2.1

• Plasma membrane


  • Outer membrane that surrounds the entire content of cell

  • Made of proteins and phospholipids

  • Thin and elastic film

  • Partially permeable
• Plasma membrane (functions)


  • Separates content of cell from the external environment

  • Controls movement of substances into and out of the cell

  • Allows exchange of nutrients, respiratory gases and waste materials between cells and their surroundings
• Mitochondrion 


  Plural: Mitochondria
• Mitochondrion


  • It is rod-shaped or spherical

  • It consists of two layers of membranes, which are the smooth outer membrane and folded inner membrane

  • Contains enzymes that play a role in cellular respiration
• Mitochondrion (functions)


  • A site that generates energy through the glucose oxidation process during cellular respiration

  • Energy released in the form of ATP molecules (adenosine triphosphate) to be used by the cells
• Centriole


  • Small cylindrical components that exist in pairs in animal cells

  • Made up of complex arrangement of microtubules

  • Does not exist in plant cells
• Centriole (function)


  Forms spindle fibre during cell division in animal cells
• Golgi apparatus


  • Consists of a stack of parallel flattened sacs that are coated by a single cell membrane

  • New membrane is added at one end of the Golgi apparatus and vesicles bud off from the other end.
• Golgi apparatus


  Modifies, transports, sort and package the proteins and carbohydrates
• Lysosome


  • Small spherical sac enclosed in a single membrane

  • Contains hydrolytic enzymes
• Lysosome (functions)


  • Hydrolyses complex organic molecules such as protein, nucleic

  acid and lipid

  • Breaks down bacteria and components of damaged cells
• Mitochondrion

  
• Centriole

  
• Golgi apparatus

  
• Plasma membrane

  A) outer environment

  B) plasma membrane

  C) cytoplasm

  
• Lysosome

  A) Lysosome

  
• Nucleus


  Plural: Nuclei
• Nucleus


  • Largest component in the cell

  • Spherical, compressed and enclosed in a nuclear membrane with many pores

  • The nucleus contains chromosomes, nucleolus and nucleoplasm.
• Nucleus (function)


  • Controls all cell activities

  • Has chromosomes that contain deoxyribonucleic acid (DNA). DNA determines the cell characteristics and metabolic function.
• Nucleus

  A) Nuclear membrane

  B) Chromatin

  C) Nucleolus

  D) Nucleoplasm

  
• Ribosome


  • Small, compact and spherical granules

  • Consists of protein and ribonucleic acid (RNA)

  • Ribosomes are present on the surface of the rough endoplasmic reticulum or exist freely in the cytoplasm.
• Ribosome (function)


  Site for protein synthesis
• Endoplasmic reticulum


  • Consists of a system of interconnected folded flattened sacs

  • Endoplasmic reticulum membrane is continuous with the nuclear membrane.

  • There are two types of endoplasmic reticulum:

  – Rough endoplasmic reticulum has ribosomes attached to the surface

  – Smooth endoplasmic reticulum does not have ribosomes
• Endoplasmic reticulum (functions)


  • The transport system within the cell

  • Provides a wide surface for enzyme attachment and biochemical

  reactions

  • The rough endoplasmic reticulum transports proteins synthesised by

  ribosomes.

  • The smooth endoplasmic reticulum synthesises and transports

  glycerol and lipids, and carries out the detoxification of drugs and

  metabolic by-products.
• Ribosome

  A) Ribosome

  
• Endoplasmic reticulum

  A) smooth endoplasmic reticulum

  B) rough endoplasmic reticulum

  
• Vacuole


  • Liquid-filled sac, which is the cell sap.

  • A vacuole is surrounded by the tonoplast membrane.

  • Young plant cells have many small vacuoles while mature plant cells have a large vacuole.

  • The vacuole in animal cells is small.

  • Cell sap contains water, organic acids, sugars, amino acids, enzymes, mineral salts, oxygen, carbon dioxide and metabolic by-products.
• Vacuole (functions)


  • Water is absorbed into the vacuole plant cell and the cell becomes turgid.

  • In unicellular animals, the vacuole contracts during osmoregulation, osmosis and excretion.
• Chloroplast 


  • Oval shaped

  • Consists of two layers of membrane

  • Contains chlorophyll pigments in the grana that give plants a green colour
• Chloroplast (function)


  Chlorophyll absorbs sunlight and converts it to chemical energy during photosynthesis.
• Cytoplasm


  • Consists of a jelly-like medium that contains components of the suspended cells

  • Contains organic compounds (such as protein, lipid and carbohydrate) and inorganic compounds (such as potassium ions)
• Cytoplasm (function)


  Acts as a medium for biochemical reactions in cells
• Cytoplasm

  A) Cytoplasm

  
• Cell wall


  • A strong and rigid outer layer

  • Made from cellulose fibre

  • Fully permeable
• Cell wall (functions)


  • Maintains the shape of plant cells

  • Provides mechanical support to plant cells
• Cell wall

  A) cytoplasm

  B) plasma membrane

  C) cell wall

  
• Animal cell

  A) nucleus

  B) plasma membrane

  C) cytoplasm

  
• Plant cell

  A) cell wall

  B) nucleus

  C) cytoplasm

  D) plasma membrane

  E) vacuole

  
• Differences between plant cell and animal cell

  • Has a fixed shape (doesn't have)

  • Has a cell wall (doesn't have)

  • Has chloroplasts (doesn't have)

  • Has a large vacuole (doesn't have/it's small)
• Differences between plant cell and animal cell

  • Stores carbohydrate in the form of starch (glycogen)
  • Does not have a centriole (Does have)