Presentation on theme: "Chapter 3. All Organisms are made up of cells Eukaryotes- Moth Juniper Protozoans Ciliates in water on plant Prokaryotes Bacteria in insect gut and on."— Presentation transcript:
All Organisms are made up of cells Eukaryotes- Moth Juniper Protozoans Ciliates in water on plant Prokaryotes Bacteria in insect gut and on surface of insect and tree
Cell theory All living organisms are made up of cells All cells come from other cells Theory refers to the body of knowledge that has been developed through scientific inquiry
Two Cell Categories ProkaryoteEukaryote Cell membrane Cytoplasm DNA (in a loop) Ribosomes (for creating proteins) Cell wall Very small DNA is loose in cytoplasm Cell membrane Cytoplasm DNA (in strands) Ribosomes Many other organelles Cell wall in plants Variable size – larger than prokaryotes Nucleus holds DNA
The organisms that cause colors in the hot springs of Yellowstone are single celled and have been around since the beginning of life on this planet. Would these organisms be prokaryotes or eukaryotes? Would their cells have a nucleus? A. Prokaryotes, yes B. Prokaryotes, no C. Eukaryotes, yes D. Eukaryotes, no meheat/yellowstone.html
Basic Cell Structures Cell Membrane Nuclear double membrane around nucleus Mitochondria for energy Processing and packaging organelles Lysosomes – digestion Cytoskeleton - support
Molecules Found in the cell Membrane Cholesterol increases membrane flexibility
Types of Membrane Proteins 1. Receptor proteins – Bind to external molecules which cause reactions in cell Ex. Target cells can detect hormones in blood – regulate development of secondary sexual characteristics 2. Recognition proteins Typically have attached carbohydrate chains Give the cell identity – other cells can recognize them Ex. During development cells interact & work together to develop structures. Recognition is essential. Ex. Autoimmune disease = faulty self-recognition
Types of Membrane Proteins 3. Transport proteins Move other molecules across the cell membrane Transmembrane proteins only Ex. Nerve cell fire – Na ions moved across 4. Enzymatic proteins Increase rate of chemical reactions associated with the cell membrane Ex. cAMP formation regulated – internal messenger created
Visual Examples Transport proteinsEnzymatic proteins
Why is the cell membrane considered a fluid mosaic? A. It’s primarily made up of water with dispersed fats and proteins in a mosaic pattern B. Proteins move back and forth through the membrane from inside to outside of the cell and back in a fluid mosaic pattern. C. It’s made up of several different types of molecules, like a mosaic, and many of those molecules float around in the lipid bilayer.
Cell Structure and Function Cells are factories Need raw materials to enter the cell Need to eliminate wastes Need to export products produced in the cell Need to keep up-to-date on needs of surrounding cells and tissues
Animation of endocytosis and exocytosis hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535 ::535::/sites/dl/free/ /120068/bio02. swf::Endocytosis%20and%20Exocytosis hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535 ::535::/sites/dl/free/ /120068/bio02. swf::Endocytosis%20and%20Exocytosis
Other means of movement Passive TransportActive Transport Requires no input of energy Diffusion Osmosis (diffusion of water across a membrane) Requires energy input to move molecules across the cell membrane or around in the cell Primary – uses ATP Secondary
Diffusion Key: Molecules tend to move from an area of high concentration to an area of low concentration When moving across a membrane – diffusion may be facilitated by a transport protein
Irrigation problems Irrigation can lead to a build up of soil salinity If soil develops a similar (or higher) salt content than the plant cells, water doesn’t flow as easily into plant roots. Soil salt concentrations make plants and soil more alike in fluid concentration (isotonic) - so water doesn’t flow across the cell membranes into the plant roots. Soil salinity creates drought like conditions in which plants can’t get water
The object depicted in the figure: A) is a bacterial cell. B) could be either a plant or an animal cell. C) is a ribosome. D) is an animal cell. E) is a plant cell.
Cell Wall Not found in animals A major component of the cell wall is the complex carbohydrate, Cellulose
If the concentrations of a particular molecule are equal on both sides of the membrane, facilitated diffusion will: A) insure that the molecule becomes concentrated outside the cell. B) insure that the molecule stays impermeable to the membrane. C) insure that the molecule becomes concentrated inside the cell. D) insure that the concentrations inside and outside the cell are both increased. E) be ineffective.
Connections Between Cells: 1. Tight Junctions > hold cells in place > keep fluids from passing around edges of cells blood brain barrier lining of gut
Connections Between Cells: 2. Desmosomes > throughout body
Connections Between Cells: 3. Gap Junctions >Allows small molecules, but not large proteins and organelles to move between cells.
Cell Size Chicken egg = mm (1mm = 1/1000 m) Paramecium caudatum = 60X 230 um (1 um = 1/1000 mm) Red blood cell = um Bacteria um Why not bigger?
What limits the size of cells? Much of what occurs in a cell depends on the movement of materials in and out of the cell through the plasma membrane Rate of production and waste removal is dependent on cell volume Rate of movement across the membrane depends on surface area of cell As cell size increases, volume increases as a cubed unit while surface area as a square unit.
Surface to volume ratio Radius1 cm2 cm3 cm Surface area (cm 2 ) Volume (cm 3 ) SA/V
Nucleus and chromosomes
Cytoskeleton Made up of protein fibers that can expand, contract, move past one another.
Microfilaments underlie the cell membrane and cytoskeletal elements can break down and reform to allow changing shape in Amoeba.
Mitochondria – have own DNA!
Mitochondria con’t Number in a cell may vary Cells with high energy demands like muscles have more than other cells Process known as aerobic respiration (Kreb cycle & electron transport phosphorylation) takes place here. Sugar (C 6 H 12 O 6 ) + 6H 2 O + 6O 2 => 6 CO water (H 2 O) + Energy Breaks down sugar to release the energy in the chemical bonds Oxygen is used and Carbon dioxide is a waste biproduct.
Chloroplasts Only in Plant Cells and Single-celled Algae Have own DNA! Similar in some ways to bacteria that do photosynthesis – especially DNA
Evolution of Eukaryote Cells
Lysosomes – Waste removal Up to 50 different types of enzymes!
Cells can be Single-celled Organisms Euglena can engulf other organisms or do photosynthesis to get food for building blocks and energy. Eyespot Flagellum Contractile Vacuole
Cells Specializations Within a Multicellular Organism All cells have the same genetic material. Cells specialize because some genes are turned off and others are turned on. Ex. Lining of small intestine Ex. Nerve cell
Design Organelle Analogies Analogy Includes similes and metaphores Similes compare things using words “as” or “like” Ex. You are as stubborn as a mule. Ex. Life is like a box of chocolates. Metaphores compare 2 unlike things for secondary meaning Ex. The gum was bursting with flavor. Ex. The relationship between them began to thaw.
The organelle in the figure is found in: A) animals only. B) plants only. C) plants, animals, and bacteria. D) plants and animals. E) bacteria only. What is it?
The lysosomes in a human cell contain approximately ________ different type(s) of digestive enzymes. A) 1 B) 500 C) 10 D) 4 E) 50
According to the theory of endosymbiosis, the origin of chloroplasts probably involved: A) the formation of cell walls around the photosynthetic pigments. B) the formation of colonies of cyanobacteria. C) the engulfing of small photosynthetic prokaryotes by larger cells. D) the accumulation of free oxygen in ocean waters. E) All of the above are correct.