Day 6 September 15th Chapters 3 and 4

Dr. Amy B HollingsworthThe University of Akron

Lysosomes

round, membrane-enclosed, acid-filled vesicles that function as garbage

disposals

The Endomembrane System

Endoplasmic reticulum: where cells build proteins and disarm toxins

Rough Endoplasmic Reticulum

The Smooth Endoplasmic Reticulum

Critical Responsibilities of the Smooth ER

How can long-term use of one drug increase your resistance to another, different drug that you have never encountered?

3.18 Golgi apparatus: Where the cell processes products for delivery throughout the body

3.19 The cell wall provides additional protection and support for plant cells.

3.20 Vacuoles: multipurpose storage sacs for cells

The central vacuole can play an important role in five different areas of plant life:

1. Nutrient storage2. Waste management3. Predator deterrence4. Sexual reproduction5. Physical support

3.21 Chloroplasts: the plant cell’s power plant

The stroma and interconnected little flattened sacs called thylakoids

Endosymbiosis Theory Revisited

Chloroplasts resemble photosynthetic bacteria

Circular DNA

Dual outer membrane

Chapter 5: DNA, Gene Expression, and Biotechnology

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

Lectures by Mark Manteuffel, St. Louis Community College

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.

Discuss biotechnology in agriculture. Describe biotechnology and its

implications for human health.

5.1–5.5

DNA: what is it, and

what does it do?

“The DNA 200”

Knowledge about DNA is increasing justice in the world.

What is the most common reason why DNA analyses overturn incorrect criminal convictions?

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

The “Age of the Gene”

DNA “Double Helix”

Nucleic acids and nucleotides

Sugars, Phosphates, and Bases

A, T, C, and Gbase pairs

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.

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

A sequence of bases in a DNA molecule that carries the information necessary for producing a functional product, usually a protein molecule or RNA

5.4 Not all DNA contains instructions for making proteins.

Insert figure 5-8

An onion has five times as much DNA as a human.

Why doesn’t that make them more complex than us?

The Proportion of the DNA That Codes for Genes Like a person with a bunch of computer programs on their laptop

Genotype• All of the genes contained in

an organism

Phenotype• The physical manifestations of

the instructions

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

Translation, in which that copy is used to direct the production of a protein

5.6–5.8

Building organisms:

information in DNA

directs the production of

the molecules that make

up an organism.

The Genetic Code

Insert figure 5-14

5.8 Cells turn genes on and off in several ways.

Gene expression and gene regulation

Microarrays

A powerful tool used to monitor the expression levels of thousands of genes simultaneously

Particularly useful in exploring how gene expression differs in response to an illness, or the treatment of an illness, or in response to aging

Controlling Gene Expression

Transcription factors• Proteins that bind to specific regulatory

sites on the DNA

“Positive control”

“Negative control”

5.9–5.10

Damage to the genetic

code has a variety of

causes and effects.

5.9 What causes a mutation, and what are its effects? Alteration of the sequence of bases

in DNA can

• lead to changes in the structure and function of the proteins produced.

• have a range of effects.

Breast Cancer in Humans

There are two human genes, called BRCA1 and BRCA2.

More than 200 different changes in the DNA sequences of these genes have been detected.

Each of these changes results in an increased risk of developing breast cancer.

Mutations in Sex Cells and Non-Sex Cells

Differences?

Which may get passed on to offspring?

Why is it dangerous to be near the core of a nuclear power plant?

Chemical-induced mutations