Notes: Cells Notes: Cells

The Cell Theory The Cell Theory 1. All living things are composed of cells. 2. Cells are the basic units of structure and function in living things. 3. New cells are produced from existing cells.

Cells Timeline Robert Hooke (1665): studied cork; saw tiny, regular shaped “boxes”; called them cells. Robert Hooke (1665): studied cork; saw tiny, regular shaped “boxes”; called them cells. Matthais Schleiden (1838) Matthais Schleiden (1838) All plants are made of cells All plants are made of cells Theodor Schwann (1839) Theodor Schwann (1839) All animals are made of cells All animals are made of cells Rudolf Virchow (1855) Rudolf Virchow (1855) Concluded all cells come from other cells Concluded all cells come from other cells Go to Section:

Cell Types There are two categories of cells: 1.Eukaryotic – Have a nucleus and membrane bound organelles Examples include plants, animals, fungi, and protists.

Cell Types There are two categories of cells: 2. Prokaryotic – Have no nucleus and no membrane bound organelles Bacteria are an example.

Prokaryotic vs. Eukaryotic Cells

Two specific organelles have made Eukaryotic cells be the most successful…. Mitochondria Mitochondria Consumes O 2 to make energy (ATP) from sugar (food) Consumes O 2 to make energy (ATP) from sugar (food) Chloroplast Chloroplast Consumes H 2 O and CO 2 as it takes in energy from the sun to make sugar (food)

But guess what…. These two organelles (mitochondria and chloroplast) are thought once be their own prokaryotic cell living inside a larger host cell…….these “prokaryotes” provided nutrients/oxygen to the host and in turn got a safe place to live. These two organelles (mitochondria and chloroplast) are thought once be their own prokaryotic cell living inside a larger host cell…….these “prokaryotes” provided nutrients/oxygen to the host and in turn got a safe place to live. ENDOSYMBIOTIC THEORY

Since BOTH these organelles have their OWN DNA even more support that they….. Chloroplast have DNA Chloroplast have DNA Mitochondria have DNA Mitochondria have DNA

Endosymbiotic theory for dummies….. 4A7R2xU 4A7R2xU

Two types of Eukaryotic cells are: PLANT Cells PLANT Cells ANIMAL Cells ANIMAL Cells

Organelles in Plant vs. Animal Cells Plant Cells: 1. Chloroplasts 2. Cell wall 3. Vacuoles are much larger Animal Cells: 1. Lysosomes 2. Vacuoles are much smaller

Plant Cells Characteristics of Plant Cells: 1.Rectangular or square shape 2.Cell wall that is composed mostly of cellulose Cell Wall Nucleus Chloroplast

Animal Cells Notice the circular shape of animal cells. Not all animals cells have this shape, but it is more common than not. Nucleus Cell membrane

Organelles Organelles - Specialized structures in a cell that have a specific function. Organelles - Specialized structures in a cell that have a specific function.

Cell Membrane Cell Membrane Cell Membrane - Thin, flexible barrier around a cell; regulates what enters and leaves the cell (selectively permeable) Cell Membrane - Thin, flexible barrier around a cell; regulates what enters and leaves the cell (selectively permeable) Prokaryote Eukaryote Plant Animal

Cell Wall Cell Wall - Strong supporting layer around the cell membrane in plants, algae, and some bacteria that supports and shapes Cell Wall - Strong supporting layer around the cell membrane in plants, algae, and some bacteria that supports and shapes Made of CELLULOSE Made of CELLULOSE in plants,chitin, etc. depending on the organism. Prokaryote Eukaryote Plant

Nucleus Nucleus – Contains DNA (genetic information) and instructions for the productions of proteins and other cellular processes Nucleus – Contains DNA (genetic information) and instructions for the productions of proteins and other cellular processes Bounded by the nuclear envelope Bounded by the nuclear envelope Eukaryote Plant Animal

Nuclear Envelope Nuclear Envelope – Layer surrounding the nucleus of a cell covered in nuclear pores, which allow material to move into and out of nucleus Nuclear Envelope – Layer surrounding the nucleus of a cell covered in nuclear pores, which allow material to move into and out of nucleus

