CellsCells Unit 4. The Cell Theory All organisms are composed of one or more cells. 7.1 Cell...

CellsUnit 4

The Cell Theory

All organisms are composed of one or more cells.

7.1 Cell Discovery and Theory

Cellular Structure and Function

The cell is the basic unit of structure and organization of organisms.

Chapter 7

All cells come from preexisting cells.


Light Microscopes

Utilizes a series of glass lenses and visible light to magnify an image

Magnifies images up to 1,000 times the actual size


Chapter 7

Electron Microscopes


Utilizes magnets to aim a beam of electronsto produce an image

Magnifies images up to 500,000 times the actual size

9560x


Chapter 7

Prokaryotic Cell

Simple structure


Contains a plasma membrane

Does not contain membrane-bound organelles 11,000x


Chapter 7

Eukaryotic Cell

More complex structure


Contains a plasma membrane

Contains membrane-bound organelles

400x


Chapter 7

Plasma (Cell) MembraneThin, flexible boundary between the

cell and its environment

7.2 The Plasma Membrane


Allows nutrients into the cellAllows waste to leave the cell

Chapter 7

Selective Permeability


The plasma membrane controls the movement ofsubstances into and out of the cell.


Chapter 7

The plasma membrane is composed of the phospholipid bilayer.


A phospholipid means:a glycerol backbonetwo fatty acid chainsa phosphate group.


Chapter 7

Fluid Mosaic Model


The phospholipid bilayer allows other molecules to “float” in the membrane.

Other ComponentsProteinsCholesterolCarbohydrates


Chapter 7

Proteins


Transmit signals inside the cell Act as a support structure Provide pathways for larger substances to enter

and leave the cell


Chapter 7

Cholesterol


Prevents fatty acid tails from sticking together


Chapter 7

Carbohydrates


Identify chemical signals


Chapter 7


7.3 Structures and Organelles

Chapter 7

CiliaShort, numerous

projections that look like hairs


FlagellaLonger and less

numerous than cilia

Create movement with a whiplike motion

400x

26,367x

7.3 Structures and Organelles

Chapter 7

Passive Transport

Movement of particles across the cell membrane without using energy

7.4 Cellular Transport


Three Modes of Passive Transport

Diffusion Facilitated Diffusion Osmosis

Chapter 7

DiffusionMovement of particles from an area of high

concentration to an area of lower concentration


Initial ConditionsDiffusion

Low High

High Low


Chapter 7

Diffusion is controlled by


Temperature PressureConcentration

Dynamic EquilibriumWhen diffusion of material into the cell

equals diffusion of material out of the cell


Chapter 7

Diffusion in a Cell



Chapter 7

Facilitated Diffusion


Movement of materials across the plasma membrane using proteins


Chapter 7


Carrier ProteinsChannel Proteins


Chapter 7

Osmosis


Diffusion of water across a selectively permeable membrane

Three Types of Solutions

Isotonic Hypotonic Hypertonic


Chapter 7

Blood CellPlant Cell

Isotonic Solution


Water and dissolved substances diffuse into and out of the cell at the same rate.

11,397x


Chapter 7

Blood Cell

Hypotonic Solution


Solute concentration is higher inside the cell.

Water diffuses into the cell.

Plant Cell

13,000x


Chapter 7

BLOWS UP the cell.

Plant Cell

Hypertonic Solution


Solute concentration is higher outside the cell.

Water diffuses out of the cell.

Blood Cell

13,000x


Chapter 7

SHRINKS the cell.

Active Transport


Movement of particles across the cell membrane using energy

Active Transport Using Carrier Proteins


Chapter 7


Endocytosis

Process by which the cell surrounds and takes particles into the cell

Exocytosis

Secretion of material out of the plasma membrane


Chapter 7

Transformation of Energy

Energy is the ability to do work.

8.1 How Organisms Obtain Energy

Cellular Energy

Thermodynamics is the study of the flow and transformation of energy in the universe.

