology to modify organisms, cells, and their molecules to achieve practical benefits.
take home message 5 101
Take-home message 5.10
  • Modern molecular methods make it possible to cut and copy DNA from one organism and deliver it to another.
  • Biotechnology has achieved some important successes in medicine, agriculture, and forensics.
5 11 treating diseases and producing medicines with biotechnology
5.11 Treating diseases and producing medicines with biotechnology
  • cure diseases
  • treating diseases
    • The treatment of diabetes
several important achievements followed the development of insulin producing bacteria including
Several important achievements followed the development of insulin-producing bacteria, including:

Human growth hormone (HGH)

Erythropoietin

take home message 5 111
Take-home message 5.11
  • Biotechnology has led to some notable successes in treating diseases, usually by producing medicines more efficiently and more effectively than they can be produced with traditional methods.
5 12 curing diseases with biotechnology

5.12 Curing diseases with biotechnology

Gene therapy and the correction of malfunctioning genes

stem cells
Stem Cells
  • Cells that have the ability to develop into any type of cell in the body
gene therapy difficulties
Gene Therapy Difficulties

(1) Difficulty getting the working gene into the specific cells where it is needed.

gene therapy difficulties1
Gene Therapy Difficulties

(2) Difficulty getting the working gene into enough cells and at the right rate to have a physiological effect.

(3) Problems with the transfer organism getting into unintended cells.

take home message 5 12
Take-home message 5.12
  • Gene therapy has had a poor record of success in curing human diseases.
  • This stems primarily from technical difficulties in transferring normal-functioning genes into the cells of a person with a genetic disease.
5 13 preventing diseases with biotechnology

5.13 Preventing diseases with biotechnology

Intervening to prevent diseases using biotechnology focuses on answering questions at three different points in time:

slide97
I would want to know if my genome or that of a loved one carries one or more copies of a gene that can cause a genetic disease.

Strongly agree

Agree

Neutral

Disagree

Strongly disagree

2 will a baby be born with a genetic disease
(2) Will a baby be born with a genetic disease?
  • cystic fibrosis
  • sickle-cell anemia
  • Down syndrome
  • others
3 is an individual likely to develop a genetic disease later in life
(3) Is an individual likely to develop a genetic disease later in life?
  • breast cancer
  • prostate cancer
  • skin cancer
ethical dilemmas
Ethical Dilemmas
  • Discrimination
  • Health insurance
  • How to proceed with the information?
take home message 5 13
Take-home message 5.13
  • Biotechnology allows us to identify:
    • whether a given set of parents is likely to produce a baby with a genetic disease,
    • whether a baby is likely to be born with a genetic disease,
    • and whether an individual carriers certain disease-causing genes that may have their effect later in life.
take home message 5 131
Take-home message 5.13
  • These tools can help us to reduce suffering and the incidence of diseases, but they also come with significant potential costs, particularly the risk of discrimination.
how might a genetically modified plant help 500 million malnourished people

How might a genetically modified plant help 500 million malnourished people?

Nutrient-rich “golden rice”

take home message 5 14
Take-home message 5.14
  • Biotechnology has led to important improvements in agriculture by using transgenic plants and animals to produce more nutritious food.
5 15 more efficient and eco friendly farming with biotechnology
5.15 More efficient and eco-friendly farming with biotechnology

And he gave it for his opinion, ‘that whoever could make two ears of corn, or two blades of grass, to grow upon a spot of ground where only one grew before, would deserve better of mankind, and do more essential service to his country, than the whole race of politicians put together.’

—Jonathan Swift, Gulliver’s Travels, 1726

almost everyone in the u s consumes genetically modified foods regularly without knowing it

Almost everyone in the U.S. consumes genetically modified foods regularly without knowing it.

What foods are responsible for this?

take home message 5 15
Take-home message 5.15
  • There has been a revolution through biotechnology.
  • Herbicide-resistant and insect-resistant crops help reduce the environmental and financial costs of producing food.
slide118
Fear #1. Organisms that we want to kill may become invincible.
  • Fear #2. Organisms that we don’t want to kill may be killed inadvertently.
  • Fear #3. Genetically modified crops are not tested or regulated adequately.
slide119
Fear #4. Eating genetically modified foods is dangerous.
  • Fear #5. Loss of genetic diversity among crop plants is risky.
  • Fear #6. Hidden costs may reduce the financial advantages of genetically modified crops.
which food below does not potentially contain gmos
Which food below does not potentially contain GMOs?

Nacho chips

Fruit juice

Corn flakes

Rice

All of the above.

take home message 5 16
Take-home message 5.16
  • More and more genetically modified foods are being created using modern methods of recombinant DNA technology.
  • Some legitimate fears among the public remain, however, as to the safety of these foods given that their development relies on such new technology.
using the dna fingerprint information below determine which suspect was present at the crime scene
Using the DNA fingerprint information below, determine which suspect was present at the crime scene?

Suspect #1

Suspect #2

Suspect #3

All of the above.

Crime

Scene

Suspect

#1

Suspect

#2

Suspect

#3

take home message 5 17
Take-home message 5.17
  • Comparisons of highly variable DNA regions have forensic value in identifying tissue specimens and determining the individual from whom they came.
take home message 5 18
Take-home message 5.18
  • Comparisons of sequence similarities across species reveal the evolutionary relatedness and make it possible to construct detailed evolutionary trees.
5 19 the promise and perils of cloning

5.19 The promise and perils of cloning

From organs to individuals

take home message 5 19
Take-home message 5.19
  • Cloning of individuals has potential benefits in agriculture and medicine, but ethical questions linger.
we should pursue cloning in animals but not humans
We should pursue cloning in animals but not humans.

Strongly agree

Agree

Neutral

Disagree

Strongly disagree

we should pursue cloning in humans for the purpose of developing or performing medical treatments
We should pursue cloning in humans for the purpose of developing or performing medical treatments.

Strongly agree

Agree

Neutral

Disagree

Strongly disagree

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