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Cell Structure

2.1.2 Comparison between the Animal Cell and Plant Cell

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Similarities of Animal Cell and Plant Cell

  1. Both animal cells and plant cells have
    1. plasma membrane
    2. nucleus with nucleic bounded by nuclear membrane
    3. cytoplasm
    4. ribosome
    5. mitochondria
    6. golgi apparatus
    7. endoplasmic recticulum



Differences between Animal Cells and Plant Cells

Animal Cells Plant Cells
Cell Wall Absent Present
Cytoplasm Present throughout the cell. Present, but usually confined to a thin layer at the edge of the cell.
Chloroplast Absent Present
Vacuole Present in some animall cells. Normally small and distributed throughout the cell. Present. Large and filled with cell sap.
Nucleus Normally in the middle of the cell Normally at the edge of the cell
Lysosome Present Normally absent
Centriole Present Absent
Storage Granule Mainly as glicogen Mainly as starch
Shape Do not have fixed shape Have fixed shape
Size Usually smaller than plant cell Usually bigger than animall cell
Cilia and Flagella Present (Usually) Absent
Secretion Produces a variety of secretions. Produces few secretions.

2.1.1 Components of a Cell

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  1. Each cell consists of a plasma membrane and protoplasm
  2. The protoplasm consist of cytoplasm and nucleus.
  3. Cytoplasm contains many types of organelles.
  4. The following is the illustration of the animal cell and plant cell.
(Animal Cell)


(Plant Cell)

Non-Organelle

Plasma Membrane

  1. The plasma membrane separates the content of the cell from its external environment.
  2. It regulates the movement of substances entering and leaving the cell.
  3. It also allows the exchange of nutrients, respiratory gases and wastes products between the cell and its environment

Cytoplasm

  1. The cytoplasm contain variety of organelle.
  2. The function of the cytoplasm is to maintain the shape of the cell.
  3. It acts as a medium for the biochemical reactions occur within the cell
  4. It also store chemical substances such as glicogen granules (in animal cells), starch granules (inplant cells) and enzymes.


Cell Wall

  1. The cell wall only contain in plant cell. It support the cell and the plant and maintain the shape of the cell.
  2. It also prevents the cell from bursting when too much water enters the cell through osmosis.
  3. It allows substances to move through it.

Nucleus

  1. The nucleus contains the genetic material of a cell.
  2. It controls the activities of the cell.
  3. It also produces ribosomes and ribonucleic acids(RNA).

Organelle

Endoplasmic Recticulum (ER)

- Rough Endoplasmic Recticulum:

  1. Transporting the newly synthesised protein.
  2. Involve in the systhesis of protein.
  3. Provides surface for chemical reaction

- Smooth Endoplasmic Recticulum:

  1. Transporting lipids and glycerols.
  2. Synthesising lipids and other non-protein substances.

Mitochonrion

  1. Produces ATP (Adenosine triphosphate.)
  2. Site of energy production through cellular respiration.

Ribosomes

  1. Site for synthesising protein.
  2. Golgi Apparatus
  3. Site for the production of enzyme andlysosome.
  4. Produces polysacharides, glycoproteins andsecretory enzyme.
  5. Storing and modifying carbohydrate and glycoprotein.
  6. Transport and store lipid.

Vacuole

  1. Stores food (Carbohydrate, amino acid) and water.
  2. Support herbaceous plants when it is turgid.
  3. Stores organic waste (in leaf cells).

Chloroplast

  1. Contain chlorophyll and hence a site for photosynthesis to take place.

Centrosome


  1. The centrosome is served as the main microtubule organizing center (MTOC) of the animal cell as well as a regulator of cell-cycle progression.
  2. It form spindle fibres during cell division in animal cell.


Lysosomes


  1. Lysosomes contain hydrolytic enzymes that digest or break down complex organic molecules such as proteins, polysaccharides and lipids.
  2. The enzymes eliminate worn out organelles and damaged organelles.

Golgi Apparatus


  1. The golgi apparatus processes proteins and lipids from the endoplasmic reticulum
  2. The products are sorted by the Golgi Apparatus and packaged into vesicles
  3. The vesicles then release their contents outside the cell.
  4. It also responsible to the formation of lysosomes.

2.1 Cell Structure and Function

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Theory of Cell

  1. The cell is the basic unit or building block for all living organisms.
  2. All organisms are made up of one or more cells .
  3. Cells are the fundamental and structural unit of life.
  4. A cell is made up of a plasma membrane which contains protoplasm.
  5. Protoplasm is made up of cytoplasm and a nucleus.
  6. A cell consist of the non-organelle structure the organelle structure.

Non-organelle/Organelle Structures of Cell

  1. The non organelle structure of a cell include
    1. Plasma membrane
    2. Cytoplasm
    3. Cell wall (plant cell only)
  2. Whereas the organelle structure of a cell include
    1. Nucleus
    2. Endoplasmic Recticulum
    3. Mitochondrion
    4. Ribosom
    5. Golgi apparatus
    6. Vacuole
    7. Chloroplast (plant cell only)

    Structure of an Animal Cell


    1. Each animal cell is enclosed by a plasma membrane.
    2. Within the plasma membrane is the protoplasm which consists of the cytoplasm and a nucleus.
    3. Animal cells do not have regular shapes.
    (This file is shared under GNU Share Document Licence from  Wikipedia)


    Structure of a Plant Cell


    1. Each plant cell is enclosed by a plasma membrane which is protected by a cell wall.
    2. Again, within the plasma membrane has a nucleus and cytoplasm.
    3. Unlike animal cell, most plant cells have chloroplasts which contain chlorophyll.
    4. Also, a mature plant cell may have a large vacuole which contains cell sap.
    5. Plant cells have a fixed shape because they have cell walls.
    (Onion Cell)