Chapter 4Chapter 4

The Cell in ActionThe Cell in Action

Section 1:ObjectivesSection 1:Objectives

Explain the process of diffusionExplain the process of diffusion

Describe how osmosis occursDescribe how osmosis occurs

Compare passive and active transportCompare passive and active transport

Explain how large particles get into and Explain how large particles get into and out of cells.out of cells.

Exchange with the EnvironmentExchange with the Environment

An organism is sort of like a factory.An organism is sort of like a factory.It must be able to do 2 things:It must be able to do 2 things:– Obtain energy and raw materialsObtain energy and raw materials– Get rid of wasteGet rid of waste

These things help keep cells healthy so These things help keep cells healthy so that they can divide.that they can divide.The exchange of materials between a cell The exchange of materials between a cell and its environment takes place at the cell and its environment takes place at the cell membrane.membrane.

Exchange with the EnvironmentExchange with the Environment

DiffusionDiffusion: the movement of particles from : the movement of particles from regions of higher density to regions of regions of higher density to regions of lower densitylower density

Diffusion occurs within and between living Diffusion occurs within and between living cells.cells.

Cells do not use energy for diffusion.Cells do not use energy for diffusion.

Exchange with the EnvironmentExchange with the Environment

Exchange with the EnvironmentExchange with the Environment

Example:Example:

When someone makes coffee, diffusion is When someone makes coffee, diffusion is occurring.occurring.

The coffee pot represents the inside of the The coffee pot represents the inside of the cell and the coffee filter represents the cell cell and the coffee filter represents the cell membrane.membrane.

Semi-permeableSemi-permeable: only certain substances : only certain substances can pass throughcan pass through

Exchange with the EnvironmentExchange with the Environment

OsmosisOsmosis: the diffusion of water through a : the diffusion of water through a semipermeable membranesemipermeable membrane

Osmosis is important to cellular functions.Osmosis is important to cellular functions.

Osmosis occurs in plant cells:Osmosis occurs in plant cells:– When a wilted plant is watered, it enters the When a wilted plant is watered, it enters the

cell membrane and supplies the plant with cell membrane and supplies the plant with water. The plant then looks healthy.water. The plant then looks healthy.

Exchange with the EnvironmentExchange with the Environment

Small particles, such as water and sugar, Small particles, such as water and sugar, cross the cell membrane through cross the cell membrane through channelschannels

Active transportActive transport: movement of particles : movement of particles across cell membrane with energyacross cell membrane with energy– High to low concentrationHigh to low concentration

Passive transportPassive transport: movement of particles : movement of particles across cell membrane without energyacross cell membrane without energy– Diffusion and osmosis are examplesDiffusion and osmosis are examples

Exchange with the EnvironmentExchange with the Environment

Exchange with the EnvironmentExchange with the Environment

Larger particles enter/exit the cell by one Larger particles enter/exit the cell by one of the following 2 processes:of the following 2 processes:– EndocytosisEndocytosis: process by which a cell : process by which a cell

membrane surrounds a particle without the membrane surrounds a particle without the use of energyuse of energy

– ExocytosisExocytosis: process by which a cell releases : process by which a cell releases a particle by enclosing the particle in a vesicle a particle by enclosing the particle in a vesicle that then moves to the cell’s surface and that then moves to the cell’s surface and fuses with the cell membrane fuses with the cell membrane

Exchange with the EnviromentExchange with the Enviroment

Exchange with the EnvironmentExchange with the Environment

EXOCYTOSISEXOCYTOSIS– ““Exo”= ExitExo”= Exit– ““Osis”= ProcessOsis”= Process– Large particles are Large particles are

packaged in packaged in vesicles vesicles vesicle vesicle travels to cell travels to cell membrane membrane cell cell releases particlereleases particle

ENDOCYTOSISENDOCYTOSIS

““Endo” = To enterEndo” = To enter

““Osis” = ProcessOsis” = Process

Cell comes into Cell comes into contact with particle contact with particle cell membrane cell membrane wraps around particle wraps around particle particle enters cell particle enters cell

Section 1: Review QuestionsSection 1: Review Questions

1) What is the difference between active 1) What is the difference between active and passive transport?and passive transport?2) What takes place at the cell 2) What takes place at the cell membrane?membrane?3) Is energy required for diffusion?3) Is energy required for diffusion?4) List 1 example of diffusion.4) List 1 example of diffusion.5) When is osmosis important?5) When is osmosis important?6) How do small particles cross the cell 6) How do small particles cross the cell membrane?membrane?

Section 2: ObjectivesSection 2: Objectives

Describe photosynthesis and cellular Describe photosynthesis and cellular respiration.respiration.

Compare cellular respiration with Compare cellular respiration with fermentation.fermentation.

From Sun to CellFrom Sun to Cell

Nearly all energy that fuels life comes from Nearly all energy that fuels life comes from the sun.the sun.

Plants capture energy from the sun and Plants capture energy from the sun and change it into food through a process change it into food through a process called called photosynthesisphotosynthesis..

What happens to the food plants make?What happens to the food plants make?

From Sun to CellFrom Sun to Cell

Plant cells contain chlorophyll, a green Plant cells contain chlorophyll, a green pigment that absorbs light energy.pigment that absorbs light energy.

This gives plants their green color.This gives plants their green color.

Where is the chlorophyll located in plant Where is the chlorophyll located in plant cells?cells?

From Sun to CellFrom Sun to Cell

Plants use the energy captured by Plants use the energy captured by chlorophyll to change carbon dioxide and chlorophyll to change carbon dioxide and water into food. water into food.

