chapter 4 table of contents section 1 the history of cell biology

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Cell Structure and FunctionChapter 4

Table of ContentsSection 1 The History of Cell Biology

Section 2 Introduction to Cells

Section 3 Cell Organelles and Features

Section 4 Unique Features of Plant Cells



Section 1 The History of Cell BiologyChapter 4

Objectives

• Name the scientists who first observed living and nonliving cells.

• Summarize the research that led to the development of the cell theory.

• State the three principles of the cell theory.

• Explain why the cell is considered to be the basic unit of life.



Introduction to the Cell

• Definition – A cell is the smallest unit of structure and function of living things that carries on life processes.



A. Discovery of the Cell

• Robert Hooke ( 1665) – 1st to see cells; – looked at cork (dead plant cell); – box-shaped structures looked like monk’s

rooms called ‘cells’.




• Anton Van Leeuwenhoek (1673) – 1st to see living cells. – Scraped mouth: bacteria, yeast.– Water: Protozoans, “Animalcules”.




• Matthias Schleiden (1838) – Botanist, – concluded all plants are made of cells.




• Theodor Schwann (1839) – Zoologist, – concluded all animals are made of cells




• Rudolf Virchow (1855) – Physician, – concluded cells come only from other living

cells.



Chapter 4

Cell Theory

Section 1 The History of Cell Biology




• This information gave evidence for the Cell Theory:

1. Cells are the basic unit of structure and function in all living things.

2. All living things are made of cells.3. Cells come only from the reproduction of other

living cells.



Section 1 The History of Cell BiologyChapter 4

The Cell Theory, continued

Think & Discuss:Think & Discuss:

• Cellular Basis of Life– All living things are made of organized parts,

obtain energy from their surroundings, perform chemical reactions, change with time, respond to their environment, and reproduce.



Section 2 Introduction to CellsChapter 4

Objectives

• Explain the relationship between cell shape and cell function.

• Identify the factor that limits cell size.

• Describe the three basic parts of a cell.

• Compare prokaryotic cells and eukaryotic cells.

• Analyze the relationship among cells, tissues, organs, organ systems, and organisms.



B. Cell Diversity1. Cell Size

– Most cells are only visible with microscope.– Cell size varies from 2 m to .2m (.2 x 10-6)– Examples:

• Bacteria - 0.2 m (.000008 in. or 8 millioneth in.)

• Giraffe leg nerve – 2 m (6 ½ ft.)• Eggs• Most body and plant cells – 10 to 50 m

(.002 in.)




Think & Discuss:Think & Discuss:• Cell Size

– Cell size is limited by a cell’s surface area–to-volume ratio.



B. Cell Diversity• Why are Cells so Small?

1. Diffusion is too slow to move nutrients & wastes through cell.

2. As cell size increases, volume increases at faster rate than surface area. Surface area becomes too small to allow materials to enter cell quickly enough to meet its needs.



B. Cell Diversity2. Cell Shape• The shape of a cell helps it to perform its function.• Examples:

a. RBCs – concave, flexible – squeeze thru vesselsb. WBCs – change shape – engulf particlesc. Nerves – long, threadlike, branched – receive & send messagesd. Epithelial tissue – flat, packed – protectione. Muscles – long, rod-like, contract – pull parts together




Cell Diversity

• Cell Shape– A cell’s shape reflects its function.




Cellular OrganizationThink & Discuss:Think & Discuss:• In multicellular eukaryotes, cells organize into tissues,

organs, organ systems, and finally organisms.



How are organelles like organs?

• Organelles perform specific functions to keep a cell healthy and alive.

• Organs perform specific functions to keep an organism healthy and alive.




Two Basic Types of Cells


• Prokaryotes– Prokaryote cells

lack a nucleus and membrane-bound organelles.



– Eukaryotes – cells that have a nucleus and membrane-bound organelles.

– Prokaryotes – cells that lack a nucleus and have no membrane-bound organelles. (bacteria)

B. Cell Diversity



Chapter 4

Comparing Prokaryotes and Eukaryotes





Basic Parts of a Cell

• The three basic parts of a cell are the plasma membrane, the cytoplasm, and the nucleus.




3. Internal Organizationa. Organelles – cell components that perform specific functions to maintain the life of the cell.b. Cell Membrane – Thin membrane surrounding cell.c. Nucleus – large organelle near center of cell; contains genetic information; directs cell activities.

B. Cell Diversity



Chapter 4

Objectives• Describe the structure and function of a cell’s plasma

membrane.

