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Cells and Cellular Processes

Biology 05.1115/3Biology 05.1115/3Fall 2008Fall 2008

Introduction

• Instructor: Dr. Jens Franck• Ph. (204) 789-1411• j.franck@uwinnipeg.ca• Rm 3L04 (Lockhart Hall)

Mark Breakdown• Lecture Midterm Exam 20%• Lecture Final Exam 40%• Lab Midterm Exam 10%• Lab Final Exam 25%• Lab Assignments 5%

• Total 100%

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A+ 90-100%A 85-89%A- 80-84%B+ 75-79%B 70-74%C+ 65-69%C 58-64%D 50-57%F <50%

����������� ���• Lab Instructor: Beata Biernacka

• Rm 4C71• b.biernacka@uwinnipeg.ca

• Lab Location: 3C42 (Centennial Hall)• Labs Start week of September 8th

• Purchase Lab Book prior to first lab at Petrified Sole Bookstore (Bulman Centre)

• The lab has a WebCT based web site (for all students in all lab sections)

• Transfer between sections possible afterfirst week of labs

• If you are waitlisted, attend the lab of your choice

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• Lectures• Textbook

• Text• CD-ROM• Text Website

• Course Website (WebCT server)• PowerPoint Slides• Class mail• https://claimid.uwinnipeg.ca/claimid

• Me

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What is Life ?• Life is highly organized• Life reproduces• Life responds to environment• Life takes in energy (and transforms it)• Life shows growth and development• Life adapts to its environment

What is Life ?

• Life is highly organized

���� ���������• Life reproduces

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���� ���������• Short term response to the environment

���� ���������• Life takes in energy and raw materials

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• Homeostasis• “Regulation”

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���� ���������• Life shows growth and development

���� ���������• Adaptation: Life adapts to its

environment through natural selection (evolution)

Pygmy Seahorse

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• Biologists explore life from the microscopic to the global scale

• The study of life• Extends from the microscope scale of

molecules and cells to the global scale of the entire living planet

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• From the biosphere to organisms

Figure 1.3

1 The biosphere

Biosphere

Ecosystem

Community

OrganismsPopulations

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• From cells to molecules

Cell

8 Cells

6 Organs and organ systems

7 Tissues

10 Molecules

9 Organelles

50 µm

10 µm

1 µm

Atoms

Figure 1.3

Ecological Level of Organization

• Organism• Population• Community• Ecosystem

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"�����#��$�%!����!�"����� �• Living organisms and their environmental

form interconnecting webs

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• The dynamics of any ecosystem include two major processes• Cycling of nutrients, in which materials

acquired by plants eventually return to the soil

• The flow of energy from sunlight to producers to consumers

The Study of Life• Chemical Level of Organization

• Atoms• Molecules• Macromolecules

Carbohydrates LipidsProteinsNucleic Acids

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Atoms

MoleculesMacromolecules

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The Study of Life

• Cellular Level of Organization• Organelles• Cells• Tissues• Organs• Organ Systems• Organism

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%$��&����#������������• All cells share certain characteristics

• They are all enclosed by a membrane• They all use DNA as genetic information

• There are two main forms of cells• Eukaryotic• Prokaryotic

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• Prokaryotic cells• Lack the kinds of membrane-enclosed

organelles found in eukaryotic cellsEUKARYOTIC CELL

Membrane

Cytoplasm

Organelles

Nucleus (contains DNA) 1 µm

PROKARYOTIC CELL

DNA (no nucleus)

Membrane

Figure 1.8

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• Cells contain chromosomes made partly of DNA, the substance of genes

Egg cell

Sperm cell

NucleicontainingDNA

Fertilized eggwith DNA fromboth parents

Embyro’s cells with copies of inherited DNA Offspring with traits

inherited fromboth parentsFigure 1.6

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The Continuity of Life

• All life uses DNA to store and inherit genetic information

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DNA directs cell metabolism and development