Glucose is the food that plants make.Glucose is the food that plants make.

Glucose is a simple sugar. (carbohydrate)Glucose is a simple sugar. (carbohydrate)

From Sun to CellFrom Sun to Cell

Animal cells have different ways of getting Animal cells have different ways of getting energy from food:energy from food:

– Cellular respirationCellular respiration: uses oxygen to break : uses oxygen to break down fooddown food

– FermentationFermentation: breakdown of food without the : breakdown of food without the use of oxygenuse of oxygen

From Sun to CellFrom Sun to Cell

Respiration = “breathing”Respiration = “breathing”

Food is broken down into CO2 and H2O.Food is broken down into CO2 and H2O.

Most of the energy released maintains Most of the energy released maintains body temperature.body temperature.

Some of the energy is used to form ATP.Some of the energy is used to form ATP.

Most of cellular respiration takes place in Most of cellular respiration takes place in the cell membrane. the cell membrane.

From Sun to CellFrom Sun to Cell

Fermentation example:Fermentation example:

One example of fermentation is when your One example of fermentation is when your muscles and tissues produce lactic acid.muscles and tissues produce lactic acid.

The buildup of lactic acid contributes to The buildup of lactic acid contributes to muscle fatigue and causes a burning muscle fatigue and causes a burning sensation.sensation.

Section 3: ObjectivesSection 3: Objectives

Explain how cells produce more cells.Explain how cells produce more cells.

Describe the process of mitosis.Describe the process of mitosis.

Explain how cell division differs in plant Explain how cell division differs in plant and animal cells.and animal cells.

The Cell CycleThe Cell Cycle

As you grow, you pass through different As you grow, you pass through different stages.stages.

Cells also pass through different stages Cells also pass through different stages ((cell cyclecell cycle: life cycle of a cell): life cycle of a cell)

It begins when the cell if formed and ends It begins when the cell if formed and ends when the cell divides.when the cell divides.

The Cell CycleThe Cell Cycle

Before a cell divides, it copies its DNA.Before a cell divides, it copies its DNA.

DNA is the hereditary material that DNA is the hereditary material that controls cell division.controls cell division.

The DNA of a cell is organized in The DNA of a cell is organized in structures called structures called chromosomeschromosomes..

Why is copying DNA important in cell Why is copying DNA important in cell division?division?

The Cell CycleThe Cell Cycle

Prokaryotic cells are less complex than Prokaryotic cells are less complex than eukaryotic cells.eukaryotic cells.

Cell division in bacteria is called Cell division in bacteria is called binary binary fissionfission..

It results in 2 cells, each with one copy of It results in 2 cells, each with one copy of the DNA. the DNA.

The Cell CycleThe Cell Cycle

Eukaryotes are more complex than prokaryotic Eukaryotes are more complex than prokaryotic cells.cells.

Eukaryotes contain more DNA than prokaryotic Eukaryotes contain more DNA than prokaryotic cells.cells.

Different eukaryotes have different numbers of Different eukaryotes have different numbers of chromosomes.chromosomes.

What is the total # of chromosomes in humans? What is the total # of chromosomes in humans? How many pairs of chromosomes is that?How many pairs of chromosomes is that?

The Cell CycleThe Cell Cycle

The eukaryotic cell cycle has 3 major The eukaryotic cell cycle has 3 major stages:stages:

– 11stst phase: cell copies organelles and phase: cell copies organelles and chromosomeschromosomes

Once chromosomes are copied they are called Once chromosomes are copied they are called chromatidschromatids

– 22ndnd phase: chromatids separate phase: chromatids separate (enters mitosis)(enters mitosis)– 33rdrd phase: cell splits into 2 cells phase: cell splits into 2 cells

Critical ThinkingCritical Thinking

Cell A contains 70% water and is normal. Cell A contains 70% water and is normal. Cell B contains 85% water and is Cell B contains 85% water and is abnormal. Cell B continually takes in water abnormal. Cell B continually takes in water and cannot release any. From what we and cannot release any. From what we have learned about diffusion, answer the have learned about diffusion, answer the following questions:following questions:– What part of the cell is not working properly?What part of the cell is not working properly?– If this continues what will happen to the cell?If this continues what will happen to the cell?– Why is this not a characteristic of diffusion Why is this not a characteristic of diffusion

working properly?working properly?

Ch. 4: Notebook QuizCh. 4: Notebook Quiz

The cell cycle begins when the cell is The cell cycle begins when the cell is _______ and ends when the cell ______._______ and ends when the cell ______.

Before a cell divides, it copies its _____.Before a cell divides, it copies its _____.

Cell division in bacteria is called ______.Cell division in bacteria is called ______.

Different eukaryotes have different Different eukaryotes have different numbers of ________.numbers of ________.

List and describe the 3 phases of the List and describe the 3 phases of the eukaryotic cell cycle.eukaryotic cell cycle.

The Cell CycleThe Cell Cycle

Cell division begins at the cell membrane.Cell division begins at the cell membrane.

The division of cytoplasm is called The division of cytoplasm is called cytokinesiscytokinesis..

Eukaryotic cells that have a cell wall form Eukaryotic cells that have a cell wall form a cell plate which divides the cell in half.a cell plate which divides the cell in half.

The Cell CycleThe Cell Cycle

There are 6 steps to mitosis:There are 6 steps to mitosis:– InterphaseInterphase– ProphaseProphase– MetaphaseMetaphase– Anaphase Anaphase – TelophaseTelophase– CytokinesisCytokinesis