ChapteChapter 2r 2

CellsCells

CellsCellsSection 2-1 H.W. Pg. 45 quesSection 2-1 H.W. Pg. 45 ques. 1-4. 1-4

What are What are cellscells??-- CellsCells are the smallest unit of living things, and are are the smallest unit of living things, and are

the building blocks of life.the building blocks of life.- All living organisms are made up of cells.All living organisms are made up of cells.- Some organisms are composed of many cells, like Some organisms are composed of many cells, like

humans, animals, trees, and flowers. These humans, animals, trees, and flowers. These multi celledmulti celled organisms can be seen without the organisms can be seen without the use of a microscope.use of a microscope.

- Other organisms are only composed of one Other organisms are only composed of one single cellsingle cell, like bacteria or some algae, and they , like bacteria or some algae, and they can only be seen with the use of a microscope.can only be seen with the use of a microscope.

History of the CellHistory of the Cell

Why do they call cells, cells?Why do they call cells, cells?- When the first microscope was created by When the first microscope was created by

Thomas Hooke, the first thing that Thomas Hooke, the first thing that scientists decided to look at was a piece of scientists decided to look at was a piece of cork, which is made from trees.cork, which is made from trees.

- What they saw was a lot of small boxes What they saw was a lot of small boxes that, to them resembled prison cells.that, to them resembled prison cells.

- Hence the name cells.Hence the name cells.- After other scientists looked at many After other scientists looked at many

animal cells they concluded that all living animal cells they concluded that all living things are composed of cells. things are composed of cells.

Plant CellPlant Cell

History of the CellHistory of the Cell

However, not all However, not all cells look like cells look like boxes. Only plant boxes. Only plant cells do.cells do.

- Human cells take - Human cells take on many different on many different shapes. As well as shapes. As well as bacterial, fungal bacterial, fungal and algal cells.and algal cells.

Cell TypesCell Types

Scientists have found that cells can be Scientists have found that cells can be separated into two groups:separated into two groups:

--Prokaryotic & EukaryoticProkaryotic & EukaryoticProkaryoticProkaryotic- cells that lack a nucleus - cells that lack a nucleus

and any other membrane bound and any other membrane bound organelles. (usually single celled organelles. (usually single celled organisms like bacteria.)organisms like bacteria.)

Eukaryotic-Eukaryotic- cells that do exhibit a cells that do exhibit a nucleus and other membrane bound nucleus and other membrane bound organelles. (could be multi- or organelles. (could be multi- or unicellular)unicellular)

Cell CompositionCell Composition

Every cell of an organism, as small as Every cell of an organism, as small as they are , is made up of even small they are , is made up of even small parts.parts.

- These smaller parts that make up a These smaller parts that make up a cell are called cell are called organellesorganelles. What do . What do you think organelle means?you think organelle means?

- It means small organ.It means small organ.

OrganellesOrganelles

Within a cell are Within a cell are many organelles many organelles that perform many that perform many specific functions. specific functions.

- We will also learn We will also learn that there are that there are different organelles different organelles in plant cells than in plant cells than there are in animal there are in animal cells.cells.

Organelles of an animal cellOrganelles of an animal cell

The organelles of an animal cell The organelles of an animal cell that we will explore are:that we will explore are:

Cell membrane-Cell membrane- this covers the outside of the cell this covers the outside of the cell and controls what material enters and leaves the and controls what material enters and leaves the cell.cell.

Cytoplasm- Cytoplasm- a gel like liquid that fills the cell. All a gel like liquid that fills the cell. All organelles move around in the cytoplasm and organelles move around in the cytoplasm and many cell activities occur here.many cell activities occur here.

Nucleus-Nucleus- This is the brain or control center of the This is the brain or control center of the cell. It controls all cell activity and houses our cell. It controls all cell activity and houses our DNA.DNA.

