Showing posts with label The cell. Show all posts
Showing posts with label The cell. Show all posts

Thursday, 15 October 2015

Cell Diversity


 Cell Diversity


By Naomi Keddy

Tissue is a group of similar cells modified to carry out the same function
Types of plant tissues:
·         Dermal tissue: surrounds and protects the plant. Eg Epidermis
·         Vascular Tissue: transports minerals in the plants. Eg Xylem; transports water and dissolved minerals and Phloem transports food.
Four Types of animal tissues:
·         Connective tissue: consists of cells dispersed in a matrix and surrounds its and supports the body.
Types of connective tissue
-Dense Connective tissue
-Adipose tissue
-Areolar tissue
-Compact bone
-Blood
Examples of connective tissue:
1.       Cartilage: Provides strength and flexibility
2.       Bone: Allows movement, Stores calcium and contains forming blood cells
3.       Blood: Transports oxygen and carbon dioxide.
Tissue Culture: is the growth of cells in sterile nutrient medium outside the body.
In vitro means outside of the body
Micropropagation: is the growth of large numbers of cells of a parent plant.
Monoclonal antibodies: combine with a specific type of antigen, this may be used to attach to and show the presence of antigens on cancer cells.
Growth of Skin: Patients skin grown outside of the body and new skin is grafted onto the wound, this is called a skin graft and is often used on badly burnt patients due the fact the their skin tissue too bad damaged to repair itself.

Conditions necessary for Tissue growth

Oxygen

• Nutrients

• Growth factors and hormones

• Correct pH

• Optimum temperature

• Sterile conditions



• Freedom from competition


An Organ: is made up of a number of tissues working together to carry out the same function.
An Organ System: contains a number of working organs working together to carry one or more functions.          


Sunday, 4 January 2015

The Cell Structure

The Cell structure

By Naomi Keddy
The Microscope:
-Coarse focus: For Approx. focusing.
-Fine Focus: For Precise focusing.
-Eye Piece: Magnifies the image.
-Nosepiece: Rotates to move to desire lens.
-Objective Lens: Magnifies the image.
-Stage: Supports the slide.
-Mirror: To supply light to the slide.

 Animal and plant cell structure:



Animal cell:
-Protoplasm: Is all the living parts of a cell.
-Cytoplasm: Is all the living material in the cell outside the nucleus.
-Ribosomes: To make protein.
-Cell membrane: To retain the cell contents
-Nucleus: Contains the strand of DNA. The Nucleus is the control of the cell.
-Mitochondrion: Is the sites of respiration.
-Chromatin: Is the name given to chromosomes when they are elongated and dividing



Mitochondria: Are the sites of respiration and it supplies energy to the cell.

Plant Cell:
-Cell Wall: To support and strengthen the cell.
-Chloroplast: Contain the green pigment that allows plants carry out photosynthesis.
-Vacuoles: contain a fluid called cell sap, this is a solution of salts, sugar and pigments



Chlororplasts: are surrounded by double membranes. They have membranes stacks which contain the green pigment chorophyll. They also have a loop of DNA.

The differences between plant and animal cells:

-Plants have a cell wall and animal do not have a cell wall.
-Plants have a chloroplasts and animal cell do not have chloroplasts.
-Plants have large vacuoles and animal do not have large vacuoles.



The Cell Membrane or Plasma Membrane:

All living membranes have the identical structure. They are composed of phospholipids and proteins. Cell membranes are thin. The phospholipids are arranged in a double layer called the lipid bilayer. The proteins are entirely or partly fixed in the bilayer and are able of movement. Phospholipids have a water loving phosphate group and a water-hating lipid group. The phosphates are on the outer surfaces and the lipids are in the middle.

Functions of membranes:
-Retain the cell contents.
-Recognise molecules that touch them.
-Control what enter or leaves the cell.
-Give support to the cell.



Prokaryotic and Eukaryotic cells:

Prokaryotic cells: do not have a nucleus or membranes-enclosed organelles.


Prokaryotic cells:
-Are singled cell
-Have a circular loop of DNA
-Have small cells
-Do not have membranes-enclosed organelles such as mitochondrion and chloroplast.
-Include bacteria

Eukaryotic Cells: Have a nucleus and cell organelles, all of which are enclosed by membranes.




Eukaryotic cells:
-Have a nucleus
-May have membrane-enclosed organelles such mitochondrion and chloroplasts
-Have large cells
-Include animals, plant and fungi