Cells and Their Functions

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Questions and Answers

What are cells fundamental to?

Physics

Biology (correct)

Chemistry

Mathematics

All organisms are made of cells.

True

What do muscle cells do?

They contract to move body parts.

Cells share common features due to their descent from earlier ______.

cells Signup and view all the answers

What tools do biologists use to study cells?

Microscopes Signup and view all the answers

What is housed in the nucleus of eukaryotic cells?

Genetic instructions Signup and view all the answers

Cell walls were first seen by Robert Hooke in 1665.

True Signup and view all the answers

What primary function is associated with the endoplasmic reticulum in the endomembrane system?

Synthesis and transport of proteins and lipids Signup and view all the answers

Which component is NOT part of the endomembrane system?

Mitochondria Signup and view all the answers

How is the endoplasmic reticulum (ER) related to the nuclear envelope?

It is continuous with the nuclear envelope. Signup and view all the answers

What does the ER lumen refer to?

The continuous compartment enclosed by the ER membrane Signup and view all the answers

What distinguishes the rough ER from the smooth ER?

The presence of ribosomes attached to its surface Signup and view all the answers

Which of the following statements about the membranes in the endomembrane system is true?

Membranes can have their thickness and composition modified over time. Signup and view all the answers

What is one of the roles of vesicles in the endomembrane system?

Transporting membrane segments between different organelles Signup and view all the answers

Which of these functions is NOT performed by the endomembrane system?

Phototrophic energy capture Signup and view all the answers

What characteristic distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells have internal membranes that compartmentalize functions. Signup and view all the answers

How would light microscopy and electron microscopy stains differ generally?

Light microscopy stains are used for viewing living cells, whereas electron microscopy stains are not. Signup and view all the answers

What is the primary function of the organelles found within the cytoplasm of eukaryotic cells?

They carry out specialized metabolic functions. Signup and view all the answers

What does the term 'cytoplasm' refer to in the context of eukaryotic cells?

The liquid portion outside the nucleus and inside the plasma membrane. Signup and view all the answers

Which of the following best describes the evolutionary relationship of prokaryotic and eukaryotic cells?

Prokaryotic cells evolved before eukaryotic cells. Signup and view all the answers

What type of microscopy would be best for observing the details of surface texture of a hair?

Electron microscopy is preferred for its visualization of surface details. Signup and view all the answers

What role does the cytosol play within eukaryotic cells?

It suspends organelles and facilitates metabolic processes. Signup and view all the answers

What initiates the method of isolating organelles for study in cell biology?

Exploiting differences in sedimentation using centrifugation. Signup and view all the answers

What is the primary function of the Golgi apparatus in the endomembrane system?

Modification and distribution of lipids and proteins Signup and view all the answers

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

Rough ER has ribosomes attached, while smooth ER does not. Signup and view all the answers

Which of the following correctly describes the relationship among organelles in the endomembrane system?

Transport vesicles carry substances to and from the Golgi apparatus. Signup and view all the answers

What is the role of lysosomes in the cell?

Digesting waste material and cellular debris Signup and view all the answers

What best describes the function of transport vesicles in cellular processes?

They carry lipids and proteins to various destinations. Signup and view all the answers

How does the cytosol contribute to the organization of the endomembrane system?

It allows for the flow of membrane lipids and proteins among organelles. Signup and view all the answers

What happens to the plasma membrane as vesicles fuse with it?

It expands by incorporating new proteins. Signup and view all the answers

In the context of plant cells, what is the significance of the central vacuole?

It maintains osmotic pressure and stores nutrients. Signup and view all the answers

What do prokaryotes comprise?

Bacteria and archaea Signup and view all the answers

Which of the following correctly describes the plasma membrane's structure within a red blood cell?

It appears as a pair of dark bands separated by a light band. Signup and view all the answers

In geometric terms, how is total surface area calculated?

Sum of the surface areas of all box sides Signup and view all the answers

What is the result of increasing surface area while keeping total volume constant?

Increase in surface-to-volume ratio Signup and view all the answers

Identify the components of the plasma membrane as shown in the provided figure.

Phospholipids, proteins, and carbohydrate side chains Signup and view all the answers

What defines the hydrophilic and hydrophobic regions of the plasma membrane?

Their charge properties and interaction with water Signup and view all the answers

What does the surface-to-volume ratio measure?

Surface area of a cell compared to its volume Signup and view all the answers

Which of the following is true regarding prokaryotic cell structure?

