Cell Biology: Apoptosis and Cancer Overview
42 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a key characteristic of apoptosis as it relates to the cell nucleus?

  • The nucleus expands and divides
  • The nucleus merges with the cytoplasm
  • The nucleus remains unchanged
  • The nucleus condenses and fragments (correct)

Which of the following correctly describes caspases?

  • Effectors of cell division
  • Enzymes activated by other proteins during apoptosis (correct)
  • Proteins involved in immune response
  • Inactive compounds that promote cell survival

What happens to the cytoplasm during the process of apoptosis?

  • It condenses and fragments into apoptotic bodies (correct)
  • It swells and merges with other cells
  • It remains stable and unchanged
  • It becomes proliferative and grows

Which apoptotic pathway is triggered by external signals?

<p>Extrinsic pathway (A)</p> Signup and view all the answers

Which of the following is a biochemical change that occurs during apoptosis?

<p>Caspase activation (D)</p> Signup and view all the answers

Which type of cell death is characterized by an immune response and can be induced by various stimuli?

<p>Immunogenic cell death (A)</p> Signup and view all the answers

What cellular process involves programmed cell death that is crucial for maintaining tissue homeostasis?

<p>Apoptosis (B)</p> Signup and view all the answers

What is the relationship between mutations in genes and the development of cancer?

<p>Most cancers result from mutations in somatic and germline cells (C)</p> Signup and view all the answers

Which of the following statements accurately describes oncogenes?

<p>They promote cell proliferation and survival when activated (B)</p> Signup and view all the answers

Which process is not typically associated with programmed cell death?

<p>Necrosis (B)</p> Signup and view all the answers

What is a key morphological characteristic of apoptosis compared to necrosis?

<p>Cellular condensation (B)</p> Signup and view all the answers

Which statement is true regarding the cellular membrane integrity in apoptosis and necrosis?

<p>Membranes remain intact in apoptosis (D)</p> Signup and view all the answers

What drives the process of apoptosis regarding cellular signals?

<p>Increased levels of oxidants (A)</p> Signup and view all the answers

Which of the following events is NOT associated with necrosis?

<p>Phagocytosis by immune cells (D)</p> Signup and view all the answers

In apoptosis, how is DNA typically fragmented?

<p>Ladder-like pattern (A)</p> Signup and view all the answers

What happens to the cell during necrosis in terms of ATP?

<p>ATP is depleted (B)</p> Signup and view all the answers

Which of the following statements best describes the tissue impact of apoptosis compared to necrosis?

<p>Individual cells are affected in apoptosis (C)</p> Signup and view all the answers

Which signal is likely to promote cell survival rather than apoptosis?

<p>Presence of Il-2 (A)</p> Signup and view all the answers

What is the primary role of caspases in cellular processes?

<p>Initiate apoptotic proteolytic cleavage (A)</p> Signup and view all the answers

What is required for caspase activation?

<p>Proteolytic cleavage and removal of prodomain (B)</p> Signup and view all the answers

What is the primary function of tumor suppressor genes?

<p>Inhibiting cell proliferation (B)</p> Signup and view all the answers

Which pathway is categorized as extrinsic in apoptosis?

<p>Death receptor mediated pathway (B)</p> Signup and view all the answers

What happens when there is a disruption or deletion of the p53 gene?

<p>Uncontrolled cell proliferation can occur (A)</p> Signup and view all the answers

Which ligand is matched correctly with its receptor?

<p>TRAIL with DR4 (C)</p> Signup and view all the answers

Which of the following genes is associated with retinoblastoma?

<p>Rb1 (D)</p> Signup and view all the answers

What is the role of p21 in relation to p53?

<p>To arrest cell cycle for DNA repair (C)</p> Signup and view all the answers

What effect does ligand-induced trimerization have on death receptors?

<p>It induces proximity of Caspase 8 (A)</p> Signup and view all the answers

Which of the following is NOT a consequence of mutated oncogenes?

<p>Promotion of programmed cell death (D)</p> Signup and view all the answers

What is Apaf1's role in the intrinsic apoptotic pathway?

<p>It serves as an adaptor molecule for procaspase activation (C)</p> Signup and view all the answers

What is a common disorder associated with the DCC gene?

<p>Colorectal cancer (C)</p> Signup and view all the answers

Which method is suitable for detecting apoptotic changes in DNA?

<p>TUNEL staining for DNA fragmentation (A)</p> Signup and view all the answers

Which molecule is a death effector in the apoptosis signaling pathway?

