Chromosomal disorders & sex linked inheritance Search Flashcards
What are chromosomes?
Chromosomes are tiny thread-like structures inside cells that carry genes, which are instructions for how the body works. Humans have 46 chromosomes in each cell, arranged in 23 pairs—one set from the mother and one from the father
What are autosomes and sex chromosomes?
The first 22 pairs of chromosomes are called autosomes and control most traits (like height or eye color). The 23rd pair is the sex chromosomes, which determine if someone is male (XY) or female (XX).
What are chromosomal disorders?
Sometimes, during the making of sperm or egg cells, mistakes happen, leading to missing or extra chromosomes. This can cause chromosomal disorders that affect growth, development, and health.
What are monosomy and trisomy?
Monosomy: A person is missing one chromosome from a pair.
Trisomy: A person has an extra chromosome (three instead of two).
Both conditions can lead to genetic disorders.
What is sex-linked inheritance?
Some traits and disorders are passed down through the X and Y chromosomes. Since males have only one X chromosome, they are more likely to inherit certain genetic conditions, like color blindness and hemophilia.
How does Down syndrome happen?
Down syndrome is caused by trisomy 21, where a person has three copies of chromosome 21 instead of two. It leads to developmental delays, distinct facial features, and sometimes heart problems.
How do errors in meiosis cause chromosomal disorders?
During meiosis, chromosomes are supposed to split evenly, but sometimes they don’t. This mistake is called nondisjunction, and it leads to missing or extra chromosomes in sperm or egg cells.
Why are males more affected by X-linked disorders?
Males have one X and one Y chromosome. If a gene on the X chromosome has a mutation, they don’t have another X to fix the problem. Females (XX) have a second X that can sometimes cover for a faulty gene.