Nucleolus Nucleolus - Small, dense region within most nuclei in which the assembly of ribosomes begins (ribosomal RNA) Nucleolus - Small, dense region within most nuclei in which the assembly of ribosomes begins (ribosomal RNA) Eukaryote Plant Animal

Cytoskeleton Cytoskeleton - Internal structure of some cells that gives shape and is involved in movement Cytoskeleton - Internal structure of some cells that gives shape and is involved in movement Consists of Consists of 1. Microtubules- hollow and tube like; made of proteins called tubulins 2. Microfilaments- thin, thread like; made of protein called actin. Prokaryote Eukaryote Plant Animal

Centrioles Centrioles - Paired structures located in the cytoplasm of animal cells near the nucleus give rise to the spindle during cell division. Centrioles - Paired structures located in the cytoplasm of animal cells near the nucleus give rise to the spindle during cell division. Eukaryote Animal

Vacuoles Vacuoles – Sac like structure that stores water, salts, proteins, and carbohydrates. Vacuoles – Sac like structure that stores water, salts, proteins, and carbohydrates. Plants contain large central vacuoles Plants contain large central vacuoles Animals contain many smaller vacuoles Animals contain many smaller vacuoles Eukaryote Plant Animal

Cytoplasm Cytoplasm – The fluid matrix that consists of water and dissolved substances such as proteins and nutrients. (cytosol) Cytoplasm – The fluid matrix that consists of water and dissolved substances such as proteins and nutrients. (cytosol) Prokaryote Eukaryote Plant Animal

Ribosomes Ribosomes – small particles of rRNA; Ribosomes – small particles of rRNA; Where proteins are assembled Where proteins are assembled Found throughout the cytoplasm and on the rough ER. Found throughout the cytoplasm and on the rough ER. Prokaryote Eukaryote Plant Animal

Endoplasmic Reticulum Endoplasmic Reticulum (ER) - Internal membrane system in cells in which lipid components of the cell membrane are assembled and some proteins are modified Endoplasmic Reticulum (ER) - Internal membrane system in cells in which lipid components of the cell membrane are assembled and some proteins are modified

Rough Endoplasmic Reticulum Rough ER- The portion of the ER involved in the synthesis of proteins Rough ER- The portion of the ER involved in the synthesis of proteins Given this name because of the ribosomes found on its surface. Given this name because of the ribosomes found on its surface. Abundant in cells that produce large amounts of protein for export. Abundant in cells that produce large amounts of protein for export. Eukaryote Plant Animal

Smooth Endoplasmic Reticulum Smooth ER – Endoplasmic reticulum where ribosomes are not found on its surface Smooth ER – Endoplasmic reticulum where ribosomes are not found on its surface Involved in: Involved in: 1. synthesis of lipids for cell membranes membranes 1. detoxification of drugs (in liver cells) Eukaryote Plant Animal

Golgi Apparatus Golgi Apparatus - Modify, sort, and package proteins (from the ER) into vesicles for storage in the cell or secretion outside the cell. Golgi Apparatus - Modify, sort, and package proteins (from the ER) into vesicles for storage in the cell or secretion outside the cell. Finishing touches are put on proteins before they are ready to leave the “factory.” Finishing touches are put on proteins before they are ready to leave the “factory.” Eukaryote Plant Animal

Chloroplasts Chloroplasts - Organelles that capture the energy from sunlight and convert it into chemical energy in food (photosynthesis). Chloroplasts - Organelles that capture the energy from sunlight and convert it into chemical energy in food (photosynthesis). Like a solar power plant. Like a solar power plant. Contain the green pigment chlorophyll. Contain the green pigment chlorophyll. Prokaryote Eukaryote Plant

Mitochondria Mitochondria - Organelles that convert the chemical energy stored in food (glucose) to make energy molecules for cells Mitochondria - Organelles that convert the chemical energy stored in food (glucose) to make energy molecules for cells Eukaryote Plant Animal

Lysosomes Lysosomes – Vesicles from a Golgi that contain digestive enzymes that Lysosomes – Vesicles from a Golgi that contain digestive enzymes that 1. Digest/break down lipids, carbohydrates, and proteins into small molecules that can be used by the cell 2. Break down/get rid of waste or worn out cell parts Eukaryote Animal