The Cell as a Unit of Health and Disease

A comprehensive set of 30 flashcards summarizing key concepts from the lecture on cellular structure and function, focusing on eukaryotic cells and their significance in health and disease.

What are the main characteristics of eukaryotic cells?

Membrane-bound nucleus, linear and organized DNA into chromosomes, and presence of membrane-bound organelles.

What does compartmentalization in eukaryotic cells contribute to?

Efficiency, safety, and the creation of unique intracellular environments.

What is the primary function of mitochondria?

Energy generation through ATP production.

What is the composition of the plasma membrane?

Phospholipids, cholesterol, glycolipids, transmembrane proteins, lipid-anchored proteins, and peripheral membrane proteins.

What role do lysosomes play in the cell?

Degradation of biological macromolecules using acidic hydrolases.

What is the significance of the nucleolus?

Site of ribosomal RNA transcription and ribosome subunit assembly.

What is the structure of chromatin?

Chromatin is composed of nucleosomes containing DNA wrapped around histone proteins.

How do proteins enter the nucleus?

Through nuclear pore complexes via active transport using importins.

What is the difference between heterochromatin and euchromatin?

Heterochromatin is dense and inactive, while euchromatin is dispersed and active in transcription.

What occurs during the process of autophagy?

Recycling of nutrients or damaged organelles when cells face nutrient deficiency.

What happens to lysosomal enzymes in the Golgi apparatus?

They are modified with mannose-6-phosphate for transport to lysosomes.

What is the role of microtubules in the cell?

Provide mechanical support, transport organelles, and participate in cell division.

What type of proteins are involved in mitochondrial movement?

Dynein and kinesin motor proteins.

What characterizes adult stem cells?

They have the ability for self-renewal and can differentiate into specialized cell types.

What is the process of protein synthesis in the rough endoplasmic reticulum?

Proteins are synthesized, undergo cotranslational modifications, and fold properly in the ER.

What is a nucleosome?

A structure consisting of DNA wrapped around a core of histone proteins.

What are the two main pathways of apoptosis?

Intrinsic and extrinsic pathways.

What does the term 'treadmilling' refer to in cytoskeleton dynamics?

The process where one end of a filament grows while the other end shrinks.

What is the consequence of defective CDK inhibitors in the cell cycle?

Cells with damaged DNA may divide, leading to mutations and potential malignancy.

What defines the endoplasmic reticulum's role in cellular processes?

Site of lipid and protein synthesis for membrane dynamics.

What is the inherited pattern of Leber hereditary optic neuropathy (LHON)?

Maternal inheritance through mitochondrial DNA.

How does cholesterol affect membrane fluidity?

It decreases fluidity at high temperatures and increases fluidity at low temperatures.

What cell types can be derived from embryonic stem cells?

Ectoderm, mesoderm, and endoderm, resulting in various tissues.

What triggers the unfolded protein response (UPR)?

The accumulation of misfolded or unfolded proteins in the endoplasmic reticulum.

What happens during the G1 phase of the cell cycle?

Cell growth and preparation for DNA synthesis.

What are the main components of the endoplasmic reticulum?

Cisternae made of phospholipid membranes.

What is the role of growth factors in cellular functions?

Promote cell growth, division, and differentiation.

What is a key characteristic of stem cells?

The ability to self-renew while also differentiating into specialized cell types.

What process occurs during cell fusion and blood coagulation?

Asymmetrical distribution of lipids in the membrane facilitates these processes.

What is the role of proteasomes?

Degrade unneeded or damaged proteins in the cell.

How is the Golgi apparatus structured in relation to its function?

It has a cis face and a trans face, facilitating the sequential modification and sorting of molecules.

What is the main feature of mitochondrial DNA?

It is circular and maternally inherited.

How is autophagy generally viewed in relation to cell survival?

It can be beneficial or detrimental depending on the context of activation.

What role does the cytoskeleton play in cellular processes?

Maintains cell shape, organizes organelles, and facilitates internal transport.

What are the main characteristics of eukaryotic cells?

Membrane-bound nucleus, linear and organized DNA into chromosomes, and presence of membrane-bound organelles.

What does compartmentalization in eukaryotic cells contribute to?

Efficiency, safety, and the creation of unique intracellular environments.

What is the primary function of mitochondria?

Energy generation through ATP production.

What is the composition of the plasma membrane?

Phospholipids, cholesterol, glycolipids, transmembrane proteins, lipid-anchored proteins, and peripheral membrane proteins.

What role do lysosomes play in the cell?

Degradation of biological macromolecules using acidic hydrolases.

What is the significance of the nucleolus?

Site of ribosomal RNA transcription and ribosome subunit assembly.

What is the structure of chromatin?

Chromatin is composed of nucleosomes containing DNA wrapped around histone proteins.

How do proteins enter the nucleus?

Through nuclear pore complexes via active transport using importins.

What is the difference between heterochromatin and euchromatin?

Heterochromatin is dense and inactive, while euchromatin is dispersed and active in transcription.

What occurs during the process of autophagy?

