30 Questions
What is the primary structural unit of life?
Cell
Which of the following is a characteristic of prokaryotic cells?
Presence of a nucleoid
What is the primary function of gut bacteria in the human body?
To produce essential dietary requirements
According to the cell theory, how can cells arise?
Through the division of preexisting cells
What is the main difference between prokaryotic and eukaryotic cells?
Presence or absence of a nucleus
What is the primary function of the plasma membrane?
To control the flow of substances in and out of the cell
What is the function of the Golgi bodies in the cell?
To act as 'marshalling yards' for materials synthesized elsewhere in the cell
What is the primary function of peroxisomes in the cell?
To protect the cell from its own production of toxic hydrogen peroxide
What is the consequence of a defect in the peroxisome associated with Adrenoleukodystrophy (ALD)?
Muscle weakness and heart beat irregularities
What is the pH level at which the hydrolytic enzymes in lysosomes are active?
Highly acidic
What is the result of excess, uncontrolled release of lysosomal enzymes into the cytoplasm?
Cell death (necrosis)
What is the role of the nuclear pores in the process of ribosome synthesis?
To transport large and small subunits into the cytoplasm
What is the function of the internal membrane system in chloroplasts?
To facilitate the light-capturing reactions of photosynthesis
What is the main function of the cytoskeleton in cells?
To provide structural support and determine shape and fluidity
What is the purpose of organelles in eukaryotic cells?
To concentrate enzymatic reactions, separate competing metabolic processes, and segregate harmful products
What is the function of the endoplasmic reticulum (ER)?
To facilitate the transport of molecules between organelles
What is the main component of the cytosol?
Proteins, electrolytes, and carbohydrates
What is the function of lysosomes?
To segregate harmful products from the rest of the cell
What is the primary function of the rough ER in a pancreatic cell?
Protein synthesis
What type of stem cells are capable of giving rise to a potentially functional organism?
Totipotent stem cells
What is the main difference between eukaryotic and prokaryotic cells?
Eukaryotic cells have a true nucleus, while prokaryotic cells do not
Which of the following is a characteristic of embryonic stem cells?
They can divide for a long time in a laboratory
What is the function of the acrosome in a sperm cell?
It helps in the fertilization process
What is the term for the process of cell death?
Apoptosis
What is the result of the absence of a lysosomal enzyme in Tay-Sachs disease?
Fat buildup on nerve cells
What is the function of mitochondria in the cell?
To generate energy for the cell
What is the origin of mitochondrial DNA?
It is inherited from the mother
What is the result of mitochondrial defects in cells?
Cell injury and cell death
What are the main components of the cytoskeleton?
Microtubules, microfilaments, and intermediate filaments
What is a common symptom of mitochondrial disease?
Loss of motor control
Study Notes
Cell Structure and Function
- Cells are the smallest living units capable of growth, movement, reproduction, and responding to stimuli.
- All cells have an outer membrane that separates them from their environment and other cells.
- The outer membrane encloses a solution of proteins, electrolytes, and carbohydrates called cytosol.
- The cytosol is divided into specialist compartments known as organelles by inner membrane systems.
Cellular Organelles
- Nucleus: contains DNA and is responsible for cell division and growth.
- Mitochondria: "powerhouse of the cell," responsible for energy production and abundant in cells with high metabolic rates.
- Endoplasmic Reticulum (ER): covers the cytoplasm with interconnecting channels, studded with ribosomes.
- Golgi apparatus: acts as a "marshalling yard" for materials synthesized elsewhere in the cell, involved in protein synthesis and secretory pathways.
- Lysosomes: break down proteins, lipids, and polysaccharides, and contain 40 or more hydrolytic enzymes.
- Peroxisomes: protect the cell from toxic hydrogen peroxide, involved in β-oxidation of fatty acids and synthesis of bile acids and cholesterol.
- Vesicles: small structures scattered throughout the cytoplasm.
Cellular Processes
- Cell division: occurs through mitosis, which takes 15-20 minutes.
- Cell death: can occur through necrosis, apoptosis, or other mechanisms.
- Protein synthesis: occurs in the ribosomes, which are attached to the Endoplasmic Reticulum.
Stem Cells
- Adult stem cells: multipotent, can differentiate into a limited number of cell types, grow slowly, and are prone to errors.
- Embryonic stem cells: totipotent, can differentiate into any cell type, and can divide for a long time in the lab.
Specialized Cells
- Adipose cells: store energy in the form of fat.
- Sperm cells: have a unique structure with an acrosome, nucleus, mitochondria, and tail.
- Lymphocytes: involved in immune responses, produce cytokines such as IL-10 and TGF-β.
- Pancreatic cells: produce digestive enzymes and hormones.
- Cerebral cortex cells: involved in neural processes and contain mitochondria.
Cell Theory
- All organisms are composed of one or more cells.
- The cell is the structural unit of life.
- Cells can arise only by division from a preexisting cell.
Prokaryotes and Eukaryotes
- Prokaryotes: lack a nucleus, have a nucleoid, and are typically bacteria.
- Eukaryotes: have a nucleus, organelles, and a cytoskeleton, and are typically found in more complex organisms.
Disorders and Diseases
- Adrenoleukodystrophy (ALD): a genetic disorder caused by a lack of protein that transports an enzyme to break down long chain fatty acids.
- Tay-Sachs disease: a lysosomal storage disorder caused by the absence of a lysosomal enzyme.
- Mitochondrial disease: can cause cell injury and death, and symptoms may include loss of motor control, muscle weakness, and gastro-intestinal disorders.
Test your knowledge of cell biology with this quiz on cell theory, prokaryotic and eukaryotic cells, plant and animal cells, organelles, and the plasma membrane. Covers the fundamental concepts of cell biology, including cell structure and function.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