• Summarize the role of the nucleus.

• List the major organelles found in the cytosol, and describe their roles.

• Identify the characteristics of mitochondria.

• Describe the structure and function of the cytoskeleton.




Chapter 4

Internal Organization of a Cell





Basic Parts of a Cell, continued

• Cytoplasm - (Cytosol)

a. Located between cell membrane & nucleusb. Contains gel-like fluid called Cytosol and

organelles.c. Helps give shape to cell.



a. Organelles – cell components that perform specific functions to maintain the life of the cell.

B. Organelles:



Chapter 4Endoplasmic Reticulum (“E.R.”)

a. Intracellular “Highway”b. Membranous tubes used to transport moleculesc. Rough ER – has ribosomes; transports proteinsd. Smooth ER – no ribosomes; makes lipids




Chapter 4

Endoplasmic Reticulum, continued

• The smooth ER builds lipids and participates in detoxification of toxins.




Chapter 4

Endoplasmic Reticulum (ER) and Ribosomes




Chapter 4

Ribosomes

• Ribosomes a. site of protein synthesis

b. Located on rough E.R. and scattered throughout cytoplasm




Chapter 4

Ribosomes




Chapter 4Golgi Apparatus (“Packing & Shipping”)

a. Stack of flat membranous sacs.b. Packages proteins from the ERc. Secretes (‘ships’) them to other parts




Chapter 4

Mitochondria

• Mitochondria (“Powerhouse”)a. site of cellular respiration- make ATP energy from glucoseb. inner membrane has many folds (Cristae) to increase surface areac. large numbers found in muscle cells




Chapter 4

Mitochondria

• Mitochondria harvest energy from organic compounds and transfer it to ATP.




Chapter 4

Mitochondrion




Chapter 4

Vesicles

• (Vesicles, including lysosomes (digestive enzymes) and peroxisomes (detoxification enzymes), are classified by their contents.)

Lysosomes (“Cleaning Crew”)a. Sac of digestive enzymesb. Break down nutrients, invaders, debris




Chapter 4

Processing of Proteins




Chapter 4

Cytoskeleton

• (The cytoskeleton is made of protein fibers that help cells move and maintain their shape.)

Cytoskeletona. Microfilaments – fine protein threads• Ex: Actin – cause muscles to contractb. Microtubules – hollow protein tubes• Ex: Spindle Fibers – move chromosomes




Chapter 4

Cytoskeleton




Chapter 4

Cytoskeleton, continued

• Cilia and Flagella– (Cilia and flagella are hairlike structures that

extend from the surface of the cell, where they assist in movement.)





Chapter 4


Ciliaa. Tiny hair-like projections on cell membrane

packed in rowsb. Wave, move mucus, catch debris

Flagellaa. Long, whip-like, on cell surfaceb. Allow sperm cells to swim




Chapter 4

Structure of Cilia and Flagella




Chapter 4


• Centrioles– A. two short cylinders of microtubules at right

angles to each other – B. involved in cell division.




Chapter 4

Nucleus

• Nucleusa. Contains DNA (genetic info) – directs cell’s activitiesb. Located near center of cellc. Nuclear Envelope – porous, double membraned. Nucleolus – produces ribosomese. Chromatin – “thread-like” DNA




Chapter 4

Nucleus of a Cell





Parts of the Eukaryotic CellA. Cell MembraneNext, we’ll discuss:• Plasma Membrane

– (The cell’s outer boundary, called the plasma membrane (or the cell membrane), covers a cell’s surface and acts as a barrier between the inside and the outside of a cell. )



Chapter 4

Plasma Membrane, continued

• Membrane Proteins– Cell membranes often contain proteins embedded

within the phospholipid bilayer.






Parts of the Eukaryotic CellA. Cell Membrane

– Selectively Permeable – controls which substances pass into and out of cell.





1. Membrane Lipids – lipids (fats) allow fat-soluble substances to pass through

2. Phospholipids form a lipid bilayer.



Chapter 3Structure of Lipid Bilayer




Chapter 4

Cell Membrane






3. Membrane Proteins – allow fat-nonsolubles to pass through

4. Fluid Mosaic Model – lipid bilayer behaves more like a fluid than a solid. Lipids and proteins can move (fluid) within bilayer, so their pattern (mosaic) changes.




Basic Parts of a CellDo You Remember?• The three basic parts of a cell are:The plasma membrane, cytoplasm, and nucleus.




