Intracellular Signalling

Multiple Choice

Which of the following is a possible cause of mutations in DNA?

• X-rays

• Exercise

• Balanced diet

• Regular sleep

Open Ended

Why is it important to understand how mutations affect genetic material in living organisms?

Multiple Choice

Which type of mutation involves the replacement of one base in the template strand of DNA with another?

• Point mutation

• Deletion mutation

• Insertion mutation

• Silent mutation

Multiple Choice

What is the correct sequence of events from DNA to protein synthesis as shown in the diagram?

• Transcription → Translation → Amino acid sequence

• Translation → Transcription → Amino acid sequence

• Amino acid sequence → Transcription → Translation

• Transcription → Amino acid sequence → Translation

Open Ended

Explain how a point mutation can affect the amino acid sequence of a protein.

Multiple Select

Which of the following changes in the DNA template strand would result in a different amino acid sequence after translation?

• Point mutation

• Deletion mutation

• Insertion mutation

• All of the above

Hotspot

Which two are Frameshift Mutations?

Match

Match the following

Deletion

Inversion

Duplication

Insertion

Translocation

• Deletion

• Inversion

• Duplication

• Insertion

• Translocation

Open Ended

Describe the potential consequences of a mutation that alters the amino acid sequence of a protein, as explained in the slides.

Multiple Choice

Identify each type of mutation as a point, deletion, or insertion mutation. A. Cytosine (C) enters the DNA sequence. B. One adenosine is removed from the DNA sequence. C. A base sequence of TGA in DNA changes to TAA.

• A: insertion, B: deletion, C: point

• A: point, B: insertion, C: deletion

• A: deletion, B: point, C: insertion

• A: insertion, B: point, C: deletion

Multiple Select

Which of the following statements about water-soluble hormones is/are correct?

• They act on plasma membrane receptors.

• They can enter the cell directly.

• They act via G protein second messengers.

• They act on intracellular receptors.

Open Ended

Explain the difference between water-soluble and lipid-soluble hormones in terms of their receptor location and mechanism of action.

Multiple Choice

Place the following steps of the cyclic AMP (cAMP) signaling mechanism in the correct order: 1. Adenylate cyclase converts ATP to cAMP. 2. Hormone binds to receptor. 3. cAMP activates protein kinases. 4. Receptor activates a G protein. 5. G protein activates adenylate cyclase.

• 2, 4, 5, 1, 3

• 2, 5, 4, 1, 3

• 1, 2, 4, 5, 3

• 4, 2, 5, 1, 3

Open Ended

What is the role of phosphodiesterase in the cAMP signaling pathway, and why is it important for cellular regulation?

Multiple Choice

What is the primary function of a receptor in cell signaling?

• To degrade the ligand

• To bind to a ligand and initiate a cellular response

• To transport ions across the membrane

• To synthesize proteins

Multiple Choice

How do protein kinases and protein phosphatases regulate cellular activities?

• By synthesizing new proteins

• By adding or removing phosphate groups from proteins

• By degrading proteins

• By transporting proteins across membranes

Multiple Choice

Which step in the cyclic AMP second-messenger mechanism involves the conversion of ATP to cAMP?

• Hormone binds to receptor

• Receptor activates G protein

• G protein activates adenylate cyclase

• Adenylate cyclase converts ATP to cAMP

Multiple Choice

What is a G protein?

• specific type of membrane-receptor protein

• a second messenger

• membrane-bound enzyme

• relay protein

Multiple Choice

What is the primary role of cAMP in the second-messenger system shown in the diagrams?

• It acts as the first messenger

• It activates protein kinases

• It binds to the receptor

• It converts ATP to GTP

Multiple Choice

Explain how G-protein coupled receptors (GPCRs) initiate a cellular response upon ligand binding.

• GPCRs directly phosphorylate proteins.

• GPCRs activate G-proteins, which then trigger a signaling cascade.

• GPCRs open ion channels directly.

• GPCRs degrade the ligand to initiate a response.

Multiple Choice

Which of the following statements best describes the function of phospholipase C in the PIP2-calcium signaling mechanism?

• It converts ATP to cAMP

• It splits PIP2 into DAG and IP3

• It activates G proteins

• It binds to hormone receptors

Multiple Select

Which of the following are second messengers in the PIP2-calcium signaling mechanism?

• Diacylglycerol (DAG)

• Adenylate cyclase

• Inositol trisphosphate (IP3)

• Phospholipase C

Multiple Choice

Which phrase best describes cancer?

• absence of cyclins
• multiple gene mutations
• uncontrolled cell growth
• precesnce of genetic defects

Multiple Choice

Cancer creates abnormal cells by disrupting

• the regulation of cell cycle

• red blood cell formation

• DNA replication

• ATP synthesis

Multiple Choice

What happens when p53 is absent or non-functional in the cell cycle?

• Uncontrolled cell division and increased risk of cancer

• Decreased cell growth

• Normal cell division

• Decreased risk of cancer

Multiple Choice

What are the consequences of p53 mutation in the cell cycle?

• Impaired cell division, disrupted DNA damage repair, and decreased risk of cancer development.

• The consequences of p53 mutation in the cell cycle include impaired DNA damage repair, disrupted cell cycle checkpoints, and increased risk of cancer development.

• Enhanced cell cycle checkpoints, improved DNA damage repair, and decreased risk of cancer development.

• Increased cell division, reduced DNA damage repair, and decreased risk of cancer development.

Multiple Choice

What is the function of p53 in preventing cancer?

• p53 inhibits DNA repair and promotes cancer development.

• p53 regulates the cell cycle, promotes DNA repair, and induces apoptosis to prevent cancer.

• p53 promotes cell division and tumor growth.

• p53 has no role in preventing cancer.

Multiple Choice

What happens when p53 detects DNA damage during the cell cycle?

• It promotes cell division.

• It inhibits DNA repair mechanisms.

• It has no effect on the cell cycle.

• It activates DNA repair mechanisms or triggers apoptosis.

Multiple Choice

What happens to MDM2 when a cell encounters stressful conditions?

• It binds with p53

• It is released, allowing p53 to be transported into the cell nucleus

• It deactivates p53 in the cell

• It promotes cell division

Multiple Choice

What is the main strategy to tackle p53 associated cancers?

• Restoring activity of MDM2

• Re-activating p53 that is bound up by too much MDM2

• Increasing cell division in cancer cells

• Reducing the levels of p53 in cancer cells

Multiple Choice

Proto-oncogenes can mutate into...

• oncogenes
• tumor suppressor genes
• DNA repair proteins

Multiple Choice

This diagram shows transduction of a signal. How is the signal being transduced to its target location in the cell?

• A hormone is binding to an intracellular protein receptor

• Transport vesicles are passing neurotransmitters to neighboring cells

• Enzymes are passing phosphate groups down a series of proteins

• cAMP is formed activating a desired response

Multiple Choice

What does the diagram represent?

• Amplification

• Specificity in Cell Response

• Apoptosis

• Intracellular Receptors

Multiple Choice

What is being depicted in the image?

• Amplification of the signal molecule

• Enzymatic proteins inhibiting process of the signal transduction pathway

• Kinase groups adding dimer groups to other enzymes

• Diffusion of molecules within the cell due to the signaling molecule