Chapter 8

Metabolism

All of the chemical reactions in a cell


Cellular Energy

Photosynthesis—light energy from the Sun is converted to chemical energy for use by the cell

Cellular respiration—organic molecules are broken down to release energy for use by the cell

Chapter 8

ATP: The Unit of Cellular Energy

ATP releases energy when the bond between the second and third phosphate groups is broken.


Cellular EnergyChapter 8

Overview of Photosynthesis

Photosynthesis occurs in two phases.

Cellular Energy

Light-dependent reactions

Light-independent reactions

8.2 Photosynthesis

Chapter 8

Light and pigments

• Photosynthesis requires light and the pigment chlorophyll

• The green pigment is the wavelength reflected rather than absorbed, by plants the most – so plants are green and other colors are absorbed

Phase One: Light Reactions

The absorption of light is the first step in photosynthesis.

Cellular Energy

Chloroplasts capture light energy.

8.2 Photosynthesis

Chapter 8

Reactions of PhotosynthesisLight dependent reactions

• Grana are stacks of thylakoids in the chloroplast that contain the chlorophyll which captures sunlight

• Light dependent reactions take place in the thylakoids

Cellular Energy

8.2 Photosynthesis

Phase Two: The Calvin Cycle (Light-Independent)

In the second phase of photosynthesis, called the Calvin cycle, energy is stored in organic molecules such as glucose.

Chapter 8

Light independent reactionsThe Calvin Cycle

• The Calvin cycle or light independent reactions take place in the stroma

• Uses ATP and NADPH from light dep. Reactions to produce high energy sugars

Overview of Cellular Respiration

Organisms obtain energy in a process called cellular respiration.

8.3 Cellular Respiration

Cellular Energy

The equation for cellular respiration is the opposite of the equation for photosynthesis.

Chapter 8

(Glucose) + (oxygen)---->(carbon dioxide) + (water) + energy* (ATP)

GlucoseGlycolysis

Cytoplasm

Pyruvic acid

Electrons carried in NADH

Krebs Cycle

Electrons carried in

NADH and FADH2 Electron

Transport Chain

Mitochondrion

Overview of Cellular Respiration

Mitochondrion


Cellular Energy

Cellular respiration occurs in 3 parts.

Glycolysis

Kreb’s Cycle

Chapter 8

Electron Transport Chain

Step 1: Glycolysis

Glucose is broken down in the cytoplasm by glycolysis (splitting glucose).

Occurs in the cytoplasm

Forms 2 pyruvate from 1 glucose


Cellular Energy

2 molecules of ATP and 2 molecules of NADH are formed for each molecule of glucose that is broken down.

Takes 2 ATP to start

Chapter 8

Step 2: Krebs Cycle

Glycolysis has a net result of two ATP and two pyruvate.


Cellular Energy

The series of reactions in which pyruvate is broken down into carbon dioxide is called the Krebs cycle.

Occurs in the mitochondria

Chapter 8


Cellular Energy

The net yield from the Krebs cycle is 6 CO2 molecules2 ATP8 NADH2 FADH2.

Chapter 8


Cellular Energy

Step 3: Electron Transport

Final step in the breakdown of glucose

Point at which ATP is produced

Produces 24 ATP

Chapter 8

Summary FlowchartSection 9-2

Glucose(C6H1206)

+Oxygen

(02)

GlycolysisKrebsCycle

ElectronTransport

Chain

Carbon Dioxide

(CO2)+

Water(H2O)

Cellular Respiration


Cellular Energy

Anaerobic Respiration

The anaerobic pathway that follows glycolysis

Two main types:

Lactic acid fermentation

Alcohol fermentation

Glucose

Glycolysis Krebs cycle

Electrontransport

Fermentation (without oxygen)

Alcohol or lactic acid

Chemical PathwaysSection 9-1

Fermentation

• A process in the absence of oxygen (anaerobic)

• Lactic acid fermentation – NADH is converted back to NAD producing lactic acid

• Occurs when body can’t supply enough oxygen to the muscles during exercise = soreness, burning, fatigue

CellsCells Unit 4. The Cell Theory All organisms are composed of one or more cells. 7.1 Cell...

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Transcript of CellsCells Unit 4. The Cell Theory All organisms are composed of one or more cells. 7.1 Cell...