ChromosomesChromosomes- Found in the nucleus and contain - Found in the nucleus and contain our DNA or genetic make up.our DNA or genetic make up.

Mitochondria- Mitochondria- This organelle is responsible for This organelle is responsible for converting our food and oxygen to energy, this is converting our food and oxygen to energy, this is called called Cellular respirationCellular respiration. Called the Power . Called the Power house of the cell.house of the cell.

Organelles of an animal cellOrganelles of an animal cellCytoskeletonCytoskeleton-- Is a framework present inside the cytoplasm Is a framework present inside the cytoplasm

that maintains or changes the cells shape. It could also that maintains or changes the cells shape. It could also allow cells to move. An amoebas cytoskeleton contracts allow cells to move. An amoebas cytoskeleton contracts and stretches to allow it to move.and stretches to allow it to move.

RibosomesRibosomes- The job of this organelle is to make proteins that - The job of this organelle is to make proteins that the cell needs for chemical reactions. They receive the cell needs for chemical reactions. They receive directions from the hereditary material in the nucleus on directions from the hereditary material in the nucleus on how, when, and in what order to make specific proteins. how, when, and in what order to make specific proteins.

- These can be found in two places in the cell.These can be found in two places in the cell.11- Freely floating in the cytoplasm.- Freely floating in the cytoplasm.22- Or, attached to the Endoplasmic reticulum.- Or, attached to the Endoplasmic reticulum.

Endoplasmic ReticulumEndoplasmic Reticulum- Is a series of folded membranes - Is a series of folded membranes that extends from the nucleus to the cell membrane and that extends from the nucleus to the cell membrane and allows for the passage and processing of materials allows for the passage and processing of materials throughout the cell. throughout the cell.

There are two types or ER:There are two types or ER:11- Smooth ER, has no ribosomes attached to it.- Smooth ER, has no ribosomes attached to it.22- Rough ER, does have many ribosomes attached to it.- Rough ER, does have many ribosomes attached to it.

Organelles of an animal cellOrganelles of an animal cell

VacuolesVacuoles- These are little storage areas in a cell - These are little storage areas in a cell that hold water, minerals, and food and waste.that hold water, minerals, and food and waste.

Golgi bodiesGolgi bodies- These are stacked, flattened - These are stacked, flattened membranes that look like a stack of plates. Their membranes that look like a stack of plates. Their job is to process proteins and to package them job is to process proteins and to package them into small membrane bound vesicles. This allows into small membrane bound vesicles. This allows the material processed by the golgi to be the material processed by the golgi to be transported around the cell.transported around the cell.

LysosomesLysosomes- - These organelles are used to These organelles are used to breakdown and recycle substances inside the cell. breakdown and recycle substances inside the cell. They contain digestive chemicals that aid in They contain digestive chemicals that aid in breaking down food, cell waste and old worn out breaking down food, cell waste and old worn out organelles.organelles.

Animal CellAnimal Cell

Organelles of a plant CellOrganelles of a plant Cell A plant cell contains all of the organelles that are A plant cell contains all of the organelles that are

present in an animal cell plus two more:present in an animal cell plus two more:

Cell Wall-Cell Wall- This is found in plants, algae, and fungi and it This is found in plants, algae, and fungi and it is a thick covering that surrounds the cell membrane. is a thick covering that surrounds the cell membrane. It gives support to the cell and together all the cell It gives support to the cell and together all the cell walls of a plant gives structure to the whole organism.walls of a plant gives structure to the whole organism.

Chloroplast –Chloroplast – These organelles contain a chemical These organelles contain a chemical called called chlorophyll, chlorophyll, a pigment that traps sunlight and a pigment that traps sunlight and converts it into energy. It uses the sun light, water converts it into energy. It uses the sun light, water and CO2 to produce O2. This process is calledand CO2 to produce O2. This process is called photosynthesisphotosynthesis..

