Tahsili Biology

Question 1

What is the function of mitochondria in a cell?

Accepted Answer

Cellular respiration — producing ATP (energy) through oxidative phosphorylation

Answer

Mitochondria are the 'powerhouses of the cell,' producing ATP through cellular respiration (glycolysis, Krebs cycle, electron transport chain). They convert glucose and oxygen into ATP, CO₂, and water.

Question 2

What is the complementary DNA strand for the sequence 5'-ATCGGA-3'?

Accepted Answer

3'-TAGCCT-5'

Answer

DNA base pairing: A pairs with T, C pairs with G. The complementary strand runs antiparallel (3' to 5'): A→T, T→A, C→G, G→C, G→C, A→T = 3'-TAGCCT-5'.

Question 3

What is the role of ribosomes in protein synthesis?

Accepted Answer

Reading mRNA and assembling amino acids into proteins (translation)

Answer

Ribosomes are the site of translation — they read the mRNA codon sequence and assemble the corresponding amino acids into polypeptide chains. Ribosomes consist of a large and small subunit made of rRNA and proteins.

Question 4

What is meiosis and what is its significance?

Accepted Answer

Cell division producing four genetically unique haploid gametes, enabling sexual reproduction and genetic diversity

Answer

Meiosis involves two divisions (meiosis I and II) producing four haploid gametes (n) from one diploid cell (2n). Genetic diversity is generated through crossing over, independent assortment, and random fertilization. Essential for sexual reproduction.

Question 5

What is the difference between genotype and phenotype?

Accepted Answer

Genotype is the genetic makeup (alleles); phenotype is the observable physical characteristics

Answer

Genotype refers to the specific alleles an organism carries (e.g., Bb for brown eyes). Phenotype is the observable expression of those genes (e.g., brown eyes). Phenotype results from genotype + environmental influences.

Tahsili Practice Test

Tahsili Practice Test

Tahsili Biology