Biology 318 Midterm Exam Study Guide

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Questions and Answers

Which types of cancer are associated with Erbb2 (Her2)?

Colorectal cancer

Breast cancer (correct)

Lung cancer

Thyroid cancer

What cancer is primarily linked with a reciprocal translocation involving c-Myc?

Small Lung Cancer

Neuroblastoma

Burkitt’s Lymphoma (correct)

Breast Cancer

What is the primary function of FTIs in cancer therapy?

To amplify Myc expression

To promote cell cycle progression

To inhibit Ras activity (correct)

To activate Ras signaling

Which genes are activated by Myc to push the cell cycle forward?

cyclinD and cdk4 Signup and view all the answers

Which form of retinoblastoma is characterized by a higher incidence of spontaneous cases?

Rare non-hereditary retinoblastoma Signup and view all the answers

What does loss of heterozygosity (LOH) indicate in the context of tumor suppressor genes?

The elimination of one allele at a tumor suppressor gene Signup and view all the answers

Which of the following cancers is NOT linked to Myc amplification?

Melanoma Signup and view all the answers

According to the Two-Hit Hypothesis, how many hits are required for tumorigenesis in tumor suppressor genes?

Two hits are required Signup and view all the answers

What is the primary consequence of missense mutations in p53?

They can result in the formation of activated proto-oncogenes. Signup and view all the answers

What is the primary role of Fas in the extrinsic death receptor pathway?

To recruit FADD protein upon ligand binding Signup and view all the answers

Which of the following roles does p21 serve when activated by p53?

It acts as a cyclin-cdk inhibitor. Signup and view all the answers

What effect does MDM2 have on p53 protein levels under normal conditions?

It fosters rapid degradation of p53. Signup and view all the answers

What effect can environmental asymmetry have on stem cells?

It can lead to the loss of molecular signals from critical stromal cells. Signup and view all the answers

How does FLIP function in the context of death receptor signaling?

It prevents the proteolytic cleavage of pro-caspase 8 Signup and view all the answers

How does p53 become activated in response to cellular stress?

Through post-translational modifications. Signup and view all the answers

How do cancer stem cells differ from normal stem cells?

Cancer stem cells are less responsive to traditional therapies. Signup and view all the answers

What triggers the autoactivation of procaspase 8 in the extrinsic death pathway?

Proximity of two procaspase 8 molecules Signup and view all the answers

What is a key advantage of death receptor pathways in lymphocyte regulation?

They help in the removal of unneeded lymphocytes Signup and view all the answers

What role does Numb play in nerve differentiation?

Numb blocks Notch signaling, promoting neuronal differentiation. Signup and view all the answers

What is a characteristic feature of null mutations in p53?

They result in complete loss of p53 protein production. Signup and view all the answers

What is the role of cytotoxic T cells and natural killer cells in apoptosis?

They stimulate FasL expression on target cells Signup and view all the answers

What method is used to isolate stem cells based on cell-surface proteins?

Fluorescence-activated cell sorter (FACS) analysis. Signup and view all the answers

Which mechanism is involved in regulating p53's localization within the cell?

Nuclear shuttling. Signup and view all the answers

What is the role of Bax in relation to p53?

It is a pro-apoptotic protein. Signup and view all the answers

What proportion of total tumor cells identified had high CD44 expression and low CD24 in breast cancer patients?

15% Signup and view all the answers

What is the first step in the ubiquitination process of regulatory proteins?

E1 ub activating enzyme binds to Ub. Signup and view all the answers

How is apoptosis primarily characterized?

It is a highly ordered, ATP-dependent process. Signup and view all the answers

What triggers necrosis?

Damage, ischemia, and the release of cellular components. Signup and view all the answers

Which proteins are associated with the intrinsic pathway of apoptosis?

Bcl-2, Bax, and Bak. Signup and view all the answers

What is the role of p53 in regulating apoptotic versus arrest genes?

It interacts with regulatory sites of arrest genes only under high stress. Signup and view all the answers

Which protein interaction is crucial for enhancing p53 binding to apoptotic targets?

JMY Signup and view all the answers

What is the function of cytochrome c in the apoptosis cascade?

It binds to Apaf-1 to trigger caspase activation. Signup and view all the answers

What effect do mutations in Bcl-2 proteins have based on the provided information?

They lead to specific defects in certain lineages. Signup and view all the answers

What role do BH3-only proteins play in apoptosis?

They inhibit pro-survival Bcl-2 proteins. Signup and view all the answers

What is the role of pro-survival Bcl proteins in the intrinsic pathway of apoptosis?

They maintain the integrity of the outer mitochondrial membrane. Signup and view all the answers

What effect does loss of growth factor signaling have on glucose metabolism?

It reduces both glucose transport and glycolysis. Signup and view all the answers

How does the Warburg effect influence cancer cells?

Cancer cells prefer glucose for lactate production. Signup and view all the answers

What role does Akt play in cell survival and metabolism?

