Chapter 7- Cell Structure & Function. I. Life is Cellular A-The Discovery of the Cell It was not until the _________ that scientists began to use.

Chapter 7-

Cell Structure & Function

I. Life is CellularA-The Discovery of the Cell• It was not until the _________ that

scientists began to use microscopes to observe organisms.

• In 1665 ____________used an early compound microscope to see tiny chambers in cork.He called these chambers cells after the tiny rooms in monasteries….we know these not to be empty now.

Mid-1600’sRobert Hooke

• About the same time in Holland________________used a single-lens microscope to look @ pond water,

Anton van Leeuwenhoek

• In 1838 Matthew Schleiden concluded plants were made of cells

• 1839 Theodore Schwann said all animals were made of cells

• 1855-Virchow said cells could only come from existing ones.

These 3 things compile_________________

– All living things composed of ___________– Cells are the basic units of

___________________of living things– New cells are produced from

______________________.

cellsStructure and function

Existing cells

B-Exploring the Cell

• Florescent labels and light microscopy have been used to follow molecules through the cell.

• _________________,which scans cells w/a laser beam can make 3-d images of cells

• Video technology make it possible to watch cell growth , division and development

Confocal light microscopy

• Light makes it difficult to visualize tiny structures because it scatters/______________________allow things like proteins to be visualized (things as much as 1000 x smaller can be visualized….TEMS allow you to see specimens cut into ultra thin slices

Electron microscopes

•W/ a ______________specimens do not have to be cut to see 3-D images….both must be placed into a vacuum so air molecules do not scatter electrons

•1990’s-____________________________have revolutionalized visualization of surfaces and atoms have been observed…can be used in ordinary air and can show DNA structure

SEMScanning probe microscopes

pollen

C .Prokaryotes and Eukaryotes

• Cells typically range from _________micrometers,but some bacteria are .2 and some amoeba are 1000 micrometers

• All cells have 2 things in common:»cell membrane-a barrier»@ some point they contain_______

5-50 micrometers DNA

2 broad categories:

– _____________________________-genetic material is NOT contained in a nucleus/generally less complicated than other cells/carry out all cell activities…present day members are ________________.

Prokaryotes bacteria

• _____________________________-contain a nucleus w/ genetic material,generally larger,much diversity

Eukaryotes

Division of Labor

•A cell is made up of many parts with different functions that work together. Similarly, the parts of a computer work together to carry out different functions.•Working with a partner, answer the following questions.•1. What are some of the different parts of a computer? What are the functions of these computer parts?

•2. How do the functions of these computer parts correspond to the functions of certain cell parts?

Section 7-2

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Prokaryotes Eukaryotes

Cell membraneRibosomesCell wall

NucleusEndoplasmic reticulumGolgi apparatusLysosomesVacuolesMitochondriaCytoskeleton

Animal Cells Plant Cells

Lysosomes

Cell membraneRibosomesNucleusEndoplasmic reticulumGolgi apparatusVacuolesMitochondriaCytoskeleton

Cell Wall

Chloroplasts

Section 7-2

Venn Diagrams

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II. EUKARYOTIC CELL STRUCTURE

• Organelles

• 2 major parts of eukaryotic cells

Specialized structure that performs important functions within an eukaryotic cell.

nucleus

cytoplasm

Cytoplasm is material inside membrane and outside nucleus

Plant Cell

Nuclearenvelope

Ribosome(attached)

Ribosome(free)

Smooth ER

Nucleus

Rough ER

Nucleolus

Golgi apparatus

Mitochondrian

Cell wall

CellMembrane

Chloroplast

Vacuole

Section 7-2

Figure 7-5 Plant and Animal Cells

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Animal Cell

Centrioles

NucleolusNucleus

Nuclearenvelope

Rough endoplasmic reticulum

Golgi apparatus

Smooth endoplasmicreticulum

Mitochondrian

CellMembrane

Ribosome(free)

Ribosome(attached)

Section 7-2

Figure 7-5 Plant and Animal Cells

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The Nucleus

• Contains nearly all the cell’s DNA• Codes for instructions to make proteins and

other molecules• Surrounded by nuclear envelope---has many

pores to allow material in and out• Contains chromatin—has DNA bound to

protein,usually spread throughout nucleus,but condenses during cell division to make CHROMOSOMES,containing genetic info

• Usually contain Nucleolus—assembly of ribosomes begin here.

Ribosomes

• Proteins are assembled here

• Made out of small particles of RNA and protein

• Found throughout cytoplasm

• Coded instructions from nucleus tell how to make proteins

• Cells active in protein synthesis have a lot of ribosomes

Endoplasmic Reticulum

• Site where lipid components of cell membrane are assembled,along w/ proteins and other materials exported from cell(those proteins are made there)

• Rough ER is involved in protein synthesis,because ribosomes are on it

• Newly made proteins leave ribosomes and insert on rough ER ,where they may be modified

• If cell makes a lot of protein ,there is much ER• Smooth ER may contain many specialized

enzymes

Lysosomes

• Small organelles filled w/enzymes

• May digest or break down lipids,carbs,and proteins into small molecules that can be used by the rest of the cell

• Lysosomes remove “junk”,or used up organelles….very important that this aspect function occurs

Vacuoles

• Sac like structures that store water ,salts ,proteins, and carbs

• Plants may have a single large water filled vacuole

• Contractile vacuoles control water in paramecium

Mitochondria and Chloroplasts

• Most all eukaryotic cells contain mitochondria that convert chemical energy stored in food into compounds convenient for cell to use

• Mitochondria have an outer and inner membranes

• In humans,nearly all mitochondria comes from ovum(egg cell)

Chloroplasts

• Capture energy from sunlight and convert into chemical energy in photosynthesis

• Contain 2 membranes and chlorophyll

Organelle DNA

• In chloroplasts and mitochondria

• Small DNA molecules

• Maybe descendants of early prokaryotes

• ----Endosymbiotic theory says these prokaryoic ancestors developed a symbiotic relationship w/ early eukaryotes and resided within---evolving into mitochondria

Cytoskeleton• Network of protein filaments that help cell maintain

shape• Also involved in movement• MICROFILAMENTS are threadlike structures made of

a protein-actin….make a major network and a tough framework///allows amoebas and such to move

• MICROTUBULES-hallow structures made of proteins called tubulins—important in holding a cell’s shape----form a mitotic spindle in cell division/which helps separate chromosomes

• CENTRIOLES are microtubules near nucleus in animals and help organize cell division

• Microtubules also help make projections like cilia or flagella

Cell membrane

Endoplasmicreticulum

Microtubule

Microfilament

Ribosomes Michondrion

Section 7-2

Figure 7-7 Cytoskeleton

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