Medical Biology 5 Altklausuren ähnlich

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What is the primary function of cell communication?

Structural support

Protein synthesis

Cellular metabolism

DNA replication

Regulating cellular activities by responding to signals from the environment (correct)

In which type of signaling do cells target themselves?

Juxtacrine signaling

Paracrine signaling

Autocrine signaling (correct)

Endocrine signaling

Direct contact signaling

What role do G protein-coupled receptors play in cell communication?

They transmit signals from the cell surface to intracellular targets (correct)

They degrade extracellular signals

They act as second messengers

They synthesize signal molecules

They directly phosphorylate target proteins

Which molecule commonly acts as a second messenger in cell signaling pathways?

$cAMP$ (cyclic Adenosine Monophosphate) (D) Signup and view all the answers

What is the main role of proteases in apoptosis?

They degrade key cellular components (C) Signup and view all the answers

What activates a ligand-gated ion channel?

The activation of G proteins (B) Signup and view all the answers

In hormone signaling, what is the role of the hormone?

To function as a signaling molecule that binds to a receptor (B) Signup and view all the answers

What is the role of a transcription factor in cell signaling?

To regulate the expression of specific genes (C) Signup and view all the answers

What best describes the role of scaffolding proteins in cell signaling?

They organize multiple signaling components into complexes (C) Signup and view all the answers

What role do phosphodiesterases play in cell signaling?

To break down cAMP, thus terminating the signal (B) Signup and view all the answers

In cell signaling, what does negative feedback primarily do?

Prevents over-activation of the pathway (C) Signup and view all the answers

'Downstream' components in cell signaling are involved in:

Involved in steps following the activation of the receptor (D) Signup and view all the answers

What is characteristic of synaptic signaling?

Nerve cells (D) Signup and view all the answers

Intracellular signaling pathways often involve:

Cascades of sequential biochemical reactions (B) Signup and view all the answers

What results from amplification of a signal in cell communication?

An increased response to a small amount of signal (A) Signup and view all the answers

Which process leads to the activation of a protein by adding a phosphate group?

Phosphorylation (D) Signup and view all the answers

What regulates the cell cycle by fluctuations in their levels?

Cyclins and cyclin-dependent kinases (D) Signup and view all the answers

During which process do somatic cells divide?

Budding (B) Signup and view all the answers

Which characteristic is associated with benign tumors?

They are typically cancerous (C) Signup and view all the answers

When does the reduction of chromosome number from diploid to haploid occur?

Mitosis (D) Signup and view all the answers

What crucial role do telomeres play?

Energy production (D) Signup and view all the answers

What accurately describes the role of growth factors in cell division?

They decrease the rate of cell division (A) Signup and view all the answers

What is the main difference between plant and animal cell cytokinesis?

The formation of a cell plate in plants (D) Signup and view all the answers

What is apoptosis?

Programmed cell death (B) Signup and view all the answers

Which enzyme is responsible for DNA replication in cells?

DNA polymerase (A) Signup and view all the answers

What is the significance of the S phase checkpoint in the cell cycle?

It ensures that DNA is properly replicated before mitosis begins (D) Signup and view all the answers

The separation of sister chromatids occurs during which phase of mitosis?

Anaphase (B) Signup and view all the answers

Which protein complex is crucial for the separation of sister chromatids during mitosis?

Anaphase-promoting complex (APC) (B) Signup and view all the answers

During which phase of the cell cycle does the cell grow and synthesize RNA and proteins in preparation for subsequent steps leading to mitosis?

G1 phase (B) Signup and view all the answers

What is the primary purpose of checkpoints in the cell cycle?

To ensure the accurate completion of key processes like DNA replication (B) Signup and view all the answers

In which phase of mitosis do chromosomes decondense and the nuclear envelope re-forms?

Telophase (A) Signup and view all the answers

What is the main function of the mitotic spindle?

Separating sister chromatids and moving them to opposite poles (B) Signup and view all the answers

What is the primary role of a kinase in cell signaling?

To add phosphate groups to proteins (C) Signup and view all the answers

Which process involves the conversion of an extracellular signal to a specific cellular response in a series of steps?

Signal transduction (A) Signup and view all the answers

Intracellular receptors typically bind to:

Gases like oxygen (D) Signup and view all the answers

In which type of cell signaling do cells communicate by direct contact?

Juxtacrine signaling (D) Signup and view all the answers

Phosphatases are enzymes that:

Synthesize ATP (A) Signup and view all the answers

What is the function of ion channel receptors in cell communication?

To allow ions to flow across the membrane in response to a signal (A) Signup and view all the answers

'Cross-talk' in cell communication refers to:

The interaction between different signaling pathways (A) Signup and view all the answers

Which process in cell signaling involves the amplification of the signal?

Signal transduction (C) Signup and view all the answers

'Apoptosis' or programmed cell death can be initiated by:

External signals binding to cell surface receptors (B) Signup and view all the answers

Which type of molecule often acts as an intracellular second messenger in G protein-coupled receptor pathways?

Protein kinases (C) Signup and view all the answers

The specificity of a signaling pathway is often determined by:

The location of the target cell (D) Signup and view all the answers

What is the main function of adhesion receptors in cell communication?

