Cells and OrganellesChapter 4 – Cells: The Basic Units of

LifeM.Elizabeth

Martin Luther King, Jr. JHS2005

Chapter 4 Cells: The Basic Units of Life

4.1 Organization of Life 4.2 The Discovery of Cells 4.3 Eukaryotic Cells: The Inside

Story Review

4.1 Organization of Life

Cells: Starting Out SmallTissues: Cells Working in TeamsOrgans: Teams Working TogetherOrgan Systems: A Great CombinationOrganisms: Independent LivingThe Big Picture –

PopulationsCommunitiesEcosystemsBiosphere

4.2 The Discovery of CellsSeeing the First CellsSeeing Cells in Other Life FormsThe Cell TheoryCell Similarities

Cell MembraneHereditary MaterialCytoplasm and OrganellesSmall Size

Giant Amoeba Eats New York City – Surface to Volume Ratio limitations

The Benefits of Being MulticellularTwo Types of Cells

ProkaryotesEukaryotic Cells

4.3 Eukaryotic Cells: The Story Inside

Holding It All Together Cell Membrane Cell Wall

The Cell’s Library - nucleusProtein Factories – ribosomesThe Cell’s Delivery SystemThe Cell’s Power Plants

MitochondriaChloroplastsEndosymbiotic Theory

The Cell’s Packaging CenterThe Cell’s Storage CentersPackages of DestructionPlant or Animal

4.1 Organization of Life Cells: Starting Out Small Terms

Tissue – a group of similar cells that work together to perform a specific job (function) in the body

Organ – A combination of two or more tissues that work together to perform a specific function in the body

Organ System – Groups of organs working together to perfomr body functions

Organism – anything that can live on its own

Unicellular – made of one cell Multicellular – made of many cells

4.1 Organization of Life Cells: Starting Out Small Terms (continued)

Population – a group of individuals of the same species that live together in the same area at the same time

Community – All of the populations of different species that live and interact in an area

Ecosystem – a community of organisms and their non-living (abiotic) environment

Biosphere – all life on Earth

Cells Starting Out Small Example of a cell that is

large enough to be seen without a microscope: Chicken egg – The first cell

of a chick is yellow with a tiny white dot in it and it is surround by a clear jellylike fluid called egg white The white dot divides over and over again to form a chick. The yellow yoke from the first cell and the egg white provide the nutrients for the developing chick’s cell growth.

Humans have about 200 different kinds of cells and each type is specialized to do a particular job.Tissues: Cells Working TogetherTissues are groups of cells that work together to perform a specific functionOrgans: Tissues working togetherTwo or more tissues working together

The skin is the body’s largest organ. An average person’s skin has a mass of about 4.5 kg (almost 10 lbs)

In your lifetime you will shed about how much dead skin?

18 kg (almost 40 lbs)

Plant Organs

1. Leaf2. Flower3. Fruit4. Stem5. Seed6. Root

http://www.urbanext.uiuc.edu/gpe/case1/c1m1app.html

Organ Systems: A Great Combination

Organs working together in groups to perform particular functions are called organ systems.

Organ system card activity

From Cell to Organ System

Muscle cell makes up heart tissue that makes up a heart (organ) that is part of the circulatory/cardiovascular system.

Respiratory System

Inhalation (Breathing in) Exhalation (Breathing out)

Humans in and out Fish in the mouth the mouth with water through the gills and out

Skeletal System

Skeletal System – Bone Tissue

Bone has calcium salts in the matrix, giving it greater strength. Bone also serves as a reservoir (or sink) for calcium.

Protein fibers provide elasticity while minerals provide strength. Two types of bone occur.

Dense bone has osteocytes (bone cells) located in lacunae connected by canaliculi. Lacunae are commonly referred to as Haversian canals.

Spongy bone occurs at the ends of bones and has bony bars and plates separated by irregular spaces. The solid portions of spongy bone pick up stress..

