Cell Biology Quiz: Understanding Cells and Diseases

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Questions and Answers

What is the primary reason for understanding the cellular basis of a disease?

To diagnose the disease more accurately. (correct)

To learn about different types of tissues in the body.

To track the inheritance patterns of traits.

To understand the environmental impact on cells.

Which of the following correctly distinguishes somatic cells from germ cells?

Somatic cells are haploid, while germ cells are diploid.

Somatic cells contribute to genetic material for offspring, while germ cells do not.

Somatic cells are reproductive, while germ cells are body cells.

Somatic cells are diploid, while germ cells are haploid. (correct)

What role do organelles play in the functioning of a cell?

They interact to secrete substances, generate energy, and remove waste. (correct)

They solely focus on structural support and shape maintenance.

They determine the genetic makeup of the organism.

They serve as passive structures without function.

Which component is NOT listed as a part of the human microbiome?

Stem cells Signup and view all the answers

During which phase of the cell cycle do chromosomes line up in the center of the cell?

Metaphase Signup and view all the answers

What is the primary function of lysosomes in macrophages?

Digest bacteria Signup and view all the answers

Which condition is caused by a malfunctioning lysosomal enzyme?

Tay-Sachs disease Signup and view all the answers

What do peroxisomes primarily detoxify?

Compounds from oxygen free radicals Signup and view all the answers

What do cristae in mitochondria hold?

Enzymes that catalyze biochemical reactions Signup and view all the answers

What role do mitochondria play in cells?

Provide energy by processing nutrient molecules Signup and view all the answers

What is a key characteristic of progenitor cells compared to stem cells?

Progenitor cells do not have the capacity of self-renewal. Signup and view all the answers

Which term describes the ability of a stem cell to give rise to every cell type in the body?

Totipotent Signup and view all the answers

How do stem cells and progenitor cells differ in terms of their developmental potential?

Stem cells can become differentiated cells, while progenitor cells have limited differentiation. Signup and view all the answers

Which statement is true regarding the differentiation of cells?

Differentiation leads to increasingly specialized cell types. Signup and view all the answers

What is the primary mechanism of cell division in stem cells?

Mitosis Signup and view all the answers

What phase of the cell cycle includes DNA replication?

S phase Signup and view all the answers

During which stage of mitosis does the nuclear membrane break down?

Prophase Signup and view all the answers

What occurs during the G1 phase of the cell cycle?

The cell prepares for division Signup and view all the answers

What is the result of DNA replication during the S phase?

Each chromosome consists of two copies joined at the centromere Signup and view all the answers

What happens to chromosomes during prophase?

They coil tightly and shorten Signup and view all the answers

What is the function of microtubules during mitosis?

To organize into a spindle Signup and view all the answers

During which phase do replicated chromosomes align along the cell’s equator?

Metaphase Signup and view all the answers

What occurs if a cell exits the cell cycle at G1 phase?

It enters a dormant state (G0) Signup and view all the answers

Which factor is known to affect the microbiome of babies born by Cesarean section?

Method of delivery Signup and view all the answers

What is one of the consequences of an altered microbiome in malnourished children?

Hastening starvation Signup and view all the answers

Which of the following statements is true regarding the role of certain skin bacteria?

Some skin bacteria keep skin clear Signup and view all the answers

How does circumcision influence viral infections?

Protects against viral infections, such as HIV Signup and view all the answers

What effect do antibiotics have on the gut microbiome?

They temporarily alter the gut microbiome Signup and view all the answers

What is the primary function of connective tissues?

Protecting, supporting, and binding cells while filling spaces Signup and view all the answers

Which of the following correctly describes somatic cells?

Body cells that contain two copies of the genome and are diploid Signup and view all the answers

What type of cells do stem cells give rise to during self-renewal?

Differentiated cells and other stem cells Signup and view all the answers

Which of the following correctly characterizes prokaryotes?

Unicellular organisms without a nucleus Signup and view all the answers

What is a defining characteristic of eukaryotic cells?