Plant CellPlant Cell

The different jobs of cellsThe different jobs of cells

It is impossible for every cell in your It is impossible for every cell in your body to be able to carry out every body to be able to carry out every job that your body needs to have job that your body needs to have done.done.

That’s why there are many different That’s why there are many different cells in our bodies that all have very cells in our bodies that all have very different, very specific jobs to do.different, very specific jobs to do.

Different types of animal cells and Different types of animal cells and how there shape is related to their how there shape is related to their

function.function. Red Blood Cell- Travel Red Blood Cell- Travel

though your blood though your blood vessels and carries vessels and carries oxygen to tissues all oxygen to tissues all over the body, and over the body, and removes any waste removes any waste products.products.

Have a dimple in the Have a dimple in the middle of them. This middle of them. This dimple is where a dimple is where a molecule of O2 will be molecule of O2 will be carried.carried.

Different types of animal cells and Different types of animal cells and how there shape is related to their how there shape is related to their

function.function. Nerve Cells- They are Nerve Cells- They are

long and shaped like long and shaped like wires in order to carry wires in order to carry electrical impulses electrical impulses around the body.around the body.

Muscle Cells- Are long Muscle Cells- Are long straight fibers that straight fibers that allow us to move our allow us to move our skeleton. They have skeleton. They have many mitochondria. many mitochondria. Why?Why?

- They need a lot of - They need a lot of energy.energy.

Different types of plant cells and Different types of plant cells and how there shape is related to their how there shape is related to their

function.function. Cells of the stem- plant Cells of the stem- plant

stems have many cells stems have many cells that are long and tube that are long and tube shaped. This allows shaped. This allows water from the ground water from the ground to be moved up the to be moved up the plant.plant.

Leaf cells- These cells Leaf cells- These cells are brick shaped and are brick shaped and have many chloroplasts. have many chloroplasts. Why?Why?

- The leaves are exposed - The leaves are exposed to the sunlight and they to the sunlight and they trap it to make food by trap it to make food by photosynthesis.photosynthesis.

Cell organizationCell organization All of these specific cells in your body, as well as All of these specific cells in your body, as well as

in plants, are not just all thrown together. in plants, are not just all thrown together. - You wouldn’t want to have liver tissue in you You wouldn’t want to have liver tissue in you

brain or a leg muscle cell in your stomach.brain or a leg muscle cell in your stomach.- All common cells are grouped together to form All common cells are grouped together to form

specific tissues.specific tissues.- Ex: A lot of cells combine form to make Ex: A lot of cells combine form to make tissuestissues. .

TissuesTissues are groups of similar cells that perform are groups of similar cells that perform similar work. similar work.

-- Tissues would than combine together with Tissues would than combine together with different tissues to form an different tissues to form an organorgan. An . An organ organ is a is a structure made up of two or more different types structure made up of two or more different types of tissue that work together.of tissue that work together.

- Ex: The stomach is an organ made up of muscle Ex: The stomach is an organ made up of muscle tissue, nerve tissue and blood tissue.tissue, nerve tissue and blood tissue.

Cell organizationCell organization

Organs than come together to form organ Organs than come together to form organ systems.systems.

- Ex: the mouth, stomach, intestines, and liver Ex: the mouth, stomach, intestines, and liver are all organs that make up the digestive are all organs that make up the digestive system.system.

- Other systems include the respiratory, Other systems include the respiratory, skeletal, and reproductive systems.skeletal, and reproductive systems.

-- Organs systems then give rise to organisms. Organs systems then give rise to organisms.

MicroscopesMicroscopesSection 2-2 H.W. Pg. 51 ques. Section 2-2 H.W. Pg. 51 ques.