Note the haversian canal and surrounded by osteocytes and a mineralized matrix

Organisms: Independent Living

Anything that can live on its own is an organism. Recall virus are not considered living –

here is another reason way – because they cannot live on their own.

Unicellular organisms– one cell, usually requires a microscope to view.

Multicellular organisms A group of cells that can remain alive

only together as a unit.

Plant Organ Systems

In flowering plants, the flower functions in sexual reproduction.

The essential flower parts are: male parts called the stamens female part called the pistil.

The stamen is the male plant organ and has two parts: anthers and

filaments.

Pollen (usually yellow) is produced at the ends of the stamens on structures called anthers.

Anthers are supported by a thread-like structure called a filament.

The pistil which is the female plant organ has three parts: stigma, style, and

ovary.

The stigma is the sticky surface at the top of the pistil; it traps and holds the pollen.

The style is the tube-like structure that supports the stigma.

The style leads down to the ovary which contains the ovules.

During the process of pollination

1. Pollen moves from the male parts to the female parts.

2. Pollen grains land on the stigma 3. A tiny tube grows from it and down the style into

the ovary.4. Sperm cells travel down the tube from the pollen

grains and join with an egg cell in the ovule resulting in fertilization.

5. The fertilized ovule becomes the seed and the ovary becomes the fruit.

The Big Picture Organisms interact in populations:

All of the red oak trees make up the forest’s red oak population.

Communities include two or more different populations living in the same area. The populations of foxes, oak trees,

lizards, flowers, and other organisms in a forest are all part of a particular forest community

Ecosystems: Community and all nonliving things (abiotic) like: water, soil, rocks, temperature, and light.

Sample Ecosystem

What makes up a community?A community is made up of the populations of

living things (biotic) in the ecosystem. So the community in the ecosystem is the deer, butterflies, trees, grasses, and flowers.

4.2 The Discovery of CellsSeeing the First Cells Robert Hooke: 1665 British

scientist. Looking for demonstration for a scientific meeting. Hooke looked at a piece of cork and noticed hundreds of little boxes. He named the little

boxes cells which means in Latin “little rooms”

http://www.roberthooke.org.uk/

Seeing Cells in Other Life Forms

Anton Leeuwenhoek Used his own handmade microscope that be built to look more closely at fabrics he was buying while in Holland.

Looked at blood, teeth tarter and all kinds of living cells. He also discovered that yeasts that make bread are unicellular.

The Cell Theory1. All organisms are composed of one or

more cells2. The cell is the basic unit of life in all living

things3. All cells come from existing cells

Three scientists involved:1. Matthias Schleiden (1838) German, plant cells2. Theordor Schwann (1839) German, animal

cells. Wrote the first two tenets of the theory.3. Rudolf Virchow (1858) German doctor. Wrote

the last tenet after observing that cells could not develop from anything but other cells.

Cell Similarities All Cells have the following in common:

Cell membranes – barriers to the outside world. Control the passage of materials into and out of the cell.

Hereditary Material – DNA (deoxyribonucleic acid) or sometimes RNA (ribonucleic acid)

Cytoplasm and Organelles Cytoplasm is the fluid that is contained within

the cell and that the organelles are found. Not all cells have membrane-bound organelles (nucleus, mitochondria, chloroplasts, golgi, etc.)

Small size – too small to be seen by the eye.

Giant Amoeba Eats New York City

The surface area and volume of a cube can be found with the following equations: SA = 6L2 , and V = L3

where S = surface area (in units squared), V = volume (in units cubed), and

L= the length of one side of the cube.

What is important about Surface-to-Volume

Cells need food, energy, and to remove wastes and heat in proportion to its size or volume, V

All of these things must be transported across the cell's surface, S, so the rate at which needs can be met is proportional to the surface area.

Size small structures that are more "surfacey" than large structures can meet their needs faster.

This can be seen by considering 2 cubes of different size.

