CMM 577 Principles of Cell Biology Quiz

Questions and Answers

What is the primary function of the nucleus in a eukaryotic cell?

Transport lipids and proteins

Store calcium ions

Regulate membrane dynamics

Direct synthesis of proteins and non-coding RNAs (correct)

What distinguishes rough endoplasmic reticulum from smooth endoplasmic reticulum?

Rough ER stores calcium ions

Smooth ER is studded with ribosomes

Rough ER synthesizes carbohydrates

Rough ER synthesizes proteins and phospholipids (correct)

Which of the following best describes the endomembrane system?

A network solely responsible for DNA replication

A series of membranes for cell division

A network that modifies, packages, and transports lipids and proteins (correct)

A structure primarily for energy production

Which type of molecules are primarily found in the membranes of cells?

Lipid molecules Signup and view all the answers

What is a key characteristic of the specialized sarcoplasmic reticulum?

It functions as a calcium store Signup and view all the answers

Which of the following features is associated with the cytoskeletal elements of a cell?

They provide structural support for the cell Signup and view all the answers

What is a function of the smooth endoplasmic reticulum?

Store calcium ions Signup and view all the answers

How do membrane proteins primarily function in a cell's membrane?

They assist in membrane transport and signaling Signup and view all the answers

What is one effect of lipid asymmetry on membrane structure?

It contributes to the stability of the membrane under varying conditions. Signup and view all the answers

Which factor primarily influences the rigidity of lipid bilayers?

The length of the acyl chain of lipids. Signup and view all the answers

What role do membrane rafts play in cellular function?

They act as platforms for protein signaling. Signup and view all the answers

How is protein asymmetry primarily established in membranes?

During the protein biogenesis process. Signup and view all the answers

What is a characteristic of the fluid-mosaic model of membranes?

Lipids and proteins can move laterally within the membrane. Signup and view all the answers

What contributes to the natural tendency of lipids to form bilayers?

The specific shape of lipid molecules. Signup and view all the answers

Which of the following can lead to increased membrane fluidity?

Shorter acyl chains in lipids. Signup and view all the answers

Which feature assists in maintaining membrane integrity against external pressures?

The fluid nature of lipid arrangement. Signup and view all the answers

What is the primary function of the Golgi apparatus in a cell?

Sort, package, and tag molecules for transport. Signup and view all the answers

Which organelle is known as the cell's powerhouse due to its role in ATP production?

Mitochondria Signup and view all the answers

What is one characteristic feature of lysosomes?

They contain many hydrolytic enzymes and have a low pH. Signup and view all the answers

What is the role of the cytoskeleton in a eukaryotic cell?

Maintain cell shape and secure organelles. Signup and view all the answers

What is the primary structural component of biological membranes?

Lipid bilayers Signup and view all the answers

Which of the following best describes the concept of partitioning in cellular membranes?

Separating cell contents from the external environment. Signup and view all the answers

What types of protein fibers are part of the cytoskeleton?

Actin filaments, intermediate filaments, and microtubules. Signup and view all the answers

What distinguishes membranes in eukaryotic cells from prokaryotic cells?

Eukaryotic membranes contain compartmentalized organelles. Signup and view all the answers

What is the primary characteristic of phospholipids that makes them suitable for biological membranes?

They have an amphipathic nature, containing both hydrophobic and hydrophilic regions. Signup and view all the answers

What do sphingolipids primarily contain that distinguishes them from phosphoglycerides?

A sphingosine backbone that is usually saturated. Signup and view all the answers

Which statement accurately describes the role of cholesterol in cell membranes?

Cholesterol provides rigidity and is found in specialized microdomains. Signup and view all the answers

What is one key feature of lipid bilayers regarding their stability?

They are self-assembling and energetically favorable. Signup and view all the answers

What is the significance of membrane asymmetry?

It is crucial for different functions and interactions of membrane components. Signup and view all the answers

What is the primary role of glycolipids in specialized cell types?

They often carry a negative charge and participate in cell recognition. Signup and view all the answers

Why is the composition of lipids in membranes considered complex?

Many lipid types exist, each with unique properties and functions. Signup and view all the answers

What is a distinguishing feature of the glycerol backbone in phosphoglycerides?

It allows for various head groups, imparting distinct properties to the lipids. Signup and view all the answers

Study Notes

Course Overview

CMM 577 focuses on principles of Cell Biology, led by Dr. Shanna Hamilton at the University of Arizona.
Core topics include cell membranes, protein sorting, and organelle functions.

Key Sections and Dates

Introduction and membranes commence on August 27.
Protein sorting sessions are divided into two parts: ER on August 29 and vesicular trafficking on September 3.
Journal club meeting scheduled for September 5.

Learning Outcomes

Students should explain the functions of major organelles.
Describe the structural support provided by cytoskeletal elements.

Structure of Eukaryotic Cells

Cells contain membrane-enclosed compartments for organization and function.
Nucleus acts as the command center, storing DNA and directing protein synthesis.

Endomembrane System

Comprises interconnected components, modifying, packaging, and transporting proteins and lipids.

Endoplasmic Reticulum (ER)

Rough ER: Studded with ribosomes; synthesizes proteins and phospholipids.
Smooth ER: Lacks ribosomes; synthesizes carbohydrates, lipids, and steroid hormones; stores calcium ions.

Golgi Apparatus

Sorts, packages, and tags molecules for transport, critical for cellular function.

Lysosomes

Serve as the cell's garbage disposal with low pH and hydrolytic enzymes for degradation.

Mitochondria

Known as the powerhouse of the cell; generate ATP through aerobic respiration and possess their own DNA.

Cytoskeleton

Composed of actin filaments, microtubules, and intermediate filaments, providing structural support and organelle organization.

Membrane Structures

Membranes are vital for enclosing cellular contents, creating unique environments, and participating in cellular communication.

Lipid Bilayers

Formed by amphipathic phospholipids, creating a hydrophobic barrier that maintains cellular integrity.

Types of Lipids in Membranes

Phosphoglycerides: Most abundant, featuring glycerol backbones and varying head groups.
Sphingolipids: Contain a sphingosine backbone, prevalent in specific microdomains.
Cholesterol: Adds rigidity and is crucial for membrane stability.

Membrane Asymmetry

Lipids and proteins are distributed unevenly across bilayers, vital for various cell functions.

Fluid-Mosaic Model

Membranes are described as fluid matrices with diverse proteins and lipids, allowing for dynamic cellular activities.
Factors influencing membrane fluidity include temperature, lipid structure, and interactions with the cytoskeleton.

Key Factors Affecting Fluidity

Temperature: Higher temperatures increase fluidity.
Lipid Structure: Longer acyl chains provide rigidity; fewer unsaturated fats maintain fluidity.
Protein Interactions: Connections to cytoskeleton and extracellular matrix impact membrane stability and fluidity.

Important Notes

Understanding the dynamic nature of cell membranes is fundamental to grasping cellular processes.
Regular review of core readings and participation in discussions is essential for successful comprehension of these concepts.

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Description

Test your knowledge of the foundational principles of cell biology as covered in CMM 577. This quiz spans topics from membrane structure to protein sorting mechanisms, including discussions from journal clubs. Perfect for Fall 2024 students looking to review key concepts.