Organelle Structure and
function
Advanced Higher Biology
Cell and molecular Biology
Activity
• Copy and complete the following
table
organelle
Plasma membrane
Nucleus
Mitochondria
Chloroplasts
Nucleolus
Structure
Function
Activity
• Copy and complete the following
table.
organelle
Rough endoplasmic
reticulum
Smooth E. R.
Golgi apparatus
Ribosomes
Lysosomes
Structure
Function
Activity
• Copy and complete the following
table
organelle
Nuclear envelope
Cilia
Centrioles
Structure
Function
Nucleus
Function of the nucleus
• Acts as the control centre of the cell
through the production of mRNA
and protein synthesis
• Retain genetic material of the cell
(DNA / chromosomes)
• Manufacture rRNA and ribosomes
• Start the process of cell division
Structure of Nucleus
• Nuclear envelope
– Controls entry and exit of materials
– Contain reactions
– Outer membrane continuous with
endoplasmic reticulum
• Nuclear pores
– Passage of large molecules (mRNA) out of
nucleus
Structure of Nucleus
• Nucleoplasm
• Chromatin
– DNA and associated proteins,
chromatin condenses into
chromosomes when the cell divides.
• nucleolus
– Manufactures ribosomal RNA and
assembles the ribosomes
Chloroplasts
Structure and Function of
Chloroplasts
• Chloroplast envelope
– Entry and exit of substances
• Stroma
– Enzymes for the light independent stages of
photosynthesis
• Grana (thylakoids/lamellae)
– Light dependent stage of photosynthesis
• Starch grains
– Temporary stores of carbohydrates
Mitochondria
Function of Mitochondria
• Site of Krebs cycle and oxidative
phosphorylation in aerobic
respiration
• Production of energy rich ATP
molecules from carbohydrates
Structure of Mitochondria
• Double membrane
– Inner membrane folded into cristae
which provide a large surface area for
attachment of stalked particles
(contain enzymes involved in ATP
synthesis)
• Matrix
– DNA, enzymes and mitochondrial
ribosomes
Endoplasmic reticulum
Endoplasmic reticulum
• Membranes spreading through the
cytoplasm of cells, continuous with the
nuclear membrane
• Enclose flattened sacs called cisternae
• Rough endoplasmic reticulum
– Ribosomes present on outer surface of
membrane
• Smooth endoplasmic reticulum
– No ribosomes, tubular in appearance.
Function of endoplasmic
reticulum
• RER
– Provide LSA for synthesis of proteins
– Provides a pathway for the transport of
materials (esp. proteins) throughout the
cell.
• SER
– Synthesis, stores and transports lipids
and carbohydrates
– Contains lytic enzymes (liver cells)
Ribosomes
Structure and function of
ribosomes
• Two types
– 80S – eukaryotic cells
– 70S – prokaryotic cells
• Make up 25% of dry mass of cell
• Important in protein synthesis
Golgi
Apparatus
Functions of Golgi
Apparatus
• Adds carbohydrates to proteins to
form glycoproteins
• Produces secretory enzymes
• Secretes carbohydrates
• Transports, modifies and stores lipids
• Forms lysosomes
Lysosomes
Functions of Lysosomes
• Destroy foreign material inside or
outside the cell.
– Breakdown material ingested by
phagocytic cells
– Release enzymes outside the cell
– Digest worn out organelles (autophagy)
– Autolysis break down cells after they
have died.
Cell surface (plasma)
membrane
Functions of cell surface
membrane
• Controls movement of substances into
and out of the cell
• Forms a recognition site for immune
system
• Receptor sites for specific hormones and
neurotransmitters
• Folded to form villi (LSA)
• Helps cells attach to one another and
forms tissues
Cilia
Structure and function of
cilia
• Threads that extend from cell
surface
• Made of nine sets of 3 microtubules
• Move an entire organism
• Move material within an organism
– E.g. cilia lining respiratory tract move
mucus towards the throat.
Centrioles
Structure and function of
centrioles
• Hollow cylinders of microtubules
• Microtubules form spindle fibres for
nuclear division
• Maybe involved in formation of
microtubules that make up cells
cytoskeleton