BSc Medical Sciences: Cell Structure and Functions

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Questions and Answers

What is the role of the cytoskeleton in a cell?

It synthesizes proteins and lipids.

It stores energy and nutrients.

It provides shape and assists movement. (correct)

It regulates the cell cycle.

In a hypotonic solution, what happens to a cell?

The cell's internal pressure decreases.

The cell shrinks due to water loss.

The cell swells as water enters. (correct)

The cell remains the same size.

What describes an isotonic environment for a cell?

The cell becomes filled with excess water.

Water moves in and out of the cell at equal rates. (correct)

Water leaves the cell at a faster rate.

The cell experiences increased pressure.

Which of the following statements about hypertonic solutions is correct?

Water leaves the cell, causing it to shrink. Signup and view all the answers

What is a common characteristic of organisms in close relation to each other?

They often benefit from each other's presence. Signup and view all the answers

Which of the following statements accurately describes the difference between prokaryotic and eukaryotic cells?

Prokaryotic cells lack membrane-bound organelles, unlike eukaryotic cells. Signup and view all the answers

What defines a prokaryotic cell?

Absence of a defined nucleus Signup and view all the answers

What is the role of the phospholipid bilayer in cellular structure?

It acts as a barrier and regulates the transport of substances. Signup and view all the answers

Which of the following organelles is NOT typically found in eukaryotic cells?

Nucleoid Signup and view all the answers

What role does the nucleus serve in a eukaryotic cell?

Regulation of gene expression Signup and view all the answers

Which component is NOT found within the phospholipid bilayer of a cell membrane?

Nucleic acids Signup and view all the answers

What best describes the origin of new cells?

They originate from the genetic material of existing cells. Signup and view all the answers

Which statement correctly distinguishes between prokaryotic and eukaryotic cells?

Prokaryotic cells are simpler and smaller. Signup and view all the answers

Which of the following statements about cell structure is true?

All living things are made of cells. Signup and view all the answers

Which characteristic is typical of eukaryotic cells?

Presence of multiple organelles Signup and view all the answers

What is the main function of ribosomes in eukaryotic cells?

Site of protein synthesis Signup and view all the answers

Which statement best explains the relationship between cellular structure and function in eukaryotic cells?

Complex structure enables specialization in functions. Signup and view all the answers

In a comparison of prokaryotic and eukaryotic cells, which of the following features is true for eukaryotic cells?

Larger and more complex Signup and view all the answers

What is the primary role of the phospholipid bilayer in the plasma membrane?

To separate hydrophilic and hydrophobic regions Signup and view all the answers

Which type of protein is primarily involved in transport across the plasma membrane?

Integral proteins Signup and view all the answers

What distinguishes active transport from passive transport?

Active transport moves substances against their concentration gradient. Signup and view all the answers

Cholesterol in the plasma membrane primarily serves what function?

Stabilizes the membrane structure Signup and view all the answers

How do carbohydrate molecules contribute to the functions of the plasma membrane?

They are crucial for cell communication and recognition Signup and view all the answers

In which scenario would a cell likely utilize facilitated diffusion?

When moving large polar molecules into the cell Signup and view all the answers

What generally triggers signal transduction in the plasma membrane?

The binding of signaling molecules to receptors Signup and view all the answers

Which transport mechanism would a cell most likely use for the rapid influx of water?

Facilitated diffusion through aquaporins Signup and view all the answers

What characteristic distinguishes eukaryotic cells from prokaryotic cells?

Complex organelles like mitochondria and chloroplasts Signup and view all the answers

Which of the following is a feature of mitochondria and chloroplasts?

They contain prokaryotic-like ribosomes. Signup and view all the answers

What role do embedded proteins in the plasma membrane primarily serve?

Manage entry and exit of substances Signup and view all the answers

Which organism is classified as prokaryotic?

Bacterial cell Signup and view all the answers

Which of the following statements is true regarding the relationship between mitochondria and chloroplasts with eukaryotic cells?

They originated from symbiotic prokaryotes. Signup and view all the answers

What defines a symbiotic relationship between larger and smaller cells?

The smaller cell is enclosed and becomes an organelle. Signup and view all the answers

Which two examples are correctly categorized as eukaryotic organisms?

Dogs and humans Signup and view all the answers

What is one significant characteristic that prokaryotic organisms do not possess compared to eukaryotic organisms?

Complexity of structure Signup and view all the answers

What primary function do mitochondria serve within a cell?

Convert nutrients into ATP through cellular respiration Signup and view all the answers

Which statement accurately describes the endoplasmic reticulum's (ER) rough and smooth types?

Rough ER synthesizes proteins and smooth ER is involved in detoxification. Signup and view all the answers

What is the primary role of the Golgi apparatus in the cell?

Modify, sort, and package proteins for distribution Signup and view all the answers

Which function is not accurately associated with lysosomes?

