Genetics and DNA

What determines the colour of eyes in humans?

What is the function of DNA molecules?

How many chromosomes are present in a human body cell?

What is the relationship between genes and DNA molecules?

What is the shape of chromosomes?

Why do chromosomes have protective proteins?

What determines the shape of wings in flies?

What is the correct sequence of the components of inheritance?

What is the number of chromosomes in a human body cell?

What is the composition of the 23rd pair of chromosomes in a male?

What is the composition of the 23rd pair of chromosomes in a female?

What is the number of chromosomes in an egg cell produced by a female?

What is the chance of a sperm cell carrying a Y chromosome?

What determines the sex of the baby?

What is the result of fertilization by a sperm cell carrying an X chromosome?

What is the function of the Y chromosome?

Genes and Characteristics

A gene is a unit of inheritance that determines specific characteristics, such as eye color, hair texture, and height.
In some cases, one gene can control one characteristic, but often, multiple genes and other factors contribute to a single trait.

Genes and DNA

DNA is a chemical molecule that contains a precise, helix-shaped arrangement of atoms.
The sequence of nucleotides along the DNA molecule forms a chemical code that instructs the cell on how to build proteins and structures.
Each gene is specified by a unique code in a different DNA molecule.
A slight difference in the DNA code sequence can result in distinct characteristics, such as straight or curly hair.

Chromosomes

DNA molecules (genes) are wrapped up with protective proteins to form a thread-like structure called a chromosome.
Chromosomes are typically "X-shaped" and only visible during cell division.
Human body cells have 46 chromosomes, arranged in 23 pairs, while sperm or egg cells have only half that number.
Chromosomes come in matching pairs, with the first 22 pairs being the same size and shape in every human.
The 23rd pair of chromosomes, the "sex chromosomes," determine an individual's sex.

Sex Chromosomes

The 23rd pair of chromosomes in females are a matching pair of large, X-shaped chromosomes (XX).
Each egg produced by a female carries a single "X" chromosome.
The 23rd pair of chromosomes in males are mismatched, with one large "X" chromosome and a small "Y" chromosome (Xy).
Half of the sperm cells produced by a male carry an X chromosome, while the other half carry a Y chromosome.
The sex of a baby is determined by the chromosome carried by the fertilizing sperm cell.

Understand the basics of genes, characteristics, and DNA. Learn how genes determine specific traits and how DNA molecules contain a chemical code that instructs the cell.