Cytology Study by Dr. Esam El-Shwihy

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary function of free ribosomes in a cell?

Synthesis of secretory proteins

Formation of lysosomal enzymes

Synthesis of structural proteins for internal use (correct)

Production of ribosomal subunits

Where are ribosomal subunits produced?

Endoplasmic reticulum

Nucleolus (correct)

Nucleus

Cytoplasm

What characterizes rough endoplasmic reticulum (rER)?

It is primarily involved in lipid synthesis.

It regulates calcium levels in muscle cells.

It gives a localized cytoplasmic basophilia due to attached ribosomes. (correct)

It has a smooth surface with no ribosomes attached.

What is the primary function of the glycocalyx associated with the external surface of the cell membrane?

Recognition, protection, and intercellular adhesions Signup and view all the answers

Which of the following is NOT a function of smooth endoplasmic reticulum (sER)?

Protein synthesis for secretion Signup and view all the answers

How does rough endoplasmic reticulum (rER) aid in the function of the Golgi apparatus?

By transferring newly synthesized proteins through vesicles. Signup and view all the answers

What distinguishes active transport from passive transport?

Active transport requires energy to move molecules against their concentration gradient Signup and view all the answers

Which process involves the incorporation of solid particles into the cell?

Phagocytosis Signup and view all the answers

What is the main role of the Golgi apparatus?

Packaging and modifying proteins Signup and view all the answers

What is the main characteristic of receptor-mediated endocytosis?

It requires specific receptors for substances at the cell surface Signup and view all the answers

In which type of cells is the Golgi apparatus typically found in a supranuclear position?

Secretory cells Signup and view all the answers

What is a common characteristic of free ribosomes?

They produce proteins that function within the cytoplasm. Signup and view all the answers

What are the folds of the inner membrane of mitochondria called?

Cristae Signup and view all the answers

Which statement about mitochondrial structure is true?

Each mitochondrion has a smooth outer membrane and a folded inner membrane Signup and view all the answers

The sodium-potassium pump is an example of which type of transport?

Active transport Signup and view all the answers

What characterizes the ribosomes found attached to the rough endoplasmic reticulum (rER)?

They make proteins destined for secretion. Signup and view all the answers

What is the function of the cristae in mitochondria?

To increase surface area for ATP production Signup and view all the answers

Which of the following structures gives rough endoplasmic reticulum its granular appearance?

Attached ribosomes and polyribosomes Signup and view all the answers

What components are present in the mitochondrial matrix space?

Free ribosomes and dense granules of Ca+ ions Signup and view all the answers

What role does exocytosis play in cellular function?

It releases cell products into the extracellular space Signup and view all the answers

Which statement about mitochondrial DNA is accurate?

Mitochondria can replicate independently of the cell. Signup and view all the answers

Which of the following is true regarding the outer mitochondrial membrane?

It resembles the cytosol in composition. Signup and view all the answers

How does the cell membrane appear under low magnification in an electron microscope?

As a dense thin line. Signup and view all the answers

Which of the following best describes ribosomes at high magnification?

They consist of two subunits, large and small. Signup and view all the answers

What is the main function of the cell membrane?

It maintains structural integrity. Signup and view all the answers

Which of the following is part of the protoplasm within a cell?

Organelles Signup and view all the answers

What structure forms the nucleolus within the nucleus?

Nuclear matrix Signup and view all the answers

How do mitochondria contribute to cellular calcium regulation?

By maintaining calcium levels to avoid toxicity. Signup and view all the answers

What is a characteristic of integral (intrinsic) proteins in the cell membrane?

They span across the lipid bilayer. Signup and view all the answers

Which component is NOT essential for the life of the cell?

Inclusions Signup and view all the answers

In the fluid-mosaic model, what contributes to the fluid property of the lipid bilayer?

Phospholipids bilayer structure. Signup and view all the answers

What is the approximate thickness of the cell membrane as seen under high magnification of an electron microscope?

3 nm Signup and view all the answers

What is the appearance of the Golgi apparatus after H&E staining in cells with intensely basophilic cytoplasm?

