Basic Structure of a Cell

History of Cell Theory 1850 – Rudolf Virchow mid 1600s – Anton van Leeuwenhoek Improved microscope, observed many living cells mid 1600s – Robert Hooke Observed many cells including cork cells Named the cell 1850 – Rudolf Virchow Proposed that all cells come from existing cells

SCI.9-12.B-2.1 - [Indicator] - Recall the three major tenets of cell theory (all living things are composed of one or more cells; cells are the basic units of structure and function in living things; and all presently existing cells arose from previously existing cells).

SCI.9-12.B-2 - [Standard The student will demonstrate an understanding of the structure and function of cells and their organelles.]

*Cell Theory All organisms consist of 1 or more cells. Cell is the smallest unit of life. All cells come from pre-existing cells.

Observing Cells (4.1) Light microscope Can observe living cells in true color Magnification of up to ~1000x Resolution ~ 0.2 microns – 0.5 microns

Observing Cells (4.1) Electron Microscopes Preparation needed kills the cells Images are black and white – may be colorized Magnifcation up to ~100,000 Transmission electron microscope (TEM) 2-D image Scanning electron microscope (SEM) 3-D image

SEM TEM

*Introduction to Cells Cells are the basic units of organisms Cells can only be observed under microscope Basic types of cells: Bacterial Cell Animal Cell Plant Cell copyright cmassengale

copyright cmassengale *Number of Cells Organisms may be: Unicellular – composed of one cell Multicellular- composed of many cells that may organize copyright cmassengale

*Cells May be Prokaryotic or Eukaryotic Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles Eukaryotes include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals)

SCI.9-12.B-2.3 - [Indicator] - Compare the structures and organelles of prokaryotic and eukaryotic cells.

*Prokaryotes Nucleoid region contains the DNA Cell membrane & cell wall Contain ribosomes (no membrane) to make proteins in their cytoplasm Only example is bacteria

*Eukaryotic Cell Contain 3 basic cell structures: Nucleus Cell Membrane Cytoplasm with organelles

Video clip about pro vs eu https://www.youtube.com/watch?v=ss19u6vJNNQ copyright cmassengale

Two Main Types of Eukaryotic Cells Animal Cell Plant Cell

Organelles Very small size Can only be observed under a microscope Have specific functions Found throughout cytoplasm

How small is a cell? http://learn.genetics.utah.edu/content/cells/scale/

SCI.9-12.B-2.2 - [Indicator] - Summarize the structures and functions of organelles found in a eukaryotic cell (including the nucleus, mitochondria, chloroplasts, lysosomes, vacuoles, ribosomes, endoplasmic reticulum [ER], Golgi apparatus, cilia, flagella, cell membrane, nuclear membrane, cell wall, and cytoplasm).

Nucleolus Chromatin Nuclear membrane CYTOSKELETON RIBOSOMES ROUGH ER MITOCHONDRION SMOOTH ER CENTRIOLES GOLGI BODY LYSOSOME PLASMA MEMBRANE Fig. 4-15b, p.59

Organelles Found in Cells Examples of Organelles include: Endoplasmic reticulum (rough & smooth) – canals for movement Golgi Bodies – wrap & export proteins Nucleolus – makes ribosomes Lysosomes – digests & gets rid of wastes Ribosomes – makes proteins

*Golgi Bodies Stacks of flattened sacs Have a shipping side & a receiving side Receive & modify proteins made by ER Transport vesicles with modified proteins pinch off the ends Transport vesicle

*Lysosome Contain digestive enzymes Break down food and worn out cell parts for cells Programmed for cell death (lyse & release enzymes to break down & recycle cell parts)

*Control Organelle Nucleus Controls the normal activities of the cell Contain the DNA Bounded by a nuclear membrane Contains chromosomes

More on the Nucleus Nucleus Each cell has fixed number of chromosomes that carry genes Genes control cell characteristics

*Nucleolus Cell may have 1 to 3 nucleoli Inside nucleus Disappears when cell divides Makes ribosomes that make proteins

SCI.9-12.B-2.2 - [Indicator] - Summarize the structures and functions of organelles found in a eukaryotic cell (including the nucleus, mitochondria, chloroplasts, lysosomes, vacuoles, ribosomes, endoplasmic reticulum [ER], Golgi apparatus, cilia, flagella, cell membrane, nuclear membrane, cell wall, and cytoplasm).

*Smooth & Rough Endoplasmic Reticulum Smooth ER lacks ribosomes & makes lipids also detoxifies poisons from medicine and alcohol Rough ER has ribosomes on its surface & makes proteins to EXPORT

Cell Powerhouse *Mitochondrion (mitochondria ) Rod shape *Site of Cellular respiration

* Mitochondria Active cells like muscles have more mitochondria *Burn sugars to produce energy ATP

Cytoskeleton

Cytoskeleton A network of fibrous proteins that help maintain cell shape, support the cell and help with movement.

Cytoskeleton All are proteins Function Structure gives cells internal organization, shape, and ability to move Structure Interconnected system of microtubules, microfilaments, and intermediate filaments (animal only) All are proteins

Cilia and flagella - structures for cell movement

SCI.9-12.B-2.2 - [Indicator] - Summarize the structures and functions of organelles found in a eukaryotic cell (including the nucleus, mitochondria, chloroplasts, lysosomes, vacuoles, ribosomes, endoplasmic reticulum [ER], Golgi apparatus, cilia, flagella, cell membrane, nuclear membrane, cell wall, and cytoplasm).

*Cell or Plasma Membrane Cell membrane Living layer Controls the movement of materials into and out of the cell Selectively permeable

Read this! Proteins and carbohydrates on the outside of cells give cells their “identity.” This lets the immune system know that the cells belong in that body. Transplanted organs are often rejected by the body because the immune system recognized the proteins and carbs as not belonging to that person’s body.

SCI.9-12.B-2.2 - [Indicator] - Summarize the structures and functions of organelles found in a eukaryotic cell (including the nucleus, mitochondria, chloroplasts, lysosomes, vacuoles, ribosomes, endoplasmic reticulum [ER], Golgi apparatus, cilia, flagella, cell membrane, nuclear membrane, cell wall, and cytoplasm).

Cytoplasm of a Cell Cytoplasm Jelly-like substance enclosed by cell membrane Provides a medium for chemical reactions to take place

*More on Cytoplasm Cytoplasm Contains organelles to carry out specific jobs Examples: chloroplast & mitochondrion