Introduction to DNA and Chromosomes

Questions and Answers

To facilitate reproduction and maintain a species (correct)

To produce proteins for cellular functions

To determine the speed of cell division

To serve as energy sources for cellular activities

Meiosis

Cytokinesis

Mitosis (correct)

Fertilization

There were 46 chromosomes per cell

The number of chromosomes varied per individual

There were 48 chromosomes per cell (correct)

Humans had no chromosomes in their cells

The cell is a male cell, regardless of X chromosome count Signup and view all the answers

Cytogenetics Signup and view all the answers

It guarantees each mature sperm and ovum have a unique set of genes Signup and view all the answers

DNA and tightly coiled genes Signup and view all the answers

Establishment of human chromosomes' correct number as 46 Signup and view all the answers

Study Notes

DNA provides a blueprint for the formation and maintenance of an organism
DNA is packaged into chromosomes, which are made up of tightly coiled long chains of genes
Chromosomes can be visualized during cell division using a light microscope and appear as threadlike structures or 'colored bodies'

Chromosomes are the factors that distinguish one species from another and enable the transmission of genetic information from one generation to the next
They ensure that each daughter cell retains its own complete genetic complement during somatic cell division in mitosis
During gamete formation in meiosis, chromosomes enable each mature ovum and sperm to contain a unique single set of parental genes

Chromosomes are the vehicles that facilitate reproduction and the maintenance of a species
They are essential for the study of cytogenetics, which is the study of chromosomes and cell division

Before the 1950s, it was incorrectly thought that each human cell contained 48 chromosomes
In 1956, more reliable techniques were developed, revealing that the correct chromosome number in humans is 46
The presence of a Y chromosome, not the number of X chromosomes, determines maleness
Abnormalities of chromosome number and structure can disrupt normal growth and development

Questions and Answers