Cell Biology Review Flashcards

This set of flashcards covers the essential concepts from the lecture notes on Cell Biology, focusing on protein structure and function, cellular processes, and the principles of membrane biology.

What are the building blocks of proteins?

Amino acids

What kind of bond links amino acids in proteins?

Peptide bonds

What type of reaction is peptide bond formation classified as?

Condensation reaction

What gas, when present, can lead to the unfolding of proteins?

Urea

What is the term for proteins that help with the folding of newly synthesized polypeptides?

Chaperone proteins

What energy molecule is required for the function of chaperone proteins?

ATP

What is the function of disulfide bonds in proteins?

They stabilize a favored protein conformation.

What is an α helix?

An orderly repeating form that some polypeptide chains fold into.

In an α helix, how are the peptide bonds configured?

The N–H of every peptide bond is hydrogen-bonded to the C=O of a neighboring peptide bond.

What is a β sheet?

A pattern where segments of a polypeptide chain are held together by hydrogen bonding.

What are amyloid structures derived from?

Stacked β sheets.

What do 'protein machines' do?

Carry out complex functions by collaborating proteins.

What does cAMP associate with to provide specificity?

Its binding site.

The Ras protein is significant in what cellular process?

Growth factor signaling pathways.

How does the Na+ pump function?

It uses ATP energy to pump Na+ out of cells and K+ in.

What influences membrane curvature?

Differential lipid composition of the two membrane monolayers.

What is the structure of biological membranes described as?

A lipid bilayer.

What is passive transport?

The movement of solutes down their concentration gradients without energy input.

What drives active transport mechanisms?

An input of energy.

What are transporters that perform active transport called?

Pumps.

Which ATP enzyme transfers protons across membranes?

ATP synthase.

What is one mechanism by which mitochondrial precursor proteins are imported?

They are unfolded during the transport process.

What is the role of the ER signal sequence?

It directs the ribosome to the ER membrane.

What does vesicular transport involve?

Transport vesicles communicating between compartments inside the cell.

What is the function of clathrin-coated vesicles?

Transport selected cargo molecules by budding from the plasma membrane.

What proteins work together to direct transport vesicles?

Rab proteins, tethering proteins, and SNAREs.

What activates the unfolded protein response (UPR) in the ER?

Accumulation of misfolded proteins.

What are the two categories of metabolism?

Catabolism and Anabolism.

What do catabolic pathways do?

Dissipate energy stored in food molecules.

What is the function of the electron transport chain?

To generate a proton gradient for ATP production.

What role does cytochrome c oxidase play?

Transmits electrons to oxygen while pumping protons across the membrane.

How do the bodies of prokaryotic cells differ from eukaryotic cells?

Prokaryotes lack membrane-bound organelles.

What is ATP hydrolysis primarily used for?

Power many cellular processes.

What is required for the formation of amyloid fibrils?

β-sheet stabilization of abnormally folded proteins.

Which types of interactions are important for cAMP binding?

Hydrogen bonds.

What does the SRP do in protein synthesis?

Slows down protein synthesis and directs the ribosome to the ER.

How are proteins transported into mitochondria?

Through translocator complexes that unfold them during import.

What transports ATP across the mitochondrial inner membrane?

An antiport process.

What drives vesicle budding in clathrin-coated vesicles?

Adaptins complex with clathrin to facilitate the process.

What is the role of SNARE proteins?

Catalyze the fusion of transport vesicles with target membranes.

During what process is the second law of thermodynamics observed?

By dissipating heat—no defiance of disorder occurs.

What are phosphorylated nucleotides used for?

As activated carriers in metabolism.

What is the primary function of membrane proteins in epithelial cells?

To mediate selective transport and communication.

What do rab proteins facilitate?

Transport vesicle docking.

What happens to proteins during the unfolded protein response?

Transcription regulators are activated for protein quality control.

What type of proteins prevent aggregation in newly synthesized polypeptides?

Chaperone proteins.

How does ATP synthase produce ATP?

By utilizing the energy of protons flowing down their gradient.

What is a key factor in directing vehicles to their specific target membrane?

Rab proteins.

How do tight junctions in epithelial cells work?

