All normal human cells have genes that may become cancerous under certain conditions. Name them and explain how.
All normal human cells have genes that may become cancerous under certain conditions. Name them and explain how.
Solution and Explanation
The genes that may become cancerous under certain conditions are oncogenes and tumor suppressor genes.
1. Oncogenes:- Oncogenes are mutated forms of normal genes called proto-oncogenes. Proto-oncogenes normally promote cell growth and division. However, when mutated or overexpressed, they become oncogenes, leading to uncontrolled cell division and potentially causing cancer.- Example: The Ras gene, when mutated, continuously signals the cell to divide, even when not needed, leading to uncontrolled cell proliferation.
2. Tumor Suppressor Genes:- Tumor suppressor genes are responsible for inhibiting cell growth and promoting the repair of damaged DNA or apoptosis (programmed cell death). If these genes are mutated or inactivated, cells can bypass growth control mechanisms and continue to divide.- Example: The p53 gene is a critical tumor suppressor gene. When it is mutated, it fails to prevent the division of cells with damaged DNA, which can lead to cancer development.
Top Questions on Human health and disease
Read the following passage and answer the questions that follow. Prevention is the frontline response to drug use. Effective interventions address the underlying conditions contributing to drug use, such as a lack of connection to family or community, instability, insecurity, trauma, mental health issues, etc. When addressed, these factors can effectively prevent the initiation of drug use and the progression to drug use disorders. Study the few key figures of drug use given below and answer the questions that follow.
(a) What do you infer from the figures in Table No. 1 about the people with drug use disorders, 2022 (in million)? State any two of your observations.
(b) How are Hepatitis C and HIV related to drug use disorders by people, as shown in Table No. 2? State the correlation between the two.
(c)
- [(i)] Give the scientific name of (p) shown in Table No. 1.
OR - [(ii)] Give the scientific name of (q) shown in Table No. 1.
- CBSE CLASS XII - 2025
- Biology
- Human health and disease
- [(i)] Give the scientific name of (p) shown in Table No. 1.
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- Maharashtra Class XII - 2025
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B. Inside RBCs, the micro-metacryptozoites become rounded and modify into a young trophozoites.
C. As the trophozoite grows in size, a central vacuole is developed so that the nucleus is pushed to one side into the peripheral cytoplasm, leading to amoeboid stage.
D. In Amoeboid stage the small red eosinophils granules appear in the cytoplasm of the host corpulses as Schuffner's granules}
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\begin{tabularx}{0.8\textwidth}{|l|X|l|X|} \hline \multicolumn{2}{|c|}{LIST-I} & \multicolumn{2}{c|}{LIST-II}
\multicolumn{2}{|c|}{Types Cancer} & \multicolumn{2}{c|}{Tissues involved}
\hline A. & Carcinoma & I. & Muscle
B. & Chondroma & II. & Cartilage
C. & Sarcoma & III. & Blood
D. & Myeloma & IV. & Epithelial Tissue
\hline \end{tabularx}
Choose the most appropriate answer from the options given below:- CUET (PG) - 2025
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Questions Asked in CBSE CLASS XII exam
- (a) Consider the so-called ‘D-T reaction’ (Deuterium-Tritium reaction).
In a thermonuclear fusion reactor, the following nuclear reaction occurs: \[ \ ^{2}_1 \text{H} + \ ^{3}_1 \text{H} \longrightarrow \ ^{4}_2 \text{He} + \ ^{1}_0 \text{n} + Q \] Find the amount of energy released in the reaction.
% Given data Given:
\( m\left(^{2}_1 \text{H}\right) = 2.014102 \, \text{u} \)
\( m\left(^{3}_1 \text{H}\right) = 3.016049 \, \text{u} \)
\( m\left(^{4}_2 \text{He}\right) = 4.002603 \, \text{u} \)
\( m\left(^{1}_0 \text{n}\right) = 1.008665 \, \text{u} \)
\( 1 \, \text{u} = 931 \, \text{MeV}/c^2 \)- CBSE CLASS XII - 2025
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- CBSE CLASS XII - 2025
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- Calculate the value of Net Value Added at Factor Cost (NVA\textsubscript{FC}):
S. No. Particulars Amount (in ₹ crore) (i) Operating Surplus 3,740 (ii) Increase in unsold stock 600 (iii) Sales 10,625 (iv) Purchase of raw materials 2,625 (v) Consumption of fixed capital 500 (vi) Subsidies 400 (vii) Indirect taxes 1,200 - CBSE CLASS XII - 2025
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