Presence of a nucleus and other organelles Signup and view all the answers

Which domain of life includes both unicellular and multicellular organisms?

Eukarya Signup and view all the answers

What is the role of ribosomes in cells?

Essential for protein synthesis Signup and view all the answers

What occurs when sperm and egg cells meet?

Restoration of the diploid state Signup and view all the answers

Study Notes

Introduction to Cells

Cells are the basic units of life, comprising the human body.
Human bodies have more than 290 specialized cell types.
Different cell types aggregate and interact to form tissues: epithelial, connective, muscle, and nervous.
All cells share fundamental characteristics, but also exhibit specialization due to differential gene expression.
Inherited traits, conditions, and diseases stem from cellular activities.

Learning Outcomes

Students will be able to explain the significance of cellular knowledge in disease understanding.
Students will be able to distinguish between germ and somatic cells, along with diploid and haploid cells.
Students will be able to define cell differentiation.
Students will be able to identify the four primary chemicals within cells.
Students will be able to describe the coordinated actions of organelles in secretion, energy use, and waste removal.
Students will be able to describe the composition and functions of biological membranes.
Students will be able to list the components of the cytoskeleton.
Students will be able to describe the primary events of the cell cycle.
Students will be able to explain the changes and interactions of chromosomes during mitosis.
Students will be able to discuss cell cycle control.
Students will be able to list the stages of apoptosis.
Students will be able to discuss characteristics of stem cells and progenitor cells.
Students will be able to describe the sources of human stem cells.
Students will be able to understand the components of the human microbiome.
Students will be able to identify factors that modify the human microbiome.

Domains of Life

Biologists recognize three domains of life: Archaea, Bacteria, and Eukarya.
Archaea and Bacteria are unicellular prokaryotes without a nucleus to contain DNA.
Eukarya includes both unicellular and multicellular eukaryotes, which possess a nucleus and other organelles.
All three domains contain ribosomes, vital for protein synthesis.
Eukaryotes may have evolved from a fusion between a bacterium and an archaean.
Eukaryotic and prokaryotic cells are visually distinct.

Cell Chemical Constituents

The major macromolecules of cells are carbohydrates, lipids, proteins, and nucleic acids (DNA and RNA).
Carbohydrates provide energy and structures.
Lipids form hormones, membranes, store energy, and provide insulation.
Proteins perform diverse functions, including constructing muscle fibers, promoting blood clotting, and forming connective tissues; enzymes catalyze biochemical reactions.
Nucleic acids (DNA and RNA) are crucial for genetic study.

A Generalized Animal Cell

Animal cells are surrounded by a plasma membrane.
Cells contain organelles.
The cytoplasm holds proteins, carbohydrates, lipids, pigment molecules, and other small chemicals.

Organelles

Organelles divide labor by partitioning areas or specializing functions.
Related biochemicals and structures are clustered to interact effectively.
Organelles enable cells to manage genetic instructions, acquire energy, secrete substances, and remove waste.

The Nucleus

The nucleus, a prominent organelle, is surrounded by a nuclear envelope.
The nucleus contains nuclear pores enabling movement of biochemicals, a nuclear lamina for mechanical support and securing nuclear pores, a nucleolus producing ribosomes, and other contents (chromosomes, RNA, and nucleoplasm).

Secretion (Making Milk)

Organelles work together to coordinate essential functions.
Secretion involves a multi-step process involving the actions of ribosomes, endoplasmic reticulum, the Golgi apparatus, and the plasma membrane, transferring molecules from the cell's interior to its exterior.
In the secretion example of milk production, the process includes gene transcription, mRNA movement, protein synthesis, lipid synthesis, sugar production, protein folding in the Golgi, and vesicle transport to the plasma membrane for release, incorporating lipid from the membrane as they exit.