Prevent protein diffusion between membrane domains.

What type of protein structure is stabilized by disulfide bonds?

Extracellular proteins.

What structural feature contributes to the stability of amyloid fibrils?

Stacked β sheets.

Which enzyme facilitates the hydrolysis of ATP?

ATPase.

What is the final product of electron transport and ATP synthesis?

Water and ATP.

What is a characteristic of a protein's conformation?

Determined solely by its amino acid sequence.

Which factor primarily drives the movement of solutes in passive transport?

Concentration gradient.

What is the essential role of glycolytic enzymes in ATP production?

They facilitate the conversion of ADP to ATP.

What analogy describes cAMP's interaction with its binding site?

A hand in a glove.

What assists in protein import into the ER?

Signal recognition particle (SRP).

How does membrane composition affect protein transport?

Different lipids can hinder or assist in transport efficiency.

What type of transporters are involved in secondary active transport?

Symporters and antiporters.

How does a proton gradient affect ATP synthesis?

It drives proton flow through ATP synthase.

What determines the specificity of a transport vesicle?

Rab protein interactions with target membranes.

What happens when the UPR is activated?

Cell prepares to handle misfolded proteins.

What facilitates the process of vesicle docking?

Tethering proteins and Rab proteins.

How does the cytoskeleton influence cell shape?

By providing structural support and stability.

What role does the Golgi apparatus play in protein sorting?

Post-translational modification and distribution of proteins.

How does the cell manage energy production?

By balancing catabolic and anabolic pathways.

What causes the release of ATP through ATP synthase?

The mechanical rotation of the F0 component.

What are the two types of macromolecules utilized by cells for metabolism?

Proteins and lipids.

In what form is energy ultimately consumed during cellular respiration?

ATP.

How do physical forces contribute to protein structure?

They drive the folding process of polypeptide chains.

What is the outcome of protein misfolding in cells?

Potentially leads to cell stress and disease.

What factors influence the stability of protein structures?

Hydrophobic interactions, hydrogen bonds, ionic bonds, and disulfide bonds.

What is the average duration of conformational change in protein machines?

Usually driven by ATP hydrolysis.

What can prolonged stress on the ER lead to in cells?

Cell apoptosis.

What type of cellular structure is impacted by changes in membrane lipid composition?

Membrane curvature.

What is a key property of chaperone proteins?

They help prevent aggregation during folding.

How do membranes ensure their orientation during vesicle transport?

The cytosolic side always faces the cytosol.

What is the effect of transport proteins on solute movement?

They facilitate movement across the membrane efficiently.

What factors support protein folding within the ER?

Chaperones and appropriate local conditions.

What is the primary purpose of the photosynthesis process?

To convert light energy into chemical energy.

What is emitted from mitochondria as a byproduct of energy production?

Carbon dioxide.

What cellular process is crucial for maintaining homeostasis?

Active transport.

What cellular function is linked with Ras protein abnormalities?

Cancer proliferation.

What determines a protein's biological activity?

Its 3D conformation.

How do membranes handle the transport of large molecules?

Via vesicular transport.

What type of protein structures do membranes consist of?

Lipids and proteins.

How does the body manage increased protein synthesis demands?

By expanding the ER and activating UPR.

What is the essential adaptive mechanism of cells under stress?

The unfolded protein response (UPR).

What is released as energy from ATP during hydrolysis?

Phosphate groups.

How does the cell cycle influence protein synthesis?

Pace and timing go through various checkpoints.

What is the role of tight junctions in epithelial cells?

Prevent leakage and maintain polarity.

What drives the folding of proteins within their cellular environment?

Energetic favorability.

What can misfolded proteins affect in a cell?

Cell viability and function.

What components contribute to membrane fluidity?

Lipid types and cholesterol content.

What facilitates efficient cell signaling through membrane proteins?

Their mobility within the lipid bilayer.

How is ATP produced during cellular respiration primarily?

Through oxidative phosphorylation.

How are membrane domains maintained in epithelial cells?

By tight junctions.

What happens during oxidative phosphorylation?

ATP is synthesized as electrons flow through the electron transport chain.

What factors can denature proteins?

Heat and solvents.