Biology: Genetic Instructions and Protein Synthesis

Male Reproductive System

• The epididymis temporarily stores sperm produced in the testes.
• Leydig cells primarily function to produce testosterone, essential for male sexual development and functions.
• Approximately 1,500 sperm cells are produced by the male reproductive system each second, translating to millions daily.

Female Reproductive System

• The endometrium is responsible for the monthly shedding of the uterine lining during menstruation.

Sperm Development

• Sperm cell development takes approximately 64 to 72 days to reach maturation.

Hormonal Regulation

• The production of testosterone by Leydig cells is regulated by luteinizing hormone (LH).

Nervous System Functions

• The parasympathetic nervous system promotes rest and recovery after a crisis, maintaining normal bodily functions.
• The sympathetic nervous system prepares the body for 'fight or flight' responses during crises.

DNA and RNA

• The primary function of DNA is to store and transmit genetic information.
• The order of the central dogma of protein synthesis is DNA → RNA → Protein.
• During DNA replication, helicase enzyme breaks the hydrogen bonds between nitrogenous bases, allowing strands to separate.
• The primary difference between DNA and RNA lies in their nucleotide composition: DNA contains deoxyribose, while RNA contains ribose.

Protein Synthesis

• Translation is the process of producing proteins directly from RNA instructions.
• tRNA (transfer RNA) transports amino acids to the ribosome to help synthesize proteins.
• The codon AUG serves as the start codon in protein synthesis, signaling the beginning of protein production.

Evolution

• According to Charles Darwin's theory of evolution, organisms acquire new traits through natural selection, where advantageous traits enhance survival and reproduction.

Role of DNA Replication

• DNA replication is crucial for cell division, ensuring that genetic information is accurately copied and passed to daughter cells.