To organize components of the signaling pathway (B) Signup and view all the answers

What is the primary role of a signal cascade in cell signaling?

To amplify the signal and produce a cellular response (A) Signup and view all the answers

In juxtacrine signaling, which type of molecule typically acts as a receptor?

Membrane-bound proteins (D) Signup and view all the answers

How do steroid hormones typically transmit their signal inside a cell?

By binding to intracellular receptors (C) Signup and view all the answers

What is the result of activating a G protein-coupled receptor?

Activation of a signal transduction pathway (C) Signup and view all the answers

Which process in cell signaling involves a relay of signals from the cell surface to target molecules inside the cell?

Signal transduction (A) Signup and view all the answers

What is the main function of a second messenger in cell signaling pathways?

To relay and amplify the signal received by a receptor (A) Signup and view all the answers

'Cross-talk' in cell communication refers to the interaction between:

Different signaling pathways (D) Signup and view all the answers

What is the role of the Ras protein in many signaling pathways?

It functions as a G protein (D) Signup and view all the answers

Which signaling molecule is commonly involved in growth factor signaling?

Insulin (B) Signup and view all the answers

What is involved in the termination of a signaling pathway?

Deactivation or removal of signaling components (A) Signup and view all the answers

What is the effect of a ligand binding to an ion channel receptor?

Change in the permeability of the cell membrane to specific ions (A) Signup and view all the answers

Intracellular signaling pathways often involve:

A series of protein modifications, such as phosphorylation (D) Signup and view all the answers

How does a cell signal often result in immediate response?

Alterations in protein function or enzyme activity (B) Signup and view all the answers

What is the role of cyclic AMP (cAMP) in a cell signaling pathway?

It serves as a secondary messenger relaying signals inside the cell (A) Signup and view all the answers

What is the function of phosphatases in signaling pathways?

Remove phosphate groups from proteins, often leading to inactivation of the signaling pathway (A) Signup and view all the answers

How are cell signaling pathways that rely on phosphorylation events typically regulated?

Kinases and phosphatases (C) Signup and view all the answers

What is the main purpose of the cell cycle?

Cell growth and division (C) Signup and view all the answers

Which phase of the cell cycle is characterized by cell growth and normal metabolic roles?

G1 phase (C) Signup and view all the answers

During which phase of the cell cycle does DNA replication occur?

S phase (D) Signup and view all the answers

What is the function of mitosis in the cell cycle?

Separation of sister chromatids (C) Signup and view all the answers

What occurs during the G2 phase of the cell cycle?

Cell growth and preparation for mitosis (A) Signup and view all the answers

What structure is responsible for the separation of chromosomes during mitosis?

Spindle apparatus (A) Signup and view all the answers

How is cytokinesis in animal cells accomplished?

Constriction of the actin ring (A) Signup and view all the answers

What are cyclins and cyclin-dependent kinases (Cdks)?

Regulatory proteins involved in cell cycle control (B) Signup and view all the answers

What is a characteristic feature of cancer cells?

Loss of contact inhibition (A) Signup and view all the answers

During which process do homologous chromosomes exchange genetic material?

Meiosis I (B) Signup and view all the answers

What is the role of telomeres in chromosomes?

Protecting chromosome ends during replication (A) Signup and view all the answers

Which enzyme is responsible for maintaining telomere length?

Helicase (C) Signup and view all the answers

What does the term 'oncogene' refer to?

A mutated form of a gene involved in normal cell growth, contributing to cancer (D) Signup and view all the answers

What is the primary function of the anaphase-promoting complex/cyclosome (APC/C) in cell division?

Regulating cytokinesis (D) Signup and view all the answers

During which stage of meiosis does synapsis, the pairing of homologous chromosomes, occur?

Prophase I (B) Signup and view all the answers

What does the G1/S checkpoint primarily ensure in cell division?

DNA is undamaged and ready for replication (C) Signup and view all the answers

Which enzyme is crucial for relieving tension in the DNA helix during DNA replication?

Helicase (C) Signup and view all the answers

In which cells does binary fission, a form of cell division, occur?

Fungal cells (D) Signup and view all the answers

What is a kinetochore?

A protein involved in chromosome condensation (D) Signup and view all the answers

What is the primary result of nondisjunction during meiosis?

Cells with an abnormal number of chromosomes (B) Signup and view all the answers

What plays a crucial role in protecting chromosome ends from degradation?

Protecting chromosome ends from degradation (D) Signup and view all the answers

During which stage of mitosis do the nuclear envelope and nucleolus disassemble?

Prophase (A) Signup and view all the answers

What is a characteristic feature of benign tumors?

They are usually encapsulated and grow slowly (A) Signup and view all the answers

What accurately describes the role of growth factors in cell division?

They stimulate cells to divide (D) Signup and view all the answers

What is the result of uncontrolled cell division?

The formation of tumors (D) Signup and view all the answers

When does the reduction of chromosome number from diploid to haploid occur?

Meiosis I (D) Signup and view all the answers

What is the role of telomeres in chromosomes?

Protecting chromosome ends from degradation (A) Signup and view all the answers

Which of the following accurately describes the role of telomeres?