1-41-4 A A microscopemicroscope is an instrument used by scientists to is an instrument used by scientists to

study cells and other microscopic material.study cells and other microscopic material.- - Microscopes are very critical to science. They allow us Microscopes are very critical to science. They allow us

to explore a world that other wise was never known.to explore a world that other wise was never known.- Light microscopes use Light microscopes use lightlight and and lenseslenses in order to in order to

magnify the object that you are looking at.magnify the object that you are looking at. Simple light microscope uses only one lenses, Simple light microscope uses only one lenses,

whereas a compound light microscope uses 2-4 whereas a compound light microscope uses 2-4 lenses. One in the eye piece and one objective lens. lenses. One in the eye piece and one objective lens.

--Electron microscopes use a magnetic field in a vacuum Electron microscopes use a magnetic field in a vacuum to direct beams of electrons onto the object your to direct beams of electrons onto the object your looking at. These microscopes are a lot more looking at. These microscopes are a lot more powerful than light microscopes. Could magnify an powerful than light microscopes. Could magnify an object up to 1 million xobject up to 1 million x

Microscope PartsMicroscope Parts

-----------Eye piece-----------Eye piece

------------------- Objectives------------------- Objectives

-------------------Stage-------------------Stage

VirusesVirusesSection 3-3 H.W. Pick a virus and write Section 3-3 H.W. Pick a virus and write

down its name, and 5 other facts about it.down its name, and 5 other facts about it. What is a Virus?What is a Virus?- A virus is a strand of hereditary material that is A virus is a strand of hereditary material that is

surrounded by a protein coat.surrounded by a protein coat.- A virus is a particle that has things in common A virus is a particle that has things in common

with both living and non-living things.with both living and non-living things.- They have the ability to reproduce so they are They have the ability to reproduce so they are

like living things.like living things.- They are like non-living things because they They are like non-living things because they

don’t grow or eat and they need to live inside a don’t grow or eat and they need to live inside a cell or a host to survive. cell or a host to survive.

- And for this reason viruses are not included And for this reason viruses are not included within the six kingdoms of life.within the six kingdoms of life.

Viruses (continued)Viruses (continued)

All viruses cause disease. And they can All viruses cause disease. And they can infect any type of living organism. (from infect any type of living organism. (from bacteria, to algae, to plant, to fungi, to bacteria, to algae, to plant, to fungi, to animal)animal)

Ex: H.I.V, Hepatitis Ex: H.I.V, Hepatitis □□ We treat viruses with vaccines, which We treat viruses with vaccines, which

are dead or weak viruses that are given are dead or weak viruses that are given by injection or by mouth. Ex: polio virus, by injection or by mouth. Ex: polio virus, mumps, measles.)mumps, measles.)

--These vaccines make our bodies produce substances These vaccines make our bodies produce substances that allow us to become resistant to the virus. that allow us to become resistant to the virus.

Virus life cycleVirus life cycle1)1) First a virus will attach and invade First a virus will attach and invade

a cell. a cell. 2)2) Next, the virus uses the cell to Next, the virus uses the cell to

make copies of its DNA.make copies of its DNA.3)3) Once the virus makes enough Once the virus makes enough

copies of itself it makes the cell it copies of itself it makes the cell it is occupying explode.is occupying explode.

4)4) The new viruses then escape and The new viruses then escape and are free to invade the surrounding are free to invade the surrounding it and start the process over again.it and start the process over again.

Virus life cycleVirus life cycle

Active Vs. Latent VirusesActive Vs. Latent Viruses

Active virusesActive viruses enter a cell and enter a cell and continuously go through there life cycle continuously go through there life cycle numerous amounts of times without numerous amounts of times without stopping.stopping.

Latent VirusesLatent Viruses will enter a cell and not will enter a cell and not necessarily begin their life cycle right away. necessarily begin their life cycle right away. The virus makes its DNA part of the host but The virus makes its DNA part of the host but new virus particles are not put together yet. new virus particles are not put together yet. They wait until a certain physical or chemical They wait until a certain physical or chemical change occurs within the cell, which triggers change occurs within the cell, which triggers the viral particles to assembled.the viral particles to assembled.

Virus pictures.Virus pictures.

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