Mitochondria Functions and Metabolism Quiz

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Questions and Answers

What is the primary function of the cristae in mitochondria?

Store calcium ions

Increase the surface area for oxidative phosphorylation (correct)

Increase the volume of the mitochondrial matrix

Settle the proton gradient

Mitochondria play a crucial role in which metabolic pathway?

Citric acid cycle (correct)

Glycolysis

Glucose storage

Lipid catabolism

What aspect of mitochondrial DNA allows it to be different from nuclear DNA?

Mitochondrial DNA has multiple copies within the mitochondrion (correct)

Mitochondrial DNA is only present in mature cells

Mitochondrial DNA contains more cytosine than other bases

Mitochondrial DNA is inherited solely from the father

Which process is directly associated with the generation of ATP in mitochondria?

Oxidative phosphorylation Signup and view all the answers

What is the significance of the outer mitochondrial membrane's permeability?

It facilitates the passage of ions and small molecules Signup and view all the answers

Which of the following functions is NOT associated with mitochondria?

DNA replication Signup and view all the answers

How do mitochondria contribute to apoptosis regulation?

Through the production of reactive oxygen species Signup and view all the answers

In which cell types would you most likely find a higher number of mitochondria?

Muscle cells Signup and view all the answers

What is a key characteristic of phospholipids in the plasma membrane?

They are composed of a hydrophilic head and hydrophobic tails. Signup and view all the answers

What role do glycolipids primarily play in the plasma membrane?

They act as cell markers and provide energy. Signup and view all the answers

Which type of proteins is specifically embedded within the lipid bilayer of the plasma membrane?

Transmembrane proteins. Signup and view all the answers

What is one of the main functions of cholesterol in the plasma membrane?

It strengthens the cell membrane. Signup and view all the answers

Which factor is critical for the fluid-dynamic movement within the plasma membrane?

The fluid-mosaic model structure. Signup and view all the answers

Which structural component provides mechanical strength and protection in plant cells?

Plant cell walls. Signup and view all the answers

What type of protein functions as an anchor within the plasma membrane?

Peripheral proteins. Signup and view all the answers

Which feature characterizes glycolipids?

They have carbohydrate groups attached to them. Signup and view all the answers

What role do cellulose microfibrils play in plant cells?

Pressure resistance Signup and view all the answers

Which of the following is NOT a function of hemicellulose in plant cell walls?

Selectivity in permeability Signup and view all the answers

What is one of the primary functions of pectin in plant cell walls?

Pressure adaptation Signup and view all the answers

Which of the following components contributes to the strength of bacterial cell walls?

Peptidoglycan layer Signup and view all the answers

What is the significance of secondary walls in plants?

Physical barrier function Signup and view all the answers

What is a primary function of lysosomes?

Protein degradation Signup and view all the answers

Which enzyme type is primarily found in lysosomes?

Hydrolytic enzymes Signup and view all the answers

Which process is associated with peroxisomes?

Lipid breakdown Signup and view all the answers

What role do lysosomes play in cellular cleanup?

Material recycling Signup and view all the answers

What is NOT a function of peroxisomes?

Protein degradation Signup and view all the answers

What is the primary role of secretory vesicles?

Exporting packaged contents from the cell Signup and view all the answers

Which process involves the fusion of vesicles with the plasma membrane?

Exocytosis Signup and view all the answers

Where do vesicles containing secretory proteins bud off from initially?

Endoplasmic reticulum Signup and view all the answers

What is a major function of the Golgi complex in relation to secretory proteins?

Modification and processing of proteins Signup and view all the answers

Which of the following is NOT a function of secretory vesicles?

Energy production Signup and view all the answers

What kind of proteins are primarily processed and packaged by the Golgi complex?

Glycoproteins Signup and view all the answers

Which mechanism regulates the transport of vesicles within the cell?

Signal molecule processing Signup and view all the answers

What structural characteristic do secretory vesicles typically have?

Single-layered membrane Signup and view all the answers

How are primary lysosomes characterized?