Recycling of nutrients or damaged organelles when cells face nutrient deficiency.

What happens to lysosomal enzymes in the Golgi apparatus?

They are modified with mannose-6-phosphate for transport to lysosomes.

What is the role of microtubules in the cell?

Provide mechanical support, transport organelles, and participate in cell division.

What type of proteins are involved in mitochondrial movement?

Dynein and kinesin motor proteins.

What characterizes adult stem cells?

They have the ability for self-renewal and can differentiate into specialized cell types.

What is the process of protein synthesis in the rough endoplasmic reticulum?

Proteins are synthesized, undergo cotranslational modifications, and fold properly in the ER.

What is a nucleosome?

A structure consisting of DNA wrapped around a core of histone proteins.

What are the two main pathways of apoptosis?

Intrinsic and extrinsic pathways.

What does the term 'treadmilling' refer to in cytoskeleton dynamics?

The process where one end of a filament grows while the other end shrinks.

What is the consequence of defective CDK inhibitors in the cell cycle?

Cells with damaged DNA may divide, leading to mutations and potential malignancy.

What defines the endoplasmic reticulum's role in cellular processes?

Site of lipid and protein synthesis for membrane dynamics.

What is the inherited pattern of Leber hereditary optic neuropathy (LHON)?

Maternal inheritance through mitochondrial DNA.

How does cholesterol affect membrane fluidity?

It decreases fluidity at high temperatures and increases fluidity at low temperatures.

What cell types can be derived from embryonic stem cells?

Ectoderm, mesoderm, and endoderm, resulting in various tissues.

What triggers the unfolded protein response (UPR)?

The accumulation of misfolded or unfolded proteins in the endoplasmic reticulum.

What happens during the G1 phase of the cell cycle?

Cell growth and preparation for DNA synthesis.

What are the main components of the endoplasmic reticulum?

Cisternae made of phospholipid membranes.

What is the role of growth factors in cellular functions?

Promote cell growth, division, and differentiation.

What is a key characteristic of stem cells?

The ability to self-renew while also differentiating into specialized cell types.

What process occurs during cell fusion and blood coagulation?

Asymmetrical distribution of lipids in the membrane facilitates these processes.

What is the role of proteasomes?

Degrade unneeded or damaged proteins in the cell.

How is the Golgi apparatus structured in relation to its function?

It has a cis face and a trans face, facilitating the sequential modification and sorting of molecules.

What is the main feature of mitochondrial DNA?

It is circular and maternally inherited.

How is autophagy generally viewed in relation to cell survival?

It can be beneficial or detrimental depending on the context of activation.

What role does the cytoskeleton play in cellular processes?

Maintains cell shape, organizes organelles, and facilitates internal transport.

Which organelle has double lipid bilayers (inner and outer membrane)?

Mitochondria.

Which histone proteins form the octamer core of a nucleosome?

Two copies each of H2A, H2B, H3, and H4.

What is the molecular weight threshold below which molecules can freely diffuse through nuclear pore complexes?

Approximately 40 \text{ kDa}.

What are caveolae in a plasma membrane?

Cholesterol-enriched membrane invaginations.

Which phospholipids are predominantly located on the inner leaflet of the plasma membrane under normal physiological conditions?

Phosphatidylserine (PS) and phosphatidylethanolamine (PE).

Which type of cytoskeletal filament has the largest diameter?

Microtubules.

Which cytoskeletal elements require energy (ATP or GTP) for assembly?

Both actin filaments and microtubules.

Which motor protein moves cargo toward the minus (-) end of microtubules?

Dynein.

What is the primary function of the nucleolus?

Ribosomal RNA synthesis and ribosome assembly.

Which organelle is the site of the unfolded protein response (UPR)?

The endoplasmic reticulum.

What signal targets lysosomal hydrolases to lysosomes?

Mannose-6-phosphate (M6P).

Approximately what percentage of cellular proteins is degraded by the ubiquitin-proteasome system?

Approximately 80\%.

What is the optimal pH for lysosomal hydrolases?

\text{pH} \le 5.0.

Which of the following does NOT support the endosymbiosis theory for mitochondrial origin: Mitochondria are similar in size to bacteria, circular DNA, double membrane structure, or division by meiosis?

Mitochondria divide by meiosis.

What is the inheritance pattern of Leber Hereditary Optic Neuropathy (LHON)?

Maternal inheritance.

Which cell cycle checkpoint prevents chromosome separation until all chromosomes are properly attached to the spindle?

The spindle assembly checkpoint.

What is the most common type of Gaucher disease?

Type I (no neurological involvement).

Which enzyme is deficient in Krabbe disease?

Galactocerebrosidase.

What is the primary function of peroxisomes?

Detoxification of reactive oxygen species and fatty acid catabolism.

Which organelle is affected by Tay-Sachs disease due to the accumulation of GM2 ganglioside?

Lysosomes.

How is Tay-Sachs disease most likely acquired?

Inheritance of the same or different HEXA mutations from both parents (autosomal recessive inheritance).