Genetics Quiz - Biology 7th

Basics of Genetics

Genetics is the branch of biology that studies heredity and variation in organisms. It explains how traits are passed from one generation to another through DNA. These inherited traits can affect physical characteristics, behavior, and even susceptibility to certain diseases.

Which of the following best describes genetics?

• The study of how traits are inherited

• The classification of organisms

• The study of blood

Genetic traits are only related to physical appearance.

• True

• False

Genes

Genes are specific sequences of DNA that code for proteins, which determine an organism’s traits. Some genes are responsible for visible characteristics, while others influence internal processes like metabolism and immune function.

What is the primary function of a gene?

• To store carbohydrates

• To produce proteins

• To break down nutrients

• To transport oxygen

All genes code for visible traits.

• True

• False

Chromosomes

Chromosomes are long, coiled structures made of DNA and proteins, containing thousands of genes. Humans have 23 pairs of chromosomes, and any alteration in their number or structure can lead to genetic disorders.

What do chromosomes primarily consist of?

• RNA and proteins

• Lipids and DNA

• Proteins and carbohydrates

• DNA and proteins

Humans inherit all 46 chromosomes from one parent.

• True

• False

Nucleotides and Bases

DNA is composed of repeating units called nucleotides, each containing a sugar, a phosphate group, and a nitrogenous base (A, T, G, C). These bases pair specifically: adenine with thymine, and guanine with cytosine, ensuring accurate genetic replication.

Which of the following is NOT a base found in DNA?

• Thymine

• Cytosine

• Uranil

• Guanine

DNA base pairing follows the rule A-T and G-C.

• True

• False

Genotype

A genotype refers to the genetic composition of an individual, including dominant and recessive alleles inherited from parents. It determines potential traits, though environmental factors can also influence their expression.

What does a genotype represent?

• A specific type of protein

• The physical characteristics of an organism

• The external environment

• The genetic code of an organism

The genotype always directly determines an individual’s traits.

• True

• False