TBBOL- Week 10

What are some functions of the ER?

Protein synthesis, protein processing, protein folding and assembly, protein sorting and quality control, biosynthesis of lipids and calcium storage.

What occurs during protein processing in the ER?

Cleavage of signal peptides and glycosylation of proteins.

What are chaperones?

Other proteins which use energy to fold protein into their proper shape.

What do calcium ions act as?

A second messenger.

What do secreted proteins contain?

An N-terminal 16-30 amino acid signal peptide directing them to the ER>

What does the ER have two-way traffic with?

The Golgi apparatus.

What does the Golgi apparatus consist of?

An ordered series of compartments.

Where can proteins be released to?

Lysosomes, the plasma membrane or secretory vesicle.

What are the two models for protein transport through the Golgi apparatus?

The vesicle transport mechanism and cisternal maturation.

What are the three pathways of sorting protein cargo?

Signal-mediated diversion to lysosomes, signal-meditated diversion to secretory vesicles and constitutive secretory pathway.

What is the pH of lysosomes?

5.

What is the protein gradient maintained by?

A hydrogen ion pump.

What do lysosomes fuse with after being fused with?

Endosomes to form endolysosomes or phagosomes to form phagolysosomes.

Are lysosomes homogenous or heterogenous?

Heterogenous.

What is autophagy?

The self-eating of cytosolic materials.

What does autophagy do?

It degrades damaged or unwanted proteins and organelles.

What are peroxisomes?

The main sites of oxygen utilisation.

What do peroxisomes perform?

An oxidation reaction without the generation of energy.

What directs the import of proteins into peroxisomes?

A short signal sequence.

What are all the self-replicating organelles?

Nucleus, centriole, flagellum, mitochondria, hydrogenosomes and chloroplasts.

What are some of the functions of the nucleus?

Containment of genetic material, transcription of genes, and replication of DNA during mitosis.

What does the nucleus contain?

The genetic material of the cell in condensed form (chromosomes).

What does DNA form when it goes around histones?

Nucleosomes.

What do the nuclear envelope’s nuclear pores act as?

Entry gates.

What controls the RanGTP-dependant protein transport?

Karyopherins.

What is at the base of the flagellum?

The basal body.

Where does the centrosome organise microtubules?

The microtubule organising centre (MTOC).

Where about do centrosomes form?

The mitotic spindle.

Where do centrioles form?

At the base of the flagellum.

What do mitochondria and chloroplasts have in common?

A similar evolutionary origin and they perform similar functions.

What are some of the functions of the matrix of the mitochondria?

It is a concentrated enzyme mix, it oxidises multiple things, produces NADH and has 70s ribosomes.

What does the inner foldings of the mitochondria allow for?

An increased surface area.

What are the two coupled pumps that generate ATP?

The electron pump and hydrogen pump.

In what directions can ATPase run?

Forward or backwards.

What does the proton gradient drive?

ATP synthesis.

What do hydrogenosomes synthesise?

ATP anaerobically by using pyruvate.

What are chloroplasts derived from?

Cyanobacteria.

What are some of the functions of the matrix of the chloroplast?

Carbon fixation, sugar, amino acid, fatty acid synthesis, and production of NADPH.

What does light absorption by chlorophyll create?

A hydrogen gradient.

What occurs in the light reaction in chlorophyll?

The reduction of NADP to NADPH and the production of ATP.

What occurs in the dark reaction in chlorophyll?

NADPH and ATP are used in the calvin cycle and sugars, amino acids and fatty acids are generated.

What dos the eukaryotic flagellum consist of?

9×2 + 2 microtubule cylinders.

What does LUCA and FECA stand for?

Last universal common ancestor and first eukaryotic common ancestor.

What are some of the properties of LECA?

Genes with introns, cell cycle, mitosis, meiosis and phagocytosis.

What did LECA end up increasing?

The level of complexity in organisms.

What is hypothesis A on the evolution of eukaryotes?

The autogenic origin of all organelles by step-wise mutations.

What is hypothesis B on the evolution of eukaryotes?

FECA is the result of an endosymbiosis event and further organelles were acquired by endocytosis.

What is a major driver of evolution?

Symbiosis.

What was the origin of mitochondria?

Alphaproteobacterial.

What are the three types of endosymbiosis?

Primary, secondary and tertiary.

How many chloroplast membranes do primary. secondary and tertiary have typically?

Primary have 2, secondary have 4/3 and tertiary have 4.

What are ciliates?

Cells covered by cilia.

What are ciliates responsible for?

Nuclear dimorphism and sexual conjugation.

What is an example of a ciliate?

Paramecium tetraurelia.

Are most eukaryotes unicellular, colonial or multicellular?

Unicellular.

What are the four “trophs” eukaryotes can be?

Heterotrophs, mixotrophs, photoautotrophs and parasites.