Endoplasmic Reticulum (ER)

The ER is a network of interconnected membranous tubules and sacs.
It extends from the nuclear envelope to the plasma membrane.
Rough ER has ribosomes and is involved in protein synthesis.
Smooth ER lacks ribosomes, important in lipid synthesis, and in some cases detoxification of substances.
Proteins exit the ER in membrane-bound vesicles.

Golgi Apparatus

A stack of interconnected flat, membrane-enclosed sacs.
It processes substances by adding sugars to form glycoproteins and glycolipids.
Products are released into vesicles that bud off to the plasma membrane.
Cells producing large amounts of secreted proteins have numerous Golgi apparatuses.

Exosomes

These membrane-bound, tiny bubbles are released by all cells.
They transport a variety of molecules (proteins, lipids, DNA, RNA).
Exosome functions include waste removal, substance transport, and cellular communication.
Faulty exosomes may contribute to disease.

Lysosomes

Membrane-bound sacs containing digestive enzymes.
They break down cellular waste, bacterial debris, worn-out organelles, and excess cholesterol.
The presence of a missing enzyme results in a lysosomal storage disease, a type of genetic disorder (e.g., Tay-Sachs disease).
Endosomes from the plasma membrane carry materials that lysosomes degrade.

Peroxisomes

Sacs with enzymes to break down lipids, rare biochemicals, and synthesize bile acids.
Important in detoxification processes involving oxygen-free radicals.
Abundant in liver and kidney cells.

Mitochondria

Mitochondria provide energy by breaking down nutrient molecular bonds.
The energy is stored as ATP.
The mitochondrion is surrounded by double membranes (the outer and inner membranes).
The inner membrane is folded into cristae, which hold enzymes responsible for biochemical reactions.

Organelles of an Animal Cell (table)

This table describes the types of organelles including their structure and function.

Biological Membranes

Biological membranes have a distinctive structure; chiefly composed of a double layer called phospholipids.
Phospholipids have a hydrophilic head and hydrophobic tails.
Proteins are embedded in phospholipid bilayers within the membrane.
Membrane structure also includes carbohydrate molecules on the external surface.
Membrane proteins can form channels for ions; faulty ion channels can cause diseases, an example of which is Cystic Fibrosis.

Plasma Membrane - Cell-to-Cell Communication

Many molecules extending from the plasma membrane are receptors.
Receptors bind ligands that initiate intracellular cascades of chemical reactions.
Signaling pathways detect signals from outside the cell and transmit them inward.
Cellular adhesion via the plasma membrane facilitates cell attachment to other cells.

The Cytoskeleton

A protein meshwork of rods and tubules forming the cell's architecture, positioning organelles, and providing structural support overall 3D shapes.
Three major components include microfilaments, microtubules, and intermediate filaments; each compose of distinct proteins (e.g., actin for microfilaments, tubulin for microtubules).
Cilia are composed of microtubules and are involved in movement and transport within the body (e.g., respiratory system).

Cell Division and Death

Cell renewal is essential for growth, development, maintaining health, and healing.
New cells form as old cells die.
Mitosis and cytokinesis constitute DNA and cell division.
Apoptosis is programmed cell death.

The Cell Cycle

A sequence of events associated with cell division.
Interphase is the phase where DNA and subcellular structures replicate.
Interphase is comprised of the G1, S, and G2 phases.
Mitosis includes stages like prophase, metaphase, anaphase, and telophase, followed by cytokinesis.

Stages of the Cell Cycle-Interphase

The phase of the cell cycle between mitosis.
It encompasses G1, S, and G2 phases.
DNA and other subcellular structures are replicated.
Cells prepared for division.
Cells may stay in interphase or exit into a quiescent phase.

Replicated and Unreplicated Chromosomes

Chromosomes replicates during the S phase.
Each chromosome consists of two sister chromatids joined at the centromere.
Unreplicated chromosomes have a single DNA molecule.
A replicated chromosome has two identical DNA molecules.

Mitosis-Prophase

In prophase, DNA tightly coils into chromosomes.
Microtubules form the mitotic spindle structure.
The nuclear envelope disintegrates, and the nucleolus is no longer visible.