Prokaryotic cells have a simpler structure compared to eukaryotic cells. Signup and view all the answers

What key characteristic of phospholipids allows them to form the bilayer in the plasma membrane?

They have hydrophilic heads and hydrophobic tails. Signup and view all the answers

How does the surface area to volume ratio change as the size of a cell increases?

It decreases because volume grows faster than surface area. Signup and view all the answers

What is the primary function of the internal membranes in eukaryotic cells?

They facilitate specific metabolic functions by creating compartments. Signup and view all the answers

What role do membrane proteins play in the plasma membrane?

They assist in the exchange of materials across the membrane. Signup and view all the answers

Which part of a phospholipid remains in contact with the aqueous solution?

The hydrophilic heads. Signup and view all the answers

What critical property of membranes allows many enzymes to participate in cellular metabolism?

Many enzymes are embedded within the membranes. Signup and view all the answers

What is the implication of a high surface-to-volume ratio for cellular function?

It facilitates efficient exchange of materials with the environment. Signup and view all the answers

As a consequence of the geometry of cells, how does surface area relate to volume when considering growth?

Surface area increases at a slower rate than volume. Signup and view all the answers

Study Notes

The Fundamental Units of Life

Cells are the foundation of living systems, similar to atoms in chemistry.
Cells are involved in various bodily functions, such as muscle contraction and nerve cell communication.
All organisms, single-celled or multicellular, are composed of cells.
Multicellular organisms rely on specialized cells working together to function.
Cells are the basic unit of structure and function in all organisms.
Cells descended from previous cells, leading to diverse adaptations.
Despite their variations, cells share fundamental characteristics.

Tools to Study Cells

Microscopes and biochemical techniques are used to study cells.
Microscopes, invented in the 1590s, enabled the discovery and initial study of cells.
Robert Hooke observed cell walls in dead cells in 1665 using a microscope.

Microscopy

Stains used for light microscopy differ from those used for electron microscopy.
Researchers use microscopy to identify organelles and their functions.

Prokaryotic Cells

Prokaryotes lack a nucleus.
Prokaryotes include bacteria and archaea.
The term prokaryotic means “before nucleus”.
Prokaryotes evolved before eukaryotic cells.

Eukaryotic Cells

Eukaryotic cells have internal membranes that compartmentalize their functions.
The region between the nucleus and the plasma membrane in a eukaryotic cell is called the cytoplasm
Cytosol is the fluid within the cytoplasm.

The Endomembrane System

The endomembrane system regulates protein traffic and performs metabolic functions.
The endomembrane system includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles, vacuoles, and the plasma membrane.
The endomembrane system synthesizes proteins, transports proteins, metabolizes lipids, and detoxifies poisons
The membranes of the endomembrane system can be connected by direct physical continuity or transfer of membrane segments in vesicles.

Endoplasmic Reticulum (ER)

The endoplasmic reticulum (ER) is an extensive network of interconnected tubules and flattened sacs.
The ER is a biosynthetic factory.
Smooth ER is involved in lipid synthesis, detoxification, and calcium storage.
Rough ER is studded with ribosomes and involved in protein synthesis.
The ER lumen is the space enclosed by the ER membrane.

Golgi Apparatus

The Golgi apparatus is a stack of flattened sacs known as cisternae.
The Golgi apparatus modifies, sorts, and packages proteins and lipids from the ER.

Lysosomes

Lysosomes are membrane-bound organelles that contain enzymes for digestion.

Vacuoles

Vacuoles are large membrane-bound sacs.
Vacuoles store water and other substances.

Plasma Membrane

The plasma membrane is a selectively permeable barrier that surrounds the cell
The plasma membrane controls the movement of substances into and out of the cell.
The plasma membrane is composed of a phospholipid bilayer with embedded proteins.
The cell membrane is also known as the plasma membrane.

The Importance of Surface Area to Volume Ratio

As a cell grows, its volume increases faster than its surface area.
A smaller object has a greater surface area to volume ratio.
A high surface-to-volume ratio allows for efficient exchange of materials between a cell and its environment.

Compartmentalization

The internal membranes of eukaryotic cells divide the cells into different compartments.
Compartmentalization provides specific environments for different metabolic functions.

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Description

Explore the fundamental units of life through this quiz on cells. Learn about the structure, function, and specialized roles of cells in both single-celled and multicellular organisms. Test your knowledge on historical tools like microscopes that revolutionized cell study.