Cell Structure and FunctionCell Structure and FunctionChapter 7Chapter 7

7-17-1 I.I. Life is CellularLife is Cellular

A.A. Discovery of the CellDiscovery of the Cell

1. 1. Robert HookeRobert Hooke

a. 1665 used simple microscope to look a. 1665 used simple microscope to look at at thin layer of cork thin layer of cork

b. called them empty “chambers” or “cells”b. called them empty “chambers” or “cells”

2. 2. Anton Van LeeuwenhoekAnton Van Leeuwenhoek

a. used single lens microscope to observe a. used single lens microscope to observe pond waterpond water

b. found a new world of living thingsb. found a new world of living things

Cells- the basic units of lifeCells- the basic units of life

Cell TheoryCell Theory – –

a. all living things are composed of cellsa. all living things are composed of cells

b. cells are the basic units of structure b. cells are the basic units of structure and function in living things and function in living things

c. new cells are produced from existing c. new cells are produced from existing cellscells

B.B. Exploring the CellExploring the Cell

1.1. Compound Light MicroscopeCompound Light Microscope

a. More than one lens or objectivea. More than one lens or objective

b. Uses a light sourceb. Uses a light source

2. 2. Electron MicroscopeElectron Microscope

a. 1000x as powerful as a light microscope a. 1000x as powerful as a light microscope sends beams of electrons through specimensends beams of electrons through specimen

3. 3. SEM’sSEM’s (scanning electron microscope) (scanning electron microscope)

a. produces 3-D images electrons scan a. produces 3-D images electrons scan surface surface of objectof object

4. 4. Confocal Light MicroscopeConfocal Light Microscope

a. scans cells with laser beama. scans cells with laser beam

C.C. Prokaryotes vs EukaryotesProkaryotes vs Eukaryotes NUCLEUS- membrane bound organelle that NUCLEUS- membrane bound organelle that

contains genetic information (DNA). Also, controls contains genetic information (DNA). Also, controls the cells the cells activities.activities.1.1. Prokaryotes:Prokaryotes:

a.a. cells that do not contain a nucleus cells that do not contain a nucleusb.b. no membrane bound organelles no membrane bound organellesc.c. DNA is found within (no specific area)DNA is found within (no specific area)Example: bacteriaExample: bacteria

2.2. Eukaryotes:Eukaryotes:a.a. cells that contain a nucleuscells that contain a nucleusb.b. DNA is found in nucleus has other DNA is found in nucleus has other

membrane bound organellesmembrane bound organellesExample: animal cell, plant cellExample: animal cell, plant cell

7-2 Eukaryotic Cell Structure

A. Comparing the Cell to a Community

1. The organelles

- Nucleus

- Ribosome

- Endoplasmic Reticulum (smooth or rough)

- Golgi Apparatus

- Lysosome

- Vacuoles

- Mitochondria

- Chloroplasts

- Cytoskeleton

NucleusNucleusHow it connects:How it connects:– School HouseSchool House

What it does: What it does: – Controls the cells processes and contains the Controls the cells processes and contains the

hereditary information of DNAhereditary information of DNA

What it is:What it is:– Surrounded by the nuclear envelope which Surrounded by the nuclear envelope which

allows material to move in and outallows material to move in and out

Also contains:Also contains:– Chromatin- consists of DNA bound to proteinsChromatin- consists of DNA bound to proteins– Nucleolus- where the assembly of the Nucleolus- where the assembly of the

ribosomes beginsribosomes begins

RibosomesRibosomesHow it connects:How it connects:– WorkersWorkers

What it does:What it does:– Site of protein assemblySite of protein assembly

What it is:What it is:– small particles of RNA and protein found small particles of RNA and protein found

throughout the cytoplasmthroughout the cytoplasm

Endoplasmic ReticulumEndoplasmic ReticulumHow it connects:How it connects:– Assembly line Assembly line

What it does:What it does:– Site where lipid components of the cell membrane are Site where lipid components of the cell membrane are

assembled for export from the cellassembled for export from the cell– Rough: synthesis of proteinsRough: synthesis of proteins– Smooth: synthesis of membrane lipids, detoxification of Smooth: synthesis of membrane lipids, detoxification of

drugs using enzymesdrugs using enzymes

What it is:What it is:– Rough: part of the ER that have ribosomes on the Rough: part of the ER that have ribosomes on the

surface; proteins chemically modifiedsurface; proteins chemically modified– Smooth: no ribosomes on its surface (found in liver Smooth: no ribosomes on its surface (found in liver

cells)cells)

