NEET Biology: Cell Biology questions with solutions

Q1. The synaptonemal complex first appears at

1. Leptotene
2. Pachytene
3. zygotene
4. Diplotene

Answer: zygotene

The synaptonemal complex assembles during synapsis, when homologous chromosomes start aligning and pairing. This occurs in zygotene, not later stages like pachytene or diplotene.

Q2. Choose the correct answers from the alternatives given : Meiosis involves:

1. two nuclear divisions with chromosomes dividing only once
2. two nuclear divisions with chromosomes dividing twice
3. two nuclear divisions with chromosomes dividing four times
4. one nuclear division with chromosomes dividing only once

Answer: two nuclear divisions with chromosomes dividing only once

Meiosis consists of two successive nuclear divisions: meiosis I and meiosis II. Chromosomes are replicated once before meiosis begins, then the homologous chromosomes separate in the first division and sister chromatids separate in the second, so the chromosomes effectively divide only once in terms of replication.

Q3. Which of the following means of transmembrane transport involves the expenditure of energy by the cell and can move materials up a concentration gradient?

1. Osmosis
2. Facilitated diffusion
3. simple diffusion
4. Active transport

Answer: Active transport

Active transport uses energy, usually from ATP, to move substances across a membrane against their concentration gradient. Osmosis, facilitated diffusion, and simple diffusion are all passive and do not require cellular energy.

Q4. The nuclear material without nuclear membrane is observed in

1. Bacteria and green algae
2. Cyanobacteria and red algae
3. Bacteria and cyanobacteria
4. Mycoplasma and green algae

Answer: Bacteria and cyanobacteria

Bacteria and cyanobacteria are prokaryotes, so their DNA lies in a nucleoid region without a nuclear membrane. Green algae and red algae are eukaryotic and do have a true nucleus.

Q5. Identify the unicellular organism.

1. Algae
2. Amoeba
3. snail
4. Ant

Answer: Amoeba

Amoeba is a unicellular organism, meaning it consists of only one cell that carries out all life processes. The other options are multicellular organisms or groups of organisms.