Clear unstained area near the nucleus Signup and view all the answers

Which facet of the Golgi apparatus is directed towards the rough endoplasmic reticulum?

Cis-face Signup and view all the answers

What do secretory vesicles bud off from in the Golgi apparatus?

Trans-face Signup and view all the answers

What process does the Golgi apparatus perform to modify newly synthesized proteins?

Glycosylation Signup and view all the answers

What are primary lysosomes primarily characterized by?

Homogenous content Signup and view all the answers

Which of the following correctly describes secondary lysosomes?

Formed by the fusion of primary lysosomes with other substances Signup and view all the answers

Where are lysosomal enzymes synthesized before being transported to the Golgi complex?

Rough endoplasmic reticulum Signup and view all the answers

What occurs when a primary lysosome interacts with a phagocytic vacuole?

Formation of a phagosome Signup and view all the answers

Study Notes

Cytology Overview

Cytology is the study of cells, which are structural and functional units of organisms.
Main components of a cell:
- Cell membrane (plasmalemma)
- Protoplasm, divided into cytoplasm and nucleus.

Cell Structure

Cytoplasm: Contains:
- Cytosol: Semifluid matrix.
- Organelles: Active structures essential for cell life.
- Inclusions: Non-essential storage forms of nutrients and pigments.
Nucleus: Contains:
- Nuclear envelope
- Nucleolus
- Chromatin
- Nuclear matrix

Cell Membrane

Every cell is enclosed by a cell membrane with several functions:
- Maintains structural integrity.
- Controls substance movement (selective permeability).
- Recognizes antigens and foreign cells.
Not visible under light microscopy; appears as a trilaminar structure under electron microscopy with outer and inner dense lines.

Molecular Structure of Cell Membrane

Follows the fluid-mosaic model, consisting of:
- Phospholipid bilayer
- Cholesterol
- Proteins (integral and peripheral).

Transport Mechanisms

Passive Transport: Molecules move based on concentration gradients without energy.
Active Transport: Movement against concentration gradients requiring energy (e.g., sodium-potassium pump).
Vesicle-mediated Transport:
- Endocytosis: Intake of materials (includes phagocytosis and receptor-mediated endocytosis).
- Exocytosis: Release of substances to the extracellular environment.

Mitochondria

Membranous organelles that produce ATP, found in all cells except mature red blood cells.
Structure includes:
- Smooth outer membrane
- Folded inner membrane (cristae) increasing surface area.
- Matrix space containing enzymes, RNA, DNA.
Functions:
- ATP production and calcium concentration regulation.
- Self-replicating organelles containing their own genetic material.

Ribosomes

Non-membranous organelles made of rRNA and proteins, present in all cells except mature erythrocytes.
Types:
- Free Ribosomes: Scattered in the cytoplasm, synthesize internal proteins.
- Attached Ribosomes: Located on rough endoplasmic reticulum, synthesize secretory proteins.
Visible under electron microscopy as small, dense particles; consist of large and small subunits.

Endoplasmic Reticulum (ER)

Comprises two types:
- Smooth ER (sER): Lacks ribosomes, involved in lipid synthesis, detoxification, glycogen metabolism, and calcium regulation.
- Rough ER (rER): Studded with ribosomes, synthesizes secretory proteins, lysosomal enzymes, and membrane proteins.

Golgi Apparatus

Membranous organelle acting as a processing and packaging center.
Structure includes:
- Stacks of flattened, smooth cisternae.
- Cis-face (receives vesicles from rER) and Trans-face (where vesicles bud off).
Functions include modifying proteins, packaging lysosomes and secretions, and recycling membrane components.

Lysosomes

Membranous organelles containing hydrolytic enzymes for intracellular digestion.
Types:
- Primary Lysosomes: Newly formed with homogeneous content.
- Secondary Lysosomes: Formed by the fusion with other organelles or substances; contain varying contents.
Functions include degrading cellular waste and releasing residual materials through exocytosis.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the fascinating field of cytology with this quiz based on the work of Dr. Esam El-Shwihy. Test your knowledge on cell structures, microscopy techniques, and various staining methods used to study cells. Perfect for students and enthusiasts looking to deepen their understanding of cellular biology.