2.5 Plant Cell Ultrastructure

Covers the basic functions of different organelles/parts of plant cells.

What is the function of the cilia?

• Move in a wave-like fashion to move substances across their surface.

What is the function of the flagellum?

• Move the whole cell (locomotion)

What are flagella called in animals?

Undulipodia (un-dull-i-podia)

What are the centrioles made of?

Microtubules

What is the function of the centrioles?

• Organises other microtubules within the cell.

• Produces spindle fibres during mitosis

What formation are the microtubles in inside the flagellum?

9 + 2 formation

What is the cell wall made of? Is it soluble?

• Cell wall is made of cellulose

• It’s insoluble

What are the functions of the cell wall?

• Provides strength and support in plants

• Only allows small molecules to pass through so acts as a barrier.

What is the function of the chloroplasts?

Site of photosynthesis

What structures make up chloroplasts?

• Thylakoid

• Granum

• Lamellae

• Stroma

What is the function of the thylakoid in chloroplasts?

• Light dependent stage of photosynthesis

• Contains chlorophyll

What is the granum?

A stack of thylakoids

What does the lamellae do?

Connects the stacks of thylakoids (it’s a flat disk)

What is the function of the stroma?

• Light independent stage of photosynthesis

• Composed of 70S ribosomes and a loop of DNA.

What is the name of the vacuole membrane?

Tonoplast

What does the vacuole contain?

Cell sap, which contains water and mineral ions.

What structures make up prokaryotes?

• Capsule

• Cell wall

• 70S ribosomes

• Cytoplasm

• Flagellum

• Chromosomal DNA

• Cell membrane

• Peli

What is the cell wall of prokaryotes made from?

Peptidoglycan (aka murein)

Are there histones with the chromosomal (loop of) DNA?

No, there are no histones.

What are the functions of the peli of the prokaryotes?

• Used to detect cells (nothing to do with movement)

• Can also allow transfer of genetic information (bacterial conjugation)

What is the function of the capsule in prokaryotes?

Protects the cell from chemicals

What is endosymbiotic theory?

• The theory that the bacterium was engulfed by a larger cell.

• This provided the bacterium with protection and the cell with energy, which allows it to get larger and divide to out-compete other cells.

• These bacteria eventually become organelles (e.g. mitochondria)

What are the organelles involved in protein production/ synthesis?

• Nucleus

• Ribosomes

• RER

• Golgi apparatus

• Cytoskeleton

What is the nucleus’ role in protein production?

To make the mRNA during transcription, which leaves through the nuclear pore.

What is the ribosomes’ role in protein production?

To transcribe the mRNA into a polypeptide.

What is the RER’s role in protein production?

To package and modify the proteins into vesicles.

What is the role of the Golgi Apparatus in protein production?

To structurally modify the proteins from the cis face to the trans face.

What is the cytoskeleton’s role in protein production?

To transport the secretory vesicles to the cell surface membrane to be exocytosed.