<p>Caspase 8 (A)</p> Signup and view all the answers

Which one of the following genes is implicated in lung cancer on a sporadic basis?

<p>WT1 (C)</p> Signup and view all the answers

Which factor is involved in regulating programmed cell death?

<p>Apoptotic signals (B)</p> Signup and view all the answers

What role does apoptosis play in adult physiology?

<p>Facilitates DNA damage repair (C)</p> Signup and view all the answers

What distinguishes necroptosis from traditional necrotic cell death?

<p>Necroptosis is a regulated process involving specific kinases (A)</p> Signup and view all the answers

In what context does autophagy mainly exert cytoprotective functions?

<p>In response to stress (A)</p> Signup and view all the answers

What is a consequence of inhibiting autophagy during developmental processes?

<p>Accelerates cell death (D)</p> Signup and view all the answers

Which of the following diseases is associated with excess apoptosis?

<p>Neurodegenerative diseases (B), Cardiac infarction (C)</p> Signup and view all the answers

What is the main characteristic of autophagic cell death?

<p>Massive cytoplasmic vacuolization (D)</p> Signup and view all the answers

What is a primary outcome of necroptosis in cells?

<p>Rapid plasma membrane permeabilization (A)</p> Signup and view all the answers

What happens when TNFalpha-mediated necrosis is inhibited?

<p>It leads to necroptosis (A)</p> Signup and view all the answers

Flashcards

Apoptosis

A form of programmed cell death characterized by cellular shrinkage, intact membranes, ATP dependence, and phagocytosis without tissue inflammation.

Necrosis

A form of cell death characterized by cellular swelling, membrane breakdown, ATP depletion, cell lysis, and inflammation.

Phagocytosis

The process of engulfing and degrading cellular debris by specialized immune cells.

DNA Fragmentation in Apoptosis vs Necrosis

Apoptosis involves ladder-like DNA fragmentation, while necrosis results in random or smeared DNA fragmentation.

Signup and view all the flashcards

Positive Signals

Signals that promote cell growth and survival, such as growth factors.

Signup and view all the flashcards

Negative Signals

Signals that trigger cell death, such as DNA damage, oxidants, or death activators.

Signup and view all the flashcards

Decision to Activate Apoptosis

A step in apoptosis where the cell decides whether or not to activate the death pathway.

Signup and view all the flashcards

Apoptosis Execution

A step in apoptosis where the cell undergoes the actual process of death.

Signup and view all the flashcards

Intrinsic Apoptosis

The intrinsic pathway is triggered by internal cellular stress, often involving mitochondria releasing proteins that activate caspases, leading to cell death

Signup and view all the flashcards

Extrinsic Apoptosis

The extrinsic pathway is triggered by external signals, usually through interactions with death receptors on the cell surface, ultimately causing cell death.

Signup and view all the flashcards

Caspases

A family of enzymes that play a crucial role in apoptosis. They are like molecular executioners that break down vital proteins, causing the cell to die.

Signup and view all the flashcards

Nucleosome Ladder

A series of DNA fragments of specific sizes generated during apoptosis, resembling a ladder on an electrophoresis gel.

Signup and view all the flashcards

Extrinsic Apoptosis Pathway

A signaling pathway triggered by external stimuli such as death receptors, leading to the activation of caspases.

Signup and view all the flashcards

Intrinsic Apoptosis Pathway

A signaling pathway initiated from inside the cell, often triggered by internal stress or damage, leading to caspase activation.

Signup and view all the flashcards

Death Receptors

A protein complex on the cell surface that binds specific ligands and triggers the extrinsic apoptosis pathway.

Signup and view all the flashcards

Death Effectors

A type of protein that directly binds to and activates caspase-8, leading to the initiation of the apoptotic cascade.

Signup and view all the flashcards

IAPs

A group of proteins that block apoptosis by inhibiting caspases.

Signup and view all the flashcards

Assesing Apoptosis

A process that uses techniques like flow cytometry and western blotting to analyze cell populations and identify apoptotic cells, usually by measuring caspase activity and DNA fragmentation.

Signup and view all the flashcards

What is apoptosis?

Apoptosis is a programmed cell death characterized by cellular shrinkage, intact membranes, ATP dependence, and phagocytosis without tissue inflammation.

Signup and view all the flashcards

What is necrosis?

Necrosis is a form of cell death characterized by cellular swelling, membrane breakdown, ATP depletion, cell lysis, and inflammation.

Signup and view all the flashcards

How is apoptosis linked to cancer?

Cancer cells evade apoptosis, allowing them to grow uncontrollably.

Signup and view all the flashcards

What are oncogenes?