Transporting nutrients to mitochondria Signup and view all the answers

In relation to cellular functions, how can the endoplasmic reticulum be analogized?

Signup and view all the answers

What is the primary function of mitochondria in the cell?

Converting nutrients into energy Signup and view all the answers

Which statement accurately describes the role of rough endoplasmic reticulum (ER)?

Synthesis and folding of proteins Signup and view all the answers

What is the main function of the Golgi apparatus in relation to proteins?

Modify, sort, and package proteins Signup and view all the answers

Which of the following accurately describes the function of lysosomes?

Breaking down cellular waste and damaged organelles Signup and view all the answers

How does smooth endoplasmic reticulum (ER) function differ from rough ER?

Smooth ER synthesizes lipids while rough ER is involved in protein synthesis. Signup and view all the answers

Study Notes

BSc Medical Sciences: Human Biology Module - Cell Structure and Functions

Cell Theory: A fundamental principle in biology, stating that all living organisms are composed of cells, new cells arise from pre-existing cells, and the cell is the basic unit of life.
Cell Theory Significance: Instrumental in medical and biological advancements, particularly in understanding the development of organisms, diseases, and treatments.
Historical Development: Cell theory was developed in the mid-19th century through the contributions of Schleiden and Schwann. They proposed that plants and animals are made of cells, laying the foundation for the field.
Major Components of Cell Theory:
- All living organisms are composed of one or more cells.
- The cell is the basic unit of life, responsible for all life's processes, including the smallest unit of livings things.
- All cells arise from pre-existing, living cells, supporting the continuity of life.
Cell Classification: Cells are categorized as prokaryotic (lacking a defined nucleus) and eukaryotic (possessing a defined nucleus and complex organelles). This classification helps understand and predict cellular behavior.
Prokaryotic vs. Eukaryotic Cells:
- Prokaryotic cells are generally smaller and simpler, lacking a nucleus and most organelles (e.g., bacteria).
- Eukaryotic cells are larger and more complex, featuring a nucleus and various organelles (e.g., plants, animals). This difference allows for greater internal complexity and function.

Cell Organelles and Functions

Organelles: Eukaryotic cells contain numerous organelles (e.g., nucleus, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus), each performing crucial roles in cell physiology. These organelles manage genetic information, generate energy, aid in protein synthesis, or facilitate detoxification.
Nucleus: The control center of the cell, housing genetic material (DNA). It controls cellular activities by regulating gene expression, vital for growth, division, and specialization.
Mitochondria: The powerhouses of the cell, responsible for converting nutrients into energy (ATP) through cellular respiration, essential for powering cellular processes.
Endoplasmic Reticulum (ER): A network of membranes within the cell, subdivided into smooth ER (lipid synthesis, detoxification) and rough ER (protein synthesis, folding).
Golgi Apparatus: Modifies, sorts, and packages proteins, transferring them to their intended destinations within or outside the cell (think of it as a post office).
Lysosomes: Contain enzymes that break down cellular waste (damaged organelles, foreign particles), crucial for maintaining cellular health.
Cytoskeleton: A network of fibers that maintain cell shape and facilitates movement, both internally (organelles) and externally (cell motility.)

Cellular Evolution (Endosymbiotic Theory)

This theory describes how larger cells engulf smaller cells, forming a symbiotic relationship, where both benefit. This helps explain the evolution of organelles such as mitochondria and chloroplasts, which were once free-living prokaryotes.

Plasma Membrane Structure and Functions

Plasma Membrane: A barrier that separates the cell from its environment, regulating the passage of substances. It's a phospholipid bilayer with embedded proteins (integral, peripheral) that aid in cell communication. Cholesterol provides membrane stability.
Membrane Transport: Cells employ various transport mechanisms (passive and active transport) to move substances across the membrane.
Passive Transport: Includes diffusion, facilitated diffusion, and osmosis, occurring spontaneously without energy expenditure. These mechanisms move substances down their concentration gradient.
Active Transport: Requires energy to move substances against their concentration gradient (pumps, vesicles). This is crucial for maintaining proper cellular concentrations of ions and molecules.
Osmosis: A special type of diffusion involving water movement across a semipermeable membrane, vital for cell volume and pressure maintenance

The Importance of Cell Theory in Modern Biology

Cell theory is essential to understanding biology and medicine, informing research into various areas (e.g., infectious diseases, genetic disorders, therapies) by linking microscopic cellular processes with biological functions.

Worksheet Examples

Classification of Cells: Distinctions between prokaryotic and eukaryotic cells are based on the presence or absence of a nucleus and organelles, with eukaryotic cells being more complex and larger. Examples of each include bacteria (prokaryotic) and plants/animals (eukaryotic)

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Description

Explore the fundamental principles of cell theory and its significance in biology and medicine. This quiz covers historical developments, major components, and the vital role cells play in life processes. Understand how this knowledge is crucial for advancements in medical science.