Cells, cells, cells

Cells Smallest living unit Most are microscopic

Review: Cell Theory The 3 Basic Components of the Cell Theory are: 1. All organisms are composed of one or more cells. (Schleiden & Schwann)( ) 2. The cell is the basic unit of life in all living things. (Schleiden & Schwann)( ) 3. All cells are produced by the division of preexisting cells. (Virchow)(1858)

Modern Cell Theory Modern Cell Theory contains 4 statements, in addition to the original Cell Theory: The cell contains hereditary information(DNA) which is passed on from cell to cell during cell division. All cells are basically the same in chemical composition and metabolic activities. All basic chemical & physiological functions are carried out inside the cells.(movement, digestion,etc) Cell activity depends on the activities of sub-cellular structures within the cell(organelles, nucleus, plasma membrane)

Two Basic Cell Types: Prokaryotic vs. Eukaryotic Cells

Two Basic Types Remember….cells are the basic unit of life for ALL living things. There are two basic types of cells: 1.Prokaryotic cells – found in bacteria 2.Eukaryotic cells – found in protists, fungi, plants and animals

Three Cellular Domains

Bacteria vs. Eukaryotes

Characteristics Shared Perform the same basic functions Surrounded by plasma membrane to control what enters and leaves the cell “Filled” with cytoplasm Contain ribosomes to make protein Contain DNA to give the general instructions for the cell’s life

What Makes Eukaryotic Cells Different? Much larger Much more complex Contain a true nucleus to house the genetic material (DNA) Linear DNA packaged into chromatin found inside the nucleus Contains specialized structures in the cytoplasm called organelles to carry out various functions Not all have a cell wall

Bacteria-Like Organelles (mitochondria and chloroplasts) Derived from symbiotic bacteria Ancient association Endosymbiotic theory – Evolution of modern cells from cells & symbiotic bacteria (live together)

Eukaryotic Cells

What Makes Prokaryotic Cells Different? Much smaller Less complex No true nucleus Circular DNA that is found in the cytoplasm No organelles found in the cytoplasm Surrounded by a cell wall

Prokaryotic Cell

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What does size have to do with it? Prokaryotic cells are much smaller than eukaryotic cells. Why? – Smaller surface area- to- volume allows nutrients to easily and quickly reach inner parts of the cell. – Eukaryotic cells are larger and can not pass nutrients as quickly. They require specialized organelles to: carry out metabolism provide energy transport chemicals throughout the cell

But….back to Eukaryotes Eukaryotes are characterized by their membrane – bound organelles. You need to know them!!!!

Organelles are membrane- bound cell parts Mini “organs” that have unique structures and functions Located in cytoplasm

Cell membrane – delicate lipid and protein skin (phospholipids) around cytoplasm – found in all cells Cell Structures

Phospholipids Polar: has an uneven distribution of charges – Hydrophilic head – Hydrophobic tail Interacts with water

Plasma Membrane

Movement Across the Plasma Membrane A few molecules move freely – Water, Carbon dioxide, Ammonia, Oxygen Carrier proteins transport some molecules – Proteins embedded in lipid bilayer – Fluid mosaic model – describes fluid nature of a lipid bilayer with proteins

Membrane Proteins 1. Channels or transporters – Move molecules in one direction 2. Receptors – Recognize certain chemicals

Membrane Proteins 3. Glycoproteins – Identify cell type 4. Enzymes – Catalyze production of substances

Nucleus – a membrane-bound sac evolved to store the cell’s chromosomes(DNA) – has pores: holes Organelles (continued)

Nucleolus – inside nucleus – location of ribosome factory – made of RNA Organelles (continued)

Mitochondrion – makes the cell’s energy – the more energy the cell needs, the more mitochondria it has Organelles (continued)

Ribosomes – build proteins from amino acids in cytoplasm – may be free-floating, or – may be attached to ER – made of RNA Organelles (continued)

Endoplasmic reticulum – may be smooth: builds lipids and carbohydrates – may be rough: stores proteins made by attached ribosomes Organelles (continued)

Golgi Complex – takes in sacs of raw material from ER – sends out sacs containing finished cell products Organelles (continued)

Lysosomes – sacs filled with digestive enzymes – digest worn out cell parts – digest food absorbed by cell Organelles (continued)

Centrioles – pair of bundled tubes – organize cell division Organelles (continued)

Cytoskeleton made of microtubules found throughout cytoplasm gives shape to cell & moves organelles around inside.

Structures found in plant cells Cell wall – very strong – made of cellulose – protects cell from rupturing – glued to other cells next door

Vacuole – huge water-filled sac – keeps cell pressurized – stores starch

Chloroplasts – filled with chlorophyll – turn solar energy into food energy

How are plant and animal cells different?

StructureAnimal cellsPlant cells cell membrane nucleus nucleolus ribosomes ER Golgi centrioles cell wall mitochondria choloroplasts One big vacuole cytoskeleton

StructureAnimal cellsPlant cells cell membraneYesyes nucleusYesyes nucleolusyes ribosomesyes ERyes Golgiyes centriolesyesno cell wallnoyes mitochondriayes choloroplastsnoyes One big vacuolenoyes cytoskeletonyesYes

Eukaryote cells can be multicellular The whole cell can be specialized for one job cells can work together as tissues Tissues can work together as organs

Advantages of each kind of cell architecture ProkaryotesEukaryotes simple, grow more quickly Complex; grow more slowly Single-celled organisms Single celled or multicellular all cells the sameSpecialized, different cells

Examples of specialized euk. cells Liver cell: specialized to detoxify blood and store glucose as glycogen.

Sperm cell: specialized to deliver DNA to egg cell

Mesophyll cell – specialized to capture as much light as possible – inside a leaf