Cell Biology Chapter: Organelles and Functions

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Questions and Answers

What is the primary function of the cell membrane?

To store genetic information

To allow selective passage of substances (correct)

To produce energy through respiration

To conduct nerve impulses

Which of the following correctly describes the structure of the cell membrane?

A rigid structure with no flexibility

A single layer of phospholipids with no proteins

A completely permeable structure allowing all substances to pass

A trilamellar membrane with two dark layers and a light layer (correct)

What type of proteins form pathways for water-soluble substances across the cell membrane?

Lipid proteins

Microtubule proteins

Peripheral proteins

Integral proteins (correct)

Which component of the cell membrane is responsible for its fluidity and flexibility?

Cholesterol Signup and view all the answers

Which organelle is primarily involved in energy production within the cell?

Mitochondria Signup and view all the answers

What is the role of ribosomes within the cell?

Protein synthesis Signup and view all the answers

Which organelle is responsible for modifying, sorting, and packaging proteins?

Golgi apparatus Signup and view all the answers

Which structure is non-living and considered temporary within the cell?

Inclusion Signup and view all the answers

What is one of the main functions of the rough endoplasmic reticulum?

Protein synthesis Signup and view all the answers

Which of the following correctly describes the appearance of the smooth endoplasmic reticulum under electron microscopy?

Membrane-bound tubules with smooth membrane Signup and view all the answers

What is the role of the Golgi apparatus in relation to proteins?

Concentration and modification of proteins Signup and view all the answers

Which face of the Golgi apparatus is known as the convex face?

Forming face Signup and view all the answers

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

Modification of proteins Signup and view all the answers

What type of enzymes are lysosomes rich in?

Hydrolytic enzymes Signup and view all the answers

Where is the Golgi apparatus typically located in relation to the nucleus?

Surrounding the nucleus Signup and view all the answers

Which of the following functions is primarily associated with lysosomes?

Digestion of cellular waste Signup and view all the answers

What structure is primarily responsible for the recognition functions of the cell surface?

Glycolipid and glycoprotein Signup and view all the answers

Which process requires energy and involves moving substances against their concentration gradient?

Active transport Signup and view all the answers

Which type of endocytosis involves the engulfing of large particles?

Phagocytosis Signup and view all the answers

What is the primary function of mitochondria in a cell?

Cellular respiration and energy production Signup and view all the answers

What distinguishes rough endoplasmic reticulum from smooth endoplasmic reticulum?

Presence of ribosomes Signup and view all the answers

What component of the mitochondria increases the surface area for enzyme deposition?

Cristae Signup and view all the answers

How do substances leave the cell during exocytosis?

Through vesicular transport Signup and view all the answers

What role do matrix granules in mitochondria play?

Binding calcium and magnesium Signup and view all the answers

What are primary lysosomes formed from?

Rough endoplasmic reticulum Signup and view all the answers

Which type of lysosome is formed by the fusion of a primary lysosome with bacteria or viruses?

Heterolysosomes Signup and view all the answers

Which statement about the nucleus is true?

It can have multiple nuclei in certain cell types Signup and view all the answers

What is the structure surrounding the nucleus called?

Nuclear envelope Signup and view all the answers

What is the function of lysosomes regarding old organelles?

To remove them Signup and view all the answers

In which shape can the nucleus NOT appear?

Rectangular Signup and view all the answers

Which type of lysosome fuses with pinocytic vesicles?

Multivesicular lysosome Signup and view all the answers

How can the appearance of the nucleus be described in nerve cells?

Lightly stained and vesicular Signup and view all the answers

Study Notes

The Cell

Fundamental unit of all living tissues.
Smallest living structure capable of independent growth, secretion, excretion, digestion, contraction, respiration and reproduction.
Variable in shape, size and function in different tissues.
Composed of cytoplasm and a nucleus.

Cytoplasm

Contains various organelles essential for the cell's vital process.
Organized into membranous and non-membranous structures.

Membranous Organelles

Cell membrane: Thin boundary of the cell.
Mitochondria: Responsible for cellular respiration and ATP production.
Endoplasmic reticulum: Extensive network responsible for protein synthesis (rough ER) and lipid synthesis (smooth ER).
Golgi apparatus: Involved in protein/lipid modification, packaging and secretion.
Lysosomes: Digest cellular waste and foreign materials like bacteria and viruses.
Peroxisomes: Breakdown fatty acids and detoxify harmful substances.

Non-Membranous Organelles

Ribosomes: Protein synthesis machines found free in the cytoplasm or attached to the rough endoplasmic reticulum.
Cytoskeleton: Network of protein filaments that provide structural support and facilitate cell movement.
Microtubules
Filaments (thin, intermediate, thick)

Cell Membrane

Outermost layer of the cell, composed of a phospholipid bilayer, proteins and carbohydrates.
Lipid component allows passage of fat-soluble substances.
Proteins act as channels for water-soluble substances and receptors for signals.
Carbohydrates (glycolipids and glycoproteins) form the cell coat (glycocalyx) which plays important roles in recognition and cell immunity.
Permeable to some substances, but acts as a barrier for others.

Mitochondrial Structure

Round or oval-shaped organelles with a double membrane:
- Outer membrane: smooth layer
- Inner membrane: Folded into cristae that increase surface area for oxidative phosphorylation.
- Matrix: Contains enzymes, DNA, RNA, lipids, proteins, and carbohydrates.

Mitochondrial Function

Production of cellular energy (ATP).
Responsible for cell respiration.
Replicate themselves independently.

Endoplasmic Reticulum

Extensive, interconnected network of membranes responsible for protein and lipid synthesis.

Rough Endoplasmic Reticulum

Ribosomes attach to its surface and are responsible for protein synthesis.
Packages proteins and transports them to the golgi apparatus.

Smooth Endoplasmic Reticulum

Lacks ribosomes and is involved in lipid and steroid hormone synthesis, glycogen storage, detoxification and calcium ion regulation.

Golgi Apparatus

Stack of flattened, sac-like structures ("cisternae").
Receives proteins and lipids from the ER.
Modifies these substances by adding carbohydrates.
Packages and packages proteins into secretory vesicles.
Forms lysosomes.
Maintains cell membrane stability.

Lysosomes

Small, spherical organelles containing hydrolytic enzymes.
Responsible for intracellular digestion.
Originate from the Golgi apparatus.

Lysosome Types

Primary lysosomes: Newly formed and homogenous.
Secondary lysosomes Contain ingested material and enzymes: - Heterolysosomes (phagosomes) - Contain bacteria or viruses. - Multivesicular lysosomes - Contain pinocytic vesicles. - Autolysosomes - Contain old organelles.
- Residual bodies - Contain undigested remnants.

Lysosomal Function

Digestion of nutrients and cellular waste.
Defense against bacteria and viruses.
Removal of damaged organelles.
Removal of dead cells (autolysis).
Activation of inactive hormones (thyroid hormone).
Penetration of sperm into the ovum.

The Nucleus

Largest and most prominent organelle in most cells.
Control center of the cell, containing DNA and RNA.
Absent in red blood cells and platelets.

Nuclear Structure

Nuclear envelope: Double membrane with nuclear pores that allow passage of molecules between the nucleus and cytoplasm.
Chromatin: DNA and associated proteins condensed into chromosomes during cell division.
Nucleolus: Region of the nucleus involved in ribosome synthesis.
Nuclear sap: Gel-like substance filling the nucleus.

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Description

Explore the fundamental concepts of cell biology, focusing on the structure and function of various organelles. This quiz will test your understanding of both membranous and non-membranous organelles and their roles in cellular processes. Perfect for students learning about the building blocks of life.