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