Akt stimulates cell growth and can inhibit apoptosis. Signup and view all the answers

What can be a potential treatment strategy targeting pro-survival Bcl proteins?

Utilizing small molecule inhibitors of pro-survival proteins. Signup and view all the answers

What is a characteristic of cells described by the Warburg effect?

They have elevated rates of glycolysis and lactate production. Signup and view all the answers

What is released from the mitochondria as an apoptotic stimulus?

Cytochrome c and Smac/Diablo. Signup and view all the answers

What is one function of BH3-only mimetics in cancer treatment?

They activate or release BH3-only proteins. Signup and view all the answers

Study Notes

Biology 318 - Fall 2024 - Midterm Exam Study Guide

Cancer Introduction (Lecture 1):
- Cancer is unregulated tissue growth, forming tumors.
- Causes of death include organ damage, infections (from immune suppression), and bleeding.
- Cancer is a group of diseases affecting multicellular organisms.
Invasiveness vs. Metastasis:
- Invasiveness is the growth of cancer cells past normal tissue boundaries.
- Metastasis is the spread and growth of cancer cells in distant sites; a critical aspect of malignancy.
- Some cancers, like gliomas and basal cell carcinomas of the skin, are highly invasive but don't typically metastasize.
Key Cancer Terms (Slides 7 & 8):
- Hyperplasia: Increased cell number; cells appear normal, able to form normal tissue despite unregulated proliferation.
- Metaplasia: Replacement of one cell type with another not normally found at that site (e.g., Barrett's esophagus).
- Dysplasia: Cytological abnormalities in cell size/shape and nucleus; increased mitotic activity, and a lack of normal cytoplasmic features relative to differentiated cells; typically a transitional state between benign and precancerous growths.
- Neoplasia: Abnormal and disorganized growth leading to a distinct mass. This includes both malignant (cancerous) and benign growths.
- Anaplasia: The loss of differentiated characteristics of tumor cells, making it hard to identify the original tissue type.
Cancer Staging & Prognosis:
- Cancer staging classifies cancer based on its extent and progression.
- Stage 1: (75-90% survival)
- Stage 2: (45-55% survival)
- Stage 3: (15-25% survival)
Cancer as a Genetic Disease & Aging:
- Cancer is a genetic disease, but inherited mutations aren't the only drivers.
- Cancer development is often associated with age. For example, colorectal cancer incidence is significantly higher for older individuals.
Monoclonal Cancer Examples:
- Leiomyomas: Benign uterine tumors exhibiting X-chromosome inactivation patterns.
- Myelomas: Cancers related to B cell precursors.
Factors Affecting Cancer Frequencies:
- Viral infections
- Chemical carcinogens
- Lifestyle factors
Ames Test:
- A test to measure the mutagenic potential of substances.
- Simple and efficient but with limitations. Limited to prokaryotic cells, and can produce false positives or negatives.
Hallmarks of Cancer:
- Loss of growth factor dependence
- Loss of response to anti-growth signals
- Resistance to apoptosis
- Limitless replicative potential
- Tumor invasion and metastasis
- Genetic instability
Oncogenes:
- Gain-of-function mutations
- Typically "always on," promoting tumorigenesis.
Tumor Suppressors:
- Loss-of-function mutations
- Typically inactive, preventing suppression of tumorigenesis.
Proto-oncogene to Oncogene Transformation Mechanisms:
- Quantitative: Gene amplification (e.g., Myc, HER2)
- Qualitative: Point mutations (e.g., Ras)
Ras Protein:
- A small G protein that relays signals from cell surface receptors to the nucleus.
- Various forms exist (K-Ras, H-Ras, N-Ras), involved in different cancers.
Myc Protein:
- A transcription factor that regulates cell growth and proliferation.
- Amplification or translocation of the Myc gene can lead to uncontrolled cell division and contribute to cancers.
MAP Kinase Pathway:
- A crucial signaling pathway critical in cell growth and differentiation.
- Dysfunction is implicated in different cancers.
Rb Protein:
- A tumor suppressor inhibiting cell cycle progression and regulating cell proliferation.
- Mutations in Rb can lead to uncontrolled cell division.
P53 Protein:
- A tumor suppressor monitoring cellular integrity and inducing apoptosis.
- Mutations in p53 commonly observed in many cancers.
Cancer Stem Cells (Lecture 4):
- Stem cells with unlimited self-renewal and capacity to produce differentiated cells.
- Some cancer cells can exhibit stem cell characteristics which contributes to cancer progression.
Apoptosis:
- Programmed cell death.
- Extrinsic and intrinsic pathways are involved.
- Crucial for normal development and tissue homeostasis.
- Defects in the process contribute to cancer uncontrolled growth.

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Description

Prepare for the Biology 318 midterm exam with this study guide, covering essential topics such as cancer introduction, invasiveness versus metastasis, and key cancer terms. Understand the characteristics, causes, and pathology of cancer to perform well on your exam.