Oncogenes are mutated genes that promote uncontrolled cell growth and act like a gas pedal in a car.

Signup and view all the flashcards

What are Tumor suppressor genes?

Tumor suppressor genes normally prevent uncontrolled cell growth and act like brakes in a car.

Signup and view all the flashcards

Proto-oncogene

A gene that normally helps control cell growth. When mutated, it can become an oncogene, leading to uncontrolled cell growth and cancer.

Signup and view all the flashcards

Oncogene

A mutated version of a proto-oncogene that promotes uncontrolled cell growth. It's always activated and stimulates cell division, even when it shouldn't.

Signup and view all the flashcards

Tumor suppressor gene

A gene that normally prevents uncontrolled cell growth. When this gene is mutated or inactive, cells can grow out of control, leading to cancer.

Signup and view all the flashcards

Programmed Cell Death

When a cell undergoes programmed death (apoptosis), it breaks down its own components in a controlled way. This process usually involves a cascade of enzymes and a series of steps.

Signup and view all the flashcards

Growth Factors

Factors that stimulate cell division.

Signup and view all the flashcards

Survival Factors

Factors that prevent cell death.

Signup and view all the flashcards

How does autophagy work?

Autophagy involves cells engulfing their own components within double-membraned vesicles called autophagosomes. This process can both help cells survive stress or trigger their death, depending on the context.

Signup and view all the flashcards

What is necroptosis?

Necroptosis is a form of cell death that involves a programmed, violent 'explosion' of the cell. It's controlled by signaling molecules like RIP1 and RIP3 kinases and often occurs in response to severe stress or infection.

Signup and view all the flashcards

How is apoptosis important in the immune system?

Apoptosis plays a crucial role in shaping the immune system by eliminating harmful or unnecessary cells, removing damaged cells, and contributing to tissue repair.

Signup and view all the flashcards

Why is apoptosis essential for development?

Apoptosis is crucial during development, helping shape organs and tissues. It also gets rid of excess cells, ensuring everything is in the right place.

Signup and view all the flashcards

What happens when there's too much or too little apoptosis?

Too much apoptosis can contribute to neurodegenerative diseases and heart attacks, causing the loss of vital cells. Conversely, too little apoptosis can contribute to cancer and autoimmunity.

Signup and view all the flashcards

What is the Comet assay?

The Comet assay is a technique used to detect DNA damage in individual cells. It relies on electrophoresis, where damaged DNA 'migrates' further, resembling a comet tail.

Signup and view all the flashcards

What are the applications of the Comet assay?

The Comet assay is useful for studying the effects of various stressors on cells, including radiation, chemicals, and toxins. It can also assess the effectiveness of DNA repair mechanisms.

Signup and view all the flashcards

Study Notes

Cell Death & Apoptosis

  • Cell death is a crucial process for maintaining a constant number of cells in the body.
  • Two major forms of cell death are apoptosis (programmed cell death) and necrosis (cell death, via injury).
  • Apoptosis is a controlled, tightly regulated process that removes cells without damaging surrounding tissues.
  • Necrosis is an uncontrolled process triggered by cell injury/damage and leads to inflammation.
  • Apoptosis is a very common process during embryo development.
  • Embryo development involves programmed cell death to mold and refine the shape.
  • The tail of the tadpole is absorbed via apoptosis.
  • In adult multicellular organisms, billions of cells are lost via apoptosis each hour. Most of these cells do not have defects and are removed based on the controls of regulation and development.

Apoptosis Objectives

  • Understand the various types of cell death pathways.
  • Assess methods to assess cell death.
  • Understand the physiological processes of apoptosis.
  • Analyze how defects in apoptotic pathways relate to diseases.

Types of Cell Death

  • Apoptosis = programmed cell death (suicide)
  • Necrosis = cell killing/decay/destruction

Morphological Apoptosis Changes

  • Changes in cell morphology during apoptosis:
    • Cell shrinkage
    • Chromatin condensation
    • Nuclear fragmentation
    • Formation of apoptotic bodies
    • Phagocytosis of apoptotic bodies

Biochemical Changes in Apoptosis

  • Caspase activation (enzymatic proteases).
  • Endonuclease activation.

Caspases

  • Enzymatic proteins (proteases) that degrade other proteins.
  • Made as inactive precursors (procaspases).
  • Activation occurs upon receiving specific signals.
  • A single caspase can cleave lamin proteins, causing breakdown of the nuclear membrane.

