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:

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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