Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Chromosomes are thread-like structures of , carrying genetic information in the form of genes, located in the nucleus of cells.
A gene is a length of that codes for a specific protein. The sequence of bases in the determines the sequence of amino acids in that protein.
Alleles are alternative forms of a particular gene (e.g., vs ).
In a diploid cell, chromosomes come in pairs. The human diploid number is .
Haploid cells, such as gametes (sperm and egg), contain only one set of chromosomes. In humans, the haploid number is .
The molecule is a double helix consisting of two strands held together by complementary base pairs: Adenine () with Thymine (), and Cytosine () with Guanine ().
Protein synthesis involves the transcription of into in the nucleus, followed by the translation of into a polypeptide chain at the ribosome.
A sequence of three bases in , called a codon, codes for one specific amino acid.
📐Formulae
💡Examples
Problem 1:
If a species has a diploid chromosome number of , determine the number of chromosomes found in its pollen grain.
Solution:
Explanation:
Pollen grains are plant gametes and are therefore haploid. Since the diploid number is , the haploid number is calculated as .
Problem 2:
A segment of has the base sequence . Determine the complementary sequence on the opposite strand.
Solution:
Explanation:
According to the base-pairing rules, pairs with and pairs with .
Problem 3:
Calculate the number of nitrogenous bases required to code for a protein consisting of amino acids.
Solution:
Explanation:
Each amino acid is coded for by a triplet of bases (a codon). Therefore, bases are required (excluding start/stop codons for simplicity).