Cells and its Organelles

Cells and its organelles : Cells and its organelles Brief description of cell organelles and their functions-------------

Structural difference b/n plant and animal cell : Structural difference b/n plant and animal cell

CELL WALL : protects the cell gives shape is made of cellulose A cell wall is found in plants, algae, fungi, & most bacteria. CELL WALL

Slide 4 : Cell wall & Plasmodesmata- In addition to cell membranes, plants have cell walls. Cell walls  provide protection and support for plants.   Unlike cell membranes materials cannot get through cell walls. This would be a problem for plant cells if not for special openings called plasmodesmata. These openings are used to communicate and transport materials between plant cells because the cell membranes are able touch and therefore exchange needed materials.

Slide 5 : One of the most important distinguishing features of plant cells is the presence of a cell wall, a which serves a variety of functions.   The cell wall protects the cellular contents; gives rigidity to the plant structure; provides a porous medium for the circulation  and distribution of water, minerals, and other small nutrient molecules; and contains specialized molecules that regulate growth and protect  the plant from disease. A structure of great tensile strength, the cell wall is formed from fibrils of cellulose molecules, embedded in a  water-saturated matrix of polysaccharides and structural glycoproteins.        .

CELL MEMBRANE : CELL MEMBRANE Outer covering, protective layer around ALL cells For cells with cell walls,the cell membrane is inside the cell wall Allows food, oxygen, & water into the cell & waste products out of the cell.

CYTOPLASM : CYTOPLASM gelatin-like inside cell membrane constantly flows aka protoplasm

Slide 8 : Cytosol Cytoplasm refers to the jelly-like material with organelles in it. If the organelles were removed, the soluble part that would be left is called the cytosol. It consists mainly of water with dissolved substances such as amino acids in it.

CYTOSKELETON : CYTOSKELETON scaffolding-like structure in cytoplasm helps the cell maintain or change its shape made of protein

Slide 10 : The fluid mosaic model describes the structure of the plasma membrane.Different kinds of cell membrane models have been proposed, and one of the most useful is the Fluid-mosaic model. In this model the membrane is seen as a bilayer of phospholipids in which protein molecules are embedded.

Slide 11 : Channels/pores- A channel in the cell's plasma membrane. This channel is made up of certain proteins whose function is to control the movement of food and water into the cell. These channels are made up of certain proteins.

NUCLEUS : NUCLEUS Directs all cell activities Contains instructions for everything the cell does These instructions are found on a hereditary material called DNA Usually the largest organelle

NUCLEAR MEMBRANE : NUCLEAR MEMBRANE separates nucleus from cytoplasm controls movement of materials in & out of nucleus

NUCLEOLUS : NUCLEOLUS Aka “little nucleus” Found in the nucleus

CHROMATIN : CHROMATIN contains genetic code that controls cell made of DNA & proteins

Slide 16 : Endoplasmic reticulum (ER)- It is a network of membranes throughout the cytoplasm of the cell. There are two types of ER. When ribosomes are attached it is called rough ER and smooth ER when there are no ribosomes attached.  The rough endoplasmic reticulum is where most protein synthesis occurs in the cell. The function of the smooth endoplasmic reticulum is to synthesize lipids in the cell. The smooth ER is also helps in the detoxification of harmful substances in the cell.

Slide 17 : Golgi complex- It is organelle in the cell that is responsible for sorting and correctly shipping the proteins produced in the ER.  Just like our postal packages which should have a correct shipping address, the proteins produced in the ER, should be correctly sent to their respective address.  In the cell, shipping and sorting done by the Golgi complex. It is a very important step in protein synthesis. If the Golgi complex makes ]a mistake in shipping the proteins to the right address, certain functions in the cell may stop.

Slide 18 : Vacuoles and vesicles are storage organelles in cells. Vacuoles are larger than vesicles. Either structure may store water, waste products, food, and other cellular materials. In plant cells, the vacuole may take up most of cells volume. The membrane surrounding the plant cell vacuole is called the tonoplast.

Slide 19 : Lysosomes function as the cell's recycling compartment. Lysosomes receive cellular and endocytosed proteins and lipids that need digesting. The metabolites that result are transported either by vesicles or directly across the membrane.

Slide 20 : Flagella may extend to the rear of a cell and push it forward by snakelike wriggling, or stick out in front and draw it along. We humans possess both flagella and cilia Each sperm cell is propelled by a trailing flagellum that acceleratesthe little torpedo forward in its quest to fertilize an egg. cilia are thread-like projections of certain cells that beat in a regular fashion to create currents that sweep materials along

Slide 21 : Chloroplast- The cell organellein which photosynthesis takes place. In this organelle the light energy of the sun is converted into chemical energy.  Chloroplasts are found only in plant cells not animal cells. The chemical energy that is produced by chloroplasts is finally used to make carbohydrates like starch, that get stored in the plant. Chloroplasts contain Tinypigments called chlorophylls.Chlorophylls are responsible for trapping the light energy from the sun.

Slide 22 : Ribosomes- Organelles that help in the synthesis of proteins. Ribosomes are made up of two parts, called subunits.  They get their names from their size. One unit is larger than than the other so they are called large and small subunits.  Both these subunits are necessary for protein synthesis in the cell. When the two units are docked together with a special information unit called messenger RNA, they make proteins.  Some ribosomes are found in the cytoplasm, but most are attached to the endoplasmic reticulum. While attached to the ER, ribosomes make proteins that the cell needs and also ones to be exported from the cell for work elsewhere in the body.

Slide 23 : Mitochondria are membrane-enclosed organelles distributed through the cytosol of most eukaryotic cells. Their main function is the conversion of the potential energy of food molecules into ATP. Every type of cell has a different amount of mitochondria.. There are more mitochondria in cells that have to perform lots of work, for example- your leg muscle cells, heart muscle cells etc. Other cells need less energy to do their work and have less mitochondria.Mitochondria have: an outer membrane that encloses the entire structure an inner membrane that encloses a fluid-filled matrix between the two is the intermembrane space the inner membrane is elaborately folded with shelflike cristae projecting into the matrix.