~Cell is the main unit of life
~Identifying and stating function of main organelles in cell like nucleus, nuclear membrane, chromatin, endoplasmic reticulum, cytoplasm, etc.
~Identify main organelles in diagrams
~Compare and contrast plant and animal cells
~explain how specialised cell structure is related to function
Cells
found in ALL living things and they come from pre-existing cells via cell division.
A cell is 3D and it can be cut longitudinally and laterally.
Definition: A cell is the smallest unit that is capable of performing life functions.
Some examples:
~Amoeba proteus
~Bacteria
~Nerve cell
 |
| A prokaryotic cell from http://library.thinkquest.org/C004535/media/prokaryote.gif |
2 types of cells
~ Prokaryotic
~ Eukaryotic
Prokaryotic
~Do not have organelles surrounded by membrane
~Few internal structures
~unicellular organisms belong in this category
Eukaryotic
~Contain organelles surrounded by membranes
~Most living organisms (multi-cellular) such as animal, plant, fungi belong in this category.
Parts of a cell
Cell wall
~Most commonly found in plant and bacteria cells (not in animal cells)
~Surrounds the cell membrane
~Rigid structure that maintains the shape, support and protects cells
~Permeable to small molecules and proteins only
~FULLY PERMEABLE
Cell membranes
~Selectively/Partially permeable membrane of cell that controls movement of substances in and out of cell
*Cell membrane is a phospolipid bilayer. This layer is made up by Hydrophilic
Nucleus
~Contains chromatin that controls cell activity
~Chromatin contains DNA (Deoxyribonucleic acid) which is genetic material
~DNA contain instructions for traits & characteristics and to carry out the cell's function
~Separated from cytoplasm by nuclear membrane
Cytoplasm
~Gel-like mixture
~surrounded by cell membrane
~contains organelles
Mitochondria
~"Powerhouse" of the cell
~Food that is eaten is transformed into energy (ATP--Adenosine5'-triphosphate) for cell and bodies.
(*ATP transports chemical energy in cells for metabolism)
Endoplasmic reticulum
~Interconnected network network of tubes of tubes and vesicles
~Synthesis (i.e. ) of proteins, fats, steroids
~Transports materials around cell
~Membrane bound organelle
2 Types
Smooth type (no ribosomes)
Rough type (ribosomes embedded in surface)
Ribosomes
~Small structures that are found in thousands in the cell (either floating throughout the cell or on rough endoplasmic reticulum)
~Make proteins (with the aid of mRNA)
Messenger sends proteins from nucleus via nuclear pores despite endoplasmic reticulum connection with nucleus
mRNA- Messenger RNA is made from DNA in chromatin which is sent to the ribosomes to be translated into proteins (comes from amino acids)
Golgi Apparatus& Bodies
Note: Apparatus and bodies can be used interchangeably. Apparatus is used when cut longitudinally and bodies used when cut laterally.
~Works with the Endoplasmic Reticulum
~Main aim is to process and package molecules such as proteins and fats made by cell
~Brings these products to the surface of the cell where they can be secreted
~Other secretions include hormones, antibodies and enzymes
Lysosome
It aids in digestion and defense in/for cell
~Contain digestive enzymes
~Digest excess or worn out organelles, food particles, or engulf bacteria or viruses
~Helps repair worn-out plasma membrane
*It repairs worn-out membranes by fusing with the membrane.
~They also provide sugars, amino acids and bases which are the foundation of macromolecules
~Cell breaks down if lysosome explodes.
*This is called necrosis, which occurs when one gets injuries.
*apoptosis is the more subtle version of necrosis, where it takes place in normal circumstances
Vacuoles
~Membrane-bound sacs for storage, digestion and waste removal
~Central large vacuoles help plant cells maintain shape
~In animal cells, vacuoles are small and numerous in number
~ Food vacuoles are formed by phagocytosis
*Phagocytosis on how the food vacuoles are formed:
When a food particle enters a cell, an organelle called the cytostome extends it "2 arms" around the particle like a membrane, thus forming a food vacuole.
Chloroplast
~Usually found in plant cells
~Contains green chlorophyll
~where photosynthesis takes place
~Converts light energy to chemical energy in glucose
The differences between Plant cells and Animal cells
Plant Cell VS. Animal Cell
~A central large vacuole ~Multiple vacuoles that are small
~Contains Chloroplasts ~ No chloroplasts present
~ Cellulose cell wall present ~ No cellulose cell wall present
~Regular shape ~ Does not have a regular shape
*In plant cells, since it mostly consists of fluids, the chloroplasts will move toward the sunlight at ALL times in what is called cytoplasmic streaming.
*In plant cells, since it mostly consists of fluids, the chloroplasts will move toward the sunlight at ALL times in what is called cytoplasmic streaming.
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