RAYAT SHIKSHA’S SANSTHA’S KANYA VIDYALAYA DEHU

Chapter 5 Std : 9 Cells : basic units of structure & function of living things

Introduction to Cell Theory History of Scientists: 1665: Robert Hooke coins the term "cell" to describe chambers in cork Anton Von Leeuwenhoek perfects techniques for grinding microscope lens to make the first microscope 1674: http://inventors.about.com/library/inventors/blmicroscope.htm http://inventors.about.com/library/inventors/blroberthooke.htm Mathais Schleiden concluded that plants are composed of cells 1838: Theodore Schwann concluded that animals are composed of cells 1839:

Robert Hooke Coined the term “cell”

Anton van Leeuwenhoek First compound light microscope

Matthias Schlieden All plants are made of cells

Theodor Schwann All animals are made of cells

Rudolf Virchow Cells can only arise from pre-existing cells

Main Ideas of Cell Theory Those early scientists did experiments on living things and developed CELL THEORY Main Ideas of Cell Theory All living things are made of one or more cells 1) Cells are the basic units of structure & function of living things 2) All cells come from existing cells 3)

What are cells made of? Cells are mostly water. The rest of the present molecules are: protein nucleic acid carbohydrate lipid other

What are cells made of? By elements, a cell is composed of: 60% hydrogen 25% oxygen 10% carbon 5% nitrogen

Special Cell Process: There are approx. 100 trillion cells in the human body 100,000,000,000,000 Cells need certain substances to stay alive ANSWER: Osmosis Diffusion QUESTION: How do they get these substances?

Rules of Diffusion & Osmosis All substances that enter or leave a cell must cross its surface Small cells function better than large cells WHY? … because substances do not have to travel as far to reach the center of small cells So, the larger the cell…the longer it takes to cross it

Osmosis- the movement of water across the cell membrane important because cells are surrounded by water molecules the number of H2O molecules inside and outside the cell must be almost equal. when the molecules are even throughout a space Equilibrium- the process of osmosis allows this balance to happen

Diffusion Diffusion – the movement of particles from an area of high concentration to an area of low concentration. http://cui.unige.ch/~chopard/CA/Animations/Diffusion/anim-diffusion.gif

Example: like a big plastic bag with tiny holes in it CELL MEMBRANE holds the cell together keeps all of the pieces (like the organelles and the cytoplasm) inside the cell controls what goes in and out of the cell Example: like a big plastic bag with tiny holes in it

How does the cell membrane work? Has 2 layers of MOLECULES = BILAYER Bi means two The layers are made up of molecules called phospholipids **THINK OF a sandwich with two pieces of bread and some stuffing on the inside

Cell Membrane: PHOSPHOLIPIDS One end of the molecule is “afraid” of the water and one end “loves” being in the water. Proteins are stuck inside the membrane Proteins are across the bilayer and make the holes that let ions and molecules in and out of the cell

CYTOPLASM Protoplasm- everything inside the cell membrane Cytoplasm- everything inside the cell membrane & outside of the nucleus except the cell’s nucleus Cytosol: Mostly H2O Contains organelles Contains salts, dissolved gasses & nutrients

CYTOPLASM cytoplasm

CYTOSKELETON Chief functions include: movement of material through the cell for stuff not diffusion or osmosis maintaining the shape of the cell keeping the cell from getting smashed

The Organelles -nucleus -cytoplasm -nucleolus -cytoskeleton -cell membrane -vacuole -mitochondria -chloroplast -golgi Apparatus -centrioles -lysosomes -ribosomes -endoplasmic reticulum(ER) *Rough ER & Smooth ER

Nucleus The “brain” of the cell Controls all of the cellular activities DNA is inside the nucleus

Nucleus are found inside the nucleus CHROMOSOMES- carry the information that determines what traits a living thing will have Chromosomes – http://www.bioethics.org.nz/publications/human-genes-discussion-jan04/html/page4.html

NUCLEOLUS The dark area in the nucleus Like a tiny nucleus inside the nucleus.