Mitosis-Metaphase

Chromosomes attach to the spindle fibers at their centromeres.
Chromosomes align along the cell's equator.

Mitosis-Anaphase

Centromeres divide, releasing tension.
Sister chromatids separate, becoming independent chromosomes.
They are pulled to opposite ends of the cell.

Mitosis-Telophase

The cell begins to assume a dumbbell shape.
The spindle fibers disassemble.
A new nuclear envelope forms around each set of chromosomes at the cell's ends.
The division of the genetic material is complete.

Mitosis-Cytokinesis

Organelles and macromolecules are distributed between the two new daughter cells.
Microfilament band contracts, separating the two daughter cells.

Control of the Cell Cycle

Mitosis control is crucial for preventing cell injury and abnormal growth from forming.
Checkpoints, groups of interacting proteins, ensure proper chromosome replication and apportionment in daughter cells at specific times in the cycle.
Internal or external factors can influence a cell's mitotic clock.

Cell Cycle Checkpoints

Checkpoints control the cell cycle.
Checkpoints regulate DNA repair, or proceed with halting the cell cycle, depending on the state and the need.
These checkpoints operate at critical stages to ensure accurate replication and distribution of genetic information in daughter cells.
The apoptosis checkpoint, for instance, triggers programmed cell death if necessary.

Telomeres

Telomeres are located at the ends of chromosomes.
Contain multiple repeats of a specific 6-base DNA sequence (TTAGGG).
Telomeres shorten with each cell division.
Shortened telomeres signal cells to stop dividing as a protection mechanism against improper/uncontrolled division leading to genetic instability.
Specialized cells (e.g., sperm, eggs) produce telomerase to prevent telomere shortening.

Hormones and Growth Factors

Hormones are chemical signals produced in glands that travel through the bloodstream to other parts of the body.
Growth factors stimulate cell division locally.
Examples of growth factors include epidermal growth factor (EGF).
The cyclins and kinases are types of protein involved in activating the gene products to carry out mitosis.

Apoptosis

Apoptosis is programmed cell death.
It starts when a "death receptor" on the cell membrane receives a signal.
Killer enzymes called caspases are activated.
Caspases degrade cellular components and dismantle the cytoskeleton.
The cell signals phagocytes to digest the remnants of the dying cell.
Apoptosis helps prevent the spread of cells associated with genetic abnormalities, and ensures tissues and organs develop and function as expected.

Death of a Cell

Mitosis and apoptosis work together to maintain the functional body.
Cancer may arise from too much mitosis or insufficient apoptosis.

Stem Cells

Stem cells can self-renew and differentiate.
Stem cells or progenitor cells.
Stem cells are classified by developmental potential: totipotent, pluripotent, and multipotent.
In various tissues and organs, stem cells or progenitor cells reside, having the ability to produce progeny cells that can mature into various cell types.

Stem Cell Sources

Stem cells can originate from embryos, induced pluripotent stem cells (iPS cells), or adult tissues.

Using Stem Cells to Heal

Stem cells can be used to differentiate into specific cell types and for various diseases and injuries treatment.
Donor stem cells are used in cell therapies and research.

Stem Cell Applications

Stem cells are used in drug discovery and development, disease diagnostics, tissue and organ generation for implants or transplants, and analyzing biological systems.
Stem cell research plays a role in improving medical approaches for a variety of ailments and injuries.

The Human Microbiome

The human body contains numerous microorganisms (bacteria, viruses, fungi).
The human microbiome refers to the microorganisms within and on the body.
The microbiome varies depending on factors such as diet, environment, antibiotic treatment, etc.
These microbes influence human health and well-being.

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Description

Test your knowledge on cell biology with this quiz that covers key concepts such as somatic and germ cells, organelles, the human microbiome, and the roles of various cells in the body. Explore the intricacies of cellular functions and the importance of stem and progenitor cells in health and disease. Perfect for students looking to deepen their understanding of cellular processes.