Surface Area = S = 6r2

Volume = V = r3

Surface/Volume = S/V = 6/r

Surface to Volume Ratio

It is harder for nutrients and wastes to get in and out from the central area of larger cells

Cell Surface Area to Volume

What are the two types of cells?

Eukaryotic cellsEukaryotic cells – have a nucleus and other membrane bound organelles

Prokaryotic cellsProkaryotic cells – do not have a nucleus or other membrane bound organelles

Prokaryotes

no nucleusno membranes except cell membrane

bacteria or blue/green algaevery smallalmost always unicellularribosomessingle circular DNA chromosome

Eukaryotesnucleus (eukaryotic means “true nucleus” in Greek)

membrane bound Organelles larger in sizeuni or multicellularmany linear DNA chromosome evidence indicates that they first appeared about 2 billion years ago during the Precambrian Era.

animals, plants, fungi, protista

4.3 Eukaryotic Cells: The Inside Story

Holding it all togetherCell Membrane - phospholipidsCell Wall

Plant cells – cellulose cell wallFungal cells – chitan usually

Cell Membrane The cell membrane is a structure that

forms the outer boundary of the cell and allows only certain materials to move into and out of the cell.

Food, oxygen and water move into the cell through the membrane. Waste products also leave through the membrane.

Cells that perform photosynthesis (plants and some protists) take in carbon dioxide through the cell membrane instead of oxygen.

Cell Membrane Function

The cell membrane allows only certain materials to move in and out of the cell

Looks like this Functions like this

Cell Membrane Composition The current best model of what a cell

membrane looks like is in the figure below.  As you can see it is made up of three parts.  phospholipids (magenta and green) proteins (orange and red) carbohydrates (black).  Carbohydrates can be

attached to either the phospholipids or the proteins in the cell membrane.  

The Cell’s Library - Nucleus

Nucleus – means “kernel or nut” because it is the “essence of cells”

In all except for plant cells is the largest and most visible organelle.

Is called the control center of the cell Stores DNA which has the information to

make all of the cell’s proteins. The dark central area is called the

nucleolus which stores materials to make ribosomes in the cytoplasm (RNA)

Protein Factories - Ribosomes

Proteins are the building blocks of all cells

Proteins are made up amino acids Ribosomes make proteins by linking

amino acids together in accordance with the information stored in DNA

All cells have ribosomes because all cells need proteins to live

Ribosomes are not covered with a membrane – NOT Membrane Bound

Review

Do prokaryotic cells have ribosomes?

Yes, prokaryotes have ribosomes because ribosomes are essential and are not membrane bound.

Cell’s Delivery System – Endoplasmic Reticulum

Membrane covered Flattened sacks stacked side by side May be covered with ribosome

(rough endoplasmic reticulum) Makes lipids and other materials for

use inside and outside of the cell. Is an internal delivery system of the

cells (tubular connections – like cars moving through tunnels

Review Question

Are endoplasmic reticulum found in prokaryotes?

No, prokaryotes do not have organelles that are membrane bound.

Cell Power plants Mitochondria and

Chloroplasts All cells need energy Mitochondria and chloroplasts both

have membranes Mitochondria are in all eukaryote

cells Mitochondria create useable energy

(ATP) from sugar using oxygen Only plant cells contain chloroplasts Plant cells create sugar using

sunlight, carbon dioxide, and water.

Cell Power plants Mitochondria and

Chloroplasts All cells need energy Mitochondria (2 or more mitochondrion)

Have 2 membranes: folded inner membrane and an outer membrane.

Where ATP is made Needs oxygen to perform cellular

respiration where glucose (sugar) is broken down to release energy in the form of ATP

ChloroplastsPlants and algae have this organelle that can covert sunlight energy, CO2 and H2O into glucose (C6H12O6)

Chloroplast means “green structure”.

Chlorophyll make chloroplasts green and is the compound that captures the light energy

Both mitochondria and chloroplasts have separate DNA.

