Cell and Molecular Biology Transport/Intracellular Compartments

Set of flashcards covering key concepts from the lecture on Transport and Intracellular Compartments in Cell and Molecular Biology.

What is the primary evolutionary event hypothesized to lead to the formation of membrane-enclosed organelles in eukaryotic cells?

Plasma Membrane Expansion.

How do membrane-enclosed organelles import proteins?

Through nuclear pores, across membranes, or by vesicles.

What directs proteins to their correct cellular locations?

Signal sequences.

What is the function of the nuclear pore complex?

It forms a gate for the entry and exit of select macromolecules.

How are mitochondrial precursor proteins transported into mitochondria?

They are unfolded during import.

What is the role of ribosomes in the endoplasmic reticulum (ER)?

They synthesize all the proteins encoded by the nuclear genome.

What happens to soluble proteins once they enter the lumen of the ER?

They undergo cleavage of a hydrophobic signal sequence.

What is the significance of the Golgi apparatus in protein processing?

It's where proteins are further modified and sorted.

What are the two pathways of exocytosis in secretory cells?

Constitutive pathway and regulated pathway.

What is receptor-mediated endocytosis?

A specific route into animal cells dictated by receptor proteins.

Name a process that allows specialized cells to ingest large particles.

Phagocytosis.

What is autophagy?

A complex process that can involve distinct cargo for cellular material degradation.

What is the main purpose of glycolysis?

To break down glucose and form ATP.

List the three stages of food breakdown in animal cells.

1. Digestion of large food molecules into simple subunits. 2. Glycolysis converting simple subunits to acetyl CoA. 3. Citric acid cycle and oxidative phosphorylation for ATP formation.

What is the role of activated carriers like NADH and FADH2?

To supply electrons for the production of ATP.

What is chemiosmotic coupling?

The coupling of electron flow to proton pumping, powering ATP synthase.

What are the key differences between mitochondria and chloroplasts?

Mitochondria are responsible for ATP production, while chloroplasts are responsible for photosynthesis.

How does stage 1 of photosynthesis differ from stage 2?

Stage 1 produces ATP and NADPH, while stage 2 fixes carbon to produce sugars.

What is the main function of the mitochondria?

ATP synthesis by oxidative phosphorylation

What is the main function of the Nucleus?

Contains main genome, DNA and RNA synthesis

What are the main functions of the Endoplasmic Reticulum in Eukaryotic cells?

Synthesis of proteins, synthesis of lipids, preparation of lipids for distribution to other organelles.

What mechanisms do membrane-enclosed organelles import proteins?

Nuclear pores, vesicular transport, membrane transport

TRUE OR FALSE: Nuclear transport of proteins carrying ER localization signals occurs passively in Eukaryotic cells.?

False

What describes the first stages of import of s single-pass membrane protein into the ER?

An n-terminus ER signal sequence initiates transer

What describes the last stages of import of a single-pass membrane protein into the ER?

The growing polypeptide is discharged into the lipid bilayer

TRUE OR FALSE: SNARE proteins can catalyze vesicle budding at target membranes?

False

A mutation causes downregulation of chaperones expressed in the ER. What is a likely outcome of the ER sensor of an active UPR?

The ER sensor is phosphorylated

A mutation causes downregulation of chaperones expressed in the ER. Which of the following is a likely outcome of misfolded proteins (active UPR)?

misfolded proteins increase

What describes the correct pathway for continual vesicular transport of newly synthesized soluble proteins and membrane lipids?

Constitutive secretion pathway.

What describes the correct mechanism of vesicular transport of newly synthesized soluble proteins and membrane lipids?

Exocytosis

TRUE OR FALSE: Autophagosomes alone breakdown long-lived proteins and organelles into simple molecules to be reused in cells.

False

TRUE OR FALSE: The purpose of the citric acid cycle is catalyze the complete oxidation of acetyl CoA to form energy carriers like NADPH.

False, the citric acid cycle generates NADH and FADH2, not NADPH.

TRUE OR FALSE: Energy carriers NADH and FADH2 donate electrons to enzyme complexes in the ETC, where oxygen is the terminal electron acceptor.

True

What is the cell location? Energy carriers NADH and FADH2 donate electrons to enzyme complexes in the ETC, where oxygen is the terminal electron acceptor.

This process occurs in the inner mitochondrial membrane, where the electron transport chain is located.

What is the cell process? Energy carriers NADH and FADH2 donate electrons to enzyme complexes in the ETC, where oxygen is the terminal electron acceptor.

The cell process involves oxidative phosphorylation, where the energy from electrons is used to pump protons across the inner mitochondrial membrane, creating a proton gradient that drives ATP synthesis.

What is the purpose of glycolysis?

to break down glucose and form ATP. (occurs in cytosol)