Each nucleus within the pollen tube contains one haploid set of chromosomes. The egg also contains a haploid set of chromosomes, while the zygote is diploid (with 2 sets of chromosomes) and the endosperm is triploid (with 3 sets of chromosomes).
How many nuclei are present in the pollen grain?
pollen grain A microspore in flowering plants, which germinates to form the male gametophyte, a structure made up of the pollen grain plus a pollen tube. The grain contains 3 haploid nuclei (a tube nucleus and 2 sperm nuclei), which pass down the tube to the ovum.
Is a stigma male or female?
The male parts of the flower are called the stamens and are made up of the anther at the top and the stalk or filament that supports the anther. The female elements are collectively called the pistil. The top of the pistil is called the stigma, which is a sticky surface receptive to pollen.
What are the 24 chromosomes?
The autosomes are normally present in pairs. The sperm contributes one sex chromosome (X or Y) and 22 autosomes . The egg contributes one sex chromosome (X only) and 22 autosomes . Sometimes microarray is referred to as 24-chromosome microarray : 22 chromosomes, and X and Y are counted as one each, for a total of 24.
How many chromosomes are needed to make a baby?
Normally, meiosis causes each parent to give 23 chromosomes to a pregnancy. When a sperm fertilizes an egg, the union leads to a baby with 46 chromosomes. But if meiosis doesn’t happen normally, a baby may have an extra chromosome (trisomy), or have a missing chromosome (monosomy).
What is the main difference between Chromatin and chromosomes?
Chromatin is a complex formed by histones packaging the DNA double helix. Chromosomes are structures of proteins and nucleic acids found in the living cells and carry genetic material. Chromatin is composed of nucleosomes. Chromosomes are composed of condensed chromatin fibers.
When two gametes unite they create a?
The process in which two gametes unite is called fertilization . The fertilized cell that results is referred to as a zygote . A zygote is a diploid (or 2N ) cell, which means it contains two copies of each chromosome.