CELLS :CELLS


At the end of this chapter: :At the end of this chapter: Identify organelles of typical plant and animal cells from diagrams, photomicrographs and as seen under the light microscope using prepared slides and fresh material treated with an appropriate temporary staining technique Chloroplasts Cell membrane Cell wall Cytoplasm Cell vacuole Nucleus Identify the following organelles from diagrams and electronmicrographs Mitochondria robosomes


At the end of this chapter: :At the end of this chapter: State the functions of the organelles identified Compare the visible differences in the structure of an animal cell and a plant cell State in simple terms, the relationship between cell function and cell structure for the following: Absorption (root hair cell) Conduction and support (xylem) Transport of oxygen (red blood cell) Differentiate cell tissue, organ and organ system


Cells: the building blocks of life :Cells: the building blocks of life Cell is the building block in living things The cell contains information that is used as instructions for growth, development and functioning The cell is the basic unit of life; the chemical reactions of life takes place within the cell


Parts of a Cell :Parts of a Cell A cell consists of living matter It contains nucleus, cytoplasm and plasma membrane (cell surface membrane)


Nucleus :Nucleus Consists of Chromosomes that contain hereditary material DNA. The DNA carry codes containing information controlling all cell activities


Nucleus :Nucleus Nucleolus, a spherical structure that forms ribosomes


Nucleus :Nucleus Nuclear membrane (envelope), surrounds the nucleus and controls substances moving in and out of nucleus


Nucleus :Nucleus Functions: Controls activities in cell, e.g. chemical reactions in the cell Responsible for cell reproduction and continued survival of cell, passing genetic information (DNA) from one generation to another


Cytoplasm :Cytoplasm Consists of semi-fluid medium called cytosol surrounding the nucleus Function: It is the place where most life processes, e.g. chemical reactions occur in the cell Organelles, small structures that carry out particular functions each, are found in the cytoplasm


Plasma Membrane/ Cell Membrane :Plasma Membrane/ Cell Membrane Surrounds the cytoplasm Function: It is a partially permeable membrane – it only allows certain substances to move in and out of the cell Transfers chemical messages from outside the cell to the inside Keeps the contents of cell inside


Mitochondria :Mitochondria Found in the cytoplasm Function: Releases energy from food during cellular respiration Energy is released in the form of molecules called ATP (adenosine triphosphate)


Mitochondria :Mitochondria


Ribosome :Ribosome Can be found attached to membranes of structures (organelles) like extended nuclear membrane or in small groups suspended in the cytoplasm Function Makes proteins


exercise :exercise Workbook Page 5 Do question 3. 5 min


Vacuole :Vacuole A large central vacuole in a plant cell is a fluid-filled space enclosed by a membrane that pushes the cytoplasm to the edge of the cell Animal cells may contain many small, temporary vacuoles


Vacuole :Vacuole Function In plant cells Contains cell sap that consist of dissolved sugars, salts and amino acids In animal cells Stores sugars Transport substances from one part of the cell to another Contain digestive enzymes to digest bacteria coming into the cell Help cell get rid of excess water


Cell Wall :Cell Wall Only found in plant cells. Forms the outermost layer of the plant cell


Cell Wall :Cell Wall Functions: Protect cell from harmful external substances, eg, pressure from surrounding cells Maintain shape of the cell Prevent cell from bursting when there is too much water


Chloroplasts :Chloroplasts Found in plant cells Contains green pigments called chlorophyll, that’s why plant cells are green


chloroplasts :chloroplasts Function: For photosynthesis (making sugars, food from carbon dioxide, water and light energy)


Exercise :Exercise Workbook pg 6 question 5


Comparison between plant and animal cells :Comparison between plant and animal cells Similarities Both have a plasma membrane surrounding the cell Both have cytoplasm Both have nucleus each Both contain mitochondria and ribosome


Differences :Differences


Questions :Questions What are the differences between the plant cell and animal cell? Name some similarities between the plant and animal cell.


Specialised Cells, tissues & organs :Specialised Cells, tissues & organs Most cells, after growing and dividing, become specialised They do one particular job Have specific shapes


Specialised Cells, tissues & organs :Specialised Cells, tissues & organs Undergo chemical changes in their cytoplasm to help them carry out their functions The structures of these specialised cells are adapted to perform its particular function


Xylem Vessels :Xylem Vessels Function of the xylem Transport water and dissolved mineral salts up from the roots


Xylem vessels -- adaptation :Xylem vessels -- adaptation


Xylem vessels -- adaptation :Xylem vessels -- adaptation


Root hair cell :Root hair cell Function: To absorb water and mineral salts


Root hair cell :Root hair cell


Red blood cell :Red blood cell Red blood cells contain a red pigment called haemoglobin that binds to oxygen This enables red blood cells to transport oxygen


Red blood cells :Red blood cells


Questions :Questions What is the function of the xylem? What feature helps the xylem do its work? What is the function of the root hair cell? What is the function of the red blood cell?


Cells, tissues, organs and organ systems :Cells, tissues, organs and organ systems Cells which carry out the same specific activity is grouped together – tissue Examples Muscle cells make up muscle tissue. The tissue contract or relax to enable movement. Nerve tissue detect changes and pass messages within the body Epithelial tissue lines inner and outer surfaces in the body Connective tissue support and join other cells or structures in the body


Cells, tissues, organs and organ systems :Cells, tissues, organs and organ systems A group of tissue working together – organ Example: all the tissues in the stomach work together, making up the stomach organ


Cells, tissues, organs and organ systems :Cells, tissues, organs and organ systems A group of organs working together – organ system Example: the mouth, stomach and intestines are organs in the digestive system


Organ systems :Organ systems


Slide 45:Organelles makes up cells Cells makes up tissues Tissues makes up organs Organs makes up organ systems Organ systems makes up the organism


Slide 46:WB exercise Pg 12, Q 6