Post by student01 on Jun 19, 2016 16:32:35 GMT
All living things are made up of cells.
The main parts in animal cells are;
-the cell membrane; a thin skin that controls what enters and leaves the cell.
-the nucleus; controls the cell's activities
-cytoplasm; a jelly-like fluid in which food,minerals and salts are dissolved.
Plant cells have the same features listed above and;
-chloroplasts; contain chlorophyll, which plants use to make food
-vacuole; space filled with sap
A single cell divides into two parts. These can divide again and again.
Growth in animals and plants is a result of cell division.
Organisms are arranged into;
cell - tissues - organs- systems
A microscope is used to view small objects in detail.
Parts of a microscope and their functions;
Eyepiece lens; enlarges the image of the object. We look through this lens to see the animal/plant being magnified.
Focusing knobs; allows a clear, sharp image to be seen by lowering or raising the stage.
Nosepiece; rotates so that different lenses can be used.
Objective lens; this is located on the nosepiece, it enlarges the image of the object.
Stage; this is used to hold the glass slide and the object being magnified in position. A small opening allows light through.
Light source; the light source may be an electric light bulb or may be natural light reflected through a mirror.
Exam Question;
Describe how to prepare a microscope slide from a plant tissue.
Place a drop of water in the centre of a glass slide. Add a drop of iodine.
Cut an onion open on a cutting board.
Use a forceps to peel away a small piece from one of the inner layers of the onion's skin.
Spread the onion skin onto the water on the slide.
Gently lower a cover slip over the onion tissue.
Examine the onion cells under high power and low-power magnification.
The main parts in animal cells are;
-the cell membrane; a thin skin that controls what enters and leaves the cell.
-the nucleus; controls the cell's activities
-cytoplasm; a jelly-like fluid in which food,minerals and salts are dissolved.
Plant cells have the same features listed above and;
-chloroplasts; contain chlorophyll, which plants use to make food
-vacuole; space filled with sap
A single cell divides into two parts. These can divide again and again.
Growth in animals and plants is a result of cell division.
Organisms are arranged into;
cell - tissues - organs- systems
- Tissues; a group of similar cells which carry out the same function.
- An organ; a structure that contains two or more tissues working together.
- A system; a number of organs working together.
A microscope is used to view small objects in detail.
Parts of a microscope and their functions;
Eyepiece lens; enlarges the image of the object. We look through this lens to see the animal/plant being magnified.
Focusing knobs; allows a clear, sharp image to be seen by lowering or raising the stage.
Nosepiece; rotates so that different lenses can be used.
Objective lens; this is located on the nosepiece, it enlarges the image of the object.
Stage; this is used to hold the glass slide and the object being magnified in position. A small opening allows light through.
Light source; the light source may be an electric light bulb or may be natural light reflected through a mirror.
- The total magnification is calculated by multiplying the power of the eyepiece lens by the power of the objective lens being used.
Exam Question;
Describe how to prepare a microscope slide from a plant tissue.
Place a drop of water in the centre of a glass slide. Add a drop of iodine.
Cut an onion open on a cutting board.
Use a forceps to peel away a small piece from one of the inner layers of the onion's skin.
Spread the onion skin onto the water on the slide.
Gently lower a cover slip over the onion tissue.
Examine the onion cells under high power and low-power magnification.