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• Due to increasing complexity• New properties emerge with each step

upward in the hierarchy of biological order

Cell

8 Cells

6 Organs and organ systems

7 Tissues

10 Molecules

9 Organelles

50 µm

10 µm

1 µm

Atoms

Figure 1.3

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• The study of DNA structure, an example of reductionism• Has led to further study of heredity,

such as the Human Genome Project

Figure 1.9

��� ����������• Systems biology

• Seeks to create models of the dynamic behavior of whole biological systems

• With such models• Scientists will be able to predict how a

change in one part of a system will affect the rest of the system

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CELL

Nucleus

Cytoplasm

Outer membraneand cell surface

Figure 1.10

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• Concept 1.3: Biologists explore life across its great diversity of species

• Diversity is a hallmark of life

Figure 1.13

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Species Genus Family Order Class Phylum Kingdom Domain

Mammalia

Ursusameri-canus(Americanblack bear)

Ursus

Ursidae

Carnivora

Chordata

Animalia

EukaryaFigure 1.14

%!����������������Three Domains of Life•Eukarya•Bacteria•Archaea

Common Ancestor?

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The Diversity of Life• Three domains

• Bacteria

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Archaea

%!������� ��������• Domain Eukarya

Protists

Kingdom Fungi

Kingdom Plantae

Kingdom Animalia

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Evolution

Evolution, Unity, and Diversity

• Diversity and unity are the dual faces of life on Earth

• Evolution is the core theme of biology

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• As diverse as life is• There is also evidence of remarkable

unity

Cilia of Paramecium.The cilia of Parameciumpropel the cell throughpond water.

Cross section of cilium, as viewedwith an electron microscope

15 µm

1.0 µm

5 µm

Cilia of windpipe cells. The cells that line the human windpipe are equipped with cilia that help keep the lungs clean by movinga film of debris-trapping mucus upward.Figure 1.16

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)� �������� ���• Population’s heritable variations exposed to

environmental factors that favor the reproductive success of some individuals over others

1 Populations with varied inherited traits

2 Elimination of individuals with certain traits.

3 Reproduction of survivors.

4 Increasing frequency of traits that enhancesurvival and reproductive success. Figure 1.21

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Webbing between digits makes bats adapted for flight.

Bat Skeleton

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Adaptive Radiation ofGalapagos Finches“Descent with Modification”

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• Inquiry is at the heart of science• A search for information and explanation,

often focusing on specific questions

• Two main processes of scientific inquiry• Discovery science• Hypothesis-based science

Hypothesis Based Inquiry

•Observation: The flashlight won’t Work.•Hypothesis 1

•Batteries are Dead

•Test Hypothesis•Replace Batteries

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• Results of Experiment• After replacing batteries: Flashlight still

doesn’t work

• New Hypothesis• Bulb is burnt out

• Test New Hypothesis• Replace Bulb

• Results of Experiment 2• After replacing bulb, flashlight now works.

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Flashlight Problem•Flashlight doesn’t work

•Formulate Hypotheses•Test Hypotheses

Scientific Method• Observation• Hypothesis• Experiment• Analysis

• Support or reject hypothesis

• New Hypothesis• Experiment - etc.

• In mimicry• A harmless species resembles a

harmful species

Flower fly(non-stinging)

Honeybee (stinging)Figure 1.26

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Controlled Experiment

Investigating Mimicry in Snake Populations

Eastern Coral Snake (poisonous)

Scarlet King Snake (non-poisonous)

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Field Experiments with Artificial Snakes

Controlled ExperimentExperimental group • artificial King snakesControl group • Brown artificial

snake

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Fig. 1-27

Artificial kingsnakes

Brownartificial snakes

83% 84%

17% 16%

Coral snakesabsent

Coral snakespresent

Per

cent

of t

otal

att

acks

on a

rtifi

cial

sna

kes

100

80

60

40

20

0

EXPERIMENTAL RESULTS