Biodiversity and Conservation — BIOLOGY STD 12 Science — Question

What is the difference between a primary oöcyte and a secondary oöcyte?

What are the unique features of acquired immunity?

1. Differentiate between analogous and homologous structures.
2. Select and write analogous structures from the list given below:

1. Wings of butterfly and birds.
2. Vertebrate hearts.
3. Tendrils of bougainvillea and cucurbita.
4. Tubers of sweet potato and potato.

What are ‘pioneer species’? Give two examples of them.

Apart from plants and animals, microbes form a permanent biotic component in an ecosystem. While plants have been referred to as autotrophs and animals as heterotrophs, what are microbes referred to as? How do the microbes fulfil their energy requirements?

Identify giving reasons, the salient features of genetic code by studying the following nucleotide sequence of mRNA strand and the polypeptide translated from it.
AUG UUU UCU UUU UUU UCU UAG
Met - Phe - Ser - Phe - Phe - Ser

Rearrange the following in the correct sequence to accomplish an important biotechnological reaction:

1. In vitro synthesis of copies of DNA of interest.
2. Chemically synthesised oligonucleotides.
3. Enzyme DNA-polymerase.
4. Complementary region of DNA.
5. Genomic DNA template.
6. Nucleotides provided.
7. Primers.
8. Thermostable DNA-polymerase (from Thermus aquatics).
9. Denaturation of ds-DNA.

How Jhum cultivation has lead to deforestation in recent years?

Study the given pedigree chart and answer the questions that follow:
Is the trait recessive or dominant?

Cold medications may contain antihistamines. What effect does this medication have on cold symptoms?