Class XI Zygote Overview

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Questions and Answers

Which of the following best describes the environment in which a zygote develops in organisms with external fertilization?

In the external medium, usually water (correct)
In a nutrient-rich egg
In a specialized reproductive organ
Inside the body of the organism

What is the significance of the thick wall that develops around the zygote in fungi and algae?

It helps the zygote to move to a more favorable location.
It protects the zygote from drying out and damage. (correct)
It allows the zygote to absorb water more efficiently.
It provides the zygote with nourishment for development.

In organisms with a haplontic life cycle, what is the result of the zygote undergoing meiosis?

The formation of a new zygote
The formation of a diploid individual
The formation of haploid spores (correct)
The formation of gametes

Which of the following is NOT true about the zygote?

<p>It develops directly into a mature organism without further cell division. (D)</p> Signup and view all the answers

What is the significance of the zygote in the context of a species' continuation?

<p>It connects organisms from one generation to the next. (A)</p> Signup and view all the answers

Flashcards

What is a zygote?

The single-celled diploid cell formed by the fusion of a sperm and egg.

Where does zygote formation occur?

In organisms with external fertilization, this process happens outside the parent's body, usually in water, while in organisms with internal fertilization, it happens inside the parent's body.

What is a haplontic life cycle?

A life cycle where the dominant stage is a haploid organism, like in fungi and algae. The zygote divides by meiosis to produce haploid spores.

How does a zygote develop in fungi and algae?

The zygote undergoes a period of rest, developing a thick wall to protect it from drying and damage.

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Why is the zygote important?

The zygote is the crucial piece that connects generations in sexually reproducing organisms. It marks the beginning of life for every new organism.

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Study Notes

The Zygote

The diploid zygote is formed during sexual reproduction in all organisms.
External fertilization forms the zygote outside the organism's body. Internal fertilization forms the zygote inside.
The development of the zygote depends on environmental factors and the organism's life cycle.
Some organisms (fungi and algae) develop a resistant wall protecting the zygote from drying and damage.
A period of rest may occur before zygote germination
In haplontic life cycles (as discussed in Class XI), the zygote divides via meiosis forming haploid spores.
The spores develop into haploid individuals.
In diplontic and haplo-diplontic organisms a subsequent development occurs; refer to your Class XI textbook
The zygote connects species of one generation to the next generation in sexually reproducing organisms.
All sexually reproducing organisms begin life as a zygote. Humans included.