What are chromosomes?
Thread-like structures in the nucleus containing genes that pass traits from parents to offspring.
What are chromosomes made of?
Proteins and nucleic acids (DNA and RNA).
What is DNA composed of?
Nucleotides, each with a deoxyribose sugar, phosphate group, and nitrogenous base.
Name the four nitrogenous bases in DNA.
Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).
What is the structure of DNA?
A double helix with A pairing with T, and G pairing with C.
How many pairs of chromosomes do humans have?
23 pairs, for a total of 46 chromosomes.
What are autosomes?
The 22 pairs of chromosomes not involved in sex determination.
What determines the sex of a human?
The 23rd pair of sex chromosomes: XX for females and XY for males.
What process forms gametes (sperm and eggs)?
Meiosis.
What is genetic recombination?
The exchange of genetic material during meiosis, increasing genetic diversity.
What is Down’s Syndrome caused by?
An extra copy of chromosome 21 (Trisomy 21).
Name two symptoms of Down’s Syndrome.
Intellectual disability and distinctive facial features.
What is Turner’s Syndrome?
A chromosomal disorder where females have only one X chromosome (XO).
List one symptom of Turner’s Syndrome.
Short stature or webbed neck.
What is Klinefelter’s Syndrome?
A disorder in males with an extra X chromosome (XXY).
Name one symptom of Klinefelter’s Syndrome.
Infertility or underdeveloped testes.
What is the role of RNA in heredity?
RNA carries genetic information and is present in some viruses.
What is crossing over in meiosis?
The exchange of genetic material between homologous chromosomes.
What determines the sex of an offspring during fertilization?
The sperm’s chromosome (X or Y) combining with the egg’s X chromosome.
What is the significance of heredity?
It allows traits to be passed from parents to offspring, ensuring species continuity.
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