Caspase Functions and Structure

  • Proteolytic cleavage activates caspases.
  • Prodomain and linker region are removed.
  • Large and small subunits form an active enzyme complex.
  • Two heterodimers interact to form a tetramer with catalytic sites.
  • Caspase family contains over 14 members.

Apoptotic Pathways

  • Extrinsic (death receptor) pathway
    • Signals via death receptors.
    • These receptors induce activation of caspase-8, leading to apoptosis.
  • Intrinsic (mitochondrial) pathway
    • Signals from inside the cell.
    • Release of cytochrome c from mitochondria triggers caspase-9 activation and apoptosis.

Ligand/Death-Induced Cell Death

  • Ligands and receptors involved in cell death. Examples provided in chart format for Ligands, FasL, TNF,TRAIL and Receptors, Fas (CD95), TNF-R, DR4 (Trail-R).

Cancer & Apoptosis

  • Evasion of apoptosis can lead to uncontrolled cell growth.
  • Activating apoptosis in cancer cells has potential as a treatment method.
  • Cancer is a genetic disease.
    • Occurring via mutations in genes. This results in altered proteins during cell division.
  • Cancer originates from mutations in somatic or germline cells.

Genes Playing a Role in Cancer Development

  • Oncogenes
  • Tumor suppressor genes
  • DNA repair genes

Functions of Proto-Oncogenes

  • Secreted growth factors.
  • Growth factor receptors
  • Cytoplasmic signal transduction proteins
  • Nuclear proteins; regulating transcription
  • Cell growth genes

Oncogenes

  • Mutated proto-oncogenes.
  • Always activated.
  • Constantly stimulate proliferation.
  • Example: mutated ras gene, always active

Tumor Suppressor Genes

  • Normal function is inhibiting cell proliferation to guard against uncontrolled cell growth.
  • Absence/inactivation leads to increased cancer risks (leading to uncontrolled cell growth).
  • Example: p53, BRCA1, BRCA2

p53 Tumor Suppressor Gene

  • Activated by DNA damage.
  • Triggers cell cycle arrest or apoptosis.
  • Inactivation is associated with cancer.
  • p53 phosphorylated; activates p21 gene causing arrest of cell cycle to allow time for DNA repair.

Cancer Treatment Therapies

  • Various methods for cancer treatment. Diagram displays the major pathways.

Promising Cancer Targets

  • HERCEPTIN
  • STI-571

Apoptosis: Programmed Cell Death

  • (True/False) In adult tissues, cell death balances cell division.
  • Apoptosis involves controlled self-destruction to prevent damage to neighboring cells.
  • Signals from within and external sources trigger apoptosis.
  • Cellular components like caspases and mitochondria are key players in the apoptotic process.
  • Distinction between mitogens, growth factors and survival factors.
  • Apoptosis occurs during a specific portion of the cell cycle.
  • Telomeres and telomerase impact cell aging/death.
  • Specific cell types in the body are designed to divide, grow, or both.

Autophagic Cell Death

  • Autophagy is a self-eating process that takes place in both healthy and diseased cells.
  • Autophagy can play a protective or destructive role during stress reactions.

Necroptosis

  • Necroptosis is a form of necrotic cell death, considered programmed or regulated.
  • Discovery of the RIP1 kinase inhibitor as necroptosis-inhibiting; lead to recognition of necroptosis in cell death pathways.
  • Necroptosis is a programmed necrotic cellular death pathway.

Other Cell Death Classifications

  • Other kinds of cell death pathways exist (such as ferroptosis, lysozomal cell death, mitotic cell death, pyroptosis, etc.)

Studying That Suits You

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

Quiz Team

Related Documents

Apoptosis in Development & Diseases PDF

Description

This quiz explores the key characteristics of apoptosis, including its relationship with the cell nucleus and the role of caspases. Additionally, it delves into how apoptosis is linked to cancer development and the distinctions between various types of cell death. Test your knowledge on these crucial aspects of cell biology!

More Like This

Cancer Cell Death: Apoptosis vs Necrosis
10 questions

Cancer Cell Death: Apoptosis vs Necrosis

ThinnerLead avatar
ThinnerLead
Lecture 21
30 questions

Lecture 21

IFAAD avatar
IFAAD
Cell Biology: Apoptosis, Cancer, and Chromosomes
16 questions

Cell Biology: Apoptosis, Cancer, and Chromosomes

BlitheNobelium avatar
BlitheNobelium
Cell Death and Cancer Biology
18 questions

Cell Death and Cancer Biology

InnovativeElation7091 avatar
InnovativeElation7091
Use Quizgecko on...
Browser
Open
Browser
Browser