They contain hydrolytic enzymes but are not yet engaged in digestive activity Signup and view all the answers

What is a key feature of peroxisomes?

They generate hydrogen peroxide Signup and view all the answers

What process is involved in lysosome formation?

Budding off the ends of the Golgi cisternae Signup and view all the answers

What role do vacuoles primarily play in plant cells?

Storage and turgor pressure regulation Signup and view all the answers

What distinguishes secondary lysosomes from primary lysosomes?

Secondary lysosomes have fused with food vacuoles or damaged organelles Signup and view all the answers

What is the main function of the selective transport proteins in vacuoles?

To regulate the transport of ions and water Signup and view all the answers

Which statement about hydrolytic enzymes in lysosomes is correct?

They can decompose various cellular constituents Signup and view all the answers

Study Notes

Cell Biology - STBP1023

Course taught by Dr. Nurul Yuziana Mohd Yusof
Focuses on the structure and function of cells.

Structure & Functions of Cells

Organelles, non-organelles, and other subcellular components are examined.
The different types of cells are reviewed in Part 1.
Part 2 details the organelles, including the nucleus, mitochondrion, Endoplasmic Reticulum, Golgi Apparatus, Lysosome & Peroxisome, Vacuole, and Chloroplast.
Part 3 covers non-organelles: Cell Wall, Cytoskeleton, Ribosomes, cell coats, and cell junctions.
Three different kingdoms – Eukarya, Bacteria, and Archaea.

Types of Cells

Eukaryotic cells contain a nucleus and other membrane-bound organelles.
Prokaryotic cells lack a nucleus or membrane-bound organelles.
Archaea: Structurally similar to prokaryotic cells, but have several genes and biochemical pathways similar to eukaryotes. Extremophiles (e.g., methanogens, halophiles, acidophiles, thermophiles).

Prokaryotic Cell

Lack a nucleus and membrane-bound organelles.
Key components: plasma membrane, cell wall, DNA (nucleoid), ribosomes, capsule, and flagella.

Archaeal Cell

Similar in size to prokaryotic cells.
Two membranes.
Contain DNA and ribosomes.
Have some metabolic pathways similar to those in eukaryotic cells.
Often found in extreme environments (extremophiles).

Eukaryotic Cells (Animal and Plant)

Eukaryotic cells are characterized by a nucleus and membrane-bound organelles.
Diagrams illustrating the different organelles and their locations within animal and plant cells are included.

Subcellular Components (Organelles and Non-Organelles)

Organelles (membrane-bound): nucleus, mitochondrion, endoplasmic reticulum (rough and smooth), Golgi complex, vacuoles, peroxisomes, lysosomes, chloroplast
Non-organelles (non-membrane-bound): plasma membrane, cell wall, cytoskeleton (microtubules, microfilaments, intermediate filaments), cytosol, ribosomes

Homeostasis

A state of balance among all body systems needed for survival and function.
Involves regulation through systems to maintain optimal conditions.
The relationship with cell organelles is crucial.
Cell organelles are specialized for maintaining specific aspects of cellular balance.
The integrated network of organelles allows coordinated responses and understanding these relationships is helpful for medical research, disease treatment, and cell engineering.

The Nucleus

Structure: double membrane (nuclear envelope), nucleoplasm, nucleolus, chromatin, nuclear pores
Function: stores genetic information (DNA—chromosomal organization), DNA replication, regulation of gene expression, control of protein synthesis.
Role in Homeostasis: coordination of cellular responses, maintenance of genetic integrity.

The Mitochondrion

Structure: outer and inner membranes (cristae), matrix
Function: ATP production through cellular respiration (oxidative phosphorylation, electron transport chain, proton gradient), role in metabolic pathways (citric acid cycle, fatty acid oxidation, amino acid metabolism).
Role in Homeostasis: energy supply for cellular processes, regulation of ATP availability, and adjustment of metabolic rate.