Protecting chromosome ends from degradation (D) Signup and view all the answers

During which stage of cell division do the nuclear envelope and nucleolus disassemble?

Prophase (B) Signup and view all the answers

What is a characteristic feature of benign tumors?

They are usually encapsulated and grow slowly (B) Signup and view all the answers

What accurately describes the role of growth factors in cell division?

They stimulate cells to divide (A) Signup and view all the answers

What is the result of uncontrolled cell division?

The formation of tumors (B) Signup and view all the answers

Somatic cells divide by the process of:

Mitosis (A) Signup and view all the answers

What is the reduction of chromosome number from diploid to haploid occurs during?

Meiosis I (C) Signup and view all the answers

A centromere is:

A structure that links sister chromatids (C) Signup and view all the answers

Which of the following is a characteristic of benign tumors?

They are usually encapsulated and grow slowly (C) Signup and view all the answers

Medical Biology 5 Altklausuren ähnlich

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Questions and Answers

What is the primary function of cell communication?

In which type of signaling do cells target themselves?

What role do G protein-coupled receptors play in cell communication?

Which molecule commonly acts as a second messenger in cell signaling pathways?

What is the main role of proteases in apoptosis?

What activates a ligand-gated ion channel?

In hormone signaling, what is the role of the hormone?

What is the role of a transcription factor in cell signaling?

What best describes the role of scaffolding proteins in cell signaling?

What role do phosphodiesterases play in cell signaling?

In cell signaling, what does negative feedback primarily do?

'Downstream' components in cell signaling are involved in:

What is characteristic of synaptic signaling?

Intracellular signaling pathways often involve:

What results from amplification of a signal in cell communication?

Which process leads to the activation of a protein by adding a phosphate group?

What regulates the cell cycle by fluctuations in their levels?

During which process do somatic cells divide?

Which characteristic is associated with benign tumors?

When does the reduction of chromosome number from diploid to haploid occur?

What crucial role do telomeres play?

What accurately describes the role of growth factors in cell division?

What is the main difference between plant and animal cell cytokinesis?

What is apoptosis?

Which enzyme is responsible for DNA replication in cells?

What is the significance of the S phase checkpoint in the cell cycle?

The separation of sister chromatids occurs during which phase of mitosis?

Which protein complex is crucial for the separation of sister chromatids during mitosis?

During which phase of the cell cycle does the cell grow and synthesize RNA and proteins in preparation for subsequent steps leading to mitosis?

What is the primary purpose of checkpoints in the cell cycle?

In which phase of mitosis do chromosomes decondense and the nuclear envelope re-forms?

What is the main function of the mitotic spindle?

What is the primary role of a kinase in cell signaling?

Which process involves the conversion of an extracellular signal to a specific cellular response in a series of steps?

Intracellular receptors typically bind to:

In which type of cell signaling do cells communicate by direct contact?

Phosphatases are enzymes that:

What is the function of ion channel receptors in cell communication?

'Cross-talk' in cell communication refers to:

Which process in cell signaling involves the amplification of the signal?

'Apoptosis' or programmed cell death can be initiated by:

Which type of molecule often acts as an intracellular second messenger in G protein-coupled receptor pathways?

The specificity of a signaling pathway is often determined by:

What is the main function of adhesion receptors in cell communication?

What is the primary role of a signal cascade in cell signaling?

In juxtacrine signaling, which type of molecule typically acts as a receptor?

How do steroid hormones typically transmit their signal inside a cell?

What is the result of activating a G protein-coupled receptor?

Which process in cell signaling involves a relay of signals from the cell surface to target molecules inside the cell?

What is the main function of a second messenger in cell signaling pathways?

'Cross-talk' in cell communication refers to the interaction between:

What is the role of the Ras protein in many signaling pathways?

Which signaling molecule is commonly involved in growth factor signaling?

What is involved in the termination of a signaling pathway?

What is the effect of a ligand binding to an ion channel receptor?

Intracellular signaling pathways often involve:

How does a cell signal often result in immediate response?

What is the role of cyclic AMP (cAMP) in a cell signaling pathway?

What is the function of phosphatases in signaling pathways?

How are cell signaling pathways that rely on phosphorylation events typically regulated?

What is the main purpose of the cell cycle?

Which phase of the cell cycle is characterized by cell growth and normal metabolic roles?

During which phase of the cell cycle does DNA replication occur?

What is the function of mitosis in the cell cycle?

What occurs during the G2 phase of the cell cycle?

What structure is responsible for the separation of chromosomes during mitosis?

How is cytokinesis in animal cells accomplished?

What are cyclins and cyclin-dependent kinases (Cdks)?

What is a characteristic feature of cancer cells?

During which process do homologous chromosomes exchange genetic material?

What is the role of telomeres in chromosomes?

Which enzyme is responsible for maintaining telomere length?

What does the term 'oncogene' refer to?

What is the primary function of the anaphase-promoting complex/cyclosome (APC/C) in cell division?

During which stage of meiosis does synapsis, the pairing of homologous chromosomes, occur?

What does the G1/S checkpoint primarily ensure in cell division?