Endoplasmic Reticulum also known as the “ER” it is an organelle inside the cell that is made up of membranes that are in the CYTOPLASM of the cell There are two different Smooth ER Rough ER

Smooth ER Main function is to collect, maintain & transport things Shaped slightly tubular Creates steroids Stores Ions for the cell to keep nutrients balanced

Rough ER It has bumps all over it giving it a “rough” appearance Bumps are called RIBOSOMES ER collects the proteins (built by the ribosomes) and creates a bubble around them VESICLE- is formed when the ER pinches off a part of its membrane

Secretion Exocytosis The release of intracellular molecules (hormones or proteins) EXOCYTOSIS-

http://www.science.siu.edu/plant-biology/PLB117/JPEGs%20CD/0073.JPG

GOLGI APPARATUS Also called the Golgi Complex It is made up of a stack of flattened out sacs …like a loose stack of pancakes WHAT DOES IT DO? 1) it takes simple molecules and combines them to make larger molecules. 2) takes those larger molecules and puts them into packs called GOLGI VESICLES

LYSOSOMES (primarily animal) They combine with the food taken in by the cell The enzymes in the lysosome bond to food & digest it (acidic interior) Next…smaller molecules are released which are absorbed by the mitochondria

LYSOSOMES When an organelle no longer works, the lysosome will attach itself to it and break it down like food (kind of like a cannibal) Chemicals can then be reabsorbed or excreted Lysosomes can also destroy the cell if it breaks open accidentally “Suicide Sacs” UV light damages lysosome membrane The enzymes inside the lysosome spread throughout the cell and digest it -

Mitochondria Mito = Mighty / Power The Power-House of the cell They break down food molecules so the cell has the energy to live If a cell needs a lot of energy…it will have more mitochondria vilenski.org/science/safari/ cellstructure/mito.html

The Mitochondria structure has three main parts: OUTER MEMBRANE: covers the mitochondria INNER MEMBRANE: folds many times to increase the surface area because chemical reactions (glycolysis) occur here http://micro.magnet.fsu.edu/cells/animals/images/mitochondria.jpg So…the more space it has the more energy it can create

MATRIX: a fluid that has water and proteins all mixed together (like a solution) The proteins take the food molecules in and combine them with Oxygen to release the energy http://cwx.prenhall.com/horton/medialib/media_portfolio/text_images/FG01_15-03UN.JPG

VACUOLE Vacuoles are “bubbles” that float in the cell Vacuoles are more important to the survival of plant cells than they are to animal cells

VACUOLE: STORAGE IN PLANT CELLS Vacuoles in plants support structure Vacuoles hold onto things that the cell might need…like a backpack There are some vacuoles that hold onto waste products, similar to having a big septic tank Storing waste products protects the cell from contamination

VACUOLE CONT’D So, when there is no water…the vacuole shrinks and the cell wall is the only thing holding the plant together.

You will know that a plant's vacuoles are shrinking when you see the plant begin to droop over HOLDING UP THE WALLS

Turgor Pressure- force exerted by the water entering (osmosis) the vacuole, which then swells exerting internal force on the cell wall Causes “rigidity” so the plant my increase by stacking cells

SOLAR energy radiated from the sun is captured by plants(chloroplast) Then it is instantaneously changed into ELECTRICAL energy Then packaged as CHEMICAL energy Chloroplast http://fig.cox.miami.edu/Faculty/Dana/chloroplast1.jpg

Chloroplast photosynthesis takes place inside the chloroplast the process in which plant use water, carbon dioxide, and energy form the sun to make food Photosynthesis-

Chloroplast No energy transformation is 100% efficient Not all the solar energy captured is converted to electrical and then chemical energy. Some of it gets lost as heat or other forms of energy (light) fig.cox.miami.edu/Faculty/ Dana/105F00_11.html

Ribosomes small dot-like structures in cells they are often associated with forming rough ER Ribosomes are the site of protein synthesis in cells they are made in the nucleus of the cell A ribosome can make the average protein in about one minute

Ribosome Structure Ribosomes are made up of proteins and ribonucleic acid(RNA) These molecules are arranged into two subunits These subunits are attached to each other and together form the entire ribosome When viewed through a light microscope the ribosomes appear as dots

Types of Cells: Eukaryotic Unicellular Protists Multicellular Fungi Plants Animals Prokaryotic Bacteria Archaea

Eukaryotic Characteristics Unicellular (Protists) Multicellular (fungi, plants, animals) Membrane bound Nucleus Contains Organelles Linear DNA

Eukaryotic Cell

Prokaryotic Characteristics Unicellular (some multicellular in very rare cases) Lacks a membrane bound nucleus Lacks membrane bound organelles Has a cell membrane (cell wall) Has ribosomes (protein production) Circular DNA

Prokaryotic Cell

THANK YOU BY:SUCHETA KHINDKAR