Golgi ApparatusGolgi Apparatus

How it connects:How it connects:– Packaging centerPackaging center

What it does:What it does:– Modifies, sorts and packages proteins and other Modifies, sorts and packages proteins and other

materials from the ER for storage or secretionmaterials from the ER for storage or secretion

What it is:What it is:– A stack of closely apposed membranesA stack of closely apposed membranes

LysosomeLysosome

How it connects:How it connects:– The trash cleanup crewThe trash cleanup crew

What it does:What it does:– Digestion, or breakdown of lipids, carbohydrates, Digestion, or breakdown of lipids, carbohydrates,

and proteins into small molecules that can be and proteins into small molecules that can be used by the rest of the cellused by the rest of the cell

– Also can break down organelles and remove Also can break down organelles and remove “junk” from the cell“junk” from the cell

What it is:What it is:– Small organelles filled with enzymesSmall organelles filled with enzymes

VacuolesVacuoles

How it connects:How it connects:– Storage facilityStorage facility

What it does:What it does:– Store materials such as water, salts, proteins, Store materials such as water, salts, proteins,

and carbohydratesand carbohydrates– In plants, they provide structure to the cellsIn plants, they provide structure to the cells– In paramecium, they maintain homeostasisIn paramecium, they maintain homeostasis

What it is:What it is:– A saclike structure that is often filled with liquidA saclike structure that is often filled with liquid

MitochondriaMitochondriaHow it connects:How it connects:– The power companyThe power company

What it does:What it does:– Convert chemical energy stored in food into Convert chemical energy stored in food into

compounds that are usable to cellscompounds that are usable to cells

What it is:What it is:– Enclosed by two membranes- outer and inner Enclosed by two membranes- outer and inner

membrane- the inner is folded up inside membrane- the inner is folded up inside

Extra info:Extra info:– In humans, they are inherited from the In humans, they are inherited from the

cytoplasm of the eggcytoplasm of the egg

ChloroplastsChloroplasts

How it connects:How it connects:– Solar Power PlantSolar Power Plant

What it does:What it does:– Capture the energy from sunlight and convert Capture the energy from sunlight and convert

it into chemical energy for photosynthesisit into chemical energy for photosynthesis

What it is:What it is:– Two membranes- inside there are stacks of Two membranes- inside there are stacks of

other membranes containing chlorophyllother membranes containing chlorophyll

CytoskeletonCytoskeletonHow it connects:How it connects:– Roads, streets and highwaysRoads, streets and highways

What it does:What it does:– Helps cells maintain shapeHelps cells maintain shape– Assists in movementAssists in movement

What it is:What it is:– A network of protein filaments, called A network of protein filaments, called

microfilaments and microtubulesmicrofilaments and microtubules

CentriolesCentrioles

How it connects:How it connects:– City PlannerCity Planner

What it does:What it does:– Helps organize cell divisionHelps organize cell division

What it is:What it is:– Formed by tubulin Formed by tubulin

7-3 Cell Boundaries7-3 Cell Boundaries

A. Cell membraneA. Cell membrane

1. regulates what enters and exits the cell and 1. regulates what enters and exits the cell and provides protectionprovides protection

2. made of two layers- phospholipid bilayer2. made of two layers- phospholipid bilayer

a. phosphate heads (hydrophilic)a. phosphate heads (hydrophilic)

b. lipid tails (hydrophobic)b. lipid tails (hydrophobic)

c. proteinsc. proteins

d. cholesterol (a lipid) (helps with structure)d. cholesterol (a lipid) (helps with structure)

Figure 8.1 Artificial membranes (cross sections)Figure 8.1 Artificial membranes (cross sections)

Figure 8.2 Two generations of membrane modelsFigure 8.2 Two generations of membrane models

Figure 8.6 The detailed structure of an animal cell’s plasma membrane, in cross sectionFigure 8.6 The detailed structure of an animal cell’s plasma membrane, in cross section

