organelle structure and function advanced higher biology cell and molecular biology
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Organelle Structure and function
Advanced Higher BiologyCell and molecular Biology
Activity
• Copy and complete the following table
organelle Structure FunctionPlasma membrane
Nucleus
Mitochondria
Chloroplasts
Nucleolus
Activity
• Copy and complete the following table.
organelle Structure FunctionRough endoplasmic reticulum
Smooth E. R.
Golgi apparatus
Ribosomes
Lysosomes
Activity
• Copy and complete the following table
organelle Structure FunctionNuclear envelope
Cilia
Centrioles
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