Do you Remember: The Two Basic Types of Cells?• Prokaryotes

– Prokaryote cells lack a nucleus and membrane-bound organelles. (Bacteria)



• Eukaryotes – cells that have a nucleus and membrane-bound organelles. (Animals, Plants, Fungus, Protist)



Chapter 4

Objectives• List three structures that are present in plant cells but not in

animal cells.

• Compare the plasma membrane,the primary cell wall, and the secondary cell wall.

• Explain the role of the central vacuole.

• Describe the roles of plastids in the life of a plant.

• Identify features that distinguish prokaryotes, eukaryotes, plant cells, and animal cells.




Chapter 4

Plant Cells• Plant cells have cell walls, central vacuoles, and

plastids.




Chapter 4

A. Cell Wall

• A solid, rigid, outer covering; provides support and protection.




Chapter 4

Parts of a Cell Wall




Chapter 4

B. Central Vacuole

1. Storage areas- store water, enzymes, and waste products and provide support for plant tissue.

2. Large – up to 90% of cell’s volume




Chapter 4

C. Plastids

1. Store starch, fats, or pigments2. Chloroplast – contains chlorophyll for

photosynthesis3. Leucoplast – stores starch4. Chromoplast – makes & stores pigments:

Carotene – orange; Xanthrophyll – yellow




Chapter 4

Chloroplasts




Chapter 4

Comparing Cells

• Prokaryotes, animal cells, and plant cells can be distinguished from each other by their unique features.




Chapter 4

Comparing Plant and Animal Cells




Multiple Choice

1. The eukaryotic nucleus houses all of the following except theA. RNAB. DNAC. nucleolusD. endoplasmic reticulum

Standardized Test PrepChapter 4



Multiple Choice, continued

1. The eukaryotic nucleus houses all of the following except theA. RNAB. DNAC. nucleolusD. endoplasmic reticulum





2. Which structure contributes to support and movement within a cell?F. cristaG. cell wallH. ribosomeJ. microfilament





3. Which of the following statements about RNA is true?A. RNA is found only in proteins.B. RNA is found only in the nucleus.C. RNA is found only in the cytoplasm.D. RNA is found in the nucleus and cytoplasm.





4. By what percentage does the surface area–to – volume ratio change when a cell grows from 1 to 2 µm in diameter?F. 10 percentG. 20 percentH. 50 percentJ. 90 percent

Chapter 4

The graph below showsthe relationship between cell size and surface area–to–volume ratio. Use the graph below to answerthe questions that follow.

Standardized Test Prep




5. What is the maximum diameter that this cell could attain before the surface area–to-volume ratio would fall below 1?A. 2 µmB. 5 µmC. 10 µmD. 15 µm

Chapter 4

The graph below showsthe relationship between cell size and surface area–to–volume ratio. Use the graph below to answerthe questions that follow.





6. mitochondria : energy release :: ribosome :F. cell supportG. protein synthesisH. cellular digestionJ. cellular transport

Chapter 4 Standardized Test Prep




7. What is the function of the structure labeled 1?A. to make ATPB. to make proteinsC. to make carbohydratesD. to move proteins through the cell

Chapter 4

The figure below showsa diagram of a cell. Use the figure to answer thequestion that follows.




Short Response

A cell’s shape is generally related to its function.Skin cells are flat and platelike. Nerve cells have long extensions. Explain the relationship between the shape of skin and nerve cells and their function in the body.




Short Response, continued

Answer: Cell shape reflects the different functions of cells. For example, the long extensions of nerve cells allow these cells to receive and transmit nerve impulses in many directions. Also, the flat shape of skin cells suits their function of covering and protecting the surface of the body.




Extended Response

Despite the diversity among cells, eukaryotic cells share many common features.Part A Describe the structure and function of the

organelles found in an animal cell.Part B Summarize the differences that distinguish

animal cells from bacteria and plant cells.




Extended Response, continued

Answer:Part A Answers may include the following: The nucleus holds

and protects DNA; Mitochondria transfer energy to ATP; Ribosomes manufacture proteins; The ER functions as an intracellular highway; The Golgi apparatus directs proteins to other parts of the cell; Vesicles digest materials, break down old cells, and play a role in protein synthesis.

Part B Plant and bacterial cells, unlike animal cells, have a cell wall. Bacterial cells, unlike plant and animal cells, lack a membrane-bound nucleus and organelles. Some bacterial cells and all plant cells have plastids.


chapter 4 table of contents section 1 the history of cell biology

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