B. Cell WallB. Cell Wall

1. Provides support and protection1. Provides support and protection

2. Made of cellulose 2. Made of cellulose

a.a. carbohydrate fiber (wood and paper is carbohydrate fiber (wood and paper is made from)made from)

3.3. found in plants, algae, fungi, and many found in plants, algae, fungi, and many prokaryotesprokaryotes

4.4. found on outside of cell membranefound on outside of cell membrane

C. Diffusion Through Cell BoundariesC. Diffusion Through Cell Boundaries

1. Diffusion- movement of molecules across a 1. Diffusion- movement of molecules across a membranemembrane

2. Concentration- mass of solute/volume of 2. Concentration- mass of solute/volume of solutionsolution

a. molecules will move from an area of HIGH a. molecules will move from an area of HIGH concentration to an area of LOW concentration to an area of LOW concentrationconcentration

b. molecules will continue to move until b. molecules will continue to move until they’re equalthey’re equal

****Diffusion requires NO energy********Diffusion requires NO energy****

Figure 8.11 OsmosisFigure 8.11 Osmosis

D.D. Osmosis- Diffusion of water through a Osmosis- Diffusion of water through a selectively permeable membrane (pg 186)selectively permeable membrane (pg 186)

1. Isotonic solution- concentrations of 1. Isotonic solution- concentrations of solutessolutes is the same inside and outside is the same inside and outside of the of the cellcell

2. Hypertonic solution- solution has a 2. Hypertonic solution- solution has a higher higher solute count than the solute count than the inside cell (cell inside cell (cell shrinks)shrinks)

3. Hypotonic solution- solution has a lower 3. Hypotonic solution- solution has a lower solute concentration than the solute concentration than the

cell (cell cell (cell will balloon up)will balloon up)

4. Osmotic Pressure- pressure that builds 4. Osmotic Pressure- pressure that builds up up inside the cell (good and bad)inside the cell (good and bad)

Figure 8.12 The water balance of living cellsFigure 8.12 The water balance of living cells

Figure 8.14 Two models for facilitated diffusionFigure 8.14 Two models for facilitated diffusion

Figure 8.13 The contractile vacuole of Figure 8.13 The contractile vacuole of ParameciumParamecium: an evolutionary adaptation for osmoregulation: an evolutionary adaptation for osmoregulation

Animation How Diffusion Works.mht

How Osmosis Works.mht

E. Active Transport- the process of moving E. Active Transport- the process of moving molecules against the concentration gradientmolecules against the concentration gradient

1. Small molecules are carried across the 1. Small molecules are carried across the

membrane by TRANSPORT membrane by TRANSPORT PROTEINS.PROTEINS.

2. Large molecules are actively transported 2. Large molecules are actively transported 1 of 2 ways1 of 2 ways

a. Endocytosis- taking material into a. Endocytosis- taking material into cell cell by engulfing the membrane by engulfing the membrane around around the moleculethe molecule

b. Exocytosis- pushing material out b. Exocytosis- pushing material out of of cellcell

****REQUIRES ENERGY********REQUIRES ENERGY****

Figure 8.16 Review: passive and active transport comparedFigure 8.16 Review: passive and active transport compared

7-4 Diversity of Cellular life7-4 Diversity of Cellular life

A. Unicellular- organism made of one A. Unicellular- organism made of one cell onlycell only

B. Multicellular- organism made of more B. Multicellular- organism made of more than one cell or manythan one cell or many

1. Specialized cells- cells that 1. Specialized cells- cells that perform a specific task.perform a specific task.

Ex. Red blood cells carry O2 Ex. Red blood cells carry O2

C. Levels of OrganizationC. Levels of Organization1. Cells- basic unit of life1. Cells- basic unit of life

2. Tissues- a group of similar cells2. Tissues- a group of similar cells

3. Organs- a group of tissues3. Organs- a group of tissues

4. Organ systems- a group of organs4. Organ systems- a group of organs

5. Organisms- a group of organ systems5. Organisms- a group of organ systems

http://www.zerobio.com/target_practice_quiz/target_practice_quiz_cells.htm

http://www.wiley.com/legacy/college/boyer/0470003790/animations/cell_structure/cell_structure.htm