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Cells*Check for notes in slideStandardsEssential QuestionsCell TheoryProkaryotes and EukaryotesProkaryotic CellsEukaryotic CellsPlants vs. AnimalsEukaryotic Cells (Plants)Cell AssessmentStandardsBenchmark:SC.912.L.14.1 Describe the scientific theory of cells (cell theory) and relate the history of its discovery to the process of science.SC.912.L.14.3 Compare and contrast the general structures of plant and animal cells.SC.912.L.14.2 Relate structure to function for the components of plant and animal cells.2Essential QuestionsBenchmark:What is the scientific theory of cells (cell theory) and what is the history of its discovery?What are the general structures of plant and animal cells and how are they the same and differentWhat are the functions of the different organelles in animal and plant cell?

3Cell Theory In 1665, Robert Hooke used an early compound microscope to look at a thin slice of corkIn 1675, Anton van Leeuwenhoek became the first person to observed living cellsIn 1831, Robert Brown identifies a structure within the cells that he terms the "nucleus." In 1838, Matthias Schleiden concludes that all plants are made up of cellsIn 1839, Theodor Schwann concludes that all animals are made up of cellsIn 1855, Rudolf Virchow stated that all cells come from the division of preexisting cells4Hooke called them cells because they reminded him of rooms in a monasteryHooke did not see living cells, he only saw parts of the cell walls of dead cellsAnton van Leeuwenhoek used a single-lens microscope to observe pond water and other thingsHe discovered that the water was filled with tiny, single-celled organisms, which he called animalculesFor hundreds of years, people had thought that organisms could come from nonliving matter, an idea known as spontaneous generationVirchows finding were not immediately accepted by the scientific community until Louis Pasteur confirmed his results in a separate experiment, while working with yeast cells, demonstrated that microorganisms can not arise from completely nonliving matterCell Theory All living things are composed of single cells or multiple cells.The cell is the basic unit of living things. All cells arise from pre-existing cells.

Mathias Schleidan Anton van LeeuwenhoekRobert HookeRobert Brown

Theodore SchwannRudolf Virchow

5Spontaneous generation, also called abiogenesis, is the belief that some living things can arise suddenly, from inanimatematter, without the need for a living progenitor to give them life. In 1966, Dr. Lynn Margulis formulated the endosymbiotic theory, which examines the cooperative existence of multiple prokaryotic organisms.

Prokaryotic & EukaryoticProkaryotic vs. Eukaryotic Cells

Cells fall into two broad categories, depending on whether they contain a nucleus Eukaryotes are cells that contain nuclei and membrane-bound organelles Eu- means true - karyote means nucleus

Prokaryotes are cells that do not contain nuclei and organelles membrane-bound Pro- means before - karyote means nucleusEukaryoteProkaryote

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Prokaryotic & Eukaryotic

EukaryoteProkaryoteNucleus is absentNo membrane-bound organellesMost 1-10 um in sizeEvolved 3.5 billion years agoOnly unicellular bacteria and archaebacteriaNucleus is presentMany membrane-bound organellesMany 2-1000um in sizeEvolved 1.5 billion years agoAll other cells (animal, plant, fungi, and protist)7Prokaryotic Cell Prokaryotic Cell Structures

Prokaryotes do not have a membrane-bound nucleus.

DNA is distributed loosely within the cell rather than in chromosomes.

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Eukaryotic Cell Eukaryotic Cell Structures

Structures within a eukaryotic cell that perform important cellular functions are known as organelles.

Cell biologists divide the eukaryotic cell into two major parts: the nucleus and the cytoplasm.

The cytoplasm is the portion of the cell outside the nucleus.9

Eukaryotic Cell Nucleus

The nucleus is the control center of the cell.

The nucleus contains nearly all the cell's DNA and with it the coded instructions for making proteins and other important molecules10The granular material in the nucleus is called chromatin.Chromatin consists of DNA bound to protein.When a cell divides, chromatin condenses to form chromosomes.Chromosomes contain the genetic information that is passed from one generation of cells to the next.Most nuclei also contain a nucleolus. The nucleolus is where the assembly of ribosomes begins.

Eukaryotic Cell Ribosomes

One of the most important jobs carried out in the cell is making proteins.

Proteins are assembled on ribosomes.

Ribosomes are small particles of RNA and protein found throughout the cytoplasm.

Ribosomes produce proteins by following coded instructions that come from the nucleus.