The Endoplasmic Reticulum

Structure: smooth ER versus rough ER; structural differences and distribution in cells, continuous membrane system, connection to the nuclear envelope; transport mechanisms; spatial organization.
Function: Protein synthesis and folding (rough ER—ribosome attachment, protein translocation, quality control); Lipid synthesis and detoxification (smooth ER—membrane lipid production, steroid hormone synthesis, drug metabolism).
Role in Homeostasis: Quality control of proteins; unfolded protein response; protein trafficking, ER stress management; modulation of lipid levels, membrane composition regulation, lipid distribution, and cellular stress response.

Golgi Apparatus

Structure: stacked cisternae; structural organization; membrane composition; vesicle formation; polarized structure (cis & trans faces)
Function: Modification of proteins and lipids (glycosylation, protein processing, sorting signals), packaging for secretion and/or delivery; vesicle formation; protein targeting; quality control.
Role in Homeostasis: regulation of cellular transport, membrane traffic control, protein distribution, vesicle targeting, maintenance of cellular communications, secretory pathway regulation, signal molecule processing , and membrane composition control.

Secretory Vesicles

Contains proteins and substances processed by the Golgi complex.
Vesicles move from the Golgi to the plasma membrane and discharge their contents into the extracellular space.

Lysosomes and Peroxisomes

Structure: membrane-bound vesicles; single membrane; specific protein composition
Function: breakdown of macromolecules (protein, lipid, carbohydrate processing), autophagy (cellular recycling), role in stress response.
Peroxisomes: breakdown of fatty acids, hydrogen peroxide production, detoxification processes.
Role in Homeostasis: cellular cleanup, recycling, waste management, material recycling, quality control, and regulation of metabolic byproducts (toxin elimination, ROS management)

Vacuoles

Structure: membrane (tonoplast); selective transport proteins
Function: storage (water retention, turgor pressure maintenance), nutrient/ion storage (Ca2+, K+, NO3-), waste products; secondary metabolites, detoxification; defense function (alkaloids, tannins, protease inhibitors)
Role in Homeostasis: turgor pressure regulation(cell expansion and growth, structural support); pH and ion balance (cytoplasmic pH regulation, ion concentration control, metal ion sequestration, salt stress management).

Chloroplasts

Structure: membrane systems, internal compartments (stroma, thylakoid membrane)
Function: Photosynthesis (light-dependent reactions, electron transport chain, ATP synthesis, NADPH production; carbon fixation, Calvin cycle, sugar synthesis, starch production, photorespiration).
Role in Homeostasis: energy balance; glucose production, ATP generation, NADPH supply, energy storage as starch; maintenance of redox state (ROS management, antioxidant production, photoprotection mechanisms)

Cell Walls

Structure: varies across cell types (plant, fungal, bacterial)
Function: provides structural support (mechanical strength, shape maintenance, growth regulation), protection (physical barrier, stress resistance, environmental protection, selective permeability), and plays a role in cell-cell communication and interaction (recognition, transport regulation).
Note: cell wall is rigid and encases the plant cell.

Cytoskeletons

Structure: composed of microtubules, microfilaments, and intermediate filaments.
Function: maintains and establish cell shape; important roles in cell movement and cell division; positioning of organelles within cytoplasm; influence in cell motility and cytoplasmic streaming; structural support.
Role in Homeostasis: structural homeostasis, transport homeostasis, mechanical response, and force distribution.

Ribosomes

Structure: prokaryotic and eukaryotic ribosomes, differing in size (70S and 80S)
Function: Protein synthesis
Role in Homeostasis: protein homeostasis; regulation of translation; energy balance and efficiency; resource allocation

Cell Coats and Junctions

Cell Coats (glycocalyx): trans-membrane adsorbed glycoproteins, glycolipid with attached carbohydrate, function as cell markers and source of energy
Cell-to-cell junctions: strengthen the cell surface and hold cells together , important in cell recognition, and intercellular communications (gap junctions, tight junctions and desmosomes)

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Description

Test your knowledge on mitochondria and their essential roles in cellular metabolism. This quiz covers topics such as the structure of mitochondria, their involvement in ATP production, and their genetic characteristics. Dive into the fascinating world of mitochondria and evaluate your understanding of their functions in cells.