Endosymbiotic Theory

Endo – inside, internal Symbiotic- living together, mutually

beneficial The Endosymbiotic Theory is an

explanation for the origins of mitochondria and chloroplasts.

The theory states that mitochondria and chloroplasts originated as prokaryotic cells that were eaten (endocytosis) and instead of being digested they survived and continued functioning

Lines of evidence for the Endosymbiotic Theory:

1. Mitochondria and chloroplasts are about the same size as bacteria (prokaryotes)

2. Mitochondria and chloroplasts are surround by two membranes

The inner membrane is thought to be the original bacterial cell membrane and the outer membrane created during endocytosis.

3. Mitochondria and chloroplasts contain a separate circular DNA which is duplicated when mitochondria and chloroplasts created.

The Cell’s Packaging Center- Golgi complex

The Golgi complex modifies and packages compounds such as lipids or proteins.

Golgi look like endoplasmic reticulum (ER) but are usually located closer to the cell membrane than ER.

Final modified products are enclosed in a piece of the Golgi membrane that pinches off to form a small compartment (vesicles) that transport the modified

The Cell’s Storage Centers

The cell’s storage centers are:VesiclesVacuoles

Vesicles are membrane covered compartments that are found in all eukaryotic cells

Vacuoles are membrane covered compartment that contain water and other liquids that help support the plant cells.

Special Vesicles

Contractile vacuoles are a type of vesicle that helps to control excess fluid in some unicellular organisms.Breath out – exhalation results from a

contraction of the diaphragm. Lysosomes are specialized vesicles that

contain digestive enzymes that get rid of waste materials and old cell parts, protect cells from foreign invaders, and helps digest food particles.

Endoplasmic reticulum

Nucleolus

Cytoplasm

DNA

Mitochondria

Cell membrane

Nucleus

Ribosomes

Golgi complex

Vesicles

Central Dogma

DNA to Proteins

Review1. (Organs or Organelles) ___________are

made up of various tissues that work together to perform a specific job.

2.The role of the cell’s ____________ (nucleus or mitochondria) is to release energy that can be used to power various cellular processes.

3. Unlike animal cells, plant cells have _____________(nuclei or chloroplasts)to capture energy from the sun.

4. DNA, the genetic material of a eukaryotic cell, is located in the cell’s ___________ (nucleus or ribosome).

Organs

mitochondria

chloroplasts

nucleus

Review5. Cells that have no membrane-covered

organelles are _____________ (prokaryotic or eukaryotic).

6. A part of the endoplasmic reticulum can pinch off and form a______________ (lysosome or vacuole), which contains digesting enzymes.

7. Which of the following statements is not part of the cell theory?a. The most basic component of any

organism is the cell.b. All cells originate from other cells.c. All cells have a nucleus and a cell

membrane.d. All living things are made up of one or

more cells.

prokayotic

lysosome

c. All cells have a nucleus and a cell membrane

8. A life scientist who observes the relationships between plants, animals, weather,and soil on a mountaintop is studying a(n) ________________a. community. c. ecosystem.b. population. d. organism.

9. Which of the following is not found in plant cells?a. lysosomes c. cell membraneb. ribosomes d. Golgi complex

10. Which of the following contain cellulose?a. all plant cell walls c. all eukaryotic cellsb. all mushroom cells d. some prokaryotic

cells

ecosystem (ecologist)

11. Which part of a cell manufactures lipids?__________________

a. nucleolus c. cell membrane

b. endoplasmic reticulum d. vesicles12. Materials that are to be released outside the

cell are transported to the cell membrane in a small compartment that has pinched off of thea. nucleus. c. rough ER.b. contractile vacuole. d. Golgi complex.

13. Which of the following is not a characteristic of bacteria?a. They are prokaryotes.b. Their DNA is one long, circular molecule.c. They have an endoplasmic reticulum.d. They have a cell membrane.

Endoplasmic reticulum