Cells that are active in protein synthesis are often packed with ribosomes11Eukaryotic Cell Endoplasmic Reticulum

Eukaryotic cells contain an internal membrane system called the endoplasmic reticulum, or ER.

The endoplasmic reticulum is where lipid components of the cell membrane are assembled, along with proteins and other materials that are exported from the cell.

RibosomesEndoplasmic Reticulum12There are two types of ERrough and smooth.The portion of the ER involved in protein synthesis is called rough endoplasmic reticulum, or rough ER.Ribosomes are found on the surface of rough ER.Rough ER is abundant in cells that produce large amounts of protein for export.

Smooth ER does not have ribosomes on its surface.Smooth ER contains collections of enzymes that perform specialized tasks, such as synthesis of membrane lipids and detoxification of drugs.

Eukaryotic Cell Golgi Apparatus

Proteins produced in the rough ER move into the Golgi apparatus.

The Golgi apparatus appears as a stack of closely apposed membranes

Golgi Apparatus

13The Golgi apparatus modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell.

From the Golgi apparatus, proteins are then shipped to their final destinations throughout the cell or outside of the cell.

Eukaryotic Cell Lysosomes

Lysosomes are small organelles filled with enzymes.

Lysosomes break down lipids, carbohydrates, and proteins into small molecules that can be used by the rest of the cell.

Lysosomes also break down organelles that have outlived their usefulness

14The Golgi apparatus modifies, sorts, and packages proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell.

From the Golgi apparatus, proteins are then shipped to their final destinations throughout the cell or outside of the cell.

Eukaryotic Cell Mitochondria

Nearly all eukaryotic cells contain mitochondria.Mitochondria convert the chemical energy stored in food into compounds that are more convenient for the cell to use.

Mitochondria15Mitochondria are enclosed by two membranesan outer membrane and an inner membrane. The inner membrane is folded up inside the organelle

Plants vs. Animal Cell

A plant cell has a cell wall for support and protection.

Animal cells don't have chloroplasts. Plant cells have thylakoids that are sites of photosynthesis chemical reactions.

Lysosomes usually not evident in plant cells.

16Plants vs. Animal Cell

Typical Animal CellTypical Plant Cell17Plants vs. Animal CellTypical Animal CellTypical Plant CellAnimal CellPlant CellNucleus:PresentPresentCilia:PresentIt is very rareShape:Round (irregular shape)Rectangular (fixed shape)Chloroplast:Animal cells don't have chloroplastsPlant cells have chloroplasts because they make their own foodCytoplasm:PresentPresentEndoplasmic Reticulum (Smooth and Rough):PresentPresentRibosomes:PresentPresentMitochondria:PresentPresentVacuole:One or more small vacuoles (much smaller than plant cells).One, large central vacuole taking up 90% of cell volume.Centrioles:Present in all animal cellsOnly present in lower plant forms.Plastids:AbsentPresentGolgi Apparatus:PresentPresentCell wall:AbsentPresentPlasma Membrane:only cell membranecell wall and a cell membraneMicrotubules/ Microfilaments:PresentPresentFlagella:May be found in some cellsMay be found in some cellsLysosomes:Lysosomes occur in cytoplasm.Lysosomes usually not evident.18

Eukaryotic Cell Chloroplasts

Plants and some other organisms contain chloroplasts.

Chloroplasts capture energy from sunlight and convert it into chemical energy in a process called photosynthesis.

Chloroplasts19In many plant cells there is a single, large central vacuole filled with liquid. The pressure of the central vacuole allows plants to support heavy structures such as leaves and flowers.

Eukaryotic Cell Vacuoles

Some cells contain saclike structures called vacuoles that store materials such as water, salts, proteins, and carbohydrates.

Vacuole20In many plant cells there is a single, large central vacuole filled with liquid. The pressure of the central vacuole allows plants to support heavy structures such as leaves and flowers. Vacuoles are also found in some unicellular organisms and in some animals.

Cell Assessment1. In 1675, Anton van Leeuwenhoek became the first person to observe living cells. He reported discovering "little animals" -- bacteria and protozoa.Which part of the cell theory is best supported by this discovery?A. All cells are animal or fungiB. All cells are the same microscopic size -10 micrometers.C. The cell is the basic unit of living things. D. All cells reproduce by meiosis.

2